Re: KMSAN: uninit-value in gf128mul_4k_lle (3)

[Ard Biesheuvel]

(+ TLS maintainers)

On Fri, 23 Nov 2018 at 23:51, syzbot
<syzbot+f8495bff23a879a6d0bd@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    cddc52641fd2 kmsan: use __memmove() in fixup_bad_iret()
> git tree:       https://github.com/google/kmsan.git/master
> console output: https://syzkaller.appspot.com/x/log.txt?x=111c426d400000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=e2808e34f8becb71
> dashboard link: https://syzkaller.appspot.com/bug?extid=f8495bff23a879a6d0bd
> compiler:       clang version 8.0.0 (trunk 343298)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17c0326d400000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17e4d45d400000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+f8495bff23a879a6d0bd@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> Local variable description: ----walk@crypto_ctr_crypt
> Variable was created at:
>   crypto_ctr_crypt+0xae/0xc30 crypto/ctr.c:129
>   skcipher_crypt_blkcipher crypto/skcipher.c:622 [inline]
>   skcipher_encrypt_blkcipher+0x232/0x340 crypto/skcipher.c:631
> ==================================================================
> BUG: KMSAN: uninit-value in gf128mul_4k_lle+0x29e/0x310
> crypto/gf128mul.c:391
> CPU: 0 PID: 8470 Comm: syz-executor696 Not tainted 4.20.0-rc2+ #88
> 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+0x32d/0x480 lib/dump_stack.c:113
>   kmsan_report+0x19f/0x300 mm/kmsan/kmsan.c:911
>   __msan_warning+0x76/0xc0 mm/kmsan/kmsan_instr.c:415
>   gf128mul_4k_lle+0x29e/0x310 crypto/gf128mul.c:391
>   ghash_update+0x9d3/0x10e0 crypto/ghash-generic.c:75
>   crypto_shash_update crypto/shash.c:103 [inline]
>   shash_ahash_update+0x4de/0x600 crypto/shash.c:244
>   shash_async_update+0x50/0x60 crypto/shash.c:252
>   crypto_ahash_update include/crypto/hash.h:557 [inline]
>   gcm_hash_update crypto/gcm.c:235 [inline]
>   gcm_hash_assoc_remain_continue crypto/gcm.c:344 [inline]
>   gcm_hash_assoc_continue crypto/gcm.c:375 [inline]
>   gcm_hash_init_continue crypto/gcm.c:400 [inline]
>   gcm_hash+0x1dbe/0x4870 crypto/gcm.c:430
>   gcm_encrypt_continue crypto/gcm.c:455 [inline]
>   crypto_gcm_encrypt+0x781/0xaa0 crypto/gcm.c:484
>   crypto_aead_encrypt include/crypto/aead.h:364 [inline]
>   tls_do_encryption net/tls/tls_sw.c:460 [inline]
>   tls_push_record+0x2545/0x4290 net/tls/tls_sw.c:657
>   bpf_exec_tx_verdict+0x16c0/0x1b40 net/tls/tls_sw.c:694
>   tls_sw_sendmsg+0x136d/0x2a30 net/tls/tls_sw.c:949
>   inet_sendmsg+0x4e9/0x800 net/ipv4/af_inet.c:798
>   sock_sendmsg_nosec net/socket.c:621 [inline]
>   sock_sendmsg net/socket.c:631 [inline]
>   __sys_sendto+0x940/0xb80 net/socket.c:1788
>   __do_sys_sendto net/socket.c:1800 [inline]
>   __se_sys_sendto+0x107/0x130 net/socket.c:1796
>   __x64_sys_sendto+0x6e/0x90 net/socket.c:1796
>   do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
>   entry_SYSCALL_64_after_hwframe+0x63/0xe7
> RIP: 0033:0x448509
> Code: e8 fc e5 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0b 01 fc ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007f9ff6aa3cd8 EFLAGS: 00000216 ORIG_RAX: 000000000000002c
> RAX: ffffffffffffffda RBX: 00000000006f0038 RCX: 0000000000448509
> RDX: 000000000039a191 RSI: 00000000200005c0 RDI: 0000000000000003
> RBP: 00000000006f0030 R08: 0000000020000000 R09: 000000000000001c
> R10: 0000000000000000 R11: 0000000000000216 R12: 00000000006f003c
> R13: 00000000007ffc6f R14: 00007f9ff6aa49c0 R15: 00000000000003e8
>
> Uninit was stored to memory at:
>   kmsan_save_stack_with_flags mm/kmsan/kmsan.c:252 [inline]
>   kmsan_save_stack mm/kmsan/kmsan.c:267 [inline]
>   kmsan_internal_chain_origin+0x136/0x240 mm/kmsan/kmsan.c:569
>   __msan_chain_origin+0x6d/0xb0 mm/kmsan/kmsan_instr.c:292
>   __crypto_xor+0x224/0x15c0 crypto/algapi.c:1029
>   crypto_xor include/crypto/algapi.h:219 [inline]
>   ghash_update+0x991/0x10e0 crypto/ghash-generic.c:74
