FAILED: patch "[PATCH] selinux: change security_compute_sid to return the ssid or" failed to apply to 6.12-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.12-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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x fde46f60f6c5138ee422087addbc5bf5b4968bf1
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025063004-landslide-grinning-5ff4@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From fde46f60f6c5138ee422087addbc5bf5b4968bf1 Mon Sep 17 00:00:00 2001
From: Stephen Smalley <stephen.smalley.work@gmail.com>
Date: Tue, 10 Jun 2025 15:48:27 -0400
Subject: [PATCH] selinux: change security_compute_sid to return the ssid or
 tsid on match

If the end result of a security_compute_sid() computation matches the
ssid or tsid, return that SID rather than looking it up again. This
avoids the problem of multiple initial SIDs that map to the same
context.

Cc: stable@vger.kernel.org
Reported-by: Guido Trentalancia <guido@trentalancia.com>
Fixes: ae254858ce07 ("selinux: introduce an initial SID for early boot processes")
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Tested-by: Guido Trentalancia <guido@trentalancia.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 7becf3808818..d185754c2786 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -1909,11 +1909,17 @@ static int security_compute_sid(u32 ssid,
 			goto out_unlock;
 	}
 	/* Obtain the sid for the context. */
-	rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid);
-	if (rc == -ESTALE) {
-		rcu_read_unlock();
-		context_destroy(&newcontext);
-		goto retry;
+	if (context_equal(scontext, &newcontext))
+		*out_sid = ssid;
+	else if (context_equal(tcontext, &newcontext))
+		*out_sid = tsid;
+	else {
+		rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid);
+		if (rc == -ESTALE) {
+			rcu_read_unlock();
+			context_destroy(&newcontext);
+			goto retry;
+		}
 	}
 out_unlock:
 	rcu_read_unlock();