From f919224c44b9828208a3cce79b93183df8ca4fb4 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Tue, 16 May 2017 16:14:58 +0200 Subject: sys, executor: extract tcp sequence numbers from /dev/net/tun This commit adds a new pseudo syscall syz_extract_tcp_res, that reads a packet from /dev/net/tun and extracts tcp sequence numbers to be used in subsequent packets. As a result this syzkaller program: 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)={0x42424242, 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$inet(r0, &(0x7f0000005000)={0x0, 0x0, @multicast1=0x0, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0]}, &(0x7f0000006000)=0x10) established a TCP connection: Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:20000 0.0.0.0:* LISTEN 5477/a.out tcp 2 0 172.20.0.170:20000 172.20.0.187:20001 ESTABLISHED 5477/a.out Similar program for IPv6: mmap(&(0x7f0000000000/0x10000)=nil, (0x10000), 0x3, 0x32, 0xffffffffffffffff, 0x0) r0 = socket$inet6_tcp(0xa, 0x1, 0x0) bind$inet6(r0, &(0x7f0000000000)={0xa, 0x1, 0x0, @empty={[0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0]}, 0x0}, 0x1c) listen(r0, 0x5) syz_emit_ethernet(0x4a, &(0x7f0000001000)={@local={[0xaa, 0xaa, 0xaa, 0xaa, 0xaa], 0x0}, @random="de895db1468d", [], {{0x86dd, @ipv6={0x0, 0x6, "a228af", 0x14, 0x6, 0x0, @remote={0xfe, 0x80, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0], 0x0, 0xbb}, @local={0xfe, 0x80, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0], 0x0, 0xaa}, {[], @tcp={{0x0, 0x1, 0x42424242, 0x42424242, 0x0, 0x0, 0x5, 0x2, 0x0, 0x0, 0x0, {[]}}, {""}}}}}}}) syz_extract_tcp_res(&(0x7f0000002000)={0x42424242, 0x42424242}, 0x1, 0x0) syz_emit_ethernet(0x4a, &(0x7f0000003000)={@local={[0xaa, 0xaa, 0xaa, 0xaa, 0xaa], 0x0}, @random="de895db1468d", [], {{0x86dd, @ipv6={0x0, 0x6, "a228af", 0x14, 0x6, 0x0, @remote={0xfe, 0x80, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0], 0x0, 0xbb}, @local={0xfe, 0x80, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0], 0x0, 0xaa}, {[], @tcp={{0x0, 0x1, r2, r1, 0x0, 0x0, 0x5, 0x10, 0x0, 0x0, 0x0, {[]}}, {""}}}}}}}) r3 = accept$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 --- sys/vnet.txt | 42 ++++++++++++++++++++++++------------------ 1 file changed, 24 insertions(+), 18 deletions(-) (limited to 'sys') diff --git a/sys/vnet.txt b/sys/vnet.txt index cf439c36e..c4ee49a02 100644 --- a/sys/vnet.txt +++ b/sys/vnet.txt @@ -6,6 +6,18 @@ include syz_emit_ethernet(len len[packet], packet ptr[in, eth_packet]) +resource tcp_seq_num[int32]: 0x42424242 + +tcp_resources { + seq tcp_seq_num + ack tcp_seq_num +} + +# These pseudo syscalls read a packet from /dev/net/tun and extract tcp sequence and acknowledgement numbers from it. +# They also adds the inc arguments to the returned values, this way sequence numbers get incremented. +syz_extract_tcp_res(res ptr[out, tcp_resources], seq_inc int32, ack_inc int32) +syz_extract_tcp_res$synack(res ptr[out, tcp_resources], seq_inc const[1], ack_inc const[0]) + ################################################################################ ################################### Ethernet ################################### ################################################################################ @@ -440,20 +452,22 @@ ipv6_addr_empty { a0 array[const[0x00, int8], 16] } -# This corresponds to LOCAL_IPV6 ("fd00::%02hxaa" % pid) in executor/common.h +# This corresponds to LOCAL_IPV6 ("fe80::%02hxaa" % pid) in executor/common.h ipv6_addr_local { - a0 const[0xfd, int8] - a1 array[const[0x00, int8], 13] - a2 proc[int8, 0, 1] - a3 const[0xaa, int8] + a0 const[0xfe, int8] + a1 const[0x80, int8] + a2 array[const[0x00, int8], 12] + a3 proc[int8, 0, 1] + a4 const[0xaa, int8] } [packed] -# This corresponds to REMOTE_IPV6 ("fd00::%02hxbb" % pid) in executor/common.h +# This corresponds to REMOTE_IPV6 ("fe80::%02hxbb" % pid) in executor/common.h ipv6_addr_remote { - a0 const[0xfd, int8] - a1 array[const[0x00, int8], 13] - a2 proc[int8, 0, 1] - a3 const[0xbb, int8] + a0 const[0xfe, int8] + a1 const[0x80, int8] + a2 array[const[0x00, int8], 12] + a3 proc[int8, 0, 1] + a4 const[0xbb, int8] } [packed] ipv6_addr_loopback { @@ -660,14 +674,6 @@ tcp_options { options array[tcp_option] } [packed, align_4] -# TODO: extract sequence numbers from packets -tcp_seq_num [ - init const[0x56565656, int32be] - next const[0x56565657, int32be] - nextn int32be[0x56565656:0x56566000] - random int32be -] - tcp_flags = 0, TCPHDR_FIN, TCPHDR_SYN, TCPHDR_RST, TCPHDR_PSH, TCPHDR_ACK, TCPHDR_URG, TCPHDR_ECE, TCPHDR_CWR, TCPHDR_SYN_ECN tcp_header { -- cgit mrf-deployment