From 1086bbe97a074844188c6c988fa0b1a98c3ccbb9 Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Tue, 19 May 2015 20:55:17 -0400 Subject: netfilter: ensure number of counters is >0 in do_replace() After improving setsockopt() coverage in trinity, I started triggering vmalloc failures pretty reliably from this code path: warn_alloc_failed+0xe9/0x140 __vmalloc_node_range+0x1be/0x270 vzalloc+0x4b/0x50 __do_replace+0x52/0x260 [ip_tables] do_ipt_set_ctl+0x15d/0x1d0 [ip_tables] nf_setsockopt+0x65/0x90 ip_setsockopt+0x61/0xa0 raw_setsockopt+0x16/0x60 sock_common_setsockopt+0x14/0x20 SyS_setsockopt+0x71/0xd0 It turns out we don't validate that the num_counters field in the struct we pass in from userspace is initialized. The same problem also exists in ebtables, arptables, ipv6, and the compat variants. Signed-off-by: Dave Jones Signed-off-by: Pablo Neira Ayuso --- net/ipv6/netfilter/ip6_tables.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'net/ipv6/netfilter/ip6_tables.c') diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 1a732a1d3c8e..62f5b0d0bc9b 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -1275,6 +1275,9 @@ do_replace(struct net *net, const void __user *user, unsigned int len) /* overflow check */ if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) return -ENOMEM; + if (tmp.num_counters == 0) + return -EINVAL; + tmp.name[sizeof(tmp.name)-1] = 0; newinfo = xt_alloc_table_info(tmp.size); @@ -1822,6 +1825,9 @@ compat_do_replace(struct net *net, void __user *user, unsigned int len) return -ENOMEM; if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) return -ENOMEM; + if (tmp.num_counters == 0) + return -EINVAL; + tmp.name[sizeof(tmp.name)-1] = 0; newinfo = xt_alloc_table_info(tmp.size); -- cgit v1.2.3-59-g8ed1b