releases/4.4.157/crypto-vmx-fix-sleep-in-atomic-bugs.patch

   1 From 0522236d4f9c5ab2e79889cb020d1acbe5da416e Mon Sep 17 00:00:00 2001
   2 From: Ondrej Mosnacek <omosnace@redhat.com>
   3 Date: Wed, 22 Aug 2018 08:26:31 +0200
   4 Subject: crypto: vmx - Fix sleep-in-atomic bugs
   5
   6 From: Ondrej Mosnacek <omosnace@redhat.com>
   7
   8 commit 0522236d4f9c5ab2e79889cb020d1acbe5da416e upstream.
   9
  10 This patch fixes sleep-in-atomic bugs in AES-CBC and AES-XTS VMX
  11 implementations. The problem is that the blkcipher_* functions should
  12 not be called in atomic context.
  13
  14 The bugs can be reproduced via the AF_ALG interface by trying to
  15 encrypt/decrypt sufficiently large buffers (at least 64 KiB) using the
  16 VMX implementations of 'cbc(aes)' or 'xts(aes)'. Such operations then
  17 trigger BUG in crypto_yield():
  18
  19 [  891.863680] BUG: sleeping function called from invalid context at include/crypto/algapi.h:424
  20 [  891.864622] in_atomic(): 1, irqs_disabled(): 0, pid: 12347, name: kcapi-enc
  21 [  891.864739] 1 lock held by kcapi-enc/12347:
  22 [  891.864811]  #0: 00000000f5d42c46 (sk_lock-AF_ALG){+.+.}, at: skcipher_recvmsg+0x50/0x530
  23 [  891.865076] CPU: 5 PID: 12347 Comm: kcapi-enc Not tainted 4.19.0-0.rc0.git3.1.fc30.ppc64le #1
  24 [  891.865251] Call Trace:
  25 [  891.865340] [c0000003387578c0] [c000000000d67ea4] dump_stack+0xe8/0x164 (unreliable)
  26 [  891.865511] [c000000338757910] [c000000000172a58] ___might_sleep+0x2f8/0x310
  27 [  891.865679] [c000000338757990] [c0000000006bff74] blkcipher_walk_done+0x374/0x4a0
  28 [  891.865825] [c0000003387579e0] [d000000007e73e70] p8_aes_cbc_encrypt+0x1c8/0x260 [vmx_crypto]
  29 [  891.865993] [c000000338757ad0] [c0000000006c0ee0] skcipher_encrypt_blkcipher+0x60/0x80
  30 [  891.866128] [c000000338757b10] [c0000000006ec504] skcipher_recvmsg+0x424/0x530
  31 [  891.866283] [c000000338757bd0] [c000000000b00654] sock_recvmsg+0x74/0xa0
  32 [  891.866403] [c000000338757c10] [c000000000b00f64] ___sys_recvmsg+0xf4/0x2f0
  33 [  891.866515] [c000000338757d90] [c000000000b02bb8] __sys_recvmsg+0x68/0xe0
  34 [  891.866631] [c000000338757e30] [c00000000000bbe4] system_call+0x5c/0x70
  35
  36 Fixes: 8c755ace357c ("crypto: vmx - Adding CBC routines for VMX module")
  37 Fixes: c07f5d3da643 ("crypto: vmx - Adding support for XTS")
  38 Cc: stable@vger.kernel.org
  39 Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
  40 Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
  41 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  42 ---
  43  drivers/crypto/vmx/aes_cbc.c |   30 ++++++++++++++----------------
  44  1 file changed, 14 insertions(+), 16 deletions(-)
  45
  46 --- a/drivers/crypto/vmx/aes_cbc.c
  47 +++ b/drivers/crypto/vmx/aes_cbc.c
  48 @@ -111,24 +111,23 @@ static int p8_aes_cbc_encrypt(struct blk
  49                 ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src,
  50                                                nbytes);
  51         } else {
  52 -               preempt_disable();
  53 -               pagefault_disable();
  54 -               enable_kernel_altivec();
  55 -               enable_kernel_vsx();
  56 -
  57                 blkcipher_walk_init(&walk, dst, src, nbytes);
  58                 ret = blkcipher_walk_virt(desc, &walk);
  59                 while ((nbytes = walk.nbytes)) {
  60 +                       preempt_disable();
  61 +                       pagefault_disable();
  62 +                       enable_kernel_vsx();
  63 +                       enable_kernel_altivec();
  64                         aes_p8_cbc_encrypt(walk.src.virt.addr,
  65                                            walk.dst.virt.addr,
  66                                            nbytes & AES_BLOCK_MASK,
  67                                            &ctx->enc_key, walk.iv, 1);
  68 +                       pagefault_enable();
  69 +                       preempt_enable();
  70 +
  71                         nbytes &= AES_BLOCK_SIZE - 1;
  72                         ret = blkcipher_walk_done(desc, &walk, nbytes);
  73                 }
  74 -
  75 -               pagefault_enable();
  76 -               preempt_enable();
  77         }
  78
  79         return ret;
  80 @@ -152,24 +151,23 @@ static int p8_aes_cbc_decrypt(struct blk
  81                 ret = crypto_blkcipher_decrypt(&fallback_desc, dst, src,
  82                                                nbytes);
  83         } else {
  84 -               preempt_disable();
  85 -               pagefault_disable();
  86 -               enable_kernel_altivec();
  87 -               enable_kernel_vsx();
  88 -
  89                 blkcipher_walk_init(&walk, dst, src, nbytes);
  90                 ret = blkcipher_walk_virt(desc, &walk);
  91                 while ((nbytes = walk.nbytes)) {
  92 +                       preempt_disable();
  93 +                       pagefault_disable();
  94 +                       enable_kernel_vsx();
  95 +                       enable_kernel_altivec();
  96                         aes_p8_cbc_encrypt(walk.src.virt.addr,
  97                                            walk.dst.virt.addr,
  98                                            nbytes & AES_BLOCK_MASK,
  99                                            &ctx->dec_key, walk.iv, 0);
 100 +                       pagefault_enable();
 101 +                       preempt_enable();
 102 +
 103                         nbytes &= AES_BLOCK_SIZE - 1;
 104                         ret = blkcipher_walk_done(desc, &walk, nbytes);
 105                 }
 106 -
 107 -               pagefault_enable();
 108 -               preempt_enable();
 109         }
 110
 111         return ret;