Re: KMSAN: uninit-value in __crc32c_le_base

[Xin Long <lucien.xin@gmail.com>]

On Wed, Nov 27, 2019 at 2:02 PM Eric Biggers <ebiggers@kernel.org> wrote:
>
> Looks like a bug in net/sctp/ where it's passing uninitialized memory into the
> crc32c() function.  SCTP maintainers, can you please take a look?
Thanks.

The issue was caused by:
transport->ipaddr set with uninit addr param, which was passed by:

  sctp_transport_init net/sctp/transport.c:47 [inline]
  sctp_transport_new+0x248/0xa00 net/sctp/transport.c:100
  sctp_assoc_add_peer+0x5ba/0x2030 net/sctp/associola.c:611
  sctp_process_param net/sctp/sm_make_chunk.c:2524 [inline]

where 'addr' is set by sctp_v4_from_addr_param(), which doesn't initialize the
padding of addr->v4.

later when calling sctp_make_heartbeat(), hbinfo.daddr(=transport->ipaddr)
will become the part of skb, and the issue occurs.

The fix should be:

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 09050c1d5517..0e73405eba4f 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2516,6 +2516,7 @@ static int sctp_process_param(struct
sctp_association *asoc,
  if (ipv6_only_sock(asoc->base.sk))
  break;
 do_addr_param:
+ memset(&addr, 0, sizeof(addr));
  af = sctp_get_af_specific(param_type2af(param.p->type));
  af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
  scope = sctp_scope(peer_addr);
@@ -3040,6 +3041,7 @@ static __be16 sctp_process_asconf_param(struct
sctp_association *asoc,
  if (unlikely(!af))
  return SCTP_ERROR_DNS_FAILED;

+ memset(&addr, 0, sizeof(addr));
  af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);

