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From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	 Paolo Abeni <pabeni@redhat.com>,
	Pablo Neira Ayuso <pablo@netfilter.org>,
	 Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
	 coreteam@netfilter.org, eric.dumazet@gmail.com,
	 Eric Dumazet <edumazet@google.com>,
	syzbot <syzkaller@googlegroups.com>
Subject: [PATCH net] netfilter: complete validation of user input
Date: Tue,  9 Apr 2024 12:07:41 +0000	[thread overview]
Message-ID: <20240409120741.3538135-1-edumazet@google.com> (raw)

In my recent commit, I missed that do_replace() handlers
use copy_from_sockptr() (which I fixed), followed
by unsafe copy_from_sockptr_offset() calls.

In all functions, we can perform the @optlen validation
before even calling xt_alloc_table_info() with the following
check:

if ((u64)optlen < (u64)tmp.size + sizeof(tmp))
        return -EINVAL;

Fixes: 0c83842df40f ("netfilter: validate user input for expected length")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/netfilter/arp_tables.c | 4 ++++
 net/ipv4/netfilter/ip_tables.c  | 4 ++++
 net/ipv6/netfilter/ip6_tables.c | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index b150c9929b12e86219a55c77da480e0c538b3449..14365b20f1c5c09964dd7024060116737f22cb63 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -966,6 +966,8 @@ static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
 		return -ENOMEM;
 	if (tmp.num_counters == 0)
 		return -EINVAL;
+	if ((u64)len < (u64)tmp.size + sizeof(tmp))
+		return -EINVAL;
 
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
@@ -1266,6 +1268,8 @@ static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
 		return -ENOMEM;
 	if (tmp.num_counters == 0)
 		return -EINVAL;
+	if ((u64)len < (u64)tmp.size + sizeof(tmp))
+		return -EINVAL;
 
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 487670759578168c5ff53bce6642898fc41936b3..fe89a056eb06c43743b2d7449e59f4e9360ba223 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1118,6 +1118,8 @@ do_replace(struct net *net, sockptr_t arg, unsigned int len)
 		return -ENOMEM;
 	if (tmp.num_counters == 0)
 		return -EINVAL;
+	if ((u64)len < (u64)tmp.size + sizeof(tmp))
+		return -EINVAL;
 
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
@@ -1504,6 +1506,8 @@ compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
 		return -ENOMEM;
 	if (tmp.num_counters == 0)
 		return -EINVAL;
+	if ((u64)len < (u64)tmp.size + sizeof(tmp))
+		return -EINVAL;
 
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 636b360311c5365fba2330f6ca2f7f1b6dd1363e..131f7bb2110d3a08244c6da40ff9be45a2be711b 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1135,6 +1135,8 @@ do_replace(struct net *net, sockptr_t arg, unsigned int len)
 		return -ENOMEM;
 	if (tmp.num_counters == 0)
 		return -EINVAL;
+	if ((u64)len < (u64)tmp.size + sizeof(tmp))
+		return -EINVAL;
 
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
@@ -1513,6 +1515,8 @@ compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
 		return -ENOMEM;
 	if (tmp.num_counters == 0)
 		return -EINVAL;
+	if ((u64)len < (u64)tmp.size + sizeof(tmp))
+		return -EINVAL;
 
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
-- 
2.44.0.478.gd926399ef9-goog


             reply	other threads:[~2024-04-09 12:07 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-09 12:07 Eric Dumazet [this message]
2024-04-10  9:23 ` [PATCH net] netfilter: complete validation of user input Pablo Neira Ayuso
2024-04-11  2:50 ` patchwork-bot+netdevbpf

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