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: [email protected]
Signed-off-by: Ondrej Mosnacek <[email protected]>
---
Still untested, please test and review if possible.
Changes in v2:
- fix leaving preemtption, etc. disabled when leaving the function
(I switched to the more obvious and less efficient variant for the
sake of clarity.)
drivers/crypto/vmx/aes_cbc.c | 30 ++++++++++++++----------------
drivers/crypto/vmx/aes_xts.c | 21 ++++++++++++++-------
2 files changed, 28 insertions(+), 23 deletions(-)
diff --git a/drivers/crypto/vmx/aes_cbc.c b/drivers/crypto/vmx/aes_cbc.c
index 5285ece4f33a..b71895871be3 100644
--- a/drivers/crypto/vmx/aes_cbc.c
+++ b/drivers/crypto/vmx/aes_cbc.c
@@ -107,24 +107,23 @@ static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc,
ret = crypto_skcipher_encrypt(req);
skcipher_request_zero(req);
} else {
- preempt_disable();
- pagefault_disable();
- 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();
aes_p8_cbc_encrypt(walk.src.virt.addr,
walk.dst.virt.addr,
nbytes & AES_BLOCK_MASK,
&ctx->enc_key, walk.iv, 1);
+ disable_kernel_vsx();
+ pagefault_enable();
+ preempt_enable();
+
nbytes &= AES_BLOCK_SIZE - 1;
ret = blkcipher_walk_done(desc, &walk, nbytes);
}
-
- disable_kernel_vsx();
- pagefault_enable();
- preempt_enable();
}
return ret;
@@ -147,24 +146,23 @@ static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc,
ret = crypto_skcipher_decrypt(req);
skcipher_request_zero(req);
} else {
- preempt_disable();
- pagefault_disable();
- 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();
aes_p8_cbc_encrypt(walk.src.virt.addr,
walk.dst.virt.addr,
nbytes & AES_BLOCK_MASK,
&ctx->dec_key, walk.iv, 0);
+ disable_kernel_vsx();
+ pagefault_enable();
+ preempt_enable();
+
nbytes &= AES_BLOCK_SIZE - 1;
ret = blkcipher_walk_done(desc, &walk, nbytes);
}
-
- disable_kernel_vsx();
- pagefault_enable();
- preempt_enable();
}
return ret;
diff --git a/drivers/crypto/vmx/aes_xts.c b/drivers/crypto/vmx/aes_xts.c
index 8bd9aff0f55f..e9954a7d4694 100644
--- a/drivers/crypto/vmx/aes_xts.c
+++ b/drivers/crypto/vmx/aes_xts.c
@@ -116,32 +116,39 @@ static int p8_aes_xts_crypt(struct blkcipher_desc *desc,
ret = enc? crypto_skcipher_encrypt(req) : crypto_skcipher_decrypt(req);
skcipher_request_zero(req);
} else {
+ blkcipher_walk_init(&walk, dst, src, nbytes);
+
+ ret = blkcipher_walk_virt(desc, &walk);
+
preempt_disable();
pagefault_disable();
enable_kernel_vsx();
- blkcipher_walk_init(&walk, dst, src, nbytes);
-
- ret = blkcipher_walk_virt(desc, &walk);
iv = walk.iv;
memset(tweak, 0, AES_BLOCK_SIZE);
aes_p8_encrypt(iv, tweak, &ctx->tweak_key);
+ disable_kernel_vsx();
+ pagefault_enable();
+ preempt_enable();
+
while ((nbytes = walk.nbytes)) {
+ preempt_disable();
+ pagefault_disable();
+ enable_kernel_vsx();
if (enc)
aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak);
else
aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak);
+ disable_kernel_vsx();
+ pagefault_enable();
+ preempt_enable();
nbytes &= AES_BLOCK_SIZE - 1;
ret = blkcipher_walk_done(desc, &walk, nbytes);
}
-
- disable_kernel_vsx();
- pagefault_enable();
- preempt_enable();
}
return ret;
}
--
2.17.1
That looks good to me. Maybe Paulo can help testing it.
--
Regards,
Marcelo
On Wed, Aug 22, 2018 at 08:26:31AM +0200, Ondrej Mosnacek wrote:
> 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: [email protected]
> Signed-off-by: Ondrej Mosnacek <[email protected]>
> ---
> Still untested, please test and review if possible.
>
> Changes in v2:
> - fix leaving preemtption, etc. disabled when leaving the function
> (I switched to the more obvious and less efficient variant for the
> sake of clarity.)
