[PATCH 6.6 091/111] rxrpc: Fix transmission of an abort in response to an abort

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells at redhat.com>

[ Upstream commit e9c0b96ec0a34fcacdf9365713578d83cecac34c ]

Under some circumstances, such as when a server socket is closing, ABORT
packets will be generated in response to incoming packets.  Unfortunately,
this also may include generating aborts in response to incoming aborts -
which may cause a cycle.  It appears this may be made possible by giving
the client a multicast address.

Fix this such that rxrpc_reject_packet() will refuse to generate aborts in
response to aborts.

Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells at redhat.com>
Reviewed-by: Jeffrey Altman <jaltman at auristor.com>
cc: Marc Dionne <marc.dionne at auristor.com>
cc: Junvyyang, Tencent Zhuque Lab <zhuque at tencent.com>
cc: LePremierHomme <kwqcheii at proton.me>
cc: Linus Torvalds <torvalds at linux-foundation.org>
cc: Simon Horman <horms at kernel.org>
cc: linux-afs at lists.infradead.org
Link: https://patch.msgid.link/20250717074350.3767366-5-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba at kernel.org>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 net/rxrpc/output.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index cad6a7d18e040..4bbb27a48bd8a 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -589,6 +589,9 @@ void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
 	__be32 code;
 	int ret, ioc;
 
+	if (sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
+		return; /* Never abort an abort. */
+
 	rxrpc_see_skb(skb, rxrpc_skb_see_reject);
 
 	iov[0].iov_base = &whdr;
-- 
2.39.5