netfilter: complete validation of user input

[ Upstream commit 65acf6e0501ac8880a4f73980d01b5d27648b956 ]

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>
Reviewed-by: Pablo Neira Ayuso <pablo@netfilter.org>
Link: https://lore.kernel.org/r/20240409120741.3538135-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index b150c9929b12e86219a55c77da480e0c538b3449..14365b20f1c5c09964dd7024060116737f22cb63 100644 (file)
--- 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 1f365e28e316c53265436f2c121428515cb6a5e5..a6208efcfccfceff57bd04cb4c6b8bd18a95b13a 100644 (file)
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1120,6 +1120,8 @@ 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;
 
@@ -1506,6 +1508,8 @@ 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 37a2b3301e42300e0476fbfa113bedbb11ef2662..b844e519da1b4eafceeda3e7f62207c8c12ad374 100644 (file)
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1137,6 +1137,8 @@ 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;
 
@@ -1515,6 +1517,8 @@ 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;