It's possible that when we go to decode the string area in the
SESSION_SETUP response, that bytes_remaining will be 0. Decrementing it at
that point will mean that it can go "negative" and wrap. Check for a
bytes_remaining value of 0, and don't try to decode the string area if
that's the case.
Cc: stable@xxxxxxxxxx
Reported-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/cifs/sess.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 2e2c911..645114a 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -916,7 +916,9 @@ ssetup_ntlmssp_authenticate:
}
/* BB check if Unicode and decode strings */
- if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
+ if (bytes_remaining == 0) {
+ /* no string area to decode, do nothing */
+ } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
/* unicode string area must be word-aligned */
if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
++bcc_ptr;
--
1.7.4.4
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