| /* |
| * NSA Security-Enhanced Linux (SELinux) security module |
| * |
| * This file contains the SELinux hook function implementations. |
| * |
| * Authors: Stephen Smalley, <sds@epoch.ncsc.mil> |
| * Chris Vance, <cvance@nai.com> |
| * Wayne Salamon, <wsalamon@nai.com> |
| * James Morris <jmorris@redhat.com> |
| * |
| * Copyright (C) 2001,2002 Networks Associates Technology, Inc. |
| * Copyright (C) 2003-2008 Red Hat, Inc., James Morris <jmorris@redhat.com> |
| * Eric Paris <eparis@redhat.com> |
| * Copyright (C) 2004-2005 Trusted Computer Solutions, Inc. |
| * <dgoeddel@trustedcs.com> |
| * Copyright (C) 2006, 2007, 2009 Hewlett-Packard Development Company, L.P. |
| * Paul Moore <paul@paul-moore.com> |
| * Copyright (C) 2007 Hitachi Software Engineering Co., Ltd. |
| * Yuichi Nakamura <ynakam@hitachisoft.jp> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2, |
| * as published by the Free Software Foundation. |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/kd.h> |
| #include <linux/kernel.h> |
| #include <linux/tracehook.h> |
| #include <linux/errno.h> |
| #include <linux/ext2_fs.h> |
| #include <linux/sched.h> |
| #include <linux/security.h> |
| #include <linux/xattr.h> |
| #include <linux/capability.h> |
| #include <linux/unistd.h> |
| #include <linux/mm.h> |
| #include <linux/mman.h> |
| #include <linux/slab.h> |
| #include <linux/pagemap.h> |
| #include <linux/proc_fs.h> |
| #include <linux/swap.h> |
| #include <linux/spinlock.h> |
| #include <linux/syscalls.h> |
| #include <linux/dcache.h> |
| #include <linux/file.h> |
| #include <linux/fdtable.h> |
| #include <linux/namei.h> |
| #include <linux/mount.h> |
| #include <linux/netfilter_ipv4.h> |
| #include <linux/netfilter_ipv6.h> |
| #include <linux/tty.h> |
| #include <net/icmp.h> |
| #include <net/ip.h> /* for local_port_range[] */ |
| #include <net/tcp.h> /* struct or_callable used in sock_rcv_skb */ |
| #include <net/net_namespace.h> |
| #include <net/netlabel.h> |
| #include <linux/uaccess.h> |
| #include <asm/ioctls.h> |
| #include <linux/atomic.h> |
| #include <linux/bitops.h> |
| #include <linux/interrupt.h> |
| #include <linux/netdevice.h> /* for network interface checks */ |
| #include <linux/netlink.h> |
| #include <linux/tcp.h> |
| #include <linux/udp.h> |
| #include <linux/dccp.h> |
| #include <linux/quota.h> |
| #include <linux/un.h> /* for Unix socket types */ |
| #include <net/af_unix.h> /* for Unix socket types */ |
| #include <linux/parser.h> |
| #include <linux/nfs_mount.h> |
| #include <net/ipv6.h> |
| #include <linux/hugetlb.h> |
| #include <linux/personality.h> |
| #include <linux/audit.h> |
| #include <linux/string.h> |
| #include <linux/selinux.h> |
| #include <linux/mutex.h> |
| #include <linux/posix-timers.h> |
| #include <linux/syslog.h> |
| #include <linux/user_namespace.h> |
| #include <linux/export.h> |
| |
| #include "avc.h" |
| #include "objsec.h" |
| #include "netif.h" |
| #include "netnode.h" |
| #include "netport.h" |
| #include "xfrm.h" |
| #include "netlabel.h" |
| #include "audit.h" |
| #include "avc_ss.h" |
| |
| #define NUM_SEL_MNT_OPTS 5 |
| |
| extern struct security_operations *security_ops; |
| |
| /* SECMARK reference count */ |
| static atomic_t selinux_secmark_refcount = ATOMIC_INIT(0); |
| |
| #ifdef CONFIG_SECURITY_SELINUX_DEVELOP |
| int selinux_enforcing; |
| |
| static int __init enforcing_setup(char *str) |
| { |
| unsigned long enforcing; |
| if (!strict_strtoul(str, 0, &enforcing)) |
| selinux_enforcing = enforcing ? 1 : 0; |
| return 1; |
| } |
| __setup("enforcing=", enforcing_setup); |
| #endif |
| |
| #ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM |
| int selinux_enabled = CONFIG_SECURITY_SELINUX_BOOTPARAM_VALUE; |
| |
| static int __init selinux_enabled_setup(char *str) |
| { |
| unsigned long enabled; |
| if (!strict_strtoul(str, 0, &enabled)) |
| selinux_enabled = enabled ? 1 : 0; |
| return 1; |
| } |
| __setup("selinux=", selinux_enabled_setup); |
| #else |
| int selinux_enabled = 1; |
| #endif |
| |
| static struct kmem_cache *sel_inode_cache; |
| |
| /** |
| * selinux_secmark_enabled - Check to see if SECMARK is currently enabled |
| * |
| * Description: |
| * This function checks the SECMARK reference counter to see if any SECMARK |
| * targets are currently configured, if the reference counter is greater than |
| * zero SECMARK is considered to be enabled. Returns true (1) if SECMARK is |
| * enabled, false (0) if SECMARK is disabled. |
| * |
| */ |
| static int selinux_secmark_enabled(void) |
| { |
| return (atomic_read(&selinux_secmark_refcount) > 0); |
| } |
| |
| /* |
| * initialise the security for the init task |
| */ |
| static void cred_init_security(void) |
| { |
| struct cred *cred = (struct cred *) current->real_cred; |
| struct task_security_struct *tsec; |
| |
| tsec = kzalloc(sizeof(struct task_security_struct), GFP_KERNEL); |
| if (!tsec) |
| panic("SELinux: Failed to initialize initial task.\n"); |
| |
| tsec->osid = tsec->sid = SECINITSID_KERNEL; |
| cred->security = tsec; |
| } |
| |
| /* |
| * get the security ID of a set of credentials |
| */ |
| static inline u32 cred_sid(const struct cred *cred) |
| { |
| const struct task_security_struct *tsec; |
| |
| tsec = cred->security; |
| return tsec->sid; |
| } |
| |
| /* |
| * get the objective security ID of a task |
| */ |
| static inline u32 task_sid(const struct task_struct *task) |
| { |
| u32 sid; |
| |
| rcu_read_lock(); |
| sid = cred_sid(__task_cred(task)); |
| rcu_read_unlock(); |
| return sid; |
| } |
| |
| /* |
| * get the subjective security ID of the current task |
| */ |
| static inline u32 current_sid(void) |
| { |
| const struct task_security_struct *tsec = current_security(); |
| |
| return tsec->sid; |
| } |
| |
| /* Allocate and free functions for each kind of security blob. */ |
| |
| static int inode_alloc_security(struct inode *inode) |
| { |
| struct inode_security_struct *isec; |
| u32 sid = current_sid(); |
| |
| isec = kmem_cache_zalloc(sel_inode_cache, GFP_NOFS); |
| if (!isec) |
| return -ENOMEM; |
| |
| mutex_init(&isec->lock); |
| INIT_LIST_HEAD(&isec->list); |
| isec->inode = inode; |
| isec->sid = SECINITSID_UNLABELED; |
| isec->sclass = SECCLASS_FILE; |
| isec->task_sid = sid; |
| inode->i_security = isec; |
| |
| return 0; |
| } |
| |
| static void inode_free_security(struct inode *inode) |
| { |
| struct inode_security_struct *isec = inode->i_security; |
| struct superblock_security_struct *sbsec = inode->i_sb->s_security; |
| |
| spin_lock(&sbsec->isec_lock); |
| if (!list_empty(&isec->list)) |
| list_del_init(&isec->list); |
| spin_unlock(&sbsec->isec_lock); |
| |
| inode->i_security = NULL; |
| kmem_cache_free(sel_inode_cache, isec); |
| } |
| |
| static int file_alloc_security(struct file *file) |
| { |
| struct file_security_struct *fsec; |
| u32 sid = current_sid(); |
| |
| fsec = kzalloc(sizeof(struct file_security_struct), GFP_KERNEL); |
| if (!fsec) |
| return -ENOMEM; |
| |
| fsec->sid = sid; |
| fsec->fown_sid = sid; |
| file->f_security = fsec; |
| |
| return 0; |
| } |
| |
| static void file_free_security(struct file *file) |
| { |
| struct file_security_struct *fsec = file->f_security; |
| file->f_security = NULL; |
| kfree(fsec); |
| } |
| |
| static int superblock_alloc_security(struct super_block *sb) |
| { |
| struct superblock_security_struct *sbsec; |
| |
| sbsec = kzalloc(sizeof(struct superblock_security_struct), GFP_KERNEL); |
| if (!sbsec) |
| return -ENOMEM; |
| |
| mutex_init(&sbsec->lock); |
| INIT_LIST_HEAD(&sbsec->isec_head); |
| spin_lock_init(&sbsec->isec_lock); |
| sbsec->sb = sb; |
| sbsec->sid = SECINITSID_UNLABELED; |
| sbsec->def_sid = SECINITSID_FILE; |
| sbsec->mntpoint_sid = SECINITSID_UNLABELED; |
| sb->s_security = sbsec; |
| |
| return 0; |
| } |
| |
| static void superblock_free_security(struct super_block *sb) |
| { |
| struct superblock_security_struct *sbsec = sb->s_security; |
| sb->s_security = NULL; |
| kfree(sbsec); |
| } |
| |
| /* The file system's label must be initialized prior to use. */ |
| |
| static const char *labeling_behaviors[6] = { |
| "uses xattr", |
| "uses transition SIDs", |
| "uses task SIDs", |
| "uses genfs_contexts", |
| "not configured for labeling", |
| "uses mountpoint labeling", |
| }; |
| |
| static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry); |
| |
| static inline int inode_doinit(struct inode *inode) |
| { |
| return inode_doinit_with_dentry(inode, NULL); |
| } |
| |
| enum { |
| Opt_error = -1, |
| Opt_context = 1, |
| Opt_fscontext = 2, |
| Opt_defcontext = 3, |
| Opt_rootcontext = 4, |
| Opt_labelsupport = 5, |
| }; |
| |
| static const match_table_t tokens = { |
| {Opt_context, CONTEXT_STR "%s"}, |
| {Opt_fscontext, FSCONTEXT_STR "%s"}, |
| {Opt_defcontext, DEFCONTEXT_STR "%s"}, |
| {Opt_rootcontext, ROOTCONTEXT_STR "%s"}, |
| {Opt_labelsupport, LABELSUPP_STR}, |
| {Opt_error, NULL}, |
| }; |
| |
| #define SEL_MOUNT_FAIL_MSG "SELinux: duplicate or incompatible mount options\n" |
| |
| static int may_context_mount_sb_relabel(u32 sid, |
| struct superblock_security_struct *sbsec, |
| const struct cred *cred) |
| { |
| const struct task_security_struct *tsec = cred->security; |
| int rc; |
| |
| rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM, |
| FILESYSTEM__RELABELFROM, NULL); |
| if (rc) |
| return rc; |
| |
| rc = avc_has_perm(tsec->sid, sid, SECCLASS_FILESYSTEM, |
| FILESYSTEM__RELABELTO, NULL); |
| return rc; |
| } |
| |
| static int may_context_mount_inode_relabel(u32 sid, |
| struct superblock_security_struct *sbsec, |
| const struct cred *cred) |
| { |
| const struct task_security_struct *tsec = cred->security; |
| int rc; |
| rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM, |
| FILESYSTEM__RELABELFROM, NULL); |
| if (rc) |
| return rc; |
| |
| rc = avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM, |
| FILESYSTEM__ASSOCIATE, NULL); |
| return rc; |
| } |
| |
| static int sb_finish_set_opts(struct super_block *sb) |
| { |
| struct superblock_security_struct *sbsec = sb->s_security; |
| struct dentry *root = sb->s_root; |
| struct inode *root_inode = root->d_inode; |
| int rc = 0; |
| |
| if (sbsec->behavior == SECURITY_FS_USE_XATTR) { |
| /* Make sure that the xattr handler exists and that no |
| error other than -ENODATA is returned by getxattr on |
| the root directory. -ENODATA is ok, as this may be |
| the first boot of the SELinux kernel before we have |
| assigned xattr values to the filesystem. */ |
| if (!root_inode->i_op->getxattr) { |
| printk(KERN_WARNING "SELinux: (dev %s, type %s) has no " |
| "xattr support\n", sb->s_id, sb->s_type->name); |
