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, 19 insertions, 15 deletions

diff --git a/security/apparmor/secid.c b/security/apparmor/secid.c
index 47dc08fc583e..28caf66b9033 100644
--- a/security/apparmor/secid.c
+++ b/security/apparmor/secid.c
@@ -47,23 +47,21 @@ struct aa_label *aa_secid_to_label(u32 secid)
 	return xa_load(&aa_secids, secid);
 }
 
-static int apparmor_label_to_secctx(struct aa_label *label, char **secdata,
-				    u32 *seclen)
+static int apparmor_label_to_secctx(struct aa_label *label,
+				    struct lsm_context *cp)
 {
 	/* TODO: cache secctx and ref count so we don't have to recreate */
 	int flags = FLAG_VIEW_SUBNS | FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT;
 	int len;
 
-	AA_BUG(!seclen);
-
 	if (!label)
 		return -EINVAL;
 
 	if (apparmor_display_secid_mode)
 		flags |= FLAG_SHOW_MODE;
 
-	if (secdata)
-		len = aa_label_asxprint(secdata, root_ns, label,
+	if (cp)
+		len = aa_label_asxprint(&cp->context, root_ns, label,
 					flags, GFP_ATOMIC);
 	else
 		len = aa_label_snxprint(NULL, 0, root_ns, label, flags);
@@ -71,26 +69,28 @@ static int apparmor_label_to_secctx(struct aa_label *label, char **secdata,
 	if (len < 0)
 		return -ENOMEM;
 
-	*seclen = len;
+	if (cp) {
+		cp->len = len;
+		cp->id = LSM_ID_APPARMOR;
+	}
 
-	return 0;
+	return len;
 }
 
-int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+int apparmor_secid_to_secctx(u32 secid, struct lsm_context *cp)
 {
 	struct aa_label *label = aa_secid_to_label(secid);
 
-	return apparmor_label_to_secctx(label, secdata, seclen);
+	return apparmor_label_to_secctx(label, cp);
 }
 
-int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata,
-			       u32 *seclen)
+int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp)
 {
 	struct aa_label *label;
 
 	label = prop->apparmor.label;
 
-	return apparmor_label_to_secctx(label, secdata, seclen);
+	return apparmor_label_to_secctx(label, cp);
 }
 
 int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
@@ -106,9 +106,13 @@ int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
 	return 0;
 }
 
-void apparmor_release_secctx(char *secdata, u32 seclen)
+void apparmor_release_secctx(struct lsm_context *cp)
 {
-	kfree(secdata);
+	if (cp->id == LSM_ID_APPARMOR) {
+		kfree(cp->context);
+		cp->context = NULL;
+		cp->id = LSM_ID_UNDEF;
+	}
 }
 
 /**