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Diffstat (limited to 'docs/linux/external_fuzzing_network.md')
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diff --git a/docs/linux/external_fuzzing_network.md b/docs/linux/external_fuzzing_network.md index a05bb5ea3..f080692b1 100644 --- a/docs/linux/external_fuzzing_network.md +++ b/docs/linux/external_fuzzing_network.md @@ -25,3 +25,41 @@ There's a `csum` type, which right now supports two different kinds of checksumm and TCP-like pseudo header checksum: `csum[tcp_packet, pseudo, IPPROTO_TCP, int16be]`. The checksums are computed and embedded right before emitting a packet though the virtual interface. There's also a nice feature: when syzkaller generates a C reproducer, it generates code to compute checksums in runtime as well. + +By using `syz_emit_ethernet` and `syz_extract_tcp_res` the following syzkaller program is able to establish a TCP connection over IPv4: + +``` +mmap(&(0x7f0000000000/0x10000)=nil, (0x10000), 0x3, 0x32, 0xffffffffffffffff, 0x0) +r0 = socket$inet_tcp(0x2, 0x1, 0x0) +bind$inet(r0, &(0x7f0000001000)={0x2, 0x0, @empty=0x0, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0]}, 0x10) +listen(r0, 0x5) +syz_emit_ethernet(0x36, &(0x7f0000002000)={@local={[0xaa, 0xaa, 0xaa, 0xaa, 0xaa], 0x0}, @random="4c6112cc15d8", [], {{0x800, @ipv4={{0x5, 0x4, 0x0, 0x0, 0x28, 0x0, 0x0, 0x0, 0x6, 0x0, @remote={0xac, 0x14, 0x0, 0xbb}, @local={0xac, 0x14, 0x0, 0xaa}, {[]}}, @tcp={{0x1, 0x0, 0x42424242, 0x42424242, 0x0, 0x0, 0x5, 0x2, 0x0, 0x0, 0x0, {[]}}, {""}}}}}}) +syz_extract_tcp_res(&(0x7f0000003000)={<r1=>0x42424242, <r2=>0x42424242}, 0x1, 0x0) +syz_emit_ethernet(0x38, &(0x7f0000004000)={@local={[0xaa, 0xaa, 0xaa, 0xaa, 0xaa], 0x0}, @remote={[0xbb, 0xbb, 0xbb, 0xbb, 0xbb], 0x0}, [], {{0x800, @ipv4={{0x5, 0x4, 0x0, 0x0, 0x2a, 0x0, 0x0, 0x0, 0x6, 0x0, @remote={0xac, 0x14, 0x0, 0xbb}, @local={0xac, 0x14, 0x0, 0xaa}, {[]}}, @tcp={{0x1, 0x0, r2, r1, 0x0, 0x0, 0x5, 0x10, 0x0, 0x0, 0x0, {[]}}, {"0c10"}}}}}}) +r3 = accept$inet(r0, &(0x7f0000005000)={0x0, 0x0, @multicast1=0x0, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0]}, &(0x7f0000006000)=0x10) +``` + +``` +Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name +tcp 0 0 0.0.0.0:20000 0.0.0.0:* LISTEN 5477/a.out +tcp 2 0 172.20.0.170:20000 172.20.0.187:20001 ESTABLISHED 5477/a.out +``` + +Similar program for IPv6: + +``` +mmap(&(0x7f0000000000/0x10000)=nil, (0x10000), 0x3, 0x32, 0xffffffffffffffff, 0x0) +r0 = socket$inet6_tcp(0xa, 0x1, 0x0) +bind$inet6(r0, &(0x7f0000000000)={0xa, 0x1, 0x0, @empty={[0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0]}, 0x0}, 0x1c) +listen(r0, 0x5) +syz_emit_ethernet(0x4a, &(0x7f0000001000)={@local={[0xaa, 0xaa, 0xaa, 0xaa, 0xaa], 0x0}, @random="de895db1468d", [], {{0x86dd, @ipv6={0x0, 0x6, "a228af", 0x14, 0x6, 0x0, @remote={0xfe, 0x80, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0], 0x0, 0xbb}, @local={0xfe, 0x80, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0], 0x0, 0xaa}, {[], @tcp={{0x0, 0x1, 0x42424242, 0x42424242, 0x0, 0x0, 0x5, 0x2, 0x0, 0x0, 0x0, {[]}}, {""}}}}}}}) +syz_extract_tcp_res(&(0x7f0000002000)={<r1=>0x42424242, <r2=>0x42424242}, 0x1, 0x0) +syz_emit_ethernet(0x4a, &(0x7f0000003000)={@local={[0xaa, 0xaa, 0xaa, 0xaa, 0xaa], 0x0}, @random="de895db1468d", [], {{0x86dd, @ipv6={0x0, 0x6, "a228af", 0x14, 0x6, 0x0, @remote={0xfe, 0x80, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0], 0x0, 0xbb}, @local={0xfe, 0x80, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0], 0x0, 0xaa}, {[], @tcp={{0x0, 0x1, r2, r1, 0x0, 0x0, 0x5, 0x10, 0x0, 0x0, 0x0, {[]}}, {""}}}}}}}) +r3 = accept$inet6(r0, &(0x7f0000004000)={0x0, 0x0, 0x0, @empty={[0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0]}, 0x0}, &(0x7f0000005000)=0x1c) +``` + +``` +Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name +tcp6 0 0 :::20001 :::* LISTEN 5527/a.out +tcp6 0 0 fe80::aa:20001 fe80::bb:20000 ESTABLISHED 5527/a.out +``` |