Subject: [net/tls] Re: KMSAN: uninit-value in aes_encrypt (4)

From: Eric Biggers <[email-masked]>
Date: Fri, 11 Sep 2020 10:01:50 -0700

Looks like the tls subsystem is encrypting uninitialized memory again.
+tls maintainers and netdev.

On Thu, Sep 10, 2020 at 07:09:24AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    3b3ea602 x86: add failure injection to get/put/clear_user
> git tree:       https://github.com/google/kmsan.git master
> console output: https://syzkaller.appspot.com/x/log.txt?x=1030dda5900000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ee5f7a0b2e48ed66
> dashboard link: https://syzkaller.appspot.com/bug?extid=828dfc12440b4f6f305d
> compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17b15055900000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12931621900000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email-masked]
> 
> =====================================================
> BUG: KMSAN: uninit-value in subshift lib/crypto/aes.c:149 [inline]
> BUG: KMSAN: uninit-value in aes_encrypt+0x12c5/0x1bc0 lib/crypto/aes.c:282
> CPU: 0 PID: 8537 Comm: syz-executor872 Not tainted 5.8.0-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+0x21c/0x280 lib/dump_stack.c:118
>  kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
>  __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
>  subshift lib/crypto/aes.c:149 [inline]
>  aes_encrypt+0x12c5/0x1bc0 lib/crypto/aes.c:282
>  aesti_encrypt+0xe8/0x130 crypto/aes_ti.c:31
>  cipher_crypt_one crypto/cipher.c:75 [inline]
>  crypto_cipher_encrypt_one+0x1e2/0x3a0 crypto/cipher.c:82
>  crypto_cbcmac_digest_update+0x3e3/0x560 crypto/ccm.c:830
>  crypto_shash_update+0x455/0x5a0 crypto/shash.c:119
>  shash_ahash_finup+0x20b/0x7a0 crypto/shash.c:291
>  shash_async_finup+0xbb/0x110 crypto/shash.c:306
>  crypto_ahash_op+0x1c3/0x770 crypto/ahash.c:370
>  crypto_ahash_finup+0x8c/0xb0 crypto/ahash.c:395
>  crypto_ccm_auth+0x16b6/0x1780 crypto/ccm.c:221
>  crypto_ccm_encrypt+0x285/0x850 crypto/ccm.c:300
>  crypto_aead_encrypt+0x107/0x190 crypto/aead.c:94
>  tls_do_encryption net/tls/tls_sw.c:528 [inline]
>  tls_push_record+0x3cb9/0x4fc0 net/tls/tls_sw.c:762
>  bpf_exec_tx_verdict+0x195a/0x29e0 net/tls/tls_sw.c:802
>  tls_sw_do_sendpage+0x138a/0x1e30 net/tls/tls_sw.c:1213
>  tls_sw_sendpage+0x1da/0x250 net/tls/tls_sw.c:1277
>  inet_sendpage+0x1dc/0x2f0 net/ipv4/af_inet.c:828
>  kernel_sendpage net/socket.c:3642 [inline]
>  sock_sendpage+0x1dc/0x2b0 net/socket.c:945
>  pipe_to_sendpage+0x3f4/0x530 fs/splice.c:448
>  splice_from_pipe_feed fs/splice.c:502 [inline]
>  __splice_from_pipe+0x5e3/0xff0 fs/splice.c:626
>  splice_from_pipe fs/splice.c:661 [inline]
>  generic_splice_sendpage+0x1d5/0x2d0 fs/splice.c:834
>  do_splice_from fs/splice.c:846 [inline]
>  do_splice+0x2727/0x39e0 fs/splice.c:1144
>  __do_sys_splice fs/splice.c:1419 [inline]
>  __se_sys_splice+0x323/0x500 fs/splice.c:1401
>  __x64_sys_splice+0x6e/0x90 fs/splice.c:1401
>  do_syscall_64+0xad/0x160 arch/x86/entry/common.c:386
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x446a29
> Code: Bad RIP value.
> RSP: 002b:00007f91f8c0bd98 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
> RAX: ffffffffffffffda RBX: 00000000006dbc48 RCX: 0000000000446a29
> RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000003
> RBP: 00000000006dbc40 R08: 00080000fffffffc R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c