| rc = -EOPNOTSUPP; |
| goto out; |
| } |
| rc = root_inode->i_op->getxattr(root, XATTR_NAME_SELINUX, NULL, 0); |
| if (rc < 0 && rc != -ENODATA) { |
| if (rc == -EOPNOTSUPP) |
| printk(KERN_WARNING "SELinux: (dev %s, type " |
| "%s) has no security xattr handler\n", |
| sb->s_id, sb->s_type->name); |
| else |
| printk(KERN_WARNING "SELinux: (dev %s, type " |
| "%s) getxattr errno %d\n", sb->s_id, |
| sb->s_type->name, -rc); |
| goto out; |
| } |
| } |
| |
| sbsec->flags |= (SE_SBINITIALIZED | SE_SBLABELSUPP); |
| |
| if (sbsec->behavior > ARRAY_SIZE(labeling_behaviors)) |
| printk(KERN_ERR "SELinux: initialized (dev %s, type %s), unknown behavior\n", |
| sb->s_id, sb->s_type->name); |
| else |
| printk(KERN_DEBUG "SELinux: initialized (dev %s, type %s), %s\n", |
| sb->s_id, sb->s_type->name, |
| labeling_behaviors[sbsec->behavior-1]); |
| |
| if (sbsec->behavior == SECURITY_FS_USE_GENFS || |
| sbsec->behavior == SECURITY_FS_USE_MNTPOINT || |
| sbsec->behavior == SECURITY_FS_USE_NONE || |
| sbsec->behavior > ARRAY_SIZE(labeling_behaviors)) |
| sbsec->flags &= ~SE_SBLABELSUPP; |
| |
| /* Special handling for sysfs. Is genfs but also has setxattr handler*/ |
| if (strncmp(sb->s_type->name, "sysfs", sizeof("sysfs")) == 0) |
| sbsec->flags |= SE_SBLABELSUPP; |
| |
| /* Initialize the root inode. */ |
| rc = inode_doinit_with_dentry(root_inode, root); |
| |
| /* Initialize any other inodes associated with the superblock, e.g. |
| inodes created prior to initial policy load or inodes created |
| during get_sb by a pseudo filesystem that directly |
| populates itself. */ |
| spin_lock(&sbsec->isec_lock); |
| next_inode: |
| if (!list_empty(&sbsec->isec_head)) { |
| struct inode_security_struct *isec = |
| list_entry(sbsec->isec_head.next, |
| struct inode_security_struct, list); |
| struct inode *inode = isec->inode; |
| spin_unlock(&sbsec->isec_lock); |
| inode = igrab(inode); |
| if (inode) { |
| if (!IS_PRIVATE(inode)) |
| inode_doinit(inode); |
| iput(inode); |
| } |
| spin_lock(&sbsec->isec_lock); |
| list_del_init(&isec->list); |
| goto next_inode; |
| } |
| spin_unlock(&sbsec->isec_lock); |
| out: |
| return rc; |
| } |
| |
| /* |
| * This function should allow an FS to ask what it's mount security |
| * options were so it can use those later for submounts, displaying |
| * mount options, or whatever. |
| */ |
| static int selinux_get_mnt_opts(const struct super_block *sb, |
| struct security_mnt_opts *opts) |
| { |
| int rc = 0, i; |
| struct superblock_security_struct *sbsec = sb->s_security; |
| char *context = NULL; |
| u32 len; |
| char tmp; |
| |
| security_init_mnt_opts(opts); |
| |
| if (!(sbsec->flags & SE_SBINITIALIZED)) |
| return -EINVAL; |
| |
| if (!ss_initialized) |
| return -EINVAL; |
| |
| tmp = sbsec->flags & SE_MNTMASK; |
| /* count the number of mount options for this sb */ |
| for (i = 0; i < 8; i++) { |
| if (tmp & 0x01) |
| opts->num_mnt_opts++; |
| tmp >>= 1; |
| } |
| /* Check if the Label support flag is set */ |
| if (sbsec->flags & SE_SBLABELSUPP) |
| opts->num_mnt_opts++; |
| |
| opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC); |
| if (!opts->mnt_opts) { |
| rc = -ENOMEM; |
| goto out_free; |
| } |
| |
| opts->mnt_opts_flags = kcalloc(opts->num_mnt_opts, sizeof(int), GFP_ATOMIC); |
| if (!opts->mnt_opts_flags) { |
| rc = -ENOMEM; |
| goto out_free; |
| } |
| |
| i = 0; |
| if (sbsec->flags & FSCONTEXT_MNT) { |
| rc = security_sid_to_context(sbsec->sid, &context, &len); |
| if (rc) |
| goto out_free; |
| opts->mnt_opts[i] = context; |
| opts->mnt_opts_flags[i++] = FSCONTEXT_MNT; |
| } |
| if (sbsec->flags & CONTEXT_MNT) { |
| rc = security_sid_to_context(sbsec->mntpoint_sid, &context, &len); |
| if (rc) |
| goto out_free; |
| opts->mnt_opts[i] = context; |
| opts->mnt_opts_flags[i++] = CONTEXT_MNT; |
| } |
| if (sbsec->flags & DEFCONTEXT_MNT) { |
| rc = security_sid_to_context(sbsec->def_sid, &context, &len); |
| if (rc) |
| goto out_free; |
| opts->mnt_opts[i] = context; |
| opts->mnt_opts_flags[i++] = DEFCONTEXT_MNT; |
| } |
| if (sbsec->flags & ROOTCONTEXT_MNT) { |
| struct inode *root = sbsec->sb->s_root->d_inode; |
| struct inode_security_struct *isec = root->i_security; |
| |
| rc = security_sid_to_context(isec->sid, &context, &len); |
| if (rc) |
| goto out_free; |
| opts->mnt_opts[i] = context; |
| opts->mnt_opts_flags[i++] = ROOTCONTEXT_MNT; |
| } |
| if (sbsec->flags & SE_SBLABELSUPP) { |
| opts->mnt_opts[i] = NULL; |
| opts->mnt_opts_flags[i++] = SE_SBLABELSUPP; |
| } |
| |
| BUG_ON(i != opts->num_mnt_opts); |
| |
| return 0; |
| |
| out_free: |
| security_free_mnt_opts(opts); |
| return rc; |
| } |
| |
| static int bad_option(struct superblock_security_struct *sbsec, char flag, |
| u32 old_sid, u32 new_sid) |
| { |
| char mnt_flags = sbsec->flags & SE_MNTMASK; |
| |
| /* check if the old mount command had the same options */ |
| if (sbsec->flags & SE_SBINITIALIZED) |
| if (!(sbsec->flags & flag) || |
| (old_sid != new_sid)) |
| return 1; |
| |
| /* check if we were passed the same options twice, |
| * aka someone passed context=a,context=b |
| */ |
| if (!(sbsec->flags & SE_SBINITIALIZED)) |
| if (mnt_flags & flag) |
| return 1; |
| return 0; |
| } |
| |
| /* |
| * Allow filesystems with binary mount data to explicitly set mount point |
| * labeling information. |
| */ |
| static int selinux_set_mnt_opts(struct super_block *sb, |
| struct security_mnt_opts *opts) |
| { |
| const struct cred *cred = current_cred(); |
| int rc = 0, i; |
| struct superblock_security_struct *sbsec = sb->s_security; |
| const char *name = sb->s_type->name; |
| struct inode *inode = sbsec->sb->s_root->d_inode; |
| struct inode_security_struct *root_isec = inode->i_security; |
| u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0; |
| u32 defcontext_sid = 0; |
| char **mount_options = opts->mnt_opts; |
| int *flags = opts->mnt_opts_flags; |
| int num_opts = opts->num_mnt_opts; |
| |
| mutex_lock(&sbsec->lock); |
| |
| if (!ss_initialized) { |
| if (!num_opts) { |
| /* Defer initialization until selinux_complete_init, |
| after the initial policy is loaded and the security |
| server is ready to handle calls. */ |
| goto out; |
| } |
| rc = -EINVAL; |
| printk(KERN_WARNING "SELinux: Unable to set superblock options " |
| "before the security server is initialized\n"); |
| goto out; |
| } |
| |
| /* |
| * Binary mount data FS will come through this function twice. Once |
| * from an explicit call and once from the generic calls from the vfs. |
| * Since the generic VFS calls will not contain any security mount data |
| * we need to skip the double mount verification. |
| * |
| * This does open a hole in which we will not notice if the first |
| * mount using this sb set explict options and a second mount using |
| * this sb does not set any security options. (The first options |
| * will be used for both mounts) |
| */ |
| if ((sbsec->flags & SE_SBINITIALIZED) && (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA) |
| && (num_opts == 0)) |
| goto out; |
| |
| /* |
| * parse the mount options, check if they are valid sids. |
| * also check if someone is trying to mount the same sb more |
| * than once with different security options. |
| */ |
| for (i = 0; i < num_opts; i++) { |
| u32 sid; |
| |
| if (flags[i] == SE_SBLABELSUPP) |
| continue; |
| rc = security_context_to_sid(mount_options[i], |
| strlen(mount_options[i]), &sid); |
| if (rc) { |
| printk(KERN_WARNING "SELinux: security_context_to_sid" |
| "(%s) failed for (dev %s, type %s) errno=%d\n", |
| mount_options[i], sb->s_id, name, rc); |
| goto out; |
| } |
| switch (flags[i]) { |
| case FSCONTEXT_MNT: |
| fscontext_sid = sid; |
| |
| if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, |
| fscontext_sid)) |
| goto out_double_mount; |
| |
| sbsec->flags |= FSCONTEXT_MNT; |
| break; |
| case CONTEXT_MNT: |
| context_sid = sid; |
| |
| if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, |
| context_sid)) |
| goto out_double_mount; |
| |
| sbsec->flags |= CONTEXT_MNT; |
| break; |
| case ROOTCONTEXT_MNT: |
| rootcontext_sid = sid; |
| |
| if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, |
| rootcontext_sid)) |
| goto out_double_mount; |
| |
| sbsec->flags |= ROOTCONTEXT_MNT; |
| |
| break; |
| case DEFCONTEXT_MNT: |
| defcontext_sid = sid; |
| |
| if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, |
| defcontext_sid)) |
| goto out_double_mount; |
| |
| sbsec->flags |= DEFCONTEXT_MNT; |
| |
| break; |
| default: |
| rc = -EINVAL; |
| goto out; |
| } |
| } |
| |
| if (sbsec->flags & SE_SBINITIALIZED) { |
| /* previously mounted with options, but not on this attempt? */ |
| if ((sbsec->flags & SE_MNTMASK) && !num_opts) |
| goto out_double_mount; |
| rc = 0; |
| goto out; |
| } |
| |
| if (strcmp(sb->s_type->name, "proc") == 0) |
| sbsec->flags |= SE_SBPROC; |
| |
| /* Determine the labeling behavior to use for this filesystem type. */ |
| rc = security_fs_use((sbsec->flags & SE_SBPROC) ? "proc" : sb->s_type->name, &sbsec->behavior, &sbsec->sid); |
| if (rc) { |
| printk(KERN_WARNING "%s: security_fs_use(%s) returned %d\n", |
| __func__, sb->s_type->name, rc); |
| goto out; |
| } |
| |
| /* sets the context of the superblock for the fs being mounted. */ |
| if (fscontext_sid) { |
| rc = may_context_mount_sb_relabel(fscontext_sid, sbsec, cred); |
| if (rc) |
| goto out; |
| |
| sbsec->sid = fscontext_sid; |
| } |
| |
| /* |
| * Switch to using mount point labeling behavior. |
| * sets the label used on all file below the mountpoint, and will set |
| * the superblock context if not already set. |
| */ |
| if (context_sid) { |
| if (!fscontext_sid) { |
| rc = may_context_mount_sb_relabel(context_sid, sbsec, |
| cred); |
| if (rc) |
| goto out; |
| sbsec->sid = context_sid; |
| } else { |
| rc = may_context_mount_inode_relabel(context_sid, sbsec, |
| cred); |
| if (rc) |
| goto out; |
| } |
| if (!rootcontext_sid) |
| rootcontext_sid = context_sid; |
| |
| sbsec->mntpoint_sid = context_sid; |
| sbsec->behavior = SECURITY_FS_USE_MNTPOINT; |
| } |
| |
| if (rootcontext_sid) { |
| rc = may_context_mount_inode_relabel(rootcontext_sid, sbsec, |
| cred); |
| if (rc) |
| goto out; |
| |
| root_isec->sid = rootcontext_sid; |
| root_isec->initialized = 1; |
| } |
| |
| if (defcontext_sid) { |
| if (sbsec->behavior != SECURITY_FS_USE_XATTR) { |
| rc = -EINVAL; |
| printk(KERN_WARNING "SELinux: defcontext option is " |
| "invalid for this filesystem type\n"); |
| goto out; |
| } |
| |
| if (defcontext_sid != sbsec->def_sid) { |
| rc = may_context_mount_inode_relabel(defcontext_sid, |
| sbsec, cred); |
| if (rc) |
