Patch "cifs: fix NULL deref in SMB2_read" has been added to the 4.14-stable tree

Patch "cifs: fix NULL deref in SMB2_read" has been added to the 4.14-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    cifs: fix NULL deref in SMB2_read

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     cifs-fix-null-deref-in-smb2_read.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From a821df3f1af72aa6a0d573eea94a7dd2613e9f4e Mon Sep 17 00:00:00 2001
From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Tue, 21 Nov 2017 09:36:33 +1100
Subject: cifs: fix NULL deref in SMB2_read

From: Ronnie Sahlberg <lsahlber@redhat.com>

commit a821df3f1af72aa6a0d573eea94a7dd2613e9f4e upstream.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/cifs/smb2pdu.c |   30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2678,27 +2678,27 @@ SMB2_read(const unsigned int xid, struct
 	cifs_small_buf_release(req);
 
 	rsp = (struct smb2_read_rsp *)rsp_iov.iov_base;
-	shdr = get_sync_hdr(rsp);
 
-	if (shdr->Status == STATUS_END_OF_FILE) {
+	if (rc) {
+		if (rc != -ENODATA) {
+			cifs_stats_fail_inc(io_parms->tcon, SMB2_READ_HE);
+			cifs_dbg(VFS, "Send error in read = %d\n", rc);
+		}
 		free_rsp_buf(resp_buftype, rsp_iov.iov_base);
-		return 0;
+		return rc == -ENODATA ? 0 : rc;
 	}
 
-	if (rc) {
-		cifs_stats_fail_inc(io_parms->tcon, SMB2_READ_HE);
-		cifs_dbg(VFS, "Send error in read = %d\n", rc);
-	} else {
-		*nbytes = le32_to_cpu(rsp->DataLength);
-		if ((*nbytes > CIFS_MAX_MSGSIZE) ||
-		    (*nbytes > io_parms->length)) {
-			cifs_dbg(FYI, "bad length %d for count %d\n",
-				 *nbytes, io_parms->length);
-			rc = -EIO;
-			*nbytes = 0;
-		}
+	*nbytes = le32_to_cpu(rsp->DataLength);
+	if ((*nbytes > CIFS_MAX_MSGSIZE) ||
+	    (*nbytes > io_parms->length)) {
+		cifs_dbg(FYI, "bad length %d for count %d\n",
+			 *nbytes, io_parms->length);
+		rc = -EIO;
+		*nbytes = 0;
 	}
 
+	shdr = get_sync_hdr(rsp);
+
 	if (*buf) {
 		memcpy(*buf, (char *)shdr + rsp->DataOffset, *nbytes);
 		free_rsp_buf(resp_buftype, rsp_iov.iov_base);


Patches currently in stable-queue which might be from lsahlber@redhat.com are

queue-4.14/cifs-fix-null-deref-in-smb2_read.patch