From 2c8ac66bb2ff89e759f0d632a27cc64205e9ddd9 Mon Sep 17 00:00:00 2001 From: Solar Designer Date: Fri, 19 May 2006 02:16:52 -0700 Subject: [NETFILTER]: Fix do_add_counters race, possible oops or info leak (CVE-2006-0039) Solar Designer found a race condition in do_add_counters(). The beginning of paddc is supposed to be the same as tmp which was sanity-checked above, but it might not be the same in reality. In case the integer overflow and/or the race condition are triggered, paddc->num_counters might not match the allocation size for paddc. If the check below (t->private->number != paddc->num_counters) nevertheless passes (perhaps this requires the race condition to be triggered), IPT_ENTRY_ITERATE() would read kernel memory beyond the allocation size, potentially causing an oops or leaking sensitive data (e.g., passwords from host system or from another VPS) via counter increments. This requires CAP_NET_ADMIN. Signed-off-by: Solar Designer Signed-off-by: Kirill Korotaev Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index c2d92f9..d0d1919 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -948,7 +948,7 @@ static int do_add_counters(void __user *user, unsigned int len) write_lock_bh(&t->lock); private = t->private; - if (private->number != paddc->num_counters) { + if (private->number != tmp.num_counters) { ret = -EINVAL; goto unlock_up_free; } diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 0a67303..2e72f89 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -1103,7 +1103,7 @@ do_add_counters(void __user *user, unsigned int len) write_lock_bh(&t->lock); private = t->private; - if (private->number != paddc->num_counters) { + if (private->number != tmp.num_counters) { ret = -EINVAL; goto unlock_up_free; } -- cgit v0.10.2