| From: Dan Carpenter <dan.carpenter@oracle.com> |
| Date: Mon, 10 Sep 2018 14:12:07 +0300 |
| Subject: 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: 4a72dafa19ba ("SMB2 FSCTL and IOCTL worker function") |
| Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> |
| Signed-off-by: Steve French <stfrench@microsoft.com> |
| Reviewed-by: Aurelien Aptel <aaptel@suse.com> |
| [bwh: Backported to 3.16: Use get_rfc1002_length(rsp) instead of |
| rsp->iov.iov_len] |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| fs/cifs/smb2pdu.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/fs/cifs/smb2pdu.c |
| +++ b/fs/cifs/smb2pdu.c |
| @@ -1394,14 +1394,14 @@ SMB2_ioctl(const unsigned int xid, struc |
| /* 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 > get_rfc1002_length(rsp) || *plen > 0xFF00) { |
| cifs_dbg(VFS, "srv returned invalid ioctl length: %d\n", *plen); |
| *plen = 0; |
| rc = -EIO; |
| 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, |
| le32_to_cpu(rsp->OutputOffset)); |
| *plen = 0; |
