From: Chen Gang <gang.chen@xxxxxxxxxxx>
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 <gang.chen@xxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
Cherry-pick: 4f36ea6eed2081340c7a7aa98c73187ecfccebff
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 7d168dc..3202b7d 100644
--- a/net/ipv4/netfilter/ipt_ULOG.c
+++ b/net/ipv4/netfilter/ipt_ULOG.c
@@ -215,8 +215,10 @@ static void ipt_ulog_packet(unsigned int hooknum,
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
--
1.7.10.4
--
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