FAILED: patch "[PATCH] cifs: integer overflow in in SMB2_ioctl()" failed to apply to 4.4-stable tree

PATCH [email protected] 1 participant 1 message Sep 24, 2018 Stable branch

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author maintainer

2018-09-24 01:26 UTC #0 lore raw

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 2d204ee9d671327915260071c19350d84344e096 Mon Sep 17 00:00:00 2001

From: Dan Carpenter <[email protected]>
Date: Mon, 10 Sep 2018 14:12:07 +0300
Subject: [PATCH] cifs: integer overflow in in SMB2_ioctl()

The "le32_to_cpu(rsp->OutputOffset) + *plen" addition can overflow and wrap around to a smaller value which looks like it would lead to an information leak.

Fixes 4a72dafa19ba ("SMB2 FSCTL and IOCTL worker function")

Signed-off-by Dan Carpenter <[email protected]>

Signed-off-by Steve French <[email protected]>

Reviewed-by Aurelien Aptel <[email protected]>

CC Stable <[email protected]>

fs/cifs/smb2pdu.c +2 -2

index 6f0e6b42599c..f54d07bda067 100644
@@ -2459,14 +2459,14 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	/* We check for obvious errors in the output buffer length and offset */
 	if (*plen == 0)
 		goto ioctl_exit; /* server returned no data */
-	else if (*plen > 0xFF00) {
+	else if (*plen > rsp_iov.iov_len || *plen > 0xFF00) {
 		cifs_dbg(VFS, "srv returned invalid ioctl length: %d\n", *plen);
 		*plen = 0;
 		rc = -EIO;
 		goto ioctl_exit;
 	}
 
-	if (rsp_iov.iov_len < le32_to_cpu(rsp->OutputOffset) + *plen) {
+	if (rsp_iov.iov_len - *plen < le32_to_cpu(rsp->OutputOffset)) {
 		cifs_dbg(VFS, "Malformed ioctl resp: len %d offset %d\n", *plen,
 			le32_to_cpu(rsp->OutputOffset));
 		*plen = 0;