>   crypto_shash_update crypto/shash.c:103 [inline]
>   shash_ahash_update+0x4de/0x600 crypto/shash.c:244
>   shash_async_update+0x50/0x60 crypto/shash.c:252
>   crypto_ahash_update include/crypto/hash.h:557 [inline]
>   gcm_hash_update crypto/gcm.c:235 [inline]
>   gcm_hash_assoc_remain_continue crypto/gcm.c:344 [inline]
>   gcm_hash_assoc_continue crypto/gcm.c:375 [inline]
>   gcm_hash_init_continue crypto/gcm.c:400 [inline]
>   gcm_hash+0x1dbe/0x4870 crypto/gcm.c:430
>   gcm_encrypt_continue crypto/gcm.c:455 [inline]
>   crypto_gcm_encrypt+0x781/0xaa0 crypto/gcm.c:484
>   crypto_aead_encrypt include/crypto/aead.h:364 [inline]
>   tls_do_encryption net/tls/tls_sw.c:460 [inline]
>   tls_push_record+0x2545/0x4290 net/tls/tls_sw.c:657
>   bpf_exec_tx_verdict+0x16c0/0x1b40 net/tls/tls_sw.c:694
>   tls_sw_sendmsg+0x136d/0x2a30 net/tls/tls_sw.c:949
>   inet_sendmsg+0x4e9/0x800 net/ipv4/af_inet.c:798
>   sock_sendmsg_nosec net/socket.c:621 [inline]
>   sock_sendmsg net/socket.c:631 [inline]
>   __sys_sendto+0x940/0xb80 net/socket.c:1788
>   __do_sys_sendto net/socket.c:1800 [inline]
>   __se_sys_sendto+0x107/0x130 net/socket.c:1796
>   __x64_sys_sendto+0x6e/0x90 net/socket.c:1796
>   do_syscall_64+0xcf/0x110 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:252 [inline]
>   kmsan_save_stack mm/kmsan/kmsan.c:267 [inline]
>   kmsan_internal_chain_origin+0x136/0x240 mm/kmsan/kmsan.c:569
>   __msan_chain_origin+0x6d/0xb0 mm/kmsan/kmsan_instr.c:292
>   __crypto_xor+0x224/0x15c0 crypto/algapi.c:1029
>   crypto_xor include/crypto/algapi.h:219 [inline]
>   crypto_ctr_crypt_inplace crypto/ctr.c:115 [inline]
>   crypto_ctr_crypt+0x776/0xc30 crypto/ctr.c:142
>   skcipher_crypt_blkcipher crypto/skcipher.c:622 [inline]
>   skcipher_encrypt_blkcipher+0x232/0x340 crypto/skcipher.c:631
>   crypto_skcipher_encrypt include/crypto/skcipher.h:534 [inline]
>   crypto_gcm_encrypt+0x512/0xaa0 crypto/gcm.c:483
>   crypto_aead_encrypt include/crypto/aead.h:364 [inline]
>   tls_do_encryption net/tls/tls_sw.c:460 [inline]
>   tls_push_record+0x2545/0x4290 net/tls/tls_sw.c:657
>   bpf_exec_tx_verdict+0x16c0/0x1b40 net/tls/tls_sw.c:694
>   tls_sw_sendmsg+0x136d/0x2a30 net/tls/tls_sw.c:949
>   inet_sendmsg+0x4e9/0x800 net/ipv4/af_inet.c:798
>   sock_sendmsg_nosec net/socket.c:621 [inline]
>   sock_sendmsg net/socket.c:631 [inline]
>   __sys_sendto+0x940/0xb80 net/socket.c:1788
>   __do_sys_sendto net/socket.c:1800 [inline]
>   __se_sys_sendto+0x107/0x130 net/socket.c:1796
>   __x64_sys_sendto+0x6e/0x90 net/socket.c:1796
>   do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
>   entry_SYSCALL_64_after_hwframe+0x63/0xe7
>
> Uninit was created at:
>   kmsan_save_stack_with_flags mm/kmsan/kmsan.c:252 [inline]
>   kmsan_internal_alloc_meta_for_pages+0x155/0x740 mm/kmsan/kmsan.c:689
>   kmsan_alloc_page+0x77/0xc0 mm/kmsan/kmsan_hooks.c:320
>   __alloc_pages_nodemask+0x12ac/0x64d0 mm/page_alloc.c:4421
>   alloc_pages_current+0x55d/0x7d0 mm/mempolicy.c:2080
>   alloc_pages include/linux/gfp.h:511 [inline]
>   skb_page_frag_refill+0x48e/0x7a0 net/core/sock.c:2213
>   sk_page_frag_refill+0xa4/0x330 net/core/sock.c:2233
>   sk_msg_alloc+0x22f/0x11a0 net/core/skmsg.c:37
>   tls_alloc_encrypted_msg net/tls/tls_sw.c:236 [inline]
>   tls_sw_sendmsg+0xd0c/0x2a30 net/tls/tls_sw.c:871
>   inet_sendmsg+0x4e9/0x800 net/ipv4/af_inet.c:798
>   sock_sendmsg_nosec net/socket.c:621 [inline]
>   sock_sendmsg net/socket.c:631 [inline]
>   __sys_sendto+0x940/0xb80 net/socket.c:1788
>   __do_sys_sendto net/socket.c:1800 [inline]
>   __se_sys_sendto+0x107/0x130 net/socket.c:1796
>   __x64_sys_sendto+0x6e/0x90 net/socket.c:1796
>   do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
>   entry_SYSCALL_64_after_hwframe+0x63/0xe7
> ==================================================================
>
>
> ---
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>
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