Azure does not send an SPNEGO blob in the negotiate protocol response,
so we shouldn't assume that it is there when validating the location
of the first negotiate context. This avoids the potential confusing
mount warning:
CIFS: Invalid negotiate context offset
CC: Stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
fs/cifs/smb2misc.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index d88e2683626e..513507e4c4ad 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -109,11 +109,14 @@ static __u32 get_neg_ctxt_len(struct
smb2_sync_hdr *hdr, __u32 len,
/* Make sure that negotiate contexts start after gss security blob */
nc_offset = le32_to_cpu(pneg_rsp->NegotiateContextOffset);
- if (nc_offset < non_ctxlen) {
- pr_warn_once("Invalid negotiate context offset\n");
+ if (nc_offset + 1 < non_ctxlen) {
+ pr_warn_once("Invalid negotiate context offset %d\n", nc_offset);
return 0;
- }
- size_of_pad_before_neg_ctxts = nc_offset - non_ctxlen;
+ } else if (nc_offset + 1 == non_ctxlen) {
+ cifs_dbg(FYI, "no SPNEGO security blob in negprot rsp\n");
+ size_of_pad_before_neg_ctxts = 0;
+ } else
+ size_of_pad_before_neg_ctxts = nc_offset - non_ctxlen;
/* Verify that at least minimal negotiate contexts fit within frame */
if (len < nc_offset + (neg_count * sizeof(struct smb2_neg_context))) {
--
Thanks,
Steve
From a26c67744b1ad06209dbf0b37aac306c1f3c7a8d Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Wed, 9 Dec 2020 01:12:35 -0600
Subject: [PATCH] SMB3.1.1: remove confusing mount warning when no SPNEGO info
on negprot rsp
Azure does not send an SPNEGO blob in the negotiate protocol response,
so we shouldn't assume that it is there when validating the location
of the first negotiate context. This avoids the potential confusing
mount warning:
CIFS: Invalid negotiate context offset
CC: Stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
fs/cifs/smb2misc.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index d88e2683626e..513507e4c4ad 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -109,11 +109,14 @@ static __u32 get_neg_ctxt_len(struct smb2_sync_hdr *hdr, __u32 len,
/* Make sure that negotiate contexts start after gss security blob */
nc_offset = le32_to_cpu(pneg_rsp->NegotiateContextOffset);
- if (nc_offset < non_ctxlen) {
- pr_warn_once("Invalid negotiate context offset\n");
+ if (nc_offset + 1 < non_ctxlen) {
+ pr_warn_once("Invalid negotiate context offset %d\n", nc_offset);
return 0;
- }
- size_of_pad_before_neg_ctxts = nc_offset - non_ctxlen;
+ } else if (nc_offset + 1 == non_ctxlen) {
+ cifs_dbg(FYI, "no SPNEGO security blob in negprot rsp\n");
+ size_of_pad_before_neg_ctxts = 0;
+ } else
+ size_of_pad_before_neg_ctxts = nc_offset - non_ctxlen;
/* Verify that at least minimal negotiate contexts fit within frame */
if (len < nc_offset + (neg_count * sizeof(struct smb2_neg_context))) {
--
2.27.0
