| Message ID | 20240421184326.1704930-1-edumazet@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 58a4c9b1e5a3e53c9148e80b90e1e43897ce77d1 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] ipv4: check for NULL idev in ip_route_use_hint() | expand |
On Sun, 2024-04-21 at 18:43 +0000, Eric Dumazet wrote: > syzbot was able to trigger a NULL deref in fib_validate_source() > in an old tree [1]. > > It appears the bug exists in latest trees. > > All calls to __in_dev_get_rcu() must be checked for a NULL result. > > [1] > general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] > CPU: 2 PID: 3257 Comm: syz-executor.3 Not tainted 5.10.0-syzkaller #0 > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 > RIP: 0010:fib_validate_source+0xbf/0x15a0 net/ipv4/fib_frontend.c:425 > Code: 18 f2 f2 f2 f2 42 c7 44 20 23 f3 f3 f3 f3 48 89 44 24 78 42 c6 44 20 27 f3 e8 5d 88 48 fc 4c 89 e8 48 c1 e8 03 48 89 44 24 18 <42> 80 3c 20 00 74 08 4c 89 ef e8 d2 15 98 fc 48 89 5c 24 10 41 bf > RSP: 0018:ffffc900015fee40 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: ffff88800f7a4000 RCX: ffff88800f4f90c0 > RDX: 0000000000000000 RSI: 0000000004001eac RDI: ffff8880160c64c0 > RBP: ffffc900015ff060 R08: 0000000000000000 R09: ffff88800f7a4000 > R10: 0000000000000002 R11: ffff88800f4f90c0 R12: dffffc0000000000 > R13: 0000000000000000 R14: 0000000000000000 R15: ffff88800f7a4000 > FS: 00007f938acfe6c0(0000) GS:ffff888058c00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f938acddd58 CR3: 000000001248e000 CR4: 0000000000352ef0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > ip_route_use_hint+0x410/0x9b0 net/ipv4/route.c:2231 > ip_rcv_finish_core+0x2c4/0x1a30 net/ipv4/ip_input.c:327 > ip_list_rcv_finish net/ipv4/ip_input.c:612 [inline] > ip_sublist_rcv+0x3ed/0xe50 net/ipv4/ip_input.c:638 > ip_list_rcv+0x422/0x470 net/ipv4/ip_input.c:673 > __netif_receive_skb_list_ptype net/core/dev.c:5572 [inline] > __netif_receive_skb_list_core+0x6b1/0x890 net/core/dev.c:5620 > __netif_receive_skb_list net/core/dev.c:5672 [inline] > netif_receive_skb_list_internal+0x9f9/0xdc0 net/core/dev.c:5764 > netif_receive_skb_list+0x55/0x3e0 net/core/dev.c:5816 > xdp_recv_frames net/bpf/test_run.c:257 [inline] > xdp_test_run_batch net/bpf/test_run.c:335 [inline] > bpf_test_run_xdp_live+0x1818/0x1d00 net/bpf/test_run.c:363 > bpf_prog_test_run_xdp+0x81f/0x1170 net/bpf/test_run.c:1376 > bpf_prog_test_run+0x349/0x3c0 kernel/bpf/syscall.c:3736 > __sys_bpf+0x45c/0x710 kernel/bpf/syscall.c:5115 > __do_sys_bpf kernel/bpf/syscall.c:5201 [inline] > __se_sys_bpf kernel/bpf/syscall.c:5199 [inline] > __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5199 > > Fixes: 02b24941619f ("ipv4: use dst hint for ipv4 list receive") > Reported-by: syzbot <syzkaller@googlegroups.com> > Signed-off-by: Eric Dumazet <edumazet@google.com> Thanks for fixing it! Acked-by: Paolo Abeni <pabeni@redhat.com> syzbot took surprisingly long to spot this, I guess the race window is very tiny? (or syzbot learned new tricks...) Cheers, Paolo
Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski <kuba@kernel.org>: On Sun, 21 Apr 2024 18:43:26 +0000 you wrote: > syzbot was able to trigger a NULL deref in fib_validate_source() > in an old tree [1]. > > It appears the bug exists in latest trees. > > All calls to __in_dev_get_rcu() must be checked for a NULL result. > > [...] Here is the summary with links: - [net] ipv4: check for NULL idev in ip_route_use_hint() https://git.kernel.org/netdev/net/c/58a4c9b1e5a3 You are awesome, thank you!
