Commit 69293500 authored by David Howells's avatar David Howells Committed by Jakub Kicinski
Browse files

rxgk: Fix potential integer overflow in length check 

Fix potential integer overflow in rxgk_extract_token() when checking the
length of the ticket.  Rather than rounding up the value to be tested
(which might overflow), round down the size of the available data.

Fixes: 2429a197 ("rxrpc: Fix untrusted unsigned subtract")
Closes: https://sashiko.dev/#/patchset/20260408121252.2249051-1-dhowells%40redhat.com


Signed-off-by: default avatarDavid 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/20260422161438.2593376-6-dhowells@redhat.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 24481a7f

net/rxrpc/rxgk_app.c

+1 −1
Original line number Diff line number Diff line
@@ -214,7 +214,7 @@ int rxgk_extract_token(struct rxrpc_connection *conn, struct sk_buff *skb, 
	ticket_len	= ntohl(container.token_len);

	ticket_offset	= token_offset + sizeof(container);



	if (xdr_round_up(ticket_len) > token_len - sizeof(container))

	if (ticket_len > xdr_round_down(token_len - sizeof(container)))

		goto short_packet;



	_debug("KVNO %u", kvno);

net/rxrpc/rxgk_common.h

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ struct rxgk_context { 
};



#define xdr_round_up(x) (round_up((x), sizeof(__be32)))

#define xdr_round_down(x) (round_down((x), sizeof(__be32)))

#define xdr_object_len(x) (4 + xdr_round_up(x))



/*