[PATCH 6.18 62/83] rxrpc: Fix key quota calculation for multitoken keys

[Greg Kroah-Hartman]

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

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

From: David Howells <dhowells at redhat.com>

commit bdbfead6d38979475df0c2f4bad2b19394fe9bdc upstream.

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 at redhat.com>
cc: Marc Dionne <marc.dionne at auristor.com>
cc: Jeffrey Altman <jaltman at auristor.com>
cc: Simon Horman <horms at kernel.org>
cc: linux-afs at lists.infradead.org
cc: stable at kernel.org
Link: https://patch.msgid.link/20260408121252.2249051-2-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba at kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 net/rxrpc/key.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/net/rxrpc/key.c
+++ b/net/rxrpc/key.c
@@ -72,7 +72,7 @@ static int rxrpc_preparse_xdr_rxkad(stru
 		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);
@@ -199,7 +199,7 @@ static int rxrpc_preparse_xdr_yfs_rxgk(s
 	}
 
 	plen = sizeof(*token) + sizeof(*token->rxgk) + tktlen + keylen;
-	prep->quotalen = datalen + plen;
+	prep->quotalen += datalen + plen;
 
 	plen -= sizeof(*token);
 	token = kzalloc(sizeof(*token), GFP_KERNEL);
@@ -460,6 +460,7 @@ static int rxrpc_preparse(struct key_pre
 	memcpy(&kver, prep->data, sizeof(kver));
 	prep->data += sizeof(kver);
 	prep->datalen -= sizeof(kver);
+	prep->quotalen = 0;
 
 	_debug("KEY I/F VERSION: %u", kver);
 
@@ -497,7 +498,7 @@ static int rxrpc_preparse(struct key_pre
 		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);