diff options
| author | Pavel Shilovsky <pshilov@microsoft.com> | 2017-04-10 20:31:33 +0300 |
|---|---|---|
| committer | Steve French <smfrench@gmail.com> | 2017-04-11 07:36:38 +0300 |
| commit | 350be257ea83029daee974c72b1fe2e6f1f8e615 (patch) | |
| tree | c02cd0c1e5bdf4b1cb58b4dcd307f508f02fda73 /fs/cifs/cifssmb.c | |
| parent | c08e611b7d0169b513e3b4515ffd51ac7f37f22c (diff) | |
| download | linux-350be257ea83029daee974c72b1fe2e6f1f8e615.tar.xz | |
CIFS: Fix null pointer deref during read resp processing
Currently during receiving a read response mid->resp_buf can be
NULL when it is being passed to cifs_discard_remaining_data() from
cifs_readv_discard(). Fix it by always passing server->smallbuf
instead and initializing mid->resp_buf at the end of read response
processing.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Acked-by: Sachin Prabhu <sprabhu@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Diffstat (limited to 'fs/cifs/cifssmb.c')
| -rw-r--r-- | fs/cifs/cifssmb.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c index 967b92631807..5d21f00ae341 100644 --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -1400,9 +1400,9 @@ openRetry: * current bigbuf. */ int -cifs_discard_remaining_data(struct TCP_Server_Info *server, char *buf) +cifs_discard_remaining_data(struct TCP_Server_Info *server) { - unsigned int rfclen = get_rfc1002_length(buf); + unsigned int rfclen = get_rfc1002_length(server->smallbuf); int remaining = rfclen + 4 - server->total_read; while (remaining > 0) { @@ -1426,8 +1426,10 @@ cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid) int length; struct cifs_readdata *rdata = mid->callback_data; - length = cifs_discard_remaining_data(server, mid->resp_buf); + length = cifs_discard_remaining_data(server); dequeue_mid(mid, rdata->result); + mid->resp_buf = server->smallbuf; + server->smallbuf = NULL; return length; } @@ -1459,7 +1461,7 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid) if (server->ops->is_status_pending && server->ops->is_status_pending(buf, server, 0)) { - cifs_discard_remaining_data(server, buf); + cifs_discard_remaining_data(server); return -1; } @@ -1519,9 +1521,6 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid) cifs_dbg(FYI, "0: iov_base=%p iov_len=%u\n", rdata->iov[0].iov_base, server->total_read); - mid->resp_buf = server->smallbuf; - server->smallbuf = NULL; - /* how much data is in the response? */ data_len = server->ops->read_data_length(buf); if (data_offset + data_len > buflen) { @@ -1544,6 +1543,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid) return cifs_readv_discard(server, mid); dequeue_mid(mid, false); + mid->resp_buf = server->smallbuf; + server->smallbuf = NULL; return length; } |