Merge tag 'lsm-pr-20221212' of git://git.kernel.org/pub/scm/linux/ker…

…nel/git/pcmoore/lsm

Pull lsm updates from Paul Moore:

 - Improve the error handling in the device cgroup such that memory
   allocation failures when updating the access policy do not
   potentially alter the policy.

 - Some minor fixes to reiserfs to ensure that it properly releases
   LSM-related xattr values.

 - Update the security_socket_getpeersec_stream() LSM hook to take
   sockptr_t values.

   Previously the net/BPF folks updated the getsockopt code in the
   network stack to leverage the sockptr_t type to make it easier to
   pass both kernel and __user pointers, but unfortunately when they did
   so they didn't convert the LSM hook.

   While there was/is no immediate risk by not converting the LSM hook,
   it seems like this is a mistake waiting to happen so this patch
   proactively does the LSM hook conversion.

 - Convert vfs_getxattr_alloc() to return an int instead of a ssize_t
   and cleanup the callers. Internally the function was never going to
   return anything larger than an int and the callers were doing some
   very odd things casting the return value; this patch fixes all that
   and helps bring a bit of sanity to vfs_getxattr_alloc() and its
   callers.

 - More verbose, and helpful, LSM debug output when the system is booted
   with "lsm.debug" on the command line. There are examples in the
   commit description, but the quick summary is that this patch provides
   better information about which LSMs are enabled and the ordering in
   which they are processed.

 - General comment and kernel-doc fixes and cleanups.

* tag 'lsm-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lsm: Fix description of fs_context_parse_param
  lsm: Add/fix return values in lsm_hooks.h and fix formatting
  lsm: Clarify documentation of vm_enough_memory hook
  reiserfs: Add missing calls to reiserfs_security_free()
  lsm,fs: fix vfs_getxattr_alloc() return type and caller error paths
  device_cgroup: Roll back to original exceptions after copy failure
  LSM: Better reporting of actual LSMs at boot
  lsm: make security_socket_getpeersec_stream() sockptr_t safe
  audit: Fix some kernel-doc warnings
  lsm: remove obsoleted comments for security hooks
  fs: edit a comment made in bad taste

fs/reiserfs/namei.c

@@ -696,6 +696,7 @@ static int reiserfs_create(struct user_namespace *mnt_userns, struct inode *dir,
 
 out_failed:
 	reiserfs_write_unlock(dir->i_sb);
+	reiserfs_security_free(&security);
 	return retval;
 }
 
@@ -779,6 +780,7 @@ static int reiserfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 
 out_failed:
 	reiserfs_write_unlock(dir->i_sb);
+	reiserfs_security_free(&security);
 	return retval;
 }
 
@@ -878,6 +880,7 @@ static int reiserfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 	retval = journal_end(&th);
 out_failed:
 	reiserfs_write_unlock(dir->i_sb);
+	reiserfs_security_free(&security);
 	return retval;
 }
 
@@ -1194,6 +1197,7 @@ static int reiserfs_symlink(struct user_namespace *mnt_userns,
 	retval = journal_end(&th);
 out_failed:
 	reiserfs_write_unlock(parent_dir->i_sb);
+	reiserfs_security_free(&security);
 	return retval;
 }
 

fs/reiserfs/xattr_security.c

@@ -50,6 +50,7 @@ int reiserfs_security_init(struct inode *dir, struct inode *inode,
 	int error;
 
 	sec->name = NULL;
+	sec->value = NULL;
 
 	/* Don't add selinux attributes on xattrs - they'll never get used */
 	if (IS_PRIVATE(dir))
@@ -95,7 +96,6 @@ int reiserfs_security_write(struct reiserfs_transaction_handle *th,
 
 void reiserfs_security_free(struct reiserfs_security_handle *sec)
 {
-	kfree(sec->name);
 	kfree(sec->value);
 	sec->name = NULL;
 	sec->value = NULL;

fs/xattr.c

@@ -368,11 +368,12 @@ xattr_getsecurity(struct user_namespace *mnt_userns, struct inode *inode,
  * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
  *
  * Allocate memory, if not already allocated, or re-allocate correct size,
- * before retrieving the extended attribute.
+ * before retrieving the extended attribute.  The xattr value buffer should
+ * always be freed by the caller, even on error.
  *
  * Returns the result of alloc, if failed, or the getxattr operation.
  */
-ssize_t
+int
 vfs_getxattr_alloc(struct user_namespace *mnt_userns, struct dentry *dentry,
 		   const char *name, char **xattr_value, size_t xattr_size,
 		   gfp_t flags)

include/linux/fs_context.h

@@ -99,7 +99,7 @@ struct fs_context {
 	const struct cred	*cred;		/* The mounter's credentials */
 	struct p_log		log;		/* Logging buffer */
 	const char		*source;	/* The source name (eg. dev path) */
-	void			*security;	/* Linux S&M options */
+	void			*security;	/* LSM options */
 	void			*s_fs_info;	/* Proposed s_fs_info */
 	unsigned int		sb_flags;	/* Proposed superblock flags (SB_*) */
 	unsigned int		sb_flags_mask;	/* Superblock flags that were changed */

include/linux/lsm_hook_defs.h

@@ -309,7 +309,7 @@ LSM_HOOK(int, 0, socket_setsockopt, struct socket *sock, int level, int optname)
 LSM_HOOK(int, 0, socket_shutdown, struct socket *sock, int how)
 LSM_HOOK(int, 0, socket_sock_rcv_skb, struct sock *sk, struct sk_buff *skb)
 LSM_HOOK(int, 0, socket_getpeersec_stream, struct socket *sock,
-	 char __user *optval, int __user *optlen, unsigned len)
+	 sockptr_t optval, sockptr_t optlen, unsigned int len)
 LSM_HOOK(int, 0, socket_getpeersec_dgram, struct socket *sock,
 	 struct sk_buff *skb, u32 *secid)
 LSM_HOOK(int, 0, sk_alloc_security, struct sock *sk, int family, gfp_t priority)