[CIFS] Fix buffer overflow if server sends corrupt response to small

request

In SendReceive() function in transport.c - it memcpy's
message payload into a buffer passed via out_buf param. The function
assumes that all buffers are of size (CIFSMaxBufSize +
MAX_CIFS_HDR_SIZE) , unfortunately it is also called with smaller
(MAX_CIFS_SMALL_BUFFER_SIZE) buffers.  There are eight callers
(SMB worker functions) which are primarily affected by this change:

TreeDisconnect, uLogoff, Close, findClose, SetFileSize, SetFileTimes,
Lock and PosixLock

CC: Dave Kleikamp <shaggy@austin.ibm.com>
CC: Przemyslaw Wegrzyn <czajnik@czajsoft.pl>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 87f51f23276..4ff8179df7e 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -471,6 +471,17 @@ struct dir_notify_req {
 #define   CIFS_LARGE_BUFFER     2
 #define   CIFS_IOVEC            4    /* array of response buffers */
 
+/* Type of Request to SendReceive2 */
+#define   CIFS_STD_OP           0    /* normal request timeout */
+#define   CIFS_LONG_OP          1    /* long op (up to 45 sec, oplock time) */
+#define   CIFS_VLONG_OP         2    /* sloow op - can take up to 180 seconds */
+#define   CIFS_BLOCKING_OP      4    /* operation can block */
+#define   CIFS_ASYNC_OP         8    /* do not wait for response */
+#define   CIFS_TIMEOUT_MASK 0x00F    /* only one of 5 above set in req */
+#define   CIFS_LOG_ERROR    0x010    /* log NT STATUS if non-zero */
+#define   CIFS_LARGE_BUF_OP 0x020    /* large request buffer */
+#define   CIFS_NO_RESP      0x040    /* no response buffer required */
+
 /* Security Flags: indicate type of session setup needed */
 #define   CIFSSEC_MAY_SIGN      0x00001
 #define   CIFSSEC_MAY_NTLM      0x00002