| goto out; |
| } |
| |
| sbsec->def_sid = defcontext_sid; |
| } |
| |
| rc = sb_finish_set_opts(sb); |
| out: |
| mutex_unlock(&sbsec->lock); |
| return rc; |
| out_double_mount: |
| rc = -EINVAL; |
| printk(KERN_WARNING "SELinux: mount invalid. Same superblock, different " |
| "security settings for (dev %s, type %s)\n", sb->s_id, name); |
| goto out; |
| } |
| |
| static void selinux_sb_clone_mnt_opts(const struct super_block *oldsb, |
| struct super_block *newsb) |
| { |
| const struct superblock_security_struct *oldsbsec = oldsb->s_security; |
| struct superblock_security_struct *newsbsec = newsb->s_security; |
| |
| int set_fscontext = (oldsbsec->flags & FSCONTEXT_MNT); |
| int set_context = (oldsbsec->flags & CONTEXT_MNT); |
| int set_rootcontext = (oldsbsec->flags & ROOTCONTEXT_MNT); |
| |
| /* |
| * if the parent was able to be mounted it clearly had no special lsm |
| * mount options. thus we can safely deal with this superblock later |
| */ |
| if (!ss_initialized) |
| return; |
| |
| /* how can we clone if the old one wasn't set up?? */ |
| BUG_ON(!(oldsbsec->flags & SE_SBINITIALIZED)); |
| |
| /* if fs is reusing a sb, just let its options stand... */ |
| if (newsbsec->flags & SE_SBINITIALIZED) |
| return; |
| |
| mutex_lock(&newsbsec->lock); |
| |
| newsbsec->flags = oldsbsec->flags; |
| |
| newsbsec->sid = oldsbsec->sid; |
| newsbsec->def_sid = oldsbsec->def_sid; |
| newsbsec->behavior = oldsbsec->behavior; |
| |
| if (set_context) { |
| u32 sid = oldsbsec->mntpoint_sid; |
| |
| if (!set_fscontext) |
| newsbsec->sid = sid; |
| if (!set_rootcontext) { |
| struct inode *newinode = newsb->s_root->d_inode; |
| struct inode_security_struct *newisec = newinode->i_security; |
| newisec->sid = sid; |
| } |
| newsbsec->mntpoint_sid = sid; |
| } |
| if (set_rootcontext) { |
| const struct inode *oldinode = oldsb->s_root->d_inode; |
| const struct inode_security_struct *oldisec = oldinode->i_security; |
| struct inode *newinode = newsb->s_root->d_inode; |
| struct inode_security_struct *newisec = newinode->i_security; |
| |
| newisec->sid = oldisec->sid; |
| } |
| |
| sb_finish_set_opts(newsb); |
| mutex_unlock(&newsbsec->lock); |
| } |
| |
| static int selinux_parse_opts_str(char *options, |
| struct security_mnt_opts *opts) |
| { |
| char *p; |
| char *context = NULL, *defcontext = NULL; |
| char *fscontext = NULL, *rootcontext = NULL; |
| int rc, num_mnt_opts = 0; |
| |
| opts->num_mnt_opts = 0; |
| |
| /* Standard string-based options. */ |
| while ((p = strsep(&options, "|")) != NULL) { |
| int token; |
| substring_t args[MAX_OPT_ARGS]; |
| |
| if (!*p) |
| continue; |
| |
| token = match_token(p, tokens, args); |
| |
| switch (token) { |
| case Opt_context: |
| if (context || defcontext) { |
| rc = -EINVAL; |
| printk(KERN_WARNING SEL_MOUNT_FAIL_MSG); |
| goto out_err; |
| } |
| context = match_strdup(&args[0]); |
| if (!context) { |
| rc = -ENOMEM; |
| goto out_err; |
| } |
| break; |
| |
| case Opt_fscontext: |
| if (fscontext) { |
| rc = -EINVAL; |
| printk(KERN_WARNING SEL_MOUNT_FAIL_MSG); |
| goto out_err; |
| } |
| fscontext = match_strdup(&args[0]); |
| if (!fscontext) { |
| rc = -ENOMEM; |
| goto out_err; |
| } |
| break; |
| |
| case Opt_rootcontext: |
| if (rootcontext) { |
| rc = -EINVAL; |
| printk(KERN_WARNING SEL_MOUNT_FAIL_MSG); |
| goto out_err; |
| } |
| rootcontext = match_strdup(&args[0]); |
| if (!rootcontext) { |
| rc = -ENOMEM; |
| goto out_err; |
| } |
| break; |
| |
| case Opt_defcontext: |
| if (context || defcontext) { |
| rc = -EINVAL; |
| printk(KERN_WARNING SEL_MOUNT_FAIL_MSG); |
| goto out_err; |
| } |
| defcontext = match_strdup(&args[0]); |
| if (!defcontext) { |
| rc = -ENOMEM; |
| goto out_err; |
| } |
| break; |
| case Opt_labelsupport: |
| break; |
| default: |
| rc = -EINVAL; |
| printk(KERN_WARNING "SELinux: unknown mount option\n"); |
| goto out_err; |
| |
| } |
| } |
| |
| rc = -ENOMEM; |
| opts->mnt_opts = kcalloc(NUM_SEL_MNT_OPTS, sizeof(char *), GFP_ATOMIC); |
| if (!opts->mnt_opts) |
| goto out_err; |
| |
| opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int), GFP_ATOMIC); |
| if (!opts->mnt_opts_flags) { |
| kfree(opts->mnt_opts); |
| goto out_err; |
| } |
| |
| if (fscontext) { |
| opts->mnt_opts[num_mnt_opts] = fscontext; |
| opts->mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT; |
| } |
| if (context) { |
| opts->mnt_opts[num_mnt_opts] = context; |
| opts->mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT; |
| } |
| if (rootcontext) { |
| opts->mnt_opts[num_mnt_opts] = rootcontext; |
| opts->mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT; |
| } |
| if (defcontext) { |
| opts->mnt_opts[num_mnt_opts] = defcontext; |
| opts->mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT; |
| } |
| |
| opts->num_mnt_opts = num_mnt_opts; |
| return 0; |
| |
| out_err: |
| kfree(context); |
| kfree(defcontext); |
| kfree(fscontext); |
| kfree(rootcontext); |
| return rc; |
| } |
| /* |
| * string mount options parsing and call set the sbsec |
| */ |
| static int superblock_doinit(struct super_block *sb, void *data) |
| { |
| int rc = 0; |
| char *options = data; |
| struct security_mnt_opts opts; |
| |
| security_init_mnt_opts(&opts); |
| |
| if (!data) |
| goto out; |
| |
| BUG_ON(sb->s_type->fs_flags & FS_BINARY_MOUNTDATA); |
| |
| rc = selinux_parse_opts_str(options, &opts); |
| if (rc) |
| goto out_err; |
| |
| out: |
| rc = selinux_set_mnt_opts(sb, &opts); |
| |
| out_err: |
| security_free_mnt_opts(&opts); |
| return rc; |
| } |
| |
| static void selinux_write_opts(struct seq_file *m, |
| struct security_mnt_opts *opts) |
| { |
| int i; |
| char *prefix; |
| |
| for (i = 0; i < opts->num_mnt_opts; i++) { |
| char *has_comma; |
| |
| if (opts->mnt_opts[i]) |
| has_comma = strchr(opts->mnt_opts[i], ','); |
| else |
| has_comma = NULL; |
| |
| switch (opts->mnt_opts_flags[i]) { |
| case CONTEXT_MNT: |
| prefix = CONTEXT_STR; |
| break; |
| case FSCONTEXT_MNT: |
| prefix = FSCONTEXT_STR; |
| break; |
| case ROOTCONTEXT_MNT: |
| prefix = ROOTCONTEXT_STR; |
| break; |
| case DEFCONTEXT_MNT: |
| prefix = DEFCONTEXT_STR; |
| break; |
| case SE_SBLABELSUPP: |
| seq_putc(m, ','); |
| seq_puts(m, LABELSUPP_STR); |
| continue; |
| default: |
| BUG(); |
| return; |
| }; |
| /* we need a comma before each option */ |
| seq_putc(m, ','); |
| seq_puts(m, prefix); |
| if (has_comma) |
| seq_putc(m, '\"'); |
| seq_puts(m, opts->mnt_opts[i]); |
| if (has_comma) |
| seq_putc(m, '\"'); |
| } |
| } |
| |
| static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb) |
| { |
| struct security_mnt_opts opts; |
| int rc; |
| |
| rc = selinux_get_mnt_opts(sb, &opts); |
| if (rc) { |
| /* before policy load we may get EINVAL, don't show anything */ |
| if (rc == -EINVAL) |
| rc = 0; |
| return rc; |
| } |
| |
| selinux_write_opts(m, &opts); |
| |
| security_free_mnt_opts(&opts); |
| |
| return rc; |
| } |
| |
| static inline u16 inode_mode_to_security_class(umode_t mode) |
| { |
| switch (mode & S_IFMT) { |
| case S_IFSOCK: |
| return SECCLASS_SOCK_FILE; |
| case S_IFLNK: |
| return SECCLASS_LNK_FILE; |
| case S_IFREG: |
| return SECCLASS_FILE; |
| case S_IFBLK: |
| return SECCLASS_BLK_FILE; |
| case S_IFDIR: |
| return SECCLASS_DIR; |
| case S_IFCHR: |
| return SECCLASS_CHR_FILE; |
| case S_IFIFO: |
| return SECCLASS_FIFO_FILE; |
| |
| } |
| |
| return SECCLASS_FILE; |
| } |
| |
| static inline int default_protocol_stream(int protocol) |
| { |
| return (protocol == IPPROTO_IP || protocol == IPPROTO_TCP); |
| } |
| |
| static inline int default_protocol_dgram(int protocol) |
| { |
| return (protocol == IPPROTO_IP || protocol == IPPROTO_UDP); |
| } |
| |
| static inline u16 socket_type_to_security_class(int family, int type, int protocol) |
| { |
| switch (family) { |
| case PF_UNIX: |
| switch (type) { |
| case SOCK_STREAM: |
| case SOCK_SEQPACKET: |
| return SECCLASS_UNIX_STREAM_SOCKET; |
| case SOCK_DGRAM: |
| return SECCLASS_UNIX_DGRAM_SOCKET; |
| } |
| break; |
| case PF_INET: |
| case PF_INET6: |
| switch (type) { |
| case SOCK_STREAM: |
| if (default_protocol_stream(protocol)) |
| return SECCLASS_TCP_SOCKET; |
| else |
| return SECCLASS_RAWIP_SOCKET; |
| case SOCK_DGRAM: |
| if (default_protocol_dgram(protocol)) |
| return SECCLASS_UDP_SOCKET; |
| else |
| return SECCLASS_RAWIP_SOCKET; |
| case SOCK_DCCP: |
| return SECCLASS_DCCP_SOCKET; |
| default: |
| return SECCLASS_RAWIP_SOCKET; |
| } |
| break; |
| case PF_NETLINK: |
| switch (protocol) { |
| case NETLINK_ROUTE: |
| return SECCLASS_NETLINK_ROUTE_SOCKET; |
| case NETLINK_FIREWALL: |
| return SECCLASS_NETLINK_FIREWALL_SOCKET; |
| case NETLINK_INET_DIAG: |
| return SECCLASS_NETLINK_TCPDIAG_SOCKET; |
| case NETLINK_NFLOG: |
| return SECCLASS_NETLINK_NFLOG_SOCKET; |
| case NETLINK_XFRM: |
| return SECCLASS_NETLINK_XFRM_SOCKET; |
| case NETLINK_SELINUX: |
| return SECCLASS_NETLINK_SELINUX_SOCKET; |
| case NETLINK_AUDIT: |
| return SECCLASS_NETLINK_AUDIT_SOCKET; |
| case NETLINK_IP6_FW: |
| return SECCLASS_NETLINK_IP6FW_SOCKET; |
| case NETLINK_DNRTMSG: |
| return SECCLASS_NETLINK_DNRT_SOCKET; |
| case NETLINK_KOBJECT_UEVENT: |
| return SECCLASS_NETLINK_KOBJECT_UEVENT_SOCKET; |
| default: |
| return SECCLASS_NETLINK_SOCKET; |
| } |
| case PF_PACKET: |
| return SECCLASS_PACKET_SOCKET; |
| case PF_KEY: |
| return SECCLASS_KEY_SOCKET; |
| case PF_APPLETALK: |
| return SECCLASS_APPLETALK_SOCKET; |
| } |
| |
| return SECCLASS_SOCKET; |
| } |
| |
| #ifdef CONFIG_PROC_FS |
| static int selinux_proc_get_sid(struct dentry *dentry, |
| u16 tclass, |
| u32 *sid) |
| { |
| int rc; |
| char *buffer, *path; |
| |
| buffer = (char *)__get_free_page(GFP_KERNEL); |
| if (!buffer) |
| return -ENOMEM; |
| |
| path = dentry_path_raw(dentry, buffer, PAGE_SIZE); |
| if (IS_ERR(path)) |
| rc = PTR_ERR(path); |
| else { |
| /* each process gets a /proc/PID/ entry. Strip off the |
| * PID part to get a valid selinux labeling. |
| * e.g. /proc/1/net/rpc/nfs -> /net/rpc/nfs */ |
| while (path[1] >= '0' && path[1] <= '9') { |
| path[1] = '/'; |
| path++; |
| } |
| rc = security_genfs_sid("proc", path, tclass, sid); |
| } |
| free_page((unsigned long)buffer); |
| return rc; |
| } |
| #else |
| static int selinux_proc_get_sid(struct dentry *dentry, |
| u16 tclass, |
| u32 *sid) |
| { |
| return -EINVAL; |
| } |
| #endif |
| |
| /* The inode's security attributes must be initialized before first use. */ |
| static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry) |
| { |
| struct superblock_security_struct *sbsec = NULL; |
| struct inode_security_struct *isec = inode->i_security; |
| u32 sid; |
| struct dentry *dentry; |
