Jeff Layton 51ddb84baf nfsd: don't replace page in rq_pages if it's a continuation of last page
[ Upstream commit 27c934dd8832dd40fd34776f916dc201e18b319b ]

The splice read calls nfsd_splice_actor to put the pages containing file
data into the svc_rqst->rq_pages array. It's possible however to get a
splice result that only has a partial page at the end, if (e.g.) the
filesystem hands back a short read that doesn't cover the whole page.

nfsd_splice_actor will plop the partial page into its rq_pages array and
return. Then later, when nfsd_splice_actor is called again, the
remainder of the page may end up being filled out. At this point,
nfsd_splice_actor will put the page into the array _again_ corrupting
the reply. If this is done enough times, rq_next_page will overrun the
array and corrupt the trailing fields -- the rq_respages and
rq_next_page pointers themselves.

If we've already added the page to the array in the last pass, don't add
it to the array a second time when dealing with a splice continuation.
This was originally handled properly in nfsd_splice_actor, but commit
91e23b1c3982 ("NFSD: Clean up nfsd_splice_actor()") removed the check
for it.

Fixes: 91e23b1c3982 ("NFSD: Clean up nfsd_splice_actor()")
Cc: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: Dario Lesca <d.lesca@solinos.it>
Tested-by: David Critch <dcritch@redhat.com>
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2150630
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30 12:49:04 +02:00
..
2023-03-22 13:33:59 +01:00
2023-01-07 11:11:40 +01:00
2022-09-24 07:00:00 +02:00
2022-10-10 19:45:17 -07:00
2022-09-11 20:26:07 -07:00
2022-10-06 17:36:48 -07:00
2023-02-22 12:59:46 +01:00
2022-09-24 07:00:00 +02:00
2022-08-20 11:34:33 -04:00
2022-10-10 19:45:17 -07:00
2022-10-29 17:49:33 -07:00
2022-10-10 14:21:11 -07:00
2022-08-03 10:35:43 -07:00
2023-01-04 11:29:01 +01:00