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 48c6aa3d91ae8ff2535a0c6c9c5081a760dadf84..5823e89b8a734b83095b42183237ac33f47d42d3 100644 (file)
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -965,6 +965,8 @@ 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;
 
@@ -1265,6 +1267,8 @@ 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 b46d58b9f3fe4e72128f59b995f8393080a19055..22e9ff592cd75f054c7f44c1ce428dab58db87d2 100644 (file)
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1119,6 +1119,8 @@ 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;
 
@@ -1505,6 +1507,8 @@ 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 d013395be05fcb23ab1b23733ad1a92adf931aa7..df7cd3d285e4f0e57a5536aed034c48db6c817a9 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;