diff options
| author | Jeff Layton | 2023-03-17 13:13:08 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2023-03-30 12:49:04 +0200 |
| commit | 51ddb84baff6f09ad62b5999ece3ec172e4e3568 (patch) | |
| tree | 5d2de3cad01a79f89c106ad3fb422bba8496f0ac /fs/nfsd | |
| parent | 1c55982beb80c7d3c30278fc6cfda8496a31dbe6 (diff) | |
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>
Diffstat (limited to 'fs/nfsd')
| -rw-r--r-- | fs/nfsd/vfs.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 59f9a8cee012..dc3ba13546dd 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -874,8 +874,15 @@ nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, struct page *last_page; last_page = page + (offset + sd->len - 1) / PAGE_SIZE; - for (page += offset / PAGE_SIZE; page <= last_page; page++) + for (page += offset / PAGE_SIZE; page <= last_page; page++) { + /* + * Skip page replacement when extending the contents + * of the current page. + */ + if (page == *(rqstp->rq_next_page - 1)) + continue; svc_rqst_replace_page(rqstp, page); + } if (rqstp->rq_res.page_len == 0) // first call rqstp->rq_res.page_base = offset % PAGE_SIZE; rqstp->rq_res.page_len += sd->len; |