From b29c457a6511435960115c0f548c4360d5f4801d Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 7 Apr 2021 21:38:57 +0200 Subject: netfilter: x_tables: fix compat match/target pad out-of-bound write xt_compat_match/target_from_user doesn't check that zeroing the area to start of next rule won't write past end of allocated ruleset blob. Remove this code and zero the entire blob beforehand. Reported-by: syzbot+cfc0247ac173f597aaaa@syzkaller.appspotmail.com Reported-by: Andy Nguyen Fixes: 9fa492cdc160c ("[NETFILTER]: x_tables: simplify compat API") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/arp_tables.c | 2 ++ net/ipv4/netfilter/ip_tables.c | 2 ++ 2 files changed, 4 insertions(+) (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 6c26533480dd..d6d45d820d79 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -1193,6 +1193,8 @@ static int translate_compat_table(struct net *net, if (!newinfo) goto out_unlock; + memset(newinfo->entries, 0, size); + newinfo->number = compatr->num_entries; for (i = 0; i < NF_ARP_NUMHOOKS; i++) { newinfo->hook_entry[i] = compatr->hook_entry[i]; diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index f15bc21d7301..f77ea0dbe656 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -1428,6 +1428,8 @@ translate_compat_table(struct net *net, if (!newinfo) goto out_unlock; + memset(newinfo->entries, 0, size); + newinfo->number = compatr->num_entries; for (i = 0; i < NF_INET_NUMHOOKS; i++) { newinfo->hook_entry[i] = compatr->hook_entry[i]; -- cgit v1.2.3