Return-Path: Received: from mail-vs1-f67.google.com ([209.85.217.67]:43043 "EHLO mail-vs1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727431AbeK1WAH (ORCPT ); Wed, 28 Nov 2018 17:00:07 -0500 Received: by mail-vs1-f67.google.com with SMTP id x1so15737171vsc.10 for ; Wed, 28 Nov 2018 02:58:50 -0800 (PST) MIME-Version: 1.0 References: <000000000000bf2457057b5ccda3@google.com> In-Reply-To: From: Alexander Potapenko Date: Wed, 28 Nov 2018 11:58:37 +0100 Message-ID: Subject: Re: KMSAN: uninit-value in gf128mul_4k_lle (3) To: Ard Biesheuvel Cc: syzbot+f8495bff23a879a6d0bd@syzkaller.appspotmail.com, borisp@mellanox.com, aviadye@mellanox.com, davejwatson@fb.com, David Miller , Herbert Xu , linux-crypto@vger.kernel.org, LKML , syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-crypto-owner@vger.kernel.org List-ID: On Sat, Nov 24, 2018 at 12:02 AM Ard Biesheuvel wrote: > > (+ TLS maintainers) This bug is also reproducible without KMSAN: if we fill the newly allocated skb fragment with "AAAA" (see the patch below) we can see these bytes being passed into the crypto functions. Note that KMSAN enables CONFIG_GENERIC_CSUM, so one might need something along the lines of https://github.com/google/kmsan/commit/fffec98ae2a605a3b8a6b3518e3d61d66c1b= fd0a to reproduce this. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D diff --git a/crypto/algapi.c b/crypto/algapi.c index 2545c5f89c4c..654b3e9877a5 100644 --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -1005,6 +1005,25 @@ void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int len) { int relalign =3D 0; + char saved; + char *s1 =3D (char*)src1, *s2 =3D (char*)src2; + if (len) { + saved =3D s1[len-1]; + s1[len-1] =3D 0; + if (strstr(s1, "AAAA")) + pr_err("src1: %s\n", s1); + s1[len-1] =3D saved; + } + if (len) { + saved =3D s2[len-1]; + s2[len-1] =3D 0; + if (strstr(s2, "AAAA")) { + pr_err("src2: %s\n", s2); + if (s1 =3D=3D s2) + pr_err("s1 =3D=3D s2\n"); + } + s2[len-1] =3D saved; + } if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) { int size =3D sizeof(unsigned long); int d =3D (((unsigned long)dst ^ (unsigned long)src1) | diff --git a/net/core/sock.c b/net/core/sock.c index 080a880a1761..83f15668c3e8 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2216,6 +2216,7 @@ bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t gfp) SKB_FRAG_PAGE_ORDER); if (likely(pfrag->page)) { pfrag->size =3D PAGE_SIZE << SKB_FRAG_PAGE_ORDER; + memset(page_address(pfrag->page), 'A', pfrag->size)= ; return true; } } The bug itself seems to be a data race, it only worked for me with the multithreaded C reproducer that collided the syscalls. > On Fri, 23 Nov 2018 at 23:51, syzbot > 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=3D111c426d400= 000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=3De2808e34f8b= ecb71 > > dashboard link: https://syzkaller.appspot.com/bug?extid=3Df8495bff23a87= 9a6d0bd > > compiler: clang version 8.0.0 (trunk 343298) > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=3D17c0326d4= 00000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=3D17e4d45d400= 000 > > > > IMPORTANT: if you fix the bug, please add the following tag to the comm= it: > > Reported-by: syzbot+f8495bff23a879a6d0bd@syzkaller.appspotmail.com > > > > 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 > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > 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 > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > > > > > --- > > 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#bug-status-tracking for how to communicate with > > syzbot. > > syzbot can test patches for this bug, for details see: > > https://goo.gl/tpsmEJ#testing-patches > > -- > You received this message because you are subscribed to the Google Groups= "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an= email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgi= d/syzkaller-bugs/CAKv%2BGu8nZhmFhSy_FJLA2HkO4O56N3BdowNKmBcmCRoH%2BiNx%2BA%= 40mail.gmail.com. > For more options, visit https://groups.google.com/d/optout. --=20 Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Stra=C3=9Fe, 33 80636 M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg