cifs: fix NULL deref in SMB2_read

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Ronnie Sahlberg 2017-11-21 09:36:33 +11:00 committed by Steve French
parent 328b4ed93b
commit a821df3f1a

View file

@ -2678,27 +2678,27 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
cifs_small_buf_release(req);
rsp = (struct smb2_read_rsp *)rsp_iov.iov_base;
shdr = get_sync_hdr(rsp);
if (shdr->Status == STATUS_END_OF_FILE) {
free_rsp_buf(resp_buftype, rsp_iov.iov_base);
return 0;
}
if (rc) {
cifs_stats_fail_inc(io_parms->tcon, SMB2_READ_HE);
cifs_dbg(VFS, "Send error in read = %d\n", rc);
} else {
*nbytes = le32_to_cpu(rsp->DataLength);
if ((*nbytes > CIFS_MAX_MSGSIZE) ||
(*nbytes > io_parms->length)) {
cifs_dbg(FYI, "bad length %d for count %d\n",
*nbytes, io_parms->length);
rc = -EIO;
*nbytes = 0;
if (rc != -ENODATA) {
cifs_stats_fail_inc(io_parms->tcon, SMB2_READ_HE);
cifs_dbg(VFS, "Send error in read = %d\n", rc);
}
free_rsp_buf(resp_buftype, rsp_iov.iov_base);
return rc == -ENODATA ? 0 : rc;
}
*nbytes = le32_to_cpu(rsp->DataLength);
if ((*nbytes > CIFS_MAX_MSGSIZE) ||
(*nbytes > io_parms->length)) {
cifs_dbg(FYI, "bad length %d for count %d\n",
*nbytes, io_parms->length);
rc = -EIO;
*nbytes = 0;
}
shdr = get_sync_hdr(rsp);
if (*buf) {
memcpy(*buf, (char *)shdr + rsp->DataOffset, *nbytes);
free_rsp_buf(resp_buftype, rsp_iov.iov_base);