[PATCH 6.1.y] rxrpc: Fix key quota calculation for multitoken keys

[Sasha Levin <sashal@kernel.org>]

From: David Howells <dhowells@redhat.com>

[ Upstream commit bdbfead6d38979475df0c2f4bad2b19394fe9bdc ]

In the rxrpc key preparsing, every token extracted sets the proposed quota
value, but for multitoken keys, this will overwrite the previous proposed
quota, losing it.

Fix this by adding to the proposed quota instead.

Fixes: 8a7a3eb4ddbe ("KEYS: RxRPC: Use key preparsing")
Closes: https://sashiko.dev/#/patchset/20260319150150.4189381-1-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/20260408121252.2249051-2-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ dropped hunk for rxrpc_preparse_xdr_yfs_rxgk() ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/rxrpc/key.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/rxrpc/key.c b/net/rxrpc/key.c
index 8d2073e0e3da5..e0e2bf7d5a1d5 100644
--- a/net/rxrpc/key.c
+++ b/net/rxrpc/key.c
@@ -72,7 +72,7 @@ static int rxrpc_preparse_xdr_rxkad(struct key_preparsed_payload *prep,
 		return -EKEYREJECTED;
 
 	plen = sizeof(*token) + sizeof(*token->kad) + tktlen;
-	prep->quotalen = datalen + plen;
+	prep->quotalen += datalen + plen;
 
 	plen -= sizeof(*token);
 	token = kzalloc(sizeof(*token), GFP_KERNEL);
@@ -303,6 +303,7 @@ static int rxrpc_preparse(struct key_preparsed_payload *prep)
 	memcpy(&kver, prep->data, sizeof(kver));
 	prep->data += sizeof(kver);
 	prep->datalen -= sizeof(kver);
+	prep->quotalen = 0;
 
 	_debug("KEY I/F VERSION: %u", kver);
 
@@ -340,7 +341,7 @@ static int rxrpc_preparse(struct key_preparsed_payload *prep)
 		goto error;
 
 	plen = sizeof(*token->kad) + v1->ticket_length;
-	prep->quotalen = plen + sizeof(*token);
+	prep->quotalen += plen + sizeof(*token);
 
 	ret = -ENOMEM;
 	token = kzalloc(sizeof(*token), GFP_KERNEL);
-- 
2.53.0