From: Andrey Albershteyn Date: Mon, 30 Jun 2025 16:20:12 +0000 (+0200) Subject: lsm: introduce new hooks for setting/getting inode fsxattr X-Git-Tag: block-6.17-20250808~51^2~2^2~4 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=defdd02d783c6fa22d0005bdc238ccd9174faf20;p=linux-block.git lsm: introduce new hooks for setting/getting inode fsxattr Introduce new hooks for setting and getting filesystem extended attributes on inode (FS_IOC_FSGETXATTR). Cc: selinux@vger.kernel.org Cc: Paul Moore Acked-by: Paul Moore Signed-off-by: Andrey Albershteyn Link: https://lore.kernel.org/20250630-xattrat-syscall-v6-2-c4e3bc35227b@kernel.org Signed-off-by: Christian Brauner --- diff --git a/fs/file_attr.c b/fs/file_attr.c index a4dd1d9646c8..0aee402acde4 100644 --- a/fs/file_attr.c +++ b/fs/file_attr.c @@ -77,10 +77,15 @@ EXPORT_SYMBOL(fileattr_fill_flags); int vfs_fileattr_get(struct dentry *dentry, struct fileattr *fa) { struct inode *inode = d_inode(dentry); + int error; if (!inode->i_op->fileattr_get) return -ENOIOCTLCMD; + error = security_inode_file_getattr(dentry, fa); + if (error) + return error; + return inode->i_op->fileattr_get(dentry, fa); } EXPORT_SYMBOL(vfs_fileattr_get); @@ -243,12 +248,20 @@ int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry, } else { fa->flags |= old_ma.flags & ~FS_COMMON_FL; } + err = fileattr_set_prepare(inode, &old_ma, fa); - if (!err) - err = inode->i_op->fileattr_set(idmap, dentry, fa); + if (err) + goto out; + err = security_inode_file_setattr(dentry, fa); + if (err) + goto out; + err = inode->i_op->fileattr_set(idmap, dentry, fa); + if (err) + goto out; } - inode_unlock(inode); +out: + inode_unlock(inode); return err; } EXPORT_SYMBOL(vfs_fileattr_set); diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index bf3bbac4e02a..9600a4350e79 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -157,6 +157,8 @@ LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap, struct dentry *dentry, const char *name) LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry, const char *name) +LSM_HOOK(int, 0, inode_file_setattr, struct dentry *dentry, struct fileattr *fa) +LSM_HOOK(int, 0, inode_file_getattr, struct dentry *dentry, struct fileattr *fa) LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl) LSM_HOOK(void, LSM_RET_VOID, inode_post_set_acl, struct dentry *dentry, diff --git a/include/linux/security.h b/include/linux/security.h index dba349629229..9ed0d0e0c81f 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -451,6 +451,10 @@ int security_inode_listxattr(struct dentry *dentry); int security_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, const char *name); void security_inode_post_removexattr(struct dentry *dentry, const char *name); +int security_inode_file_setattr(struct dentry *dentry, + struct fileattr *fa); +int security_inode_file_getattr(struct dentry *dentry, + struct fileattr *fa); int security_inode_need_killpriv(struct dentry *dentry); int security_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry); int security_inode_getsecurity(struct mnt_idmap *idmap, @@ -1052,6 +1056,18 @@ static inline void security_inode_post_removexattr(struct dentry *dentry, const char *name) { } +static inline int security_inode_file_setattr(struct dentry *dentry, + struct fileattr *fa) +{ + return 0; +} + +static inline int security_inode_file_getattr(struct dentry *dentry, + struct fileattr *fa) +{ + return 0; +} + static inline int security_inode_need_killpriv(struct dentry *dentry) { return cap_inode_need_killpriv(dentry); diff --git a/security/security.c b/security/security.c index 596d41818577..711b4de40b8d 100644 --- a/security/security.c +++ b/security/security.c @@ -2622,6 +2622,36 @@ void security_inode_post_removexattr(struct dentry *dentry, const char *name) call_void_hook(inode_post_removexattr, dentry, name); } +/** + * security_inode_file_setattr() - check if setting fsxattr is allowed + * @dentry: file to set filesystem extended attributes on + * @fa: extended attributes to set on the inode + * + * Called when file_setattr() syscall or FS_IOC_FSSETXATTR ioctl() is called on + * inode + * + * Return: Returns 0 if permission is granted. + */ +int security_inode_file_setattr(struct dentry *dentry, struct fileattr *fa) +{ + return call_int_hook(inode_file_setattr, dentry, fa); +} + +/** + * security_inode_file_getattr() - check if retrieving fsxattr is allowed + * @dentry: file to retrieve filesystem extended attributes from + * @fa: extended attributes to get + * + * Called when file_getattr() syscall or FS_IOC_FSGETXATTR ioctl() is called on + * inode + * + * Return: Returns 0 if permission is granted. + */ +int security_inode_file_getattr(struct dentry *dentry, struct fileattr *fa) +{ + return call_int_hook(inode_file_getattr, dentry, fa); +} + /** * security_inode_need_killpriv() - Check if security_inode_killpriv() required * @dentry: associated dentry