  /* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast


>
> Also, this might be a duplicate of "KMSAN: uninit-value in __skb_checksum_complete (4)"
> (https://lore.kernel.org/lkml/0000000000000924780598075f4b@google.com/T/#u).
>
> On Sat, Nov 23, 2019 at 10:05:09AM -0800, syzbot wrote:
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit:    3db92f3b kmsan: process DMA pages separately in kmsan_hand..
> > git tree:       https://github.com/google/kmsan.git master
> > console output: https://syzkaller.appspot.com/x/log.txt?x=17bad222e00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=9e324dfe9c7b0360
> > dashboard link: https://syzkaller.appspot.com/bug?extid=6dcbfea81cd3d4dd0b02
> > compiler:       clang version 9.0.0 (/home/glider/llvm/clang
> > 80fee25776c2fb61e74c1ecb1a523375c2500b69)
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=128145cee00000
> >
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+6dcbfea81cd3d4dd0b02@syzkaller.appspotmail.com
> >
> > =====================================================
> > BUG: KMSAN: uninit-value in crc32_body lib/crc32.c:112 [inline]
> > BUG: KMSAN: uninit-value in crc32_le_generic lib/crc32.c:179 [inline]
> > BUG: KMSAN: uninit-value in __crc32c_le_base+0x4fa/0xd30 lib/crc32.c:202
> > CPU: 1 PID: 12411 Comm: syz-executor.1 Not tainted 5.4.0-rc5-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+0x191/0x1f0 lib/dump_stack.c:113
> >  kmsan_report+0x128/0x220 mm/kmsan/kmsan_report.c:108
> >  __msan_warning+0x73/0xe0 mm/kmsan/kmsan_instr.c:245
> >  crc32_body lib/crc32.c:112 [inline]
> >  crc32_le_generic lib/crc32.c:179 [inline]
> >  __crc32c_le_base+0x4fa/0xd30 lib/crc32.c:202
> >  chksum_update+0xb2/0x110 crypto/crc32c_generic.c:90
> >  crypto_shash_update+0x4c5/0x530 crypto/shash.c:107
> >  crc32c+0x150/0x220 lib/libcrc32c.c:47
> >  sctp_csum_update+0x89/0xa0 include/net/sctp/checksum.h:36
> >  __skb_checksum+0x1297/0x12a0 net/core/skbuff.c:2640
> >  sctp_compute_cksum include/net/sctp/checksum.h:59 [inline]
> >  sctp_packet_pack net/sctp/output.c:528 [inline]
> >  sctp_packet_transmit+0x40fb/0x4250 net/sctp/output.c:597
> >  sctp_outq_flush_transports net/sctp/outqueue.c:1146 [inline]
> >  sctp_outq_flush+0x1823/0x5d80 net/sctp/outqueue.c:1194
> >  sctp_outq_uncork+0xd0/0xf0 net/sctp/outqueue.c:757
> >  sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1781 [inline]
> >  sctp_side_effects net/sctp/sm_sideeffect.c:1184 [inline]
> >  sctp_do_sm+0x8fe1/0x9720 net/sctp/sm_sideeffect.c:1155
> >  sctp_primitive_REQUESTHEARTBEAT+0x175/0x1a0 net/sctp/primitive.c:185
> >  sctp_apply_peer_addr_params+0x212/0x1d40 net/sctp/socket.c:2433
> >  sctp_setsockopt_peer_addr_params net/sctp/socket.c:2686 [inline]
> >  sctp_setsockopt+0x189bb/0x19090 net/sctp/socket.c:4672
> >  sock_common_setsockopt+0x13b/0x170 net/core/sock.c:3151
> >  __sys_setsockopt+0x7c3/0xa30 net/socket.c:2084
> >  __do_sys_setsockopt net/socket.c:2100 [inline]
> >  __se_sys_setsockopt+0xdd/0x100 net/socket.c:2097
> >  __x64_sys_setsockopt+0x62/0x80 net/socket.c:2097
> >  do_syscall_64+0xb6/0x160 arch/x86/entry/common.c:291
> >  entry_SYSCALL_64_after_hwframe+0x63/0xe7
> > RIP: 0033:0x45a639
> > Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
> > RSP: 002b:00007f2a8cb65c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
> > RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a639
> > RDX: 0000000000000009 RSI: 0000000000000084 RDI: 0000000000000004
> > RBP: 000000000075bfc8 R08: 0000000000000098 R09: 0000000000000000
> > R10: 0000000020000440 R11: 0000000000000246 R12: 00007f2a8cb666d4