| #define INITCONTEXTLEN 255 |
| char *context = NULL; |
| unsigned len = 0; |
| int rc = 0; |
| |
| if (isec->initialized) |
| goto out; |
| |
| mutex_lock(&isec->lock); |
| if (isec->initialized) |
| goto out_unlock; |
| |
| sbsec = inode->i_sb->s_security; |
| if (!(sbsec->flags & SE_SBINITIALIZED)) { |
| /* Defer initialization until selinux_complete_init, |
| after the initial policy is loaded and the security |
| server is ready to handle calls. */ |
| spin_lock(&sbsec->isec_lock); |
| if (list_empty(&isec->list)) |
| list_add(&isec->list, &sbsec->isec_head); |
| spin_unlock(&sbsec->isec_lock); |
| goto out_unlock; |
| } |
| |
| switch (sbsec->behavior) { |
| case SECURITY_FS_USE_XATTR: |
| if (!inode->i_op->getxattr) { |
| isec->sid = sbsec->def_sid; |
| break; |
| } |
| |
| /* Need a dentry, since the xattr API requires one. |
| Life would be simpler if we could just pass the inode. */ |
| if (opt_dentry) { |
| /* Called from d_instantiate or d_splice_alias. */ |
| dentry = dget(opt_dentry); |
| } else { |
| /* Called from selinux_complete_init, try to find a dentry. */ |
| dentry = d_find_alias(inode); |
| } |
| if (!dentry) { |
| /* |
| * this is can be hit on boot when a file is accessed |
| * before the policy is loaded. When we load policy we |
| * may find inodes that have no dentry on the |
| * sbsec->isec_head list. No reason to complain as these |
| * will get fixed up the next time we go through |
| * inode_doinit with a dentry, before these inodes could |
| * be used again by userspace. |
| */ |
| goto out_unlock; |
| } |
| |
| len = INITCONTEXTLEN; |
| context = kmalloc(len+1, GFP_NOFS); |
| if (!context) { |
| rc = -ENOMEM; |
| dput(dentry); |
| goto out_unlock; |
| } |
| context[len] = '\0'; |
| rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX, |
| context, len); |
| if (rc == -ERANGE) { |
| kfree(context); |
| |
| /* Need a larger buffer. Query for the right size. */ |
| rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX, |
| NULL, 0); |
| if (rc < 0) { |
| dput(dentry); |
| goto out_unlock; |
| } |
| len = rc; |
| context = kmalloc(len+1, GFP_NOFS); |
| if (!context) { |
| rc = -ENOMEM; |
| dput(dentry); |
| goto out_unlock; |
| } |
| context[len] = '\0'; |
| rc = inode->i_op->getxattr(dentry, |
| XATTR_NAME_SELINUX, |
| context, len); |
| } |
| dput(dentry); |
| if (rc < 0) { |
| if (rc != -ENODATA) { |
| printk(KERN_WARNING "SELinux: %s: getxattr returned " |
| "%d for dev=%s ino=%ld\n", __func__, |
| -rc, inode->i_sb->s_id, inode->i_ino); |
| kfree(context); |
| goto out_unlock; |
| } |
| /* Map ENODATA to the default file SID */ |
| sid = sbsec->def_sid; |
| rc = 0; |
| } else { |
| rc = security_context_to_sid_default(context, rc, &sid, |
| sbsec->def_sid, |
| GFP_NOFS); |
| if (rc) { |
| char *dev = inode->i_sb->s_id; |
| unsigned long ino = inode->i_ino; |
| |
| if (rc == -EINVAL) { |
| if (printk_ratelimit()) |
| printk(KERN_NOTICE "SELinux: inode=%lu on dev=%s was found to have an invalid " |
| "context=%s. This indicates you may need to relabel the inode or the " |
| "filesystem in question.\n", ino, dev, context); |
| } else { |
| printk(KERN_WARNING "SELinux: %s: context_to_sid(%s) " |
| "returned %d for dev=%s ino=%ld\n", |
| __func__, context, -rc, dev, ino); |
| } |
| kfree(context); |
| /* Leave with the unlabeled SID */ |
| rc = 0; |
| break; |
| } |
| } |
| kfree(context); |
| isec->sid = sid; |
| break; |
| case SECURITY_FS_USE_TASK: |
| isec->sid = isec->task_sid; |
| break; |
| case SECURITY_FS_USE_TRANS: |
| /* Default to the fs SID. */ |
| isec->sid = sbsec->sid; |
| |
| /* Try to obtain a transition SID. */ |
| isec->sclass = inode_mode_to_security_class(inode->i_mode); |
| rc = security_transition_sid(isec->task_sid, sbsec->sid, |
| isec->sclass, NULL, &sid); |
| if (rc) |
| goto out_unlock; |
| isec->sid = sid; |
| break; |
| case SECURITY_FS_USE_MNTPOINT: |
| isec->sid = sbsec->mntpoint_sid; |
| break; |
| default: |
| /* Default to the fs superblock SID. */ |
| isec->sid = sbsec->sid; |
| |
| if ((sbsec->flags & SE_SBPROC) && !S_ISLNK(inode->i_mode)) { |
| if (opt_dentry) { |
| isec->sclass = inode_mode_to_security_class(inode->i_mode); |
| rc = selinux_proc_get_sid(opt_dentry, |
| isec->sclass, |
| &sid); |
| if (rc) |
| goto out_unlock; |
| isec->sid = sid; |
| } |
| } |
| break; |
| } |
| |
| isec->initialized = 1; |
| |
| out_unlock: |
| mutex_unlock(&isec->lock); |
| out: |
| if (isec->sclass == SECCLASS_FILE) |
| isec->sclass = inode_mode_to_security_class(inode->i_mode); |
| return rc; |
| } |
| |
| /* Convert a Linux signal to an access vector. */ |
| static inline u32 signal_to_av(int sig) |
| { |
| u32 perm = 0; |
| |
| switch (sig) { |
| case SIGCHLD: |
| /* Commonly granted from child to parent. */ |
| perm = PROCESS__SIGCHLD; |
| break; |
| case SIGKILL: |
| /* Cannot be caught or ignored */ |
| perm = PROCESS__SIGKILL; |
| break; |
| case SIGSTOP: |
| /* Cannot be caught or ignored */ |
| perm = PROCESS__SIGSTOP; |
| break; |
| default: |
| /* All other signals. */ |
| perm = PROCESS__SIGNAL; |
| break; |
| } |
| |
| return perm; |
| } |
| |
| /* |
| * Check permission between a pair of credentials |
| * fork check, ptrace check, etc. |
| */ |
| static int cred_has_perm(const struct cred *actor, |
| const struct cred *target, |
| u32 perms) |
| { |
| u32 asid = cred_sid(actor), tsid = cred_sid(target); |
| |
| return avc_has_perm(asid, tsid, SECCLASS_PROCESS, perms, NULL); |
| } |
| |
| /* |
| * Check permission between a pair of tasks, e.g. signal checks, |
| * fork check, ptrace check, etc. |
| * tsk1 is the actor and tsk2 is the target |
| * - this uses the default subjective creds of tsk1 |
| */ |
| static int task_has_perm(const struct task_struct *tsk1, |
| const struct task_struct *tsk2, |
| u32 perms) |
| { |
| const struct task_security_struct *__tsec1, *__tsec2; |
| u32 sid1, sid2; |
| |
| rcu_read_lock(); |
| __tsec1 = __task_cred(tsk1)->security; sid1 = __tsec1->sid; |
| __tsec2 = __task_cred(tsk2)->security; sid2 = __tsec2->sid; |
| rcu_read_unlock(); |
| return avc_has_perm(sid1, sid2, SECCLASS_PROCESS, perms, NULL); |
| } |
| |
| /* |
| * Check permission between current and another task, e.g. signal checks, |
| * fork check, ptrace check, etc. |
| * current is the actor and tsk2 is the target |
| * - this uses current's subjective creds |
| */ |
| static int current_has_perm(const struct task_struct *tsk, |
| u32 perms) |
| { |
| u32 sid, tsid; |
| |
| sid = current_sid(); |
| tsid = task_sid(tsk); |
| return avc_has_perm(sid, tsid, SECCLASS_PROCESS, perms, NULL); |
| } |
| |
| #if CAP_LAST_CAP > 63 |
| #error Fix SELinux to handle capabilities > 63. |
| #endif |
| |
| /* Check whether a task is allowed to use a capability. */ |
| static int task_has_capability(struct task_struct *tsk, |
| const struct cred *cred, |
| int cap, int audit) |
| { |
| struct common_audit_data ad; |
| struct av_decision avd; |
| u16 sclass; |
| u32 sid = cred_sid(cred); |
| u32 av = CAP_TO_MASK(cap); |
| int rc; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, CAP); |
| ad.tsk = tsk; |
| ad.u.cap = cap; |
| |
| switch (CAP_TO_INDEX(cap)) { |
| case 0: |
| sclass = SECCLASS_CAPABILITY; |
| break; |
| case 1: |
| sclass = SECCLASS_CAPABILITY2; |
| break; |
| default: |
| printk(KERN_ERR |
| "SELinux: out of range capability %d\n", cap); |
| BUG(); |
| return -EINVAL; |
| } |
| |
| rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd); |
| if (audit == SECURITY_CAP_AUDIT) { |
| int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad, 0); |
| if (rc2) |
| return rc2; |
| } |
| return rc; |
| } |
| |
| /* Check whether a task is allowed to use a system operation. */ |
| static int task_has_system(struct task_struct *tsk, |
| u32 perms) |
| { |
| u32 sid = task_sid(tsk); |
| |
| return avc_has_perm(sid, SECINITSID_KERNEL, |
| SECCLASS_SYSTEM, perms, NULL); |
| } |
| |
| /* Check whether a task has a particular permission to an inode. |
| The 'adp' parameter is optional and allows other audit |
| data to be passed (e.g. the dentry). */ |
| static int inode_has_perm(const struct cred *cred, |
| struct inode *inode, |
| u32 perms, |
| struct common_audit_data *adp, |
| unsigned flags) |
| { |
| struct inode_security_struct *isec; |
| u32 sid; |
| |
| validate_creds(cred); |
| |
| if (unlikely(IS_PRIVATE(inode))) |
| return 0; |
| |
| sid = cred_sid(cred); |
| isec = inode->i_security; |
| |
| return avc_has_perm_flags(sid, isec->sid, isec->sclass, perms, adp, flags); |
| } |
| |
| static int inode_has_perm_noadp(const struct cred *cred, |
| struct inode *inode, |
| u32 perms, |
| unsigned flags) |
| { |
| struct common_audit_data ad; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, INODE); |
| ad.u.inode = inode; |
| return inode_has_perm(cred, inode, perms, &ad, flags); |
| } |
| |
| /* Same as inode_has_perm, but pass explicit audit data containing |
| the dentry to help the auditing code to more easily generate the |
| pathname if needed. */ |
| static inline int dentry_has_perm(const struct cred *cred, |
| struct dentry *dentry, |
| u32 av) |
| { |
| struct inode *inode = dentry->d_inode; |
| struct common_audit_data ad; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, DENTRY); |
| ad.u.dentry = dentry; |
| return inode_has_perm(cred, inode, av, &ad, 0); |
| } |
| |
| /* Same as inode_has_perm, but pass explicit audit data containing |
| the path to help the auditing code to more easily generate the |
| pathname if needed. */ |
| static inline int path_has_perm(const struct cred *cred, |
| struct path *path, |
| u32 av) |
| { |
| struct inode *inode = path->dentry->d_inode; |
| struct common_audit_data ad; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, PATH); |
| ad.u.path = *path; |
| return inode_has_perm(cred, inode, av, &ad, 0); |
| } |
| |
| /* Check whether a task can use an open file descriptor to |
| access an inode in a given way. Check access to the |
| descriptor itself, and then use dentry_has_perm to |
| check a particular permission to the file. |
| Access to the descriptor is implicitly granted if it |
| has the same SID as the process. If av is zero, then |
| access to the file is not checked, e.g. for cases |
| where only the descriptor is affected like seek. */ |
| static int file_has_perm(const struct cred *cred, |
| struct file *file, |
| u32 av) |
| { |
| struct file_security_struct *fsec = file->f_security; |
| struct inode *inode = file->f_path.dentry->d_inode; |
| struct common_audit_data ad; |
| u32 sid = cred_sid(cred); |
| int rc; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, PATH); |
