diff options
| -rw-r--r-- | fs/overlayfs/copy_up.c | 7 | ||||
| -rw-r--r-- | include/linux/lsm_hooks.h | 10 | ||||
| -rw-r--r-- | include/linux/security.h | 6 | ||||
| -rw-r--r-- | security/security.c | 8 |
4 files changed, 31 insertions, 0 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index c297b1f5a05e..cd65f12b3464 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -103,6 +103,13 @@ retry: goto retry; } + error = security_inode_copy_up_xattr(name); + if (error < 0 && error != -EOPNOTSUPP) + break; + if (error == 1) { + error = 0; + continue; /* Discard */ + } error = vfs_setxattr(new, name, value, size, 0); if (error) break; diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index cb69fc829053..57971229551b 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -410,6 +410,14 @@ * @src indicates the union dentry of file that is being copied up. * @new pointer to pointer to return newly allocated creds. * Returns 0 on success or a negative error code on error. + * @inode_copy_up_xattr: + * Filter the xattrs being copied up when a unioned file is copied + * up from a lower layer to the union/overlay layer. + * @name indicates the name of the xattr. + * Returns 0 to accept the xattr, 1 to discard the xattr, -EOPNOTSUPP if + * security module does not know about attribute or a negative error code + * to abort the copy up. Note that the caller is responsible for reading + * and writing the xattrs as this hook is merely a filter. * * Security hooks for file operations * @@ -1435,6 +1443,7 @@ union security_list_options { size_t buffer_size); void (*inode_getsecid)(struct inode *inode, u32 *secid); int (*inode_copy_up)(struct dentry *src, struct cred **new); + int (*inode_copy_up_xattr)(const char *name); int (*file_permission)(struct file *file, int mask); int (*file_alloc_security)(struct file *file); @@ -1707,6 +1716,7 @@ struct security_hook_heads { struct list_head inode_listsecurity; struct list_head inode_getsecid; struct list_head inode_copy_up; + struct list_head inode_copy_up_xattr; struct list_head file_permission; struct list_head file_alloc_security; struct list_head file_free_security; diff --git a/include/linux/security.h b/include/linux/security.h index c5b0ccd6c8b6..536fafdfa10a 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -283,6 +283,7 @@ int security_inode_setsecurity(struct inode *inode, const char *name, const void int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size); void security_inode_getsecid(struct inode *inode, u32 *secid); int security_inode_copy_up(struct dentry *src, struct cred **new); +int security_inode_copy_up_xattr(const char *name); int security_file_permission(struct file *file, int mask); int security_file_alloc(struct file *file); void security_file_free(struct file *file); @@ -764,6 +765,11 @@ static inline int security_inode_copy_up(struct dentry *src, struct cred **new) return 0; } +static inline int security_inode_copy_up_xattr(const char *name) +{ + return -EOPNOTSUPP; +} + static inline int security_file_permission(struct file *file, int mask) { return 0; diff --git a/security/security.c b/security/security.c index f2a7f27bd3e9..a9e2bb9fb9d3 100644 --- a/security/security.c +++ b/security/security.c @@ -754,6 +754,12 @@ int security_inode_copy_up(struct dentry *src, struct cred **new) } EXPORT_SYMBOL(security_inode_copy_up); +int security_inode_copy_up_xattr(const char *name) +{ + return call_int_hook(inode_copy_up_xattr, -EOPNOTSUPP, name); +} +EXPORT_SYMBOL(security_inode_copy_up_xattr); + int security_file_permission(struct file *file, int mask) { int ret; @@ -1692,6 +1698,8 @@ struct security_hook_heads security_hook_heads = { LIST_HEAD_INIT(security_hook_heads.inode_getsecid), .inode_copy_up = LIST_HEAD_INIT(security_hook_heads.inode_copy_up), + .inode_copy_up_xattr = + LIST_HEAD_INIT(security_hook_heads.inode_copy_up_xattr), .file_permission = LIST_HEAD_INIT(security_hook_heads.file_permission), .file_alloc_security = |