> > R13: 00000000004d1a88 R14: 00000000004e08f0 R15: 00000000ffffffff
> >
> > Uninit was stored to memory at:
> >  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:151 [inline]
> >  kmsan_internal_chain_origin+0xbd/0x180 mm/kmsan/kmsan.c:319
> >  kmsan_memcpy_memmove_metadata+0x25c/0x2e0 mm/kmsan/kmsan.c:254
> >  kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:274
> >  __msan_memcpy+0x56/0x70 mm/kmsan/kmsan_instr.c:129
> >  skb_put_data include/linux/skbuff.h:2217 [inline]
> >  sctp_packet_pack net/sctp/output.c:470 [inline]
> >  sctp_packet_transmit+0x1d9e/0x4250 net/sctp/output.c:597
> >  sctp_outq_flush_transports net/sctp/outqueue.c:1146 [inline]
> >  sctp_outq_flush+0x1823/0x5d80 net/sctp/outqueue.c:1194
> >  sctp_outq_uncork+0xd0/0xf0 net/sctp/outqueue.c:757
> >  sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1781 [inline]
> >  sctp_side_effects net/sctp/sm_sideeffect.c:1184 [inline]
> >  sctp_do_sm+0x8fe1/0x9720 net/sctp/sm_sideeffect.c:1155
> >  sctp_primitive_REQUESTHEARTBEAT+0x175/0x1a0 net/sctp/primitive.c:185
> >  sctp_apply_peer_addr_params+0x212/0x1d40 net/sctp/socket.c:2433
> >  sctp_setsockopt_peer_addr_params net/sctp/socket.c:2686 [inline]
> >  sctp_setsockopt+0x189bb/0x19090 net/sctp/socket.c:4672
> >  sock_common_setsockopt+0x13b/0x170 net/core/sock.c:3151
> >  __sys_setsockopt+0x7c3/0xa30 net/socket.c:2084
> >  __do_sys_setsockopt net/socket.c:2100 [inline]
> >  __se_sys_setsockopt+0xdd/0x100 net/socket.c:2097
> >  __x64_sys_setsockopt+0x62/0x80 net/socket.c:2097
> >  do_syscall_64+0xb6/0x160 arch/x86/entry/common.c:291
> >  entry_SYSCALL_64_after_hwframe+0x63/0xe7
> >
> > Uninit was stored to memory at:
> >  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:151 [inline]
> >  kmsan_internal_chain_origin+0xbd/0x180 mm/kmsan/kmsan.c:319
> >  kmsan_memcpy_memmove_metadata+0x25c/0x2e0 mm/kmsan/kmsan.c:254
> >  kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:274
> >  __msan_memcpy+0x56/0x70 mm/kmsan/kmsan_instr.c:129
> >  skb_put_data include/linux/skbuff.h:2217 [inline]
> >  sctp_addto_chunk net/sctp/sm_make_chunk.c:1494 [inline]
> >  sctp_make_heartbeat+0x612/0x9e0 net/sctp/sm_make_chunk.c:1164
> >  sctp_sf_heartbeat net/sctp/sm_statefuns.c:990 [inline]
> >  sctp_sf_do_prm_requestheartbeat+0x8f/0x4b0 net/sctp/sm_statefuns.c:5329
> >  sctp_do_sm+0x2b2/0x9720 net/sctp/sm_sideeffect.c:1152
> >  sctp_primitive_REQUESTHEARTBEAT+0x175/0x1a0 net/sctp/primitive.c:185
> >  sctp_apply_peer_addr_params+0x212/0x1d40 net/sctp/socket.c:2433
> >  sctp_setsockopt_peer_addr_params net/sctp/socket.c:2686 [inline]
> >  sctp_setsockopt+0x189bb/0x19090 net/sctp/socket.c:4672
> >  sock_common_setsockopt+0x13b/0x170 net/core/sock.c:3151
> >  __sys_setsockopt+0x7c3/0xa30 net/socket.c:2084
> >  __do_sys_setsockopt net/socket.c:2100 [inline]
> >  __se_sys_setsockopt+0xdd/0x100 net/socket.c:2097
> >  __x64_sys_setsockopt+0x62/0x80 net/socket.c:2097
> >  do_syscall_64+0xb6/0x160 arch/x86/entry/common.c:291
> >  entry_SYSCALL_64_after_hwframe+0x63/0xe7
> >
> > Uninit was stored to memory at:
> >  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:151 [inline]
> >  kmsan_internal_chain_origin+0xbd/0x180 mm/kmsan/kmsan.c:319
> >  kmsan_memcpy_memmove_metadata+0x25c/0x2e0 mm/kmsan/kmsan.c:254
> >  kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:274
> >  __msan_memcpy+0x56/0x70 mm/kmsan/kmsan_instr.c:129
> >  sctp_make_heartbeat+0x3e9/0x9e0 net/sctp/sm_make_chunk.c:1156
> >  sctp_sf_heartbeat net/sctp/sm_statefuns.c:990 [inline]
> >  sctp_sf_do_prm_requestheartbeat+0x8f/0x4b0 net/sctp/sm_statefuns.c:5329