On Tue, 23 Apr 2024 at 15:57, Paolo Abeni <pabeni@redhat.com> wrote: > > On Sun, 2024-04-21 at 18:43 +0000, Eric Dumazet wrote: > > syzbot was able to trigger a NULL deref in fib_validate_source() > > in an old tree [1]. > > > > It appears the bug exists in latest trees. > > > > All calls to __in_dev_get_rcu() must be checked for a NULL result. > > > > [1] > > general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN > > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] > > CPU: 2 PID: 3257 Comm: syz-executor.3 Not tainted 5.10.0-syzkaller #0 > > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 > > RIP: 0010:fib_validate_source+0xbf/0x15a0 net/ipv4/fib_frontend.c:425 > > Code: 18 f2 f2 f2 f2 42 c7 44 20 23 f3 f3 f3 f3 48 89 44 24 78 42 c6 44 20 27 f3 e8 5d 88 48 fc 4c 89 e8 48 c1 e8 03 48 89 44 24 18 <42> 80 3c 20 00 74 08 4c 89 ef e8 d2 15 98 fc 48 89 5c 24 10 41 bf > > RSP: 0018:ffffc900015fee40 EFLAGS: 00010246 > > RAX: 0000000000000000 RBX: ffff88800f7a4000 RCX: ffff88800f4f90c0 > > RDX: 0000000000000000 RSI: 0000000004001eac RDI: ffff8880160c64c0 > > RBP: ffffc900015ff060 R08: 0000000000000000 R09: ffff88800f7a4000 > > R10: 0000000000000002 R11: ffff88800f4f90c0 R12: dffffc0000000000 > > R13: 0000000000000000 R14: 0000000000000000 R15: ffff88800f7a4000 > > FS: 00007f938acfe6c0(0000) GS:ffff888058c00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007f938acddd58 CR3: 000000001248e000 CR4: 0000000000352ef0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > ip_route_use_hint+0x410/0x9b0 net/ipv4/route.c:2231 > > ip_rcv_finish_core+0x2c4/0x1a30 net/ipv4/ip_input.c:327 > > ip_list_rcv_finish net/ipv4/ip_input.c:612 [inline] > > ip_sublist_rcv+0x3ed/0xe50 net/ipv4/ip_input.c:638 > > ip_list_rcv+0x422/0x470 net/ipv4/ip_input.c:673 > > __netif_receive_skb_list_ptype net/core/dev.c:5572 [inline] > > __netif_receive_skb_list_core+0x6b1/0x890 net/core/dev.c:5620 > > __netif_receive_skb_list net/core/dev.c:5672 [inline] > > netif_receive_skb_list_internal+0x9f9/0xdc0 net/core/dev.c:5764 > > netif_receive_skb_list+0x55/0x3e0 net/core/dev.c:5816 > > xdp_recv_frames net/bpf/test_run.c:257 [inline] > > xdp_test_run_batch net/bpf/test_run.c:335 [inline] > > bpf_test_run_xdp_live+0x1818/0x1d00 net/bpf/test_run.c:363 > > bpf_prog_test_run_xdp+0x81f/0x1170 net/bpf/test_run.c:1376 > > bpf_prog_test_run+0x349/0x3c0 kernel/bpf/syscall.c:3736 > > __sys_bpf+0x45c/0x710 kernel/bpf/syscall.c:5115 > > __do_sys_bpf kernel/bpf/syscall.c:5201 [inline] > > __se_sys_bpf kernel/bpf/syscall.c:5199 [inline] > > __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5199 > > > > Fixes: 02b24941619f ("ipv4: use dst hint for ipv4 list receive") > > Reported-by: syzbot <syzkaller@googlegroups.com> > > Signed-off-by: Eric Dumazet <edumazet@google.com> > > Thanks for fixing it! > > Acked-by: Paolo Abeni <pabeni@redhat.com> > > syzbot took surprisingly long to spot this, I guess the race window is > very tiny? (or syzbot learned new tricks...) From the stack it looks like this requires creating a non-trivial valid BPF program, this may still be challenging for the fuzzer.
