On Mon, Sep 10, 2018 at 9:42 AM Ondrej Mosnacek omosnace@redhat.com wrote:

commit 0522236d4f9c5ab2e79889cb020d1acbe5da416e upstream.

Conflicts: drivers/crypto/vmx/ aes_cbc.c - adapted enable/disable calls to v4.4 state aes_xts.c - did not exist yet in v4.4

This patch fixes sleep-in-atomic bugs in AES-CBC and AES-XTS VMX implementations. The problem is that the blkcipher_* functions should not be called in atomic context.

The bugs can be reproduced via the AF_ALG interface by trying to encrypt/decrypt sufficiently large buffers (at least 64 KiB) using the VMX implementations of 'cbc(aes)' or 'xts(aes)'. Such operations then trigger BUG in crypto_yield():

[ 891.863680] BUG: sleeping function called from invalid context at include/crypto/algapi.h:424 [ 891.864622] in_atomic(): 1, irqs_disabled(): 0, pid: 12347, name: kcapi-enc [ 891.864739] 1 lock held by kcapi-enc/12347: [ 891.864811] #0: 00000000f5d42c46 (sk_lock-AF_ALG){+.+.}, at: skcipher_recvmsg+0x50/0x530 [ 891.865076] CPU: 5 PID: 12347 Comm: kcapi-enc Not tainted 4.19.0-0.rc0.git3.1.fc30.ppc64le #1 [ 891.865251] Call Trace: [ 891.865340] [c0000003387578c0] [c000000000d67ea4] dump_stack+0xe8/0x164 (unreliable) [ 891.865511] [c000000338757910] [c000000000172a58] ___might_sleep+0x2f8/0x310 [ 891.865679] [c000000338757990] [c0000000006bff74] blkcipher_walk_done+0x374/0x4a0 [ 891.865825] [c0000003387579e0] [d000000007e73e70] p8_aes_cbc_encrypt+0x1c8/0x260 [vmx_crypto] [ 891.865993] [c000000338757ad0] [c0000000006c0ee0] skcipher_encrypt_blkcipher+0x60/0x80 [ 891.866128] [c000000338757b10] [c0000000006ec504] skcipher_recvmsg+0x424/0x530 [ 891.866283] [c000000338757bd0] [c000000000b00654] sock_recvmsg+0x74/0xa0 [ 891.866403] [c000000338757c10] [c000000000b00f64] ___sys_recvmsg+0xf4/0x2f0 [ 891.866515] [c000000338757d90] [c000000000b02bb8] __sys_recvmsg+0x68/0xe0 [ 891.866631] [c000000338757e30] [c00000000000bbe4] system_call+0x5c/0x70

Fixes: 8c755ace357c ("crypto: vmx - Adding CBC routines for VMX module") Fixes: c07f5d3da643 ("crypto: vmx - Adding support for XTS") Cc: stable@vger.kernel.org Signed-off-by: Ondrej Mosnacek omosnace@redhat.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

Whoops, sorry about that last Signed-off-by, I cherry-picked from another stable commit and forgot to edit it out...

---

drivers/crypto/vmx/aes_cbc.c | 30 ++++++++++++++---------------- 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/drivers/crypto/vmx/aes_cbc.c b/drivers/crypto/vmx/aes_cbc.c index 9506e8693c81..d8ef1147b344 100644 --- a/drivers/crypto/vmx/aes_cbc.c +++ b/drivers/crypto/vmx/aes_cbc.c @@ -111,24 +111,23 @@ static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc, ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src, nbytes); } else {

•           preempt_disable();
  

•           pagefault_disable();
  

•           enable_kernel_altivec();
  

•           enable_kernel_vsx();
  

•           blkcipher_walk_init(&walk, dst, src, nbytes);
            ret = blkcipher_walk_virt(desc, &walk);
            while ((nbytes = walk.nbytes)) {
  

•                   preempt_disable();
  

•                   pagefault_disable();
  

•                   enable_kernel_vsx();
  

•                   enable_kernel_altivec();
                    aes_p8_cbc_encrypt(walk.src.virt.addr,
                                       walk.dst.virt.addr,
                                       nbytes & AES_BLOCK_MASK,
                                       &ctx->enc_key, walk.iv, 1);
  

•                   pagefault_enable();
  

•                   preempt_enable();
  

•                   nbytes &= AES_BLOCK_SIZE - 1;
                    ret = blkcipher_walk_done(desc, &walk, nbytes);
            }
  

•           pagefault_enable();
  

•           preempt_enable();
    }
  
    return ret;
  

@@ -152,24 +151,23 @@ static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc, ret = crypto_blkcipher_decrypt(&fallback_desc, dst, src, nbytes); } else {

•           preempt_disable();
  

•           pagefault_disable();
  

•           enable_kernel_altivec();
  

•           enable_kernel_vsx();
  

•           blkcipher_walk_init(&walk, dst, src, nbytes);
            ret = blkcipher_walk_virt(desc, &walk);
            while ((nbytes = walk.nbytes)) {
  

•                   preempt_disable();
  

•                   pagefault_disable();
  

•                   enable_kernel_vsx();
  

•                   enable_kernel_altivec();
                    aes_p8_cbc_encrypt(walk.src.virt.addr,
                                       walk.dst.virt.addr,
                                       nbytes & AES_BLOCK_MASK,
                                       &ctx->dec_key, walk.iv, 0);
  

•                   pagefault_enable();
  

•                   preempt_enable();
  

•                   nbytes &= AES_BLOCK_SIZE - 1;
                    ret = blkcipher_walk_done(desc, &walk, nbytes);
            }
  

•           pagefault_enable();
  

•           preempt_enable();
    }
  
    return ret;
  

-- 2.17.1