| From | Paul Gortmaker <> | Subject | [34-longterm 171/196] cifs: check for bytes_remaining going to zero in CIFS_SessSetup | Date | Mon, 12 Mar 2012 20:21:24 -0400 |
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From: Jeff Layton <jlayton@redhat.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
commit fcda7f4578bbf9717444ca6da8a421d21489d078 upstream.
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.
Reported-and-Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- fs/cifs/sess.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c index c7d78c0..ff4f5b1 100644 --- a/fs/cifs/sess.c +++ b/fs/cifs/sess.c @@ -906,7 +906,9 @@ 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; -- 1.7.9.3
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