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index d36ace160d426f6224f8e692f3b438ae863bb9b9..b814fdab19f710d066d323970be6ce57a3b583c5 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2166,6 +2166,9 @@ int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, int err = -EINVAL; u32 tag = 0; + if (!in_dev) + return -EINVAL; + if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) goto martian_source;
syzbot was able to trigger a NULL deref in fib_validate_source() in an old tree [1]. It appears the bug exists in latest trees. All calls to __in_dev_get_rcu() must be checked for a NULL result. [1] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 2 PID: 3257 Comm: syz-executor.3 Not tainted 5.10.0-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:fib_validate_source+0xbf/0x15a0 net/ipv4/fib_frontend.c:425 Code: 18 f2 f2 f2 f2 42 c7 44 20 23 f3 f3 f3 f3 48 89 44 24 78 42 c6 44 20 27 f3 e8 5d 88 48 fc 4c 89 e8 48 c1 e8 03 48 89 44 24 18 <42> 80 3c 20 00 74 08 4c 89 ef e8 d2 15 98 fc 48 89 5c 24 10 41 bf RSP: 0018:ffffc900015fee40 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88800f7a4000 RCX: ffff88800f4f90c0 RDX: 0000000000000000 RSI: 0000000004001eac RDI: ffff8880160c64c0 RBP: ffffc900015ff060 R08: 0000000000000000 R09: ffff88800f7a4000 R10: 0000000000000002 R11: ffff88800f4f90c0 R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88800f7a4000 FS: 00007f938acfe6c0(0000) GS:ffff888058c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f938acddd58 CR3: 000000001248e000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ip_route_use_hint+0x410/0x9b0 net/ipv4/route.c:2231 ip_rcv_finish_core+0x2c4/0x1a30 net/ipv4/ip_input.c:327 ip_list_rcv_finish net/ipv4/ip_input.c:612 [inline] ip_sublist_rcv+0x3ed/0xe50 net/ipv4/ip_input.c:638 ip_list_rcv+0x422/0x470 net/ipv4/ip_input.c:673 __netif_receive_skb_list_ptype net/core/dev.c:5572 [inline] __netif_receive_skb_list_core+0x6b1/0x890 net/core/dev.c:5620 __netif_receive_skb_list net/core/dev.c:5672 [inline] netif_receive_skb_list_internal+0x9f9/0xdc0 net/core/dev.c:5764 netif_receive_skb_list+0x55/0x3e0 net/core/dev.c:5816 xdp_recv_frames net/bpf/test_run.c:257 [inline] xdp_test_run_batch net/bpf/test_run.c:335 [inline] bpf_test_run_xdp_live+0x1818/0x1d00 net/bpf/test_run.c:363 bpf_prog_test_run_xdp+0x81f/0x1170 net/bpf/test_run.c:1376 bpf_prog_test_run+0x349/0x3c0 kernel/bpf/syscall.c:3736 __sys_bpf+0x45c/0x710 kernel/bpf/syscall.c:5115 __do_sys_bpf kernel/bpf/syscall.c:5201 [inline] __se_sys_bpf kernel/bpf/syscall.c:5199 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5199 Fixes: 02b24941619f ("ipv4: use dst hint for ipv4 list receive") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> --- net/ipv4/route.c | 3 +++ 1 file changed, 3 insertions(+)