| ad.u.path = file->f_path; |
| |
| if (sid != fsec->sid) { |
| rc = avc_has_perm(sid, fsec->sid, |
| SECCLASS_FD, |
| FD__USE, |
| &ad); |
| if (rc) |
| goto out; |
| } |
| |
| /* av is zero if only checking access to the descriptor. */ |
| rc = 0; |
| if (av) |
| rc = inode_has_perm(cred, inode, av, &ad, 0); |
| |
| out: |
| return rc; |
| } |
| |
| /* Check whether a task can create a file. */ |
| static int may_create(struct inode *dir, |
| struct dentry *dentry, |
| u16 tclass) |
| { |
| const struct task_security_struct *tsec = current_security(); |
| struct inode_security_struct *dsec; |
| struct superblock_security_struct *sbsec; |
| u32 sid, newsid; |
| struct common_audit_data ad; |
| int rc; |
| |
| dsec = dir->i_security; |
| sbsec = dir->i_sb->s_security; |
| |
| sid = tsec->sid; |
| newsid = tsec->create_sid; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, DENTRY); |
| ad.u.dentry = dentry; |
| |
| rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR, |
| DIR__ADD_NAME | DIR__SEARCH, |
| &ad); |
| if (rc) |
| return rc; |
| |
| if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) { |
| rc = security_transition_sid(sid, dsec->sid, tclass, |
| &dentry->d_name, &newsid); |
| if (rc) |
| return rc; |
| } |
| |
| rc = avc_has_perm(sid, newsid, tclass, FILE__CREATE, &ad); |
| if (rc) |
| return rc; |
| |
| return avc_has_perm(newsid, sbsec->sid, |
| SECCLASS_FILESYSTEM, |
| FILESYSTEM__ASSOCIATE, &ad); |
| } |
| |
| /* Check whether a task can create a key. */ |
| static int may_create_key(u32 ksid, |
| struct task_struct *ctx) |
| { |
| u32 sid = task_sid(ctx); |
| |
| return avc_has_perm(sid, ksid, SECCLASS_KEY, KEY__CREATE, NULL); |
| } |
| |
| #define MAY_LINK 0 |
| #define MAY_UNLINK 1 |
| #define MAY_RMDIR 2 |
| |
| /* Check whether a task can link, unlink, or rmdir a file/directory. */ |
| static int may_link(struct inode *dir, |
| struct dentry *dentry, |
| int kind) |
| |
| { |
| struct inode_security_struct *dsec, *isec; |
| struct common_audit_data ad; |
| u32 sid = current_sid(); |
| u32 av; |
| int rc; |
| |
| dsec = dir->i_security; |
| isec = dentry->d_inode->i_security; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, DENTRY); |
| ad.u.dentry = dentry; |
| |
| av = DIR__SEARCH; |
| av |= (kind ? DIR__REMOVE_NAME : DIR__ADD_NAME); |
| rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR, av, &ad); |
| if (rc) |
| return rc; |
| |
| switch (kind) { |
| case MAY_LINK: |
| av = FILE__LINK; |
| break; |
| case MAY_UNLINK: |
| av = FILE__UNLINK; |
| break; |
| case MAY_RMDIR: |
| av = DIR__RMDIR; |
| break; |
| default: |
| printk(KERN_WARNING "SELinux: %s: unrecognized kind %d\n", |
| __func__, kind); |
| return 0; |
| } |
| |
| rc = avc_has_perm(sid, isec->sid, isec->sclass, av, &ad); |
| return rc; |
| } |
| |
| static inline int may_rename(struct inode *old_dir, |
| struct dentry *old_dentry, |
| struct inode *new_dir, |
| struct dentry *new_dentry) |
| { |
| struct inode_security_struct *old_dsec, *new_dsec, *old_isec, *new_isec; |
| struct common_audit_data ad; |
| u32 sid = current_sid(); |
| u32 av; |
| int old_is_dir, new_is_dir; |
| int rc; |
| |
| old_dsec = old_dir->i_security; |
| old_isec = old_dentry->d_inode->i_security; |
| old_is_dir = S_ISDIR(old_dentry->d_inode->i_mode); |
| new_dsec = new_dir->i_security; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, DENTRY); |
| |
| ad.u.dentry = old_dentry; |
| rc = avc_has_perm(sid, old_dsec->sid, SECCLASS_DIR, |
| DIR__REMOVE_NAME | DIR__SEARCH, &ad); |
| if (rc) |
| return rc; |
| rc = avc_has_perm(sid, old_isec->sid, |
| old_isec->sclass, FILE__RENAME, &ad); |
| if (rc) |
| return rc; |
| if (old_is_dir && new_dir != old_dir) { |
| rc = avc_has_perm(sid, old_isec->sid, |
| old_isec->sclass, DIR__REPARENT, &ad); |
| if (rc) |
| return rc; |
| } |
| |
| ad.u.dentry = new_dentry; |
| av = DIR__ADD_NAME | DIR__SEARCH; |
| if (new_dentry->d_inode) |
| av |= DIR__REMOVE_NAME; |
| rc = avc_has_perm(sid, new_dsec->sid, SECCLASS_DIR, av, &ad); |
| if (rc) |
| return rc; |
| if (new_dentry->d_inode) { |
| new_isec = new_dentry->d_inode->i_security; |
| new_is_dir = S_ISDIR(new_dentry->d_inode->i_mode); |
| rc = avc_has_perm(sid, new_isec->sid, |
| new_isec->sclass, |
| (new_is_dir ? DIR__RMDIR : FILE__UNLINK), &ad); |
| if (rc) |
| return rc; |
| } |
| |
| return 0; |
| } |
| |
| /* Check whether a task can perform a filesystem operation. */ |
| static int superblock_has_perm(const struct cred *cred, |
| struct super_block *sb, |
| u32 perms, |
| struct common_audit_data *ad) |
| { |
| struct superblock_security_struct *sbsec; |
| u32 sid = cred_sid(cred); |
| |
| sbsec = sb->s_security; |
| return avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM, perms, ad); |
| } |
| |
| /* Convert a Linux mode and permission mask to an access vector. */ |
| static inline u32 file_mask_to_av(int mode, int mask) |
| { |
| u32 av = 0; |
| |
| if ((mode & S_IFMT) != S_IFDIR) { |
| if (mask & MAY_EXEC) |
| av |= FILE__EXECUTE; |
| if (mask & MAY_READ) |
| av |= FILE__READ; |
| |
| if (mask & MAY_APPEND) |
| av |= FILE__APPEND; |
| else if (mask & MAY_WRITE) |
| av |= FILE__WRITE; |
| |
| } else { |
| if (mask & MAY_EXEC) |
| av |= DIR__SEARCH; |
| if (mask & MAY_WRITE) |
| av |= DIR__WRITE; |
| if (mask & MAY_READ) |
| av |= DIR__READ; |
| } |
| |
| return av; |
| } |
| |
| /* Convert a Linux file to an access vector. */ |
| static inline u32 file_to_av(struct file *file) |
| { |
| u32 av = 0; |
| |
| if (file->f_mode & FMODE_READ) |
| av |= FILE__READ; |
| if (file->f_mode & FMODE_WRITE) { |
| if (file->f_flags & O_APPEND) |
| av |= FILE__APPEND; |
| else |
| av |= FILE__WRITE; |
| } |
| if (!av) { |
| /* |
| * Special file opened with flags 3 for ioctl-only use. |
| */ |
| av = FILE__IOCTL; |
| } |
| |
| return av; |
| } |
| |
| /* |
| * Convert a file to an access vector and include the correct open |
| * open permission. |
| */ |
| static inline u32 open_file_to_av(struct file *file) |
| { |
| u32 av = file_to_av(file); |
| |
| if (selinux_policycap_openperm) |
| av |= FILE__OPEN; |
| |
| return av; |
| } |
| |
| /* Hook functions begin here. */ |
| |
| static int selinux_ptrace_access_check(struct task_struct *child, |
| unsigned int mode) |
| { |
| int rc; |
| |
| rc = cap_ptrace_access_check(child, mode); |
| if (rc) |
| return rc; |
| |
| if (mode == PTRACE_MODE_READ) { |
| u32 sid = current_sid(); |
| u32 csid = task_sid(child); |
| return avc_has_perm(sid, csid, SECCLASS_FILE, FILE__READ, NULL); |
| } |
| |
| return current_has_perm(child, PROCESS__PTRACE); |
| } |
| |
| static int selinux_ptrace_traceme(struct task_struct *parent) |
| { |
| int rc; |
| |
| rc = cap_ptrace_traceme(parent); |
| if (rc) |
| return rc; |
| |
| return task_has_perm(parent, current, PROCESS__PTRACE); |
| } |
| |
| static int selinux_capget(struct task_struct *target, kernel_cap_t *effective, |
| kernel_cap_t *inheritable, kernel_cap_t *permitted) |
| { |
| int error; |
| |
| error = current_has_perm(target, PROCESS__GETCAP); |
| if (error) |
| return error; |
| |
| return cap_capget(target, effective, inheritable, permitted); |
| } |
| |
| static int selinux_capset(struct cred *new, const struct cred *old, |
| const kernel_cap_t *effective, |
| const kernel_cap_t *inheritable, |
| const kernel_cap_t *permitted) |
| { |
| int error; |
| |
| error = cap_capset(new, old, |
| effective, inheritable, permitted); |
| if (error) |
| return error; |
| |
| return cred_has_perm(old, new, PROCESS__SETCAP); |
| } |
| |
| /* |
| * (This comment used to live with the selinux_task_setuid hook, |
| * which was removed). |
| * |
| * Since setuid only affects the current process, and since the SELinux |
| * controls are not based on the Linux identity attributes, SELinux does not |
| * need to control this operation. However, SELinux does control the use of |
| * the CAP_SETUID and CAP_SETGID capabilities using the capable hook. |
| */ |
| |
| static int selinux_capable(struct task_struct *tsk, const struct cred *cred, |
| struct user_namespace *ns, int cap, int audit) |
| { |
| int rc; |
| |
| rc = cap_capable(tsk, cred, ns, cap, audit); |
| if (rc) |
| return rc; |
| |
| return task_has_capability(tsk, cred, cap, audit); |
| } |
| |
| static int selinux_quotactl(int cmds, int type, int id, struct super_block *sb) |
| { |
| const struct cred *cred = current_cred(); |
| int rc = 0; |
| |
| if (!sb) |
| return 0; |
| |
| switch (cmds) { |
| case Q_SYNC: |
| case Q_QUOTAON: |
| case Q_QUOTAOFF: |
| case Q_SETINFO: |
| case Q_SETQUOTA: |
| rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAMOD, NULL); |
| break; |
| case Q_GETFMT: |
| case Q_GETINFO: |
| case Q_GETQUOTA: |
| rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAGET, NULL); |
| break; |
| default: |
| rc = 0; /* let the kernel handle invalid cmds */ |
| break; |
| } |
| return rc; |
| } |
| |
| static int selinux_quota_on(struct dentry *dentry) |
| { |
| const struct cred *cred = current_cred(); |
| |
| return dentry_has_perm(cred, dentry, FILE__QUOTAON); |
| } |
| |
| static int selinux_syslog(int type) |
| { |
| int rc; |
| |
| switch (type) { |
| case SYSLOG_ACTION_READ_ALL: /* Read last kernel messages */ |
| case SYSLOG_ACTION_SIZE_BUFFER: /* Return size of the log buffer */ |
| rc = task_has_system(current, SYSTEM__SYSLOG_READ); |
| break; |
| case SYSLOG_ACTION_CONSOLE_OFF: /* Disable logging to console */ |
| case SYSLOG_ACTION_CONSOLE_ON: /* Enable logging to console */ |
| /* Set level of messages printed to console */ |
| case SYSLOG_ACTION_CONSOLE_LEVEL: |
| rc = task_has_system(current, SYSTEM__SYSLOG_CONSOLE); |
| break; |
| case SYSLOG_ACTION_CLOSE: /* Close log */ |
| case SYSLOG_ACTION_OPEN: /* Open log */ |
| case SYSLOG_ACTION_READ: /* Read from log */ |
| case SYSLOG_ACTION_READ_CLEAR: /* Read/clear last kernel messages */ |
| case SYSLOG_ACTION_CLEAR: /* Clear ring buffer */ |
| default: |
| rc = task_has_system(current, SYSTEM__SYSLOG_MOD); |
| break; |
| } |
| return rc; |
| } |
| |
| /* |
| * Check that a process has enough memory to allocate a new virtual |
| * mapping. 0 means there is enough memory for the allocation to |
| * succeed and -ENOMEM implies there is not. |
| * |
| * Do not audit the selinux permission check, as this is applied to all |
| * processes that allocate mappings. |
| */ |
| static int selinux_vm_enough_memory(struct mm_struct *mm, long pages) |
| { |
| int rc, cap_sys_admin = 0; |
| |
| rc = selinux_capable(current, current_cred(), |
| &init_user_ns, CAP_SYS_ADMIN, |
| SECURITY_CAP_NOAUDIT); |
| if (rc == 0) |
| cap_sys_admin = 1; |
| |
