[PATCH 5.15 18/45] netfilter: complete validation of user input

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@google.com>

[ 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>
---
 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 07ecb16231cd0..a9d5a1973224a 100644
--- 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 1e1e7488d6bf1..aee7cd584c926 100644
--- 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 b17990d514ee9..afd22ea9f555b 100644
--- 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;
 
-- 
2.43.0