FAILED: patch "[PATCH] rxrpc: Fix conn-level packet handling to unshare RESPONSE" failed to apply to 5.15-stable tree

gregkh
2026-05-01T12:02:13Z

The patch below does not apply to the 5.15-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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 24481a7f573305706054c59e275371f8d0fe919f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026050110-amplify-sadly-0de4@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 24481a7f573305706054c59e275371f8d0fe919f Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Wed, 22 Apr 2026 17:14:33 +0100
Subject: [PATCH] rxrpc: Fix conn-level packet handling to unshare RESPONSE
packets

The security operations that verify the RESPONSE packets decrypt bits of it
in place - however, the sk_buff may be shared with a packet sniffer, which
would lead to the sniffer seeing an apparently corrupt packet (actually
decrypted).

Fix this by handing a copy of the packet off to the specific security
handler if the packet was cloned.

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Closes: https://sashiko.dev/#/patchset/20260408121252.2249051-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Jeffrey Altman <jaltman@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
cc: stable@kernel.org
Link: https://patch.msgid.link/20260422161438.2593376-5-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index 9a41ec708aeb..aee977291d90 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -240,6 +240,33 @@ static void rxrpc_call_is_secure(struct rxrpc_call *call)
rxrpc_notify_socket(call);
}

+static int rxrpc_verify_response(struct rxrpc_connection *conn,
+ struct sk_buff *skb)
+{
+ int ret;
+
+ if (skb_cloned(skb)) {
+ /* Copy the packet if shared so that we can do in-place
+ * decryption.
+ */
+ struct sk_buff *nskb = skb_copy(skb, GFP_NOFS);
+
+ if (nskb) {
+ rxrpc_new_skb(nskb, rxrpc_skb_new_unshared);
+ ret = conn->security->verify_response(conn, nskb);
+ rxrpc_free_skb(nskb, rxrpc_skb_put_response_copy);
+ } else {
+ /* OOM - Drop the packet. */
+ rxrpc_see_skb(skb, rxrpc_skb_see_unshare_nomem);
+ ret = -ENOMEM;
+ }
+ } else {
+ ret = conn->security->verify_response(conn, skb);
+ }
+
+ return ret;
+}
+
/*
* connection-level Rx packet processor
*/
@@ -270,7 +297,7 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
}
spin_unlock_irq(&conn->state_lock);

- ret = conn->security->verify_response(conn, skb);
+ ret = rxrpc_verify_response(conn, skb);
if (ret < 0)
return ret;