| return __vm_enough_memory(mm, pages, cap_sys_admin); |
| } |
| |
| /* binprm security operations */ |
| |
| static int selinux_bprm_set_creds(struct linux_binprm *bprm) |
| { |
| const struct task_security_struct *old_tsec; |
| struct task_security_struct *new_tsec; |
| struct inode_security_struct *isec; |
| struct common_audit_data ad; |
| struct inode *inode = bprm->file->f_path.dentry->d_inode; |
| int rc; |
| |
| rc = cap_bprm_set_creds(bprm); |
| if (rc) |
| return rc; |
| |
| /* SELinux context only depends on initial program or script and not |
| * the script interpreter */ |
| if (bprm->cred_prepared) |
| return 0; |
| |
| old_tsec = current_security(); |
| new_tsec = bprm->cred->security; |
| isec = inode->i_security; |
| |
| /* Default to the current task SID. */ |
| new_tsec->sid = old_tsec->sid; |
| new_tsec->osid = old_tsec->sid; |
| |
| /* Reset fs, key, and sock SIDs on execve. */ |
| new_tsec->create_sid = 0; |
| new_tsec->keycreate_sid = 0; |
| new_tsec->sockcreate_sid = 0; |
| |
| if (old_tsec->exec_sid) { |
| new_tsec->sid = old_tsec->exec_sid; |
| /* Reset exec SID on execve. */ |
| new_tsec->exec_sid = 0; |
| } else { |
| /* Check for a default transition on this program. */ |
| rc = security_transition_sid(old_tsec->sid, isec->sid, |
| SECCLASS_PROCESS, NULL, |
| &new_tsec->sid); |
| if (rc) |
| return rc; |
| } |
| |
| COMMON_AUDIT_DATA_INIT(&ad, PATH); |
| ad.u.path = bprm->file->f_path; |
| |
| if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) |
| new_tsec->sid = old_tsec->sid; |
| |
| if (new_tsec->sid == old_tsec->sid) { |
| rc = avc_has_perm(old_tsec->sid, isec->sid, |
| SECCLASS_FILE, FILE__EXECUTE_NO_TRANS, &ad); |
| if (rc) |
| return rc; |
| } else { |
| /* Check permissions for the transition. */ |
| rc = avc_has_perm(old_tsec->sid, new_tsec->sid, |
| SECCLASS_PROCESS, PROCESS__TRANSITION, &ad); |
| if (rc) |
| return rc; |
| |
| rc = avc_has_perm(new_tsec->sid, isec->sid, |
| SECCLASS_FILE, FILE__ENTRYPOINT, &ad); |
| if (rc) |
| return rc; |
| |
| /* Check for shared state */ |
| if (bprm->unsafe & LSM_UNSAFE_SHARE) { |
| rc = avc_has_perm(old_tsec->sid, new_tsec->sid, |
| SECCLASS_PROCESS, PROCESS__SHARE, |
| NULL); |
| if (rc) |
| return -EPERM; |
| } |
| |
| /* Make sure that anyone attempting to ptrace over a task that |
| * changes its SID has the appropriate permit */ |
| if (bprm->unsafe & |
| (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { |
| struct task_struct *tracer; |
| struct task_security_struct *sec; |
| u32 ptsid = 0; |
| |
| rcu_read_lock(); |
| tracer = ptrace_parent(current); |
| if (likely(tracer != NULL)) { |
| sec = __task_cred(tracer)->security; |
| ptsid = sec->sid; |
| } |
| rcu_read_unlock(); |
| |
| if (ptsid != 0) { |
| rc = avc_has_perm(ptsid, new_tsec->sid, |
| SECCLASS_PROCESS, |
| PROCESS__PTRACE, NULL); |
| if (rc) |
| return -EPERM; |
| } |
| } |
| |
| /* Clear any possibly unsafe personality bits on exec: */ |
| bprm->per_clear |= PER_CLEAR_ON_SETID; |
| } |
| |
| return 0; |
| } |
| |
| static int selinux_bprm_secureexec(struct linux_binprm *bprm) |
| { |
| const struct task_security_struct *tsec = current_security(); |
| u32 sid, osid; |
| int atsecure = 0; |
| |
| sid = tsec->sid; |
| osid = tsec->osid; |
| |
| if (osid != sid) { |
| /* Enable secure mode for SIDs transitions unless |
| the noatsecure permission is granted between |
| the two SIDs, i.e. ahp returns 0. */ |
| atsecure = avc_has_perm(osid, sid, |
| SECCLASS_PROCESS, |
| PROCESS__NOATSECURE, NULL); |
| } |
| |
| return (atsecure || cap_bprm_secureexec(bprm)); |
| } |
| |
| /* Derived from fs/exec.c:flush_old_files. */ |
| static inline void flush_unauthorized_files(const struct cred *cred, |
| struct files_struct *files) |
| { |
| struct common_audit_data ad; |
| struct file *file, *devnull = NULL; |
| struct tty_struct *tty; |
| struct fdtable *fdt; |
| long j = -1; |
| int drop_tty = 0; |
| |
| tty = get_current_tty(); |
| if (tty) { |
| spin_lock(&tty_files_lock); |
| if (!list_empty(&tty->tty_files)) { |
| struct tty_file_private *file_priv; |
| struct inode *inode; |
| |
| /* Revalidate access to controlling tty. |
| Use inode_has_perm on the tty inode directly rather |
| than using file_has_perm, as this particular open |
| file may belong to another process and we are only |
| interested in the inode-based check here. */ |
| file_priv = list_first_entry(&tty->tty_files, |
| struct tty_file_private, list); |
| file = file_priv->file; |
| inode = file->f_path.dentry->d_inode; |
| if (inode_has_perm_noadp(cred, inode, |
| FILE__READ | FILE__WRITE, 0)) { |
| drop_tty = 1; |
| } |
| } |
| spin_unlock(&tty_files_lock); |
| tty_kref_put(tty); |
| } |
| /* Reset controlling tty. */ |
| if (drop_tty) |
| no_tty(); |
| |
| /* Revalidate access to inherited open files. */ |
| |
| COMMON_AUDIT_DATA_INIT(&ad, INODE); |
| |
| spin_lock(&files->file_lock); |
| for (;;) { |
| unsigned long set, i; |
| int fd; |
| |
| j++; |
| i = j * __NFDBITS; |
| fdt = files_fdtable(files); |
| if (i >= fdt->max_fds) |
| break; |
| set = fdt->open_fds->fds_bits[j]; |
| if (!set) |
| continue; |
| spin_unlock(&files->file_lock); |
| for ( ; set ; i++, set >>= 1) { |
| if (set & 1) { |
| file = fget(i); |
| if (!file) |
| continue; |
| if (file_has_perm(cred, |
| file, |
| file_to_av(file))) { |
| sys_close(i); |
| fd = get_unused_fd(); |
| if (fd != i) { |
| if (fd >= 0) |
| put_unused_fd(fd); |
| fput(file); |
| continue; |
| } |
| if (devnull) { |
| get_file(devnull); |
| } else { |
| devnull = dentry_open( |
| dget(selinux_null), |
| mntget(selinuxfs_mount), |
| O_RDWR, cred); |
| if (IS_ERR(devnull)) { |
| devnull = NULL; |
| put_unused_fd(fd); |
| fput(file); |
| continue; |
| } |
| } |
| fd_install(fd, devnull); |
| } |
| fput(file); |
| } |
| } |
| spin_lock(&files->file_lock); |
| |
| } |
| spin_unlock(&files->file_lock); |
| } |
| |
| /* |
| * Prepare a process for imminent new credential changes due to exec |
| */ |
| static void selinux_bprm_committing_creds(struct linux_binprm *bprm) |
| { |
| struct task_security_struct *new_tsec; |
| struct rlimit *rlim, *initrlim; |
| int rc, i; |
| |
| new_tsec = bprm->cred->security; |
| if (new_tsec->sid == new_tsec->osid) |
| return; |
| |
| /* Close files for which the new task SID is not authorized. */ |
| flush_unauthorized_files(bprm->cred, current->files); |
| |
| /* Always clear parent death signal on SID transitions. */ |
| current->pdeath_signal = 0; |
| |
| /* Check whether the new SID can inherit resource limits from the old |
| * SID. If not, reset all soft limits to the lower of the current |
| * task's hard limit and the init task's soft limit. |
| * |
| * Note that the setting of hard limits (even to lower them) can be |
| * controlled by the setrlimit check. The inclusion of the init task's |
| * soft limit into the computation is to avoid resetting soft limits |
| * higher than the default soft limit for cases where the default is |
| * lower than the hard limit, e.g. RLIMIT_CORE or RLIMIT_STACK. |
| */ |
| rc = avc_has_perm(new_tsec->osid, new_tsec->sid, SECCLASS_PROCESS, |
| PROCESS__RLIMITINH, NULL); |
| if (rc) { |
| /* protect against do_prlimit() */ |
| task_lock(current); |
| for (i = 0; i < RLIM_NLIMITS; i++) { |
| rlim = current->signal->rlim + i; |
| initrlim = init_task.signal->rlim + i; |
| rlim->rlim_cur = min(rlim->rlim_max, initrlim->rlim_cur); |
| } |
| task_unlock(current); |
| update_rlimit_cpu(current, rlimit(RLIMIT_CPU)); |
| } |
| } |
| |
| /* |
| * Clean up the process immediately after the installation of new credentials |
| * due to exec |
| */ |
| static void selinux_bprm_committed_creds(struct linux_binprm *bprm) |
| { |
| const struct task_security_struct *tsec = current_security(); |
| struct itimerval itimer; |
| u32 osid, sid; |
| int rc, i; |
| |
| osid = tsec->osid; |
| sid = tsec->sid; |
| |
| if (sid == osid) |
| return; |
| |
| /* Check whether the new SID can inherit signal state from the old SID. |
| * If not, clear itimers to avoid subsequent signal generation and |
| * flush and unblock signals. |
| * |
| * This must occur _after_ the task SID has been updated so that any |
| * kill done after the flush will be checked against the new SID. |
| */ |
| rc = avc_has_perm(osid, sid, SECCLASS_PROCESS, PROCESS__SIGINH, NULL); |
| if (rc) { |
| memset(&itimer, 0, sizeof itimer); |
| for (i = 0; i < 3; i++) |
| do_setitimer(i, &itimer, NULL); |
| spin_lock_irq(¤t->sighand->siglock); |
| if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) { |
| __flush_signals(current); |
| flush_signal_handlers(current, 1); |
| sigemptyset(¤t->blocked); |
| } |
| spin_unlock_irq(¤t->sighand->siglock); |
| } |
| |
| /* Wake up the parent if it is waiting so that it can recheck |
| * wait permission to the new task SID. */ |
| read_lock(&tasklist_lock); |
| __wake_up_parent(current, current->real_parent); |
| read_unlock(&tasklist_lock); |
| } |
| |
| /* superblock security operations */ |
| |
| static int selinux_sb_alloc_security(struct super_block *sb) |
| { |
| return superblock_alloc_security(sb); |
| } |
| |
| static void selinux_sb_free_security(struct super_block *sb) |
| { |
| superblock_free_security(sb); |
| } |
| |
| static inline int match_prefix(char *prefix, int plen, char *option, int olen) |
| { |
| if (plen > olen) |
| return 0; |
| |
| return !memcmp(prefix, option, plen); |
| } |
| |
| static inline int selinux_option(char *option, int len) |
| { |
| return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) || |
| match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) || |
| match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) || |
| match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len) || |
| match_prefix(LABELSUPP_STR, sizeof(LABELSUPP_STR)-1, option, len)); |
| } |
| |
| static inline void take_option(char **to, char *from, int *first, int len) |
| { |
| if (!*first) { |
| **to = ','; |
| *to += 1; |
| } else |
| *first = 0; |
| memcpy(*to, from, len); |
| *to += len; |
| } |
| |
| static inline void take_selinux_option(char **to, char *from, int *first, |
| int len) |
| { |
| int current_size = 0; |
| |
| if (!*first) { |
| **to = '|'; |
| *to += 1; |
| } else |
| *first = 0; |
| |
| while (current_size < len) { |
| if (*from != '"') { |
| **to = *from; |
| *to += 1; |
| } |
| from += 1; |
| current_size += 1; |
| } |
| } |
| |
| static int selinux_sb_copy_data(char *orig, char *copy) |
| { |
| int fnosec, fsec, rc = 0; |
| char *in_save, *in_curr, *in_end; |
| char *sec_curr, *nosec_save, *nosec; |
| int open_quote = 0; |
| |
| in_curr = orig; |
| sec_curr = copy; |
| |
