From: Eric Dumazet edumazet@google.com
commit 68ad89de918e1c5a79c9c56127e5e31741fd517e upstream.
syzbot found that we are not validating user input properly before copying 16 bytes [1].
Using NLA_BINARY in ipaddr_policy[] for IPv6 address is not correct, since it ensures at most 16 bytes were provided.
We should instead make sure user provided exactly 16 bytes.
In old kernels (before v4.20), fix would be to remove the NLA_BINARY, since NLA_POLICY_EXACT_LEN() was not yet available.
[1] BUG: KMSAN: uninit-value in hash_ip6_add+0x1cba/0x3a50 net/netfilter/ipset/ip_set_hash_gen.h:892 CPU: 1 PID: 11611 Comm: syz-executor.0 Not tainted 5.10.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x21c/0x280 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197 hash_ip6_add+0x1cba/0x3a50 net/netfilter/ipset/ip_set_hash_gen.h:892 hash_ip6_uadt+0x976/0xbd0 net/netfilter/ipset/ip_set_hash_ip.c:267 call_ad+0x329/0xd00 net/netfilter/ipset/ip_set_core.c:1720 ip_set_ad+0x111f/0x1440 net/netfilter/ipset/ip_set_core.c:1808 ip_set_uadd+0xf6/0x110 net/netfilter/ipset/ip_set_core.c:1833 nfnetlink_rcv_msg+0xc7d/0xdf0 net/netfilter/nfnetlink.c:252 netlink_rcv_skb+0x70a/0x820 net/netlink/af_netlink.c:2494 nfnetlink_rcv+0x4f0/0x4380 net/netfilter/nfnetlink.c:600 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x11da/0x14b0 net/netlink/af_netlink.c:1330 netlink_sendmsg+0x173c/0x1840 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0xc7a/0x1240 net/socket.c:2353 ___sys_sendmsg net/socket.c:2407 [inline] __sys_sendmsg+0x6d5/0x830 net/socket.c:2440 __do_sys_sendmsg net/socket.c:2449 [inline] __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45deb9 Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fe2e503fc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000029ec0 RCX: 000000000045deb9 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003 RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 000000000169fb7f R14: 00007fe2e50409c0 R15: 000000000118bf2c
Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289 __msan_chain_origin+0x57/0xa0 mm/kmsan/kmsan_instr.c:147 ip6_netmask include/linux/netfilter/ipset/pfxlen.h:49 [inline] hash_ip6_netmask net/netfilter/ipset/ip_set_hash_ip.c:185 [inline] hash_ip6_uadt+0xb1c/0xbd0 net/netfilter/ipset/ip_set_hash_ip.c:263 call_ad+0x329/0xd00 net/netfilter/ipset/ip_set_core.c:1720 ip_set_ad+0x111f/0x1440 net/netfilter/ipset/ip_set_core.c:1808 ip_set_uadd+0xf6/0x110 net/netfilter/ipset/ip_set_core.c:1833 nfnetlink_rcv_msg+0xc7d/0xdf0 net/netfilter/nfnetlink.c:252 netlink_rcv_skb+0x70a/0x820 net/netlink/af_netlink.c:2494 nfnetlink_rcv+0x4f0/0x4380 net/netfilter/nfnetlink.c:600 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x11da/0x14b0 net/netlink/af_netlink.c:1330 netlink_sendmsg+0x173c/0x1840 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0xc7a/0x1240 net/socket.c:2353 ___sys_sendmsg net/socket.c:2407 [inline] __sys_sendmsg+0x6d5/0x830 net/socket.c:2440 __do_sys_sendmsg net/socket.c:2449 [inline] __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289 kmsan_memcpy_memmove_metadata+0x25e/0x2d0 mm/kmsan/kmsan.c:226 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:246 __msan_memcpy+0x46/0x60 mm/kmsan/kmsan_instr.c:110 ip_set_get_ipaddr6+0x2cb/0x370 net/netfilter/ipset/ip_set_core.c:310 hash_ip6_uadt+0x439/0xbd0 net/netfilter/ipset/ip_set_hash_ip.c:255 call_ad+0x329/0xd00 net/netfilter/ipset/ip_set_core.c:1720 ip_set_ad+0x111f/0x1440 net/netfilter/ipset/ip_set_core.c:1808 ip_set_uadd+0xf6/0x110 net/netfilter/ipset/ip_set_core.c:1833 nfnetlink_rcv_msg+0xc7d/0xdf0 net/netfilter/nfnetlink.c:252 netlink_rcv_skb+0x70a/0x820 net/netlink/af_netlink.c:2494 nfnetlink_rcv+0x4f0/0x4380 net/netfilter/nfnetlink.c:600 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x11da/0x14b0 net/netlink/af_netlink.c:1330 netlink_sendmsg+0x173c/0x1840 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0xc7a/0x1240 net/socket.c:2353 ___sys_sendmsg net/socket.c:2407 [inline] __sys_sendmsg+0x6d5/0x830 net/socket.c:2440 __do_sys_sendmsg net/socket.c:2449 [inline] __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline] kmsan_internal_poison_shadow+0x5c/0xf0 mm/kmsan/kmsan.c:104 kmsan_slab_alloc+0x8d/0xe0 mm/kmsan/kmsan_hooks.c:76 slab_alloc_node mm/slub.c:2906 [inline] __kmalloc_node_track_caller+0xc61/0x15f0 mm/slub.c:4512 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0x309/0xae0 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1094 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1176 [inline] netlink_sendmsg+0xdb8/0x1840 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0xc7a/0x1240 net/socket.c:2353 ___sys_sendmsg net/socket.c:2407 [inline] __sys_sendmsg+0x6d5/0x830 net/socket.c:2440 __do_sys_sendmsg net/socket.c:2449 [inline] __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: a7b4f989a629 ("netfilter: ipset: IP set core support") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Acked-by: Jozsef Kadlecsik kadlec@netfilter.org Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/netfilter/ipset/ip_set_core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -286,8 +286,7 @@ flag_nested(const struct nlattr *nla)
static const struct nla_policy ipaddr_policy[IPSET_ATTR_IPADDR_MAX + 1] = { [IPSET_ATTR_IPADDR_IPV4] = { .type = NLA_U32 }, - [IPSET_ATTR_IPADDR_IPV6] = { .type = NLA_BINARY, - .len = sizeof(struct in6_addr) }, + [IPSET_ATTR_IPADDR_IPV6] = NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)), };
int