netdev - [PATCH net] packet: packet_getname_spkt: make sure string is always 0-terminated

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-next>] [day] [month] [year] [list]

Message-Id: <1371045747-15203-1-git-send-email-dborkman@redhat.com>
Date:	Wed, 12 Jun 2013 16:02:27 +0200
From:	Daniel Borkmann <dborkman@...hat.com>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org
Subject: [PATCH net] packet: packet_getname_spkt: make sure string is always 0-terminated

uaddr->sa_data is exactly of size 14, which is hard-coded here and
passed as a size argument to strncpy(). A device name can be of size
IFNAMSIZ (== 16), meaning we might leave the destination string
unterminated. Thus, use strlcpy() and also sizeof() while we're
at it. We need to memset the data area beforehand, since strlcpy
does not padd the remaining buffer with zeroes for user space, so
that we do not possibly leak anything.

Signed-off-by: Daniel Borkmann <dborkman@...hat.com>
---
 net/packet/af_packet.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 8ec1bca..20a1bd0 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2851,12 +2851,11 @@ static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr,
 		return -EOPNOTSUPP;
 
 	uaddr->sa_family = AF_PACKET;
+	memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data));
 	rcu_read_lock();
 	dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex);
 	if (dev)
-		strncpy(uaddr->sa_data, dev->name, 14);
-	else
-		memset(uaddr->sa_data, 0, 14);
+		strlcpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data));
 	rcu_read_unlock();
 	*uaddr_len = sizeof(*uaddr);
 
-- 
1.7.11.7

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html