> >  sctp_do_sm+0x2b2/0x9720 net/sctp/sm_sideeffect.c:1152
> >  sctp_primitive_REQUESTHEARTBEAT+0x175/0x1a0 net/sctp/primitive.c:185
> >  sctp_apply_peer_addr_params+0x212/0x1d40 net/sctp/socket.c:2433
> >  sctp_setsockopt_peer_addr_params net/sctp/socket.c:2686 [inline]
> >  sctp_setsockopt+0x189bb/0x19090 net/sctp/socket.c:4672
> >  sock_common_setsockopt+0x13b/0x170 net/core/sock.c:3151
> >  __sys_setsockopt+0x7c3/0xa30 net/socket.c:2084
> >  __do_sys_setsockopt net/socket.c:2100 [inline]
> >  __se_sys_setsockopt+0xdd/0x100 net/socket.c:2097
> >  __x64_sys_setsockopt+0x62/0x80 net/socket.c:2097
> >  do_syscall_64+0xb6/0x160 arch/x86/entry/common.c:291
> >  entry_SYSCALL_64_after_hwframe+0x63/0xe7
> >
> > Uninit was stored to memory at:
> >  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:151 [inline]
> >  kmsan_internal_chain_origin+0xbd/0x180 mm/kmsan/kmsan.c:319
> >  kmsan_memcpy_memmove_metadata+0x25c/0x2e0 mm/kmsan/kmsan.c:254
> >  kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:274
> >  __msan_memcpy+0x56/0x70 mm/kmsan/kmsan_instr.c:129
> >  sctp_transport_init net/sctp/transport.c:47 [inline]
> >  sctp_transport_new+0x248/0xa00 net/sctp/transport.c:100
> >  sctp_assoc_add_peer+0x5ba/0x2030 net/sctp/associola.c:611
> >  sctp_process_param net/sctp/sm_make_chunk.c:2524 [inline]
> >  sctp_process_init+0x162b/0x3e30 net/sctp/sm_make_chunk.c:2345
> >  sctp_cmd_process_init net/sctp/sm_sideeffect.c:667 [inline]
> >  sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1374 [inline]
> >  sctp_side_effects net/sctp/sm_sideeffect.c:1184 [inline]
> >  sctp_do_sm+0x1b8b/0x9720 net/sctp/sm_sideeffect.c:1155
> >  sctp_assoc_bh_rcv+0x65a/0xd80 net/sctp/associola.c:1048
> >  sctp_inq_push+0x300/0x420 net/sctp/inqueue.c:80
> >  sctp_backlog_rcv+0x2d7/0x11a0 net/sctp/input.c:344
> >  sk_backlog_rcv include/net/sock.h:950 [inline]
> >  __release_sock+0x448/0x640 net/core/sock.c:2439
> >  release_sock+0x99/0x2a0 net/core/sock.c:2955
> >  sctp_wait_for_connect+0x3d7/0x840 net/sctp/socket.c:9167
> >  __sctp_connect+0x1e9d/0x1f20 net/sctp/socket.c:1226
> >  __sctp_setsockopt_connectx net/sctp/socket.c:1322 [inline]
> >  sctp_setsockopt_connectx_old net/sctp/socket.c:1338 [inline]
> >  sctp_setsockopt+0x960d/0x19090 net/sctp/socket.c:4647
> >  sock_common_setsockopt+0x13b/0x170 net/core/sock.c:3151
> >  __sys_setsockopt+0x7c3/0xa30 net/socket.c:2084
> >  __do_sys_setsockopt net/socket.c:2100 [inline]
> >  __se_sys_setsockopt+0xdd/0x100 net/socket.c:2097
> >  __x64_sys_setsockopt+0x62/0x80 net/socket.c:2097
> >  do_syscall_64+0xb6/0x160 arch/x86/entry/common.c:291
> >  entry_SYSCALL_64_after_hwframe+0x63/0xe7
> >
> > Local variable description: ----addr.i@sctp_process_init
> > Variable was created at:
> >  sctp_process_param net/sctp/sm_make_chunk.c:2495 [inline]
> >  sctp_process_init+0x603/0x3e30 net/sctp/sm_make_chunk.c:2345
> >  sctp_process_param net/sctp/sm_make_chunk.c:2495 [inline]
> >  sctp_process_init+0x603/0x3e30 net/sctp/sm_make_chunk.c:2345
> > =====================================================
> >
> >
> > ---
> > This bug is generated by a bot. It may contain errors.
> > See https://goo.gl/tpsmEJ for more information about syzbot.
> > syzbot engineers can be reached at syzkaller@googlegroups.com.
> >
> > syzbot will keep track of this bug report. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > syzbot can test patches for this bug, for details see:
> > https://goo.gl/tpsmEJ#testing-patches
> >
> > --
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