> R13: 0000000020000680 R14: 00000000004ae948 R15: 20c49ba5e353f7cf
> 
> Uninit was stored to memory at:
>  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
>  kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310
>  __msan_chain_origin+0x50/0x90 mm/kmsan/kmsan_instr.c:165
>  __crypto_xor+0x251/0x1610 crypto/algapi.c:1000
>  crypto_xor include/crypto/algapi.h:152 [inline]
>  crypto_cbcmac_digest_update+0x2b8/0x560 crypto/ccm.c:824
>  crypto_shash_update+0x455/0x5a0 crypto/shash.c:119
>  shash_ahash_finup+0x20b/0x7a0 crypto/shash.c:291
>  shash_async_finup+0xbb/0x110 crypto/shash.c:306
>  crypto_ahash_op+0x1c3/0x770 crypto/ahash.c:370
>  crypto_ahash_finup+0x8c/0xb0 crypto/ahash.c:395
>  crypto_ccm_auth+0x16b6/0x1780 crypto/ccm.c:221
>  crypto_ccm_encrypt+0x285/0x850 crypto/ccm.c:300
>  crypto_aead_encrypt+0x107/0x190 crypto/aead.c:94
>  tls_do_encryption net/tls/tls_sw.c:528 [inline]
>  tls_push_record+0x3cb9/0x4fc0 net/tls/tls_sw.c:762
>  bpf_exec_tx_verdict+0x195a/0x29e0 net/tls/tls_sw.c:802
>  tls_sw_do_sendpage+0x138a/0x1e30 net/tls/tls_sw.c:1213
>  tls_sw_sendpage+0x1da/0x250 net/tls/tls_sw.c:1277
>  inet_sendpage+0x1dc/0x2f0 net/ipv4/af_inet.c:828
>  kernel_sendpage net/socket.c:3642 [inline]
>  sock_sendpage+0x1dc/0x2b0 net/socket.c:945
>  pipe_to_sendpage+0x3f4/0x530 fs/splice.c:448
>  splice_from_pipe_feed fs/splice.c:502 [inline]
>  __splice_from_pipe+0x5e3/0xff0 fs/splice.c:626
>  splice_from_pipe fs/splice.c:661 [inline]
>  generic_splice_sendpage+0x1d5/0x2d0 fs/splice.c:834
>  do_splice_from fs/splice.c:846 [inline]
>  do_splice+0x2727/0x39e0 fs/splice.c:1144
>  __do_sys_splice fs/splice.c:1419 [inline]
>  __se_sys_splice+0x323/0x500 fs/splice.c:1401
>  __x64_sys_splice+0x6e/0x90 fs/splice.c:1401
>  do_syscall_64+0xad/0x160 arch/x86/entry/common.c:386
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> 
> Uninit was created at:
>  kmsan_save_stack_with_flags+0x3c/0x90 mm/kmsan/kmsan.c:144
>  kmsan_internal_alloc_meta_for_pages mm/kmsan/kmsan_shadow.c:269 [inline]
>  kmsan_alloc_page+0xc5/0x1a0 mm/kmsan/kmsan_shadow.c:293
>  __alloc_pages_nodemask+0xdf0/0x1030 mm/page_alloc.c:4889
>  alloc_pages_current+0x685/0xb50 mm/mempolicy.c:2292
>  alloc_pages include/linux/gfp.h:545 [inline]
>  skb_page_frag_refill+0x540/0x780 net/core/sock.c:2487
>  sk_page_frag_refill+0xa3/0x3b0 net/core/sock.c:2507
>  sk_msg_alloc+0x26e/0x1340 net/core/skmsg.c:38
>  tls_alloc_encrypted_msg net/tls/tls_sw.c:289 [inline]
>  tls_sw_do_sendpage+0xb0d/0x1e30 net/tls/tls_sw.c:1191
>  tls_sw_sendpage+0x1da/0x250 net/tls/tls_sw.c:1277
>  inet_sendpage+0x1dc/0x2f0 net/ipv4/af_inet.c:828
>  kernel_sendpage net/socket.c:3642 [inline]
>  sock_sendpage+0x1dc/0x2b0 net/socket.c:945
>  pipe_to_sendpage+0x3f4/0x530 fs/splice.c:448
>  splice_from_pipe_feed fs/splice.c:502 [inline]
>  __splice_from_pipe+0x5e3/0xff0 fs/splice.c:626
>  splice_from_pipe fs/splice.c:661 [inline]
>  generic_splice_sendpage+0x1d5/0x2d0 fs/splice.c:834
>  do_splice_from fs/splice.c:846 [inline]
>  do_splice+0x2727/0x39e0 fs/splice.c:1144
>  __do_sys_splice fs/splice.c:1419 [inline]
>  __se_sys_splice+0x323/0x500 fs/splice.c:1401
>  __x64_sys_splice+0x6e/0x90 fs/splice.c:1401
>  do_syscall_64+0xad/0x160 arch/x86/entry/common.c:386
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> =====================================================
> 
> 
> ---
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