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/bridge/netfilter/ebtables.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'net/bridge') diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 91180a7fc943..24c7c96bf5f8 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1117,6 +1117,8 @@ static int do_replace(struct net *net, const void __user *user, return -ENOMEM; if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter)) return -ENOMEM; + if (tmp.num_counters == 0) + return -EINVAL; tmp.name[sizeof(tmp.name) - 1] = 0; @@ -2159,6 +2161,8 @@ static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl, return -ENOMEM; if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter)) return -ENOMEM; + if (tmp.num_counters == 0) + return -EINVAL; memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry)); -- cgit v1.2.3