| nosec = (char *)get_zeroed_page(GFP_KERNEL); |
| if (!nosec) { |
| rc = -ENOMEM; |
| goto out; |
| } |
| |
| nosec_save = nosec; |
| fnosec = fsec = 1; |
| in_save = in_end = orig; |
| |
| do { |
| if (*in_end == '"') |
| open_quote = !open_quote; |
| if ((*in_end == ',' && open_quote == 0) || |
| *in_end == '\0') { |
| int len = in_end - in_curr; |
| |
| if (selinux_option(in_curr, len)) |
| take_selinux_option(&sec_curr, in_curr, &fsec, len); |
| else |
| take_option(&nosec, in_curr, &fnosec, len); |
| |
| in_curr = in_end + 1; |
| } |
| } while (*in_end++); |
| |
| strcpy(in_save, nosec_save); |
| free_page((unsigned long)nosec_save); |
| out: |
| return rc; |
| } |
| |
| static int selinux_sb_remount(struct super_block *sb, void *data) |
| { |
| int rc, i, *flags; |
| struct security_mnt_opts opts; |
| char *secdata, **mount_options; |
| struct superblock_security_struct *sbsec = sb->s_security; |
| |
| if (!(sbsec->flags & SE_SBINITIALIZED)) |
| return 0; |
| |
| if (!data) |
| return 0; |
| |
| if (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA) |
| return 0; |
| |
| security_init_mnt_opts(&opts); |
| secdata = alloc_secdata(); |
| if (!secdata) |
| return -ENOMEM; |
| rc = selinux_sb_copy_data(data, secdata); |
| if (rc) |
| goto out_free_secdata; |
| |
| rc = selinux_parse_opts_str(secdata, &opts); |
| if (rc) |
| goto out_free_secdata; |
| |
| mount_options = opts.mnt_opts; |
| flags = opts.mnt_opts_flags; |
| |
| for (i = 0; i < opts.num_mnt_opts; i++) { |
| u32 sid; |
| size_t len; |
| |
| if (flags[i] == SE_SBLABELSUPP) |
| continue; |
| len = strlen(mount_options[i]); |
| rc = security_context_to_sid(mount_options[i], len, &sid); |
| if (rc) { |
| printk(KERN_WARNING "SELinux: security_context_to_sid" |
| "(%s) failed for (dev %s, type %s) errno=%d\n", |
| mount_options[i], sb->s_id, sb->s_type->name, rc); |
| goto out_free_opts; |
| } |
| rc = -EINVAL; |
| switch (flags[i]) { |
| case FSCONTEXT_MNT: |
| if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid)) |
| goto out_bad_option; |
| break; |
| case CONTEXT_MNT: |
| if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid)) |
| goto out_bad_option; |
| break; |
| case ROOTCONTEXT_MNT: { |
| struct inode_security_struct *root_isec; |
| root_isec = sb->s_root->d_inode->i_security; |
| |
| if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid)) |
| goto out_bad_option; |
| break; |
| } |
| case DEFCONTEXT_MNT: |
| if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid)) |
| goto out_bad_option; |
| break; |
| default: |
| goto out_free_opts; |
| } |
| } |
| |
| rc = 0; |
| out_free_opts: |
| security_free_mnt_opts(&opts); |
| out_free_secdata: |
| free_secdata(secdata); |
| return rc; |
| out_bad_option: |
| printk(KERN_WARNING "SELinux: unable to change security options " |
| "during remount (dev %s, type=%s)\n", sb->s_id, |
| sb->s_type->name); |
| goto out_free_opts; |
| } |
| |
| static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data) |
| { |
| const struct cred *cred = current_cred(); |
| struct common_audit_data ad; |
| int rc; |
| |
| rc = superblock_doinit(sb, data); |
| if (rc) |
| return rc; |
| |
| /* Allow all mounts performed by the kernel */ |
| if (flags & MS_KERNMOUNT) |
| return 0; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, DENTRY); |
| ad.u.dentry = sb->s_root; |
| return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad); |
| } |
| |
| static int selinux_sb_statfs(struct dentry *dentry) |
| { |
| const struct cred *cred = current_cred(); |
| struct common_audit_data ad; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, DENTRY); |
| ad.u.dentry = dentry->d_sb->s_root; |
| return superblock_has_perm(cred, dentry->d_sb, FILESYSTEM__GETATTR, &ad); |
| } |
| |
| static int selinux_mount(char *dev_name, |
| struct path *path, |
| char *type, |
| unsigned long flags, |
| void *data) |
| { |
| const struct cred *cred = current_cred(); |
| |
| if (flags & MS_REMOUNT) |
| return superblock_has_perm(cred, path->mnt->mnt_sb, |
| FILESYSTEM__REMOUNT, NULL); |
| else |
| return path_has_perm(cred, path, FILE__MOUNTON); |
| } |
| |
| static int selinux_umount(struct vfsmount *mnt, int flags) |
| { |
| const struct cred *cred = current_cred(); |
| |
| return superblock_has_perm(cred, mnt->mnt_sb, |
| FILESYSTEM__UNMOUNT, NULL); |
| } |
| |
| /* inode security operations */ |
| |
| static int selinux_inode_alloc_security(struct inode *inode) |
| { |
| return inode_alloc_security(inode); |
| } |
| |
| static void selinux_inode_free_security(struct inode *inode) |
| { |
| inode_free_security(inode); |
| } |
| |
| static int selinux_inode_init_security(struct inode *inode, struct inode *dir, |
| const struct qstr *qstr, char **name, |
| void **value, size_t *len) |
| { |
| const struct task_security_struct *tsec = current_security(); |
| struct inode_security_struct *dsec; |
| struct superblock_security_struct *sbsec; |
| u32 sid, newsid, clen; |
| int rc; |
| char *namep = NULL, *context; |
| |
| dsec = dir->i_security; |
| sbsec = dir->i_sb->s_security; |
| |
| sid = tsec->sid; |
| newsid = tsec->create_sid; |
| |
| if ((sbsec->flags & SE_SBINITIALIZED) && |
| (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) |
| newsid = sbsec->mntpoint_sid; |
| else if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) { |
| rc = security_transition_sid(sid, dsec->sid, |
| inode_mode_to_security_class(inode->i_mode), |
| qstr, &newsid); |
| if (rc) { |
| printk(KERN_WARNING "%s: " |
| "security_transition_sid failed, rc=%d (dev=%s " |
| "ino=%ld)\n", |
| __func__, |
| -rc, inode->i_sb->s_id, inode->i_ino); |
| return rc; |
| } |
| } |
| |
| /* Possibly defer initialization to selinux_complete_init. */ |
| if (sbsec->flags & SE_SBINITIALIZED) { |
| struct inode_security_struct *isec = inode->i_security; |
| isec->sclass = inode_mode_to_security_class(inode->i_mode); |
| isec->sid = newsid; |
| isec->initialized = 1; |
| } |
| |
| if (!ss_initialized || !(sbsec->flags & SE_SBLABELSUPP)) |
| return -EOPNOTSUPP; |
| |
| if (name) { |
| namep = kstrdup(XATTR_SELINUX_SUFFIX, GFP_NOFS); |
| if (!namep) |
| return -ENOMEM; |
| *name = namep; |
| } |
| |
| if (value && len) { |
| rc = security_sid_to_context_force(newsid, &context, &clen); |
| if (rc) { |
| kfree(namep); |
| return rc; |
| } |
| *value = context; |
| *len = clen; |
| } |
| |
| return 0; |
| } |
| |
| static int selinux_inode_create(struct inode *dir, struct dentry *dentry, int mask) |
| { |
| return may_create(dir, dentry, SECCLASS_FILE); |
| } |
| |
| static int selinux_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) |
| { |
| return may_link(dir, old_dentry, MAY_LINK); |
| } |
| |
| static int selinux_inode_unlink(struct inode *dir, struct dentry *dentry) |
| { |
| return may_link(dir, dentry, MAY_UNLINK); |
| } |
| |
| static int selinux_inode_symlink(struct inode *dir, struct dentry *dentry, const char *name) |
| { |
| return may_create(dir, dentry, SECCLASS_LNK_FILE); |
| } |
| |
| static int selinux_inode_mkdir(struct inode *dir, struct dentry *dentry, int mask) |
| { |
| return may_create(dir, dentry, SECCLASS_DIR); |
| } |
| |
| static int selinux_inode_rmdir(struct inode *dir, struct dentry *dentry) |
| { |
| return may_link(dir, dentry, MAY_RMDIR); |
| } |
| |
| static int selinux_inode_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) |
| { |
| return may_create(dir, dentry, inode_mode_to_security_class(mode)); |
| } |
| |
| static int selinux_inode_rename(struct inode *old_inode, struct dentry *old_dentry, |
| struct inode *new_inode, struct dentry *new_dentry) |
| { |
| return may_rename(old_inode, old_dentry, new_inode, new_dentry); |
| } |
| |
| static int selinux_inode_readlink(struct dentry *dentry) |
| { |
| const struct cred *cred = current_cred(); |
| |
| return dentry_has_perm(cred, dentry, FILE__READ); |
| } |
| |
| static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *nameidata) |
| { |
| const struct cred *cred = current_cred(); |
| |
| return dentry_has_perm(cred, dentry, FILE__READ); |
| } |
| |
| static int selinux_inode_permission(struct inode *inode, int mask) |
| { |
| const struct cred *cred = current_cred(); |
| struct common_audit_data ad; |
| u32 perms; |
| bool from_access; |
| unsigned flags = mask & MAY_NOT_BLOCK; |
| |
| from_access = mask & MAY_ACCESS; |
| mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND); |
| |
| /* No permission to check. Existence test. */ |
| if (!mask) |
| return 0; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, INODE); |
| ad.u.inode = inode; |
| |
| if (from_access) |
| ad.selinux_audit_data.auditdeny |= FILE__AUDIT_ACCESS; |
| |
| perms = file_mask_to_av(inode->i_mode, mask); |
| |
| return inode_has_perm(cred, inode, perms, &ad, flags); |
| } |
| |
| static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) |
| { |
| const struct cred *cred = current_cred(); |
| unsigned int ia_valid = iattr->ia_valid; |
| |
| /* ATTR_FORCE is just used for ATTR_KILL_S[UG]ID. */ |
| if (ia_valid & ATTR_FORCE) { |
| ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_MODE | |
| ATTR_FORCE); |
| if (!ia_valid) |
| return 0; |
| } |
| |
| if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | |
| ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET)) |
| return dentry_has_perm(cred, dentry, FILE__SETATTR); |
| |
| return dentry_has_perm(cred, dentry, FILE__WRITE); |
| } |
| |
| static int selinux_inode_getattr(struct vfsmount *mnt, struct dentry *dentry) |
| { |
| const struct cred *cred = current_cred(); |
| struct path path; |
| |
| path.dentry = dentry; |
| path.mnt = mnt; |
| |
| return path_has_perm(cred, &path, FILE__GETATTR); |
| } |
| |
| static int selinux_inode_setotherxattr(struct dentry *dentry, const char *name) |
| { |
| const struct cred *cred = current_cred(); |
| |
| if (!strncmp(name, XATTR_SECURITY_PREFIX, |
| sizeof XATTR_SECURITY_PREFIX - 1)) { |
| if (!strcmp(name, XATTR_NAME_CAPS)) { |
| if (!capable(CAP_SETFCAP)) |
| return -EPERM; |
| } else if (!capable(CAP_SYS_ADMIN)) { |
| /* A different attribute in the security namespace. |
| Restrict to administrator. */ |
| return -EPERM; |
| } |
| } |
| |
| /* Not an attribute we recognize, so just check the |
| ordinary setattr permission. */ |
| return dentry_has_perm(cred, dentry, FILE__SETATTR); |
| } |
| |
| static int selinux_inode_setxattr(struct dentry *dentry, const char *name, |
| const void *value, size_t size, int flags) |
| { |
| struct inode *inode = dentry->d_inode; |
| struct inode_security_struct *isec = inode->i_security; |
| struct superblock_security_struct *sbsec; |
