From 4f36ea6eed2081340c7a7aa98c73187ecfccebff Mon Sep 17 00:00:00 2001 From: Chen Gang Date: Thu, 23 May 2013 01:50:46 +0000 Subject: [PATCH] netfilter: ipt_ULOG: fix non-null terminated string in the nf_log path If nf_log uses ipt_ULOG as logging output, we can deliver non-null terminated strings to user-space since the maximum length of the prefix that is passed by nf_log is NF_LOG_PREFIXLEN but pm->prefix is 32 bytes long (ULOG_PREFIX_LEN). This is actually happening already from nf_conntrack_tcp if ipt_ULOG is used, since it is passing strings longer than 32 bytes. Signed-off-by: Chen Gang Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/ipt_ULOG.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c index cf08218ddbcf..ff4b781b1056 100644 --- a/net/ipv4/netfilter/ipt_ULOG.c +++ b/net/ipv4/netfilter/ipt_ULOG.c @@ -231,8 +231,10 @@ static void ipt_ulog_packet(struct net *net, put_unaligned(tv.tv_usec, &pm->timestamp_usec); put_unaligned(skb->mark, &pm->mark); pm->hook = hooknum; - if (prefix != NULL) - strncpy(pm->prefix, prefix, sizeof(pm->prefix)); + if (prefix != NULL) { + strncpy(pm->prefix, prefix, sizeof(pm->prefix) - 1); + pm->prefix[sizeof(pm->prefix) - 1] = '\0'; + } else if (loginfo->prefix[0] != '\0') strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix)); else