From: Kuniyuki Iwashima kuniyu@amazon.com
commit ad42a35bdfc6d3c0fc4cb4027d7b2757ce665665 upstream.
syzbot reported [0] a null-ptr-deref in sk_get_rmem0() while using IPPROTO_UDPLITE (0x88):
14:25:52 executing program 1: r0 = socket$inet6(0xa, 0x80002, 0x88)
We had a similar report [1] for probably sk_memory_allocated_add() in __sk_mem_raise_allocated(), and commit c915fe13cbaa ("udplite: fix NULL pointer dereference") fixed it by setting .memory_allocated for udplite_prot and udplitev6_prot.
To fix the variant, we need to set either .sysctl_wmem_offset or .sysctl_rmem.
Now UDP and UDPLITE share the same value for .memory_allocated, so we use the same .sysctl_wmem_offset for UDP and UDPLITE.
[0]: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 6829 Comm: syz-executor.1 Not tainted 6.4.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 RIP: 0010:sk_get_rmem0 include/net/sock.h:2907 [inline] RIP: 0010:__sk_mem_raise_allocated+0x806/0x17a0 net/core/sock.c:3006 Code: c1 ea 03 80 3c 02 00 0f 85 23 0f 00 00 48 8b 44 24 08 48 8b 98 38 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 0f 8d 6f 0a 00 00 8b RSP: 0018:ffffc90005d7f450 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90004d92000 RDX: 0000000000000000 RSI: ffffffff88066482 RDI: ffffffff8e2ccbb8 RBP: ffff8880173f7000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000030000 R13: 0000000000000001 R14: 0000000000000340 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9800000(0063) knlGS:00000000f7f1cb40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 000000002e82f000 CR3: 0000000034ff0000 CR4: 00000000003506f0 Call Trace: <TASK> __sk_mem_schedule+0x6c/0xe0 net/core/sock.c:3077 udp_rmem_schedule net/ipv4/udp.c:1539 [inline] __udp_enqueue_schedule_skb+0x776/0xb30 net/ipv4/udp.c:1581 __udpv6_queue_rcv_skb net/ipv6/udp.c:666 [inline] udpv6_queue_rcv_one_skb+0xc39/0x16c0 net/ipv6/udp.c:775 udpv6_queue_rcv_skb+0x194/0xa10 net/ipv6/udp.c:793 __udp6_lib_mcast_deliver net/ipv6/udp.c:906 [inline] __udp6_lib_rcv+0x1bda/0x2bd0 net/ipv6/udp.c:1013 ip6_protocol_deliver_rcu+0x2e7/0x1250 net/ipv6/ip6_input.c:437 ip6_input_finish+0x150/0x2f0 net/ipv6/ip6_input.c:482 NF_HOOK include/linux/netfilter.h:303 [inline] NF_HOOK include/linux/netfilter.h:297 [inline] ip6_input+0xa0/0xd0 net/ipv6/ip6_input.c:491 ip6_mc_input+0x40b/0xf50 net/ipv6/ip6_input.c:585 dst_input include/net/dst.h:468 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline] NF_HOOK include/linux/netfilter.h:303 [inline] NF_HOOK include/linux/netfilter.h:297 [inline] ipv6_rcv+0x250/0x380 net/ipv6/ip6_input.c:309 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5491 __netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5605 netif_receive_skb_internal net/core/dev.c:5691 [inline] netif_receive_skb+0x133/0x7a0 net/core/dev.c:5750 tun_rx_batched+0x4b3/0x7a0 drivers/net/tun.c:1553 tun_get_user+0x2452/0x39c0 drivers/net/tun.c:1989 tun_chr_write_iter+0xdf/0x200 drivers/net/tun.c:2035 call_write_iter include/linux/fs.h:1868 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x945/0xd50 fs/read_write.c:584 ksys_write+0x12b/0x250 fs/read_write.c:637 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7f21579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f7f1c590 EFLAGS: 00000282 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 00000000000000c8 RCX: 0000000020000040 RDX: 0000000000000083 RSI: 00000000f734e000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> Modules linked in:
Link: https://lore.kernel.org/netdev/CANaxB-yCk8hhP68L4Q2nFOJht8sqgXGGQO2AftpHs0u1... [1] Fixes: 850cbaddb52d ("udp: use it's own memory accounting schema") Reported-by: syzbot+444ca0907e96f7c5e48b@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=444ca0907e96f7c5e48b Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://lore.kernel.org/r/20230523163305.66466-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/udplite.c | 2 ++ net/ipv6/udplite.c | 2 ++ 2 files changed, 4 insertions(+)
--- a/net/ipv4/udplite.c +++ b/net/ipv4/udplite.c @@ -61,6 +61,8 @@ struct proto udplite_prot = { .get_port = udp_v4_get_port, .memory_allocated = &udp_memory_allocated, .sysctl_mem = sysctl_udp_mem, + .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_udp_wmem_min), + .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_udp_rmem_min), .obj_size = sizeof(struct udp_sock), .h.udp_table = &udplite_table, }; --- a/net/ipv6/udplite.c +++ b/net/ipv6/udplite.c @@ -57,6 +57,8 @@ struct proto udplitev6_prot = { .get_port = udp_v6_get_port, .memory_allocated = &udp_memory_allocated, .sysctl_mem = sysctl_udp_mem, + .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_udp_wmem_min), + .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_udp_rmem_min), .obj_size = sizeof(struct udp6_sock), .h.udp_table = &udplite_table, };