Merge tag 'lsm-pr-20250121' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull lsm updates from Paul Moore:

 - Improved handling of LSM "secctx" strings through lsm_context struct

   The LSM secctx string interface is from an older time when only one
   LSM was supported, migrate over to the lsm_context struct to better
   support the different LSMs we now have and make it easier to support
   new LSMs in the future.

   These changes explain the Rust, VFS, and networking changes in the
   diffstat.

 - Only build lsm_audit.c if CONFIG_SECURITY and CONFIG_AUDIT are
   enabled

   Small tweak to be a bit smarter about when we build the LSM's common
   audit helpers.

 - Check for absurdly large policies from userspace in SafeSetID

   SafeSetID policies rules are fairly small, basically just "UID:UID",
   it easy to impose a limit of KMALLOC_MAX_SIZE on policy writes which
   helps quiet a number of syzbot related issues. While work is being
   done to address the syzbot issues through other mechanisms, this is a
   trivial and relatively safe fix that we can do now.

 - Various minor improvements and cleanups

   A collection of improvements to the kernel selftests, constification
   of some function parameters, removing redundant assignments, and
   local variable renames to improve readability.

* tag 'lsm-pr-20250121' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lockdown: initialize local array before use to quiet static analysis
  safesetid: check size of policy writes
  net: corrections for security_secid_to_secctx returns
  lsm: rename variable to avoid shadowing
  lsm: constify function parameters
  security: remove redundant assignment to return variable
  lsm: Only build lsm_audit.c if CONFIG_SECURITY and CONFIG_AUDIT are set
  selftests: refactor the lsm `flags_overset_lsm_set_self_attr` test
  binder: initialize lsm_context structure
  rust: replace lsm context+len with lsm_context
  lsm: secctx provider check on release
  lsm: lsm_context in security_dentry_init_security
  lsm: use lsm_context in security_inode_getsecctx
  lsm: replace context+len with lsm_context
  lsm: ensure the correct LSM context releaser

1 files changed, 30 insertions, 37 deletions

diff --git a/security/security.c b/security/security.c
index 09664e09fec9..39df4451455b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1735,8 +1735,7 @@ void security_inode_free(struct inode *inode)
  * @mode: mode used to determine resource type
  * @name: name of the last path component
  * @xattr_name: name of the security/LSM xattr
- * @ctx: pointer to the resulting LSM context
- * @ctxlen: length of @ctx
+ * @lsmctx: pointer to the resulting LSM context
  *
  * Compute a context for a dentry as the inode is not yet available since NFSv4
  * has no label backed by an EA anyway.  It is important to note that
@@ -1746,11 +1745,11 @@ void security_inode_free(struct inode *inode)
  */
 int security_dentry_init_security(struct dentry *dentry, int mode,
 				  const struct qstr *name,
-				  const char **xattr_name, void **ctx,
-				  u32 *ctxlen)
+				  const char **xattr_name,
+				  struct lsm_context *lsmctx)
 {
 	return call_int_hook(dentry_init_security, dentry, mode, name,
-			     xattr_name, ctx, ctxlen);
+			     xattr_name, lsmctx);
 }
 EXPORT_SYMBOL(security_dentry_init_security);
 
@@ -4139,10 +4138,8 @@ int security_getselfattr(unsigned int attr, struct lsm_ctx __user *uctx,
 		if (base)
 			uctx = (struct lsm_ctx __user *)(base + total);
 		rc = scall->hl->hook.getselfattr(attr, uctx, &entrysize, flags);
-		if (rc == -EOPNOTSUPP) {
-			rc = 0;
+		if (rc == -EOPNOTSUPP)
 			continue;
-		}
 		if (rc == -E2BIG) {
 			rc = 0;
 			left = 0;
@@ -4304,40 +4301,36 @@ EXPORT_SYMBOL(security_ismaclabel);
 /**
  * security_secid_to_secctx() - Convert a secid to a secctx
  * @secid: secid
- * @secdata: secctx
- * @seclen: secctx length
+ * @cp: the LSM context
  *
- * Convert secid to security context.  If @secdata is NULL the length of the
- * result will be returned in @seclen, but no @secdata will be returned.  This
+ * Convert secid to security context.  If @cp is NULL the length of the
+ * result will be returned, but no data will be returned.  This
  * does mean that the length could change between calls to check the length and
- * the next call which actually allocates and returns the @secdata.
+ * the next call which actually allocates and returns the data.
  *
- * Return: Return 0 on success, error on failure.
+ * Return: Return length of data on success, error on failure.
  */
-int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+int security_secid_to_secctx(u32 secid, struct lsm_context *cp)
 {
-	return call_int_hook(secid_to_secctx, secid, secdata, seclen);
+	return call_int_hook(secid_to_secctx, secid, cp);
 }
 EXPORT_SYMBOL(security_secid_to_secctx);
 
 /**
  * security_lsmprop_to_secctx() - Convert a lsm_prop to a secctx
  * @prop: lsm specific information
- * @secdata: secctx
- * @seclen: secctx length
+ * @cp: the LSM context
  *
- * Convert a @prop entry to security context.  If @secdata is NULL the
- * length of the result will be returned in @seclen, but no @secdata
- * will be returned.  This does mean that the length could change between
- * calls to check the length and the next call which actually allocates
- * and returns the @secdata.
+ * Convert a @prop entry to security context.  If @cp is NULL the
+ * length of the result will be returned. This does mean that the
+ * length could change between calls to check the length and the
+ * next call which actually allocates and returns the @cp.
  *
- * Return: Return 0 on success, error on failure.
+ * Return: Return length of data on success, error on failure.
  */
-int security_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata,
-			       u32 *seclen)
+int security_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp)
 {
-	return call_int_hook(lsmprop_to_secctx, prop, secdata, seclen);
+	return call_int_hook(lsmprop_to_secctx, prop, cp);
 }
 EXPORT_SYMBOL(security_lsmprop_to_secctx);
 
@@ -4360,14 +4353,14 @@ EXPORT_SYMBOL(security_secctx_to_secid);
 
 /**
  * security_release_secctx() - Free a secctx buffer
- * @secdata: secctx
- * @seclen: length of secctx
+ * @cp: the security context
  *
  * Release the security context.
  */
-void security_release_secctx(char *secdata, u32 seclen)
+void security_release_secctx(struct lsm_context *cp)
 {
-	call_void_hook(release_secctx, secdata, seclen);
+	call_void_hook(release_secctx, cp);
+	memset(cp, 0, sizeof(*cp));
 }
 EXPORT_SYMBOL(security_release_secctx);
 
@@ -4430,17 +4423,17 @@ EXPORT_SYMBOL(security_inode_setsecctx);
 /**
  * security_inode_getsecctx() - Get the security label of an inode
  * @inode: inode
- * @ctx: secctx
- * @ctxlen: length of secctx
+ * @cp: security context
  *
- * On success, returns 0 and fills out @ctx and @ctxlen with the security
- * context for the given @inode.
+ * On success, returns 0 and fills out @cp with the security context
+ * for the given @inode.
  *
  * Return: Returns 0 on success, error on failure.
  */
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+int security_inode_getsecctx(struct inode *inode, struct lsm_context *cp)
 {
-	return call_int_hook(inode_getsecctx, inode, ctx, ctxlen);
+	memset(cp, 0, sizeof(*cp));
+	return call_int_hook(inode_getsecctx, inode, cp);
 }
 EXPORT_SYMBOL(security_inode_getsecctx);