Subject: FAILED: patch "[PATCH] selinux: reject a permission value exceeding the class" failed to apply to 5.10-stable tree
To: hexlabsecurity@proton.me,paul@paul-moore.com,stephen.smalley.work@gmail.com
Cc: <stable@vger.kernel.org>
From: <gregkh@linuxfoundation.org>
Date: Thu, 20 Aug 2026 12:46:39 +0200
Message-ID: <2026082039-vindicate-eel-90a8@gregkh>
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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 <stable@vger.kernel.org>.

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 '<stable@vger.kernel.org>' --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 <hexlabsecurity@proton.me>
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.

Cc: stable@vger.kernel.org
Fixes: 55fcf09b3fe4 ("selinux: add support for querying object classes and permissions from the running policy")
Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
[PM: tweak comment for line length]
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index ead504a639e3..5ff4d095ec2e 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -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)