linux-kernel - [PATCH 3/4] [SMB3] Fix dereference before null check warning

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1427434082-4299-4-git-send-email-smfrench@gmail.com>
Date:	Fri, 27 Mar 2015 00:28:01 -0500
From:	Steve French <smfrench@...il.com>
To:	linux-cifs@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	smfrench@...il.com
Subject: [PATCH 3/4] [SMB3] Fix dereference before null check warning

null tcon is not likely in these paths in current
code, but obviously it does clarify the code to
check for null (if at all) before derefrencing
rather than after.

Reported by Coverity (CID 1042666)

Signed-off-by: Steve French <smfrench@...il.com>
---
 fs/cifs/smb2pdu.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 1b906de..78b329f 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1218,7 +1218,7 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	struct smb2_ioctl_req *req;
 	struct smb2_ioctl_rsp *rsp;
 	struct TCP_Server_Info *server;
-	struct cifs_ses *ses = tcon->ses;
+	struct cifs_ses *ses;
 	struct kvec iov[2];
 	int resp_buftype;
 	int num_iovecs;
@@ -1233,6 +1233,11 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	if (plen)
 		*plen = 0;
 
+	if (tcon)
+		ses = tcon->ses;
+	else
+		return -EIO;
+
 	if (ses && (ses->server))
 		server = ses->server;
 	else
@@ -1296,14 +1301,12 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	rsp = (struct smb2_ioctl_rsp *)iov[0].iov_base;
 
 	if ((rc != 0) && (rc != -EINVAL)) {
-		if (tcon)
-			cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
+		cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
 		goto ioctl_exit;
 	} else if (rc == -EINVAL) {
 		if ((opcode != FSCTL_SRV_COPYCHUNK_WRITE) &&
 		    (opcode != FSCTL_SRV_COPYCHUNK)) {
-			if (tcon)
-				cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
+			cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
 			goto ioctl_exit;
 		}
 	}
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/