From: Ronnie Sahlberg Date: Fri, 8 Sep 2017 00:37:35 +0000 (+1000) Subject: cifs: check rsp for NULL before dereferencing in SMB2_open X-Git-Tag: v4.13.5~110 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=aa4ccfd1e2726f0d71d0ad08aeea9efbc6601e48;p=users%2Fdwmw2%2Flinux.git cifs: check rsp for NULL before dereferencing in SMB2_open commit bf2afee14e07de16d3cafc67edbfc2a3cc65e4bc upstream. In SMB2_open there are several paths where the SendReceive2 call will return an error before it sets rsp_iov.iov_base thus leaving iov_base uninitialized. Thus we need to check rsp before we dereference it in the call to get_rfc1002_length(). A report of this issue was previously reported in http://www.spinics.net/lists/linux-cifs/msg12846.html RH-bugzilla : 1476151 Version 2 : * Lets properly initialize rsp_iov before we use it. Signed-off-by: Ronnie Sahlberg Reviewed-by: Pavel Shilovsky Signed-off-by: Steve French Reported-by: Xiaoli Feng Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 7aa67206f6da2..11a15d77b85b8 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -1622,7 +1622,7 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path, struct cifs_tcon *tcon = oparms->tcon; struct cifs_ses *ses = tcon->ses; struct kvec iov[4]; - struct kvec rsp_iov; + struct kvec rsp_iov = {NULL, 0}; int resp_buftype; int uni_path_len; __le16 *copy_path = NULL; @@ -1751,7 +1751,7 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path, if (rc != 0) { cifs_stats_fail_inc(tcon, SMB2_CREATE_HE); - if (err_buf) + if (err_buf && rsp) *err_buf = kmemdup(rsp, get_rfc1002_length(rsp) + 4, GFP_KERNEL); goto creat_exit;