FAILED: patch "[PATCH] selinux: reject a permission value exceeding the class" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x d14b5d0e97fccd27974fedc03b903408872907fd
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026082039-vindicate-eel-90a8@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d14b5d0e97fccd27974fedc03b903408872907fd Mon Sep 17 00:00:00 2001
From: Bryam Vargas <[email protected]>
Date: Mon, 27 Jul 2026 20:30:58 -0500
Subject: [PATCH] selinux: reject a permission value exceeding the class
permission count

perm_read() bounds a permission value by SEL_VEC_MAX but never by the nprim of the owning class or common, which is taken verbatim from the policy image. security_get_permissions() then writes perms[value - 1] into an nprim-sized kcalloc() array, so a class declaring fewer permissions than its largest permission value drives an out-of-bounds heap write. The top-level symbol tables are validated this way; the nested per-class permission table is not.

Reject a permission whose value exceeds nprim, which is already set when perm_read() runs. Well-formed policies are unaffected.

index ead504a639e3..5ff4d095ec2e 100644
@@ -1175,6 +1175,9 @@ static int perm_read(struct policydb *p, struct symtab *s, struct policy_file *f
 	rc = -EINVAL;
 	if (perdatum->value < 1 || perdatum->value > SEL_VEC_MAX)
 		goto bad;
+	/* indexes an nprim-sized array in security_get_permissions() */
+	if (perdatum->value > s->nprim)
+		goto bad;
 
 	rc = str_read(&key, GFP_KERNEL, fp, len);
 	if (rc)