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Commit 3845c736 authored by Dan Carpenter's avatar Dan Carpenter Committed by Greg Kroah-Hartman
Browse files

cifs: integer overflow in in SMB2_ioctl() 



commit 2d204ee9d671327915260071c19350d84344e096 upstream

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: 4a72dafa ("SMB2 FSCTL and IOCTL worker function")
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
Reviewed-by: default avatarAurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: default avatarSudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 0d9b5136

fs/cifs/smb2pdu.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -2020,14 +2020,14 @@ 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 */

	/* We check for obvious errors in the output buffer length and offset */

	if (*plen == 0)

	if (*plen == 0)

		goto ioctl_exit; /* server returned no data */

		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);

		cifs_dbg(VFS, "srv returned invalid ioctl length: %d\n", *plen);

		*plen = 0;

		*plen = 0;

		rc = -EIO;

		rc = -EIO;

		goto ioctl_exit;

		goto ioctl_exit;

	}

	}





	if (get_rfc1002_length(rsp) < le32_to_cpu(rsp->OutputOffset) + *plen) {

	if (get_rfc1002_length(rsp) - *plen < le32_to_cpu(rsp->OutputOffset)) {

		cifs_dbg(VFS, "Malformed ioctl resp: len %d offset %d\n", *plen,

		cifs_dbg(VFS, "Malformed ioctl resp: len %d offset %d\n", *plen,

			le32_to_cpu(rsp->OutputOffset));

			le32_to_cpu(rsp->OutputOffset));

		*plen = 0;

		*plen = 0;