2 files changed, 9 insertions, 5 deletions

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index 9df9f0b48160..68ea8491c160 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -94,7 +94,8 @@ static const __le16 smb2_rsp_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
 };
 
 #ifdef CONFIG_CIFS_SMB311
-static __u32 get_neg_ctxt_len(struct smb2_hdr *hdr, __u32 len, __u32 non_ctxlen)
+static __u32 get_neg_ctxt_len(struct smb2_hdr *hdr, __u32 len, __u32 non_ctxlen,
+                                size_t hdr_preamble_size)
 {
         __u16 neg_count;
         __u32 nc_offset, size_of_pad_before_neg_ctxts;
@@ -108,11 +109,12 @@ static __u32 get_neg_ctxt_len(struct smb2_hdr *hdr, __u32 len, __u32 non_ctxlen)
 
         /* Make sure that negotiate contexts start after gss security blob */
         nc_offset = le32_to_cpu(pneg_rsp->NegotiateContextOffset);
-        if (nc_offset < non_ctxlen - 4 /* RFC1001 len field */) {
+        if (nc_offset < non_ctxlen - hdr_preamble_size /* RFC1001 len */) {
                 printk_once(KERN_WARNING "invalid negotiate context offset\n");
                 return 0;
         }
-        size_of_pad_before_neg_ctxts = nc_offset - (non_ctxlen - 4);
+        size_of_pad_before_neg_ctxts = nc_offset -
+                                        (non_ctxlen - hdr_preamble_size);
 
         /* Verify that at least minimal negotiate contexts fit within frame */
         if (len < nc_offset + (neg_count * sizeof(struct smb2_neg_context))) {
@@ -235,7 +237,8 @@ smb2_check_message(char *buf, unsigned int length, struct TCP_Server_Info *srvr)
 
 #ifdef CONFIG_CIFS_SMB311
         if (shdr->Command == SMB2_NEGOTIATE)
-                clc_len += get_neg_ctxt_len(hdr, len, clc_len);
+                clc_len += get_neg_ctxt_len(hdr, len, clc_len,
+                                        srvr->vals->header_preamble_size);
 #endif /* SMB311 */
         if (srvr->vals->header_preamble_size + len != clc_len) {
                 cifs_dbg(FYI, "Calculated size %u length %zu mismatch mid %llu\n",
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 5cbdddcafaec..be44c5c3e77e 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -474,7 +474,8 @@ static int smb311_decode_neg_context(struct smb2_negotiate_rsp *rsp,
                 if (len_of_ctxts < sizeof(struct smb2_neg_context))
                         break;
 
-                pctx = (struct smb2_neg_context *)(offset + 4 + (char *)rsp);
+                pctx = (struct smb2_neg_context *)(offset +
+                        server->vals->header_preamble_size + (char *)rsp);
                 clen = le16_to_cpu(pctx->DataLength);
                 if (clen > len_of_ctxts)
                         break;