>
> drivers/crypto/vmx/aes_cbc.c | 30 ++++++++++++++----------------
> drivers/crypto/vmx/aes_xts.c | 21 ++++++++++++++-------
> 2 files changed, 28 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/crypto/vmx/aes_cbc.c b/drivers/crypto/vmx/aes_cbc.c
> index 5285ece4f33a..b71895871be3 100644
> --- a/drivers/crypto/vmx/aes_cbc.c
> +++ b/drivers/crypto/vmx/aes_cbc.c
> @@ -107,24 +107,23 @@ static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc,
> ret = crypto_skcipher_encrypt(req);
> skcipher_request_zero(req);
> } else {
> - preempt_disable();
> - pagefault_disable();
> - 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();
> aes_p8_cbc_encrypt(walk.src.virt.addr,
> walk.dst.virt.addr,
> nbytes & AES_BLOCK_MASK,
> &ctx->enc_key, walk.iv, 1);
> + disable_kernel_vsx();
> + pagefault_enable();
> + preempt_enable();
> +
> nbytes &= AES_BLOCK_SIZE - 1;
> ret = blkcipher_walk_done(desc, &walk, nbytes);
> }
> -
> - disable_kernel_vsx();
> - pagefault_enable();
> - preempt_enable();
> }
>
> return ret;
> @@ -147,24 +146,23 @@ static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc,
> ret = crypto_skcipher_decrypt(req);
> skcipher_request_zero(req);
> } else {
> - preempt_disable();
> - pagefault_disable();
> - 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();
> aes_p8_cbc_encrypt(walk.src.virt.addr,
> walk.dst.virt.addr,
> nbytes & AES_BLOCK_MASK,
> &ctx->dec_key, walk.iv, 0);
> + disable_kernel_vsx();
> + pagefault_enable();
> + preempt_enable();
> +
> nbytes &= AES_BLOCK_SIZE - 1;
> ret = blkcipher_walk_done(desc, &walk, nbytes);
> }
> -
> - disable_kernel_vsx();
> - pagefault_enable();
> - preempt_enable();
> }
>
> return ret;
> diff --git a/drivers/crypto/vmx/aes_xts.c b/drivers/crypto/vmx/aes_xts.c
> index 8bd9aff0f55f..e9954a7d4694 100644
> --- a/drivers/crypto/vmx/aes_xts.c
> +++ b/drivers/crypto/vmx/aes_xts.c
> @@ -116,32 +116,39 @@ static int p8_aes_xts_crypt(struct blkcipher_desc *desc,
> ret = enc? crypto_skcipher_encrypt(req) : crypto_skcipher_decrypt(req);
> skcipher_request_zero(req);
> } else {
> + blkcipher_walk_init(&walk, dst, src, nbytes);
> +
> + ret = blkcipher_walk_virt(desc, &walk);
> +
> preempt_disable();
> pagefault_disable();
> enable_kernel_vsx();
>
> - blkcipher_walk_init(&walk, dst, src, nbytes);
> -
> - ret = blkcipher_walk_virt(desc, &walk);
> iv = walk.iv;
> memset(tweak, 0, AES_BLOCK_SIZE);
> aes_p8_encrypt(iv, tweak, &ctx->tweak_key);
>
> + disable_kernel_vsx();
> + pagefault_enable();
> + preempt_enable();
> +
> while ((nbytes = walk.nbytes)) {
> + preempt_disable();
> + pagefault_disable();
> + enable_kernel_vsx();
> if (enc)
> aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
> nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak);
> else
> aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
> nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak);
> + disable_kernel_vsx();
> + pagefault_enable();
> + preempt_enable();
>
> nbytes &= AES_BLOCK_SIZE - 1;
> ret = blkcipher_walk_done(desc, &walk, nbytes);
> }
> -
> - disable_kernel_vsx();
> - pagefault_enable();
> - preempt_enable();
> }
> return ret;
> }
> --
> 2.17.1
>
On 2018-08-22 21:04, Marcelo Henrique Cerri wrote:
> That looks good to me. Maybe Paulo can help testing it.
>
> --
> Regards,
> Marcelo
>
> On Wed, Aug 22, 2018 at 08:26:31AM +0200, Ondrej Mosnacek wrote:
>> 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: [email protected]
>> Signed-off-by: Ondrej Mosnacek <[email protected]>
>> ---
>> Still untested, please test and review if possible.
>>
>> Changes in v2:
>> - fix leaving preemtption, etc. disabled when leaving the function
>> (I switched to the more obvious and less efficient variant for the
>> sake of clarity.)
>>
>> drivers/crypto/vmx/aes_cbc.c | 30 ++++++++++++++----------------
>> drivers/crypto/vmx/aes_xts.c | 21 ++++++++++++++-------
>> 2 files changed, 28 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/crypto/vmx/aes_cbc.c
>> b/drivers/crypto/vmx/aes_cbc.c
>> index 5285ece4f33a..b71895871be3 100644
>> --- a/drivers/crypto/vmx/aes_cbc.c
>> +++ b/drivers/crypto/vmx/aes_cbc.c
>> @@ -107,24 +107,23 @@ static int p8_aes_cbc_encrypt(struct
>> blkcipher_desc *desc,
>> ret = crypto_skcipher_encrypt(req);
>> skcipher_request_zero(req);
>> } else {
>> - preempt_disable();
>> - pagefault_disable();
>> - 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();
>> aes_p8_cbc_encrypt(walk.src.virt.addr,
>> walk.dst.virt.addr,
>> nbytes & AES_BLOCK_MASK,
>> &ctx->enc_key, walk.iv, 1);
>> + disable_kernel_vsx();
>> + pagefault_enable();
>> + preempt_enable();
>> +
>> nbytