CIFS: Clarify SMB1 code for POSIX delete file

Coverity also complains about the way we calculate the offset
(starting from the address of a 4 byte array within the
header structure rather than from the beginning of the struct
plus 4 bytes) for SMB1 CIFSPOSIXDelFile. This changeset
doesn't change the address but makes it slightly clearer.

Addresses-Coverity: 711519 ("Out of bounds write")
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index d4144c1..65d1a65 100644 (file)
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -873,8 +873,11 @@ PsxDelete:
                                InformationLevel) - 4;
        offset = param_offset + params;
 
-       /* Setup pointer to Request Data (inode type) */
-       pRqD = (struct unlink_psx_rq *)(((char *)&pSMB->hdr.Protocol) + offset);
+       /* Setup pointer to Request Data (inode type).
+        * Note that SMB offsets are from the beginning of SMB which is 4 bytes
+        * in, after RFC1001 field
+        */
+       pRqD = (struct unlink_psx_rq *)((char *)(pSMB) + offset + 4);
        pRqD->type = cpu_to_le16(type);
        pSMB->ParameterOffset = cpu_to_le16(param_offset);
        pSMB->DataOffset = cpu_to_le16(offset);