cifs: do not include page data when checking signature

commit 30b2b2196d6e4cc24cbec633535a2404f258ce69 upstream.

On async reads, page data is allocated before sending.  When the
response is received but it has no data to fill (e.g.
STATUS_END_OF_FILE), __calc_signature() will still include the pages in
its computation, leading to an invalid signature check.

This patch fixes this by not setting the async read smb_rqst page data
(zeroed by default) if its got_bytes is 0.

This can be reproduced/verified with xfstests generic/465.

Cc: <stable@vger.kernel.org>
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 727f16b..92f3905 100644 (file)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -4162,12 +4162,15 @@ smb2_readv_callback(struct mid_q_entry *mid)
                                (struct smb2_hdr *)rdata->iov[0].iov_base;
        struct cifs_credits credits = { .value = 0, .instance = 0 };
        struct smb_rqst rqst = { .rq_iov = &rdata->iov[1],
-                                .rq_nvec = 1,
-                                .rq_pages = rdata->pages,
-                                .rq_offset = rdata->page_offset,
-                                .rq_npages = rdata->nr_pages,
-                                .rq_pagesz = rdata->pagesz,
-                                .rq_tailsz = rdata->tailsz };
+                                .rq_nvec = 1, };
+
+       if (rdata->got_bytes) {
+               rqst.rq_pages = rdata->pages;
+               rqst.rq_offset = rdata->page_offset;
+               rqst.rq_npages = rdata->nr_pages;
+               rqst.rq_pagesz = rdata->pagesz;
+               rqst.rq_tailsz = rdata->tailsz;
+       }
 
        WARN_ONCE(rdata->server != mid->server,
                  "rdata server %p != mid server %p",