| struct common_audit_data ad; |
| u32 newsid, sid = current_sid(); |
| int rc = 0; |
| |
| if (strcmp(name, XATTR_NAME_SELINUX)) |
| return selinux_inode_setotherxattr(dentry, name); |
| |
| sbsec = inode->i_sb->s_security; |
| if (!(sbsec->flags & SE_SBLABELSUPP)) |
| return -EOPNOTSUPP; |
| |
| if (!inode_owner_or_capable(inode)) |
| return -EPERM; |
| |
| COMMON_AUDIT_DATA_INIT(&ad, DENTRY); |
| ad.u.dentry = dentry; |
| |
| rc = avc_has_perm(sid, isec->sid, isec->sclass, |
| FILE__RELABELFROM, &ad); |
| if (rc) |
| return rc; |
| |
| rc = security_context_to_sid(value, size, &newsid); |
| if (rc == -EINVAL) { |
| if (!capable(CAP_MAC_ADMIN)) |
| return rc; |
| rc = security_context_to_sid_force(value, size, &newsid); |
| } |
| if (rc) |
| return rc; |
| |
| rc = avc_has_perm(sid, newsid, isec->sclass, |
| FILE__RELABELTO, &ad); |
| if (rc) |
| return rc; |
| |
| rc = security_validate_transition(isec->sid, newsid, sid, |
| isec->sclass); |
| if (rc) |
| return rc; |
| |
| return avc_has_perm(newsid, |
| sbsec->sid, |
| SECCLASS_FILESYSTEM, |
| FILESYSTEM__ASSOCIATE, |
| &ad); |
| } |
| |
| static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name, |
| const void *value, size_t size, |
| int flags) |
| { |
| struct inode *inode = dentry->d_inode; |
| struct inode_security_struct *isec = inode->i_security; |
| u32 newsid; |
| int rc; |
| |
| if (strcmp(name, XATTR_NAME_SELINUX)) { |
| /* Not an attribute we recognize, so nothing to do. */ |
| return; |
| } |
| |
| rc = security_context_to_sid_force(value, size, &newsid); |
| if (rc) { |
| printk(KERN_ERR "SELinux: unable to map context to SID" |
| "for (%s, %lu), rc=%d\n", |
| inode->i_sb->s_id, inode->i_ino, -rc); |
| return; |
| } |
| |
| isec->sid = newsid; |
| return; |
| } |
| |
| static int selinux_inode_getxattr(struct dentry *dentry, const char *name) |
| { |
| const struct cred *cred = current_cred(); |
| |
| return dentry_has_perm(cred, dentry, FILE__GETATTR); |
| } |
| |
| static int selinux_inode_listxattr(struct dentry *dentry) |
| { |
| const struct cred *cred = current_cred(); |
| |
| return dentry_has_perm(cred, dentry, FILE__GETATTR); |
| } |
| |
| static int selinux_inode_removexattr(struct dentry *dentry, const char *name) |
| { |
| if (strcmp(name, XATTR_NAME_SELINUX)) |
| return selinux_inode_setotherxattr(dentry, name); |
| |
| /* No one is allowed to remove a SELinux security label. |
| You can change the label, but all data must be labeled. */ |
| return -EACCES; |
| } |
| |
| /* |
| * Copy the inode security context value to the user. |
| * |
| * Permission check is handled by selinux_inode_getxattr hook. |
| */ |
| static int selinux_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc) |
| { |
| u32 size; |
| int error; |
| char *context = NULL; |
| struct inode_security_struct *isec = inode->i_security; |
| |
| if (strcmp(name, XATTR_SELINUX_SUFFIX)) |
| return -EOPNOTSUPP; |
| |
| /* |
| * If the caller has CAP_MAC_ADMIN, then get the raw context |
| * value even if it is not defined by current policy; otherwise, |
| * use the in-core value under current policy. |
| * Use the non-auditing forms of the permission checks since |
| * getxattr may be called by unprivileged processes commonly |
| * and lack of permission just means that we fall back to the |
| * in-core context value, not a denial. |
| */ |
| error = selinux_capable(current, current_cred(), |
| &init_user_ns, CAP_MAC_ADMIN, |
| SECURITY_CAP_NOAUDIT); |
| if (!error) |
| error = security_sid_to_context_force(isec->sid, &context, |
| &size); |
| else |
| error = security_sid_to_context(isec->sid, &context, &size); |
| if (error) |
| return error; |
| error = size; |
| if (alloc) { |
| *buffer = context; |
| goto out_nofree; |
| } |
| kfree(context); |
| out_nofree: |
| return error; |
| } |
| |
| static int selinux_inode_setsecurity(struct inode *inode, const char *name, |
| const void *value, size_t size, int flags) |
| { |
| struct inode_security_struct *isec = inode->i_security; |
| u32 newsid; |
| int rc; |
| |
| if (strcmp(name, XATTR_SELINUX_SUFFIX)) |
| return -EOPNOTSUPP; |
| |
| if (!value || !size) |
| return -EACCES; |
| |
| rc = security_context_to_sid((void *)value, size, &newsid); |
| if (rc) |
| return rc; |
| |
| isec->sid = newsid; |
| isec->initialized = 1; |
| return 0; |
| } |
| |
| static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size) |
| { |
| const int len = sizeof(XATTR_NAME_SELINUX); |
| if (buffer && len <= buffer_size) |
| memcpy(buffer, XATTR_NAME_SELINUX, len); |
| return len; |
| } |
| |
| static void selinux_inode_getsecid(const struct inode *inode, u32 *secid) |
| { |
| struct inode_security_struct *isec = inode->i_security; |
| *secid = isec->sid; |
| } |
| |
| /* file security operations */ |
| |
| static int selinux_revalidate_file_permission(struct file *file, int mask) |
| { |
| const struct cred *cred = current_cred(); |
| struct inode *inode = file->f_path.dentry->d_inode; |
| |
| /* file_mask_to_av won't add FILE__WRITE if MAY_APPEND is set */ |
| if ((file->f_flags & O_APPEND) && (mask & MAY_WRITE)) |
| mask |= MAY_APPEND; |
| |
| return file_has_perm(cred, file, |
| file_mask_to_av(inode->i_mode, mask)); |
| } |
| |
| static int selinux_file_permission(struct file *file, int mask) |
| { |
| struct inode *inode = file->f_path.dentry->d_inode; |
| struct file_security_struct *fsec = file->f_security; |
| struct inode_security_struct *isec = inode->i_security; |
| u32 sid = current_sid(); |
| |
| if (!mask) |
| /* No permission to check. Existence test. */ |
| return 0; |
| |
| if (sid == fsec->sid && fsec->isid == isec->sid && |
| fsec->pseqno == avc_policy_seqno()) |
| /* No change since dentry_open check. */ |
| return 0; |
| |
| return selinux_revalidate_file_permission(file, mask); |
| } |
| |
| static int selinux_file_alloc_security(struct file *file) |
| { |
| return file_alloc_security(file); |
| } |
| |
| static void selinux_file_free_security(struct file *file) |
| { |
| file_free_security(file); |
| } |
| |
| static int selinux_file_ioctl(struct file *file, unsigned int cmd, |
| unsigned long arg) |
| { |
| const struct cred *cred = current_cred(); |
| int error = 0; |
| |
| switch (cmd) { |
| case FIONREAD: |
| /* fall through */ |
| case FIBMAP: |
| /* fall through */ |
| case FIGETBSZ: |
| /* fall through */ |
| case EXT2_IOC_GETFLAGS: |
| /* fall through */ |
| case EXT2_IOC_GETVERSION: |
| error = file_has_perm(cred, file, FILE__GETATTR); |
| break; |
| |
| case EXT2_IOC_SETFLAGS: |
| /* fall through */ |
| case EXT2_IOC_SETVERSION: |
| error = file_has_perm(cred, file, FILE__SETATTR); |
| break; |
| |
| /* sys_ioctl() checks */ |
| case FIONBIO: |
| /* fall through */ |
| case FIOASYNC: |
| error = file_has_perm(cred, file, 0); |
| break; |
| |
| case KDSKBENT: |
| case KDSKBSENT: |
| error = task_has_capability(current, cred, CAP_SYS_TTY_CONFIG, |
| SECURITY_CAP_AUDIT); |
| break; |
| |
| /* default case assumes that the command will go |
| * to the file's ioctl() function. |
| */ |
| default: |
| error = file_has_perm(cred, file, FILE__IOCTL); |
| } |
| return error; |
| } |
| |
| static int default_noexec; |
| |
| static int file_map_prot_check(struct file *file, unsigned long prot, int shared) |
| { |
| const struct cred *cred = current_cred(); |
| int rc = 0; |
| |
| if (default_noexec && |
| (prot & PROT_EXEC) && (!file || (!shared && (prot & PROT_WRITE)))) { |
| /* |
| * We are making executable an anonymous mapping or a |
| * private file mapping that will also be writable. |
| * This has an additional check. |
| */ |
| rc = cred_has_perm(cred, cred, PROCESS__EXECMEM); |
| if (rc) |
| goto error; |
| } |
| |
| if (file) { |
| /* read access is always possible with a mapping */ |
| u32 av = FILE__READ; |
| |
| /* write access only matters if the mapping is shared */ |
| if (shared && (prot & PROT_WRITE)) |
| av |= FILE__WRITE; |
| |
| if (prot & PROT_EXEC) |
| av |= FILE__EXECUTE; |
| |
| return file_has_perm(cred, file, av); |
| } |
| |
| error: |
| return rc; |
| } |
| |
| static int selinux_file_mmap(struct file *file, unsigned long reqprot, |
| unsigned long prot, unsigned long flags, |
| unsigned long addr, unsigned long addr_only) |
| { |
| int rc = 0; |
| u32 sid = current_sid(); |
| |
| /* |
| * notice that we are intentionally putting the SELinux check before |
| * the secondary cap_file_mmap check. This is such a likely attempt |
| * at bad behaviour/exploit that we always want to get the AVC, even |
| * if DAC would have also denied the operation. |
| */ |
| if (addr < CONFIG_LSM_MMAP_MIN_ADDR) { |
| rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT, |
| MEMPROTECT__MMAP_ZERO, NULL); |
| if (rc) |
| return rc; |
| } |
| |
| /* do DAC check on address space usage */ |
| rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only); |
| if (rc || addr_only) |
| return rc; |
| |
| if (selinux_checkreqprot) |
| prot = reqprot; |
| |
| return file_map_prot_check(file, prot, |
| (flags & MAP_TYPE) == MAP_SHARED); |
| } |
| |
| static int selinux_file_mprotect(struct vm_area_struct *vma, |
| unsigned long reqprot, |
| unsigned long prot) |
| { |
| const struct cred *cred = current_cred(); |
| |
| if (selinux_checkreqprot) |
| prot = reqprot; |
| |
| if (default_noexec && |
| (prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) { |
| int rc = 0; |
| if (vma->vm_start >= vma->vm_mm->start_brk && |
| vma->vm_end <= vma->vm_mm->brk) { |
| rc = cred_has_perm(cred, cred, PROCESS__EXECHEAP); |
| } else if (!vma->vm_file && |
| vma->vm_start <= vma->vm_mm->start_stack && |
| vma->vm_end >= vma->vm_mm->start_stack) { |
| rc = current_has_perm(current, PROCESS__EXECSTACK); |
| } else if (vma->vm_file && vma->anon_vma) { |
| /* |
| * We are making executable a file mapping that has |
| * had some COW done. Since pages might have been |
| * written, check ability to execute the possibly |
| * modified content. This typically should only |
| * occur for text relocations. |
| */ |
| rc = file_has_perm(cred, vma->vm_file, FILE__EXECMOD); |
| } |
| if (rc) |
| return rc; |
| } |
| |
| return file_map_prot_check(vma->vm_file, prot, vma->vm_flags&VM_SHARED); |
| } |
| |
| static int selinux_file_lock(struct file *file, unsigned int cmd) |
| { |
| const struct cred *cred = current_cred(); |
| |
| return file_has_perm(cred, file, FILE__LOCK); |
| } |
| |
| static int selinux_file_fcntl(struct file *file, unsigned int cmd, |
| unsigned long arg) |
| { |
| const struct cred *cred = current_cred(); |
| int err = 0; |
| |
| switch (cmd) { |
| case F_SETFL: |
| if (!file->f_path.dentry || !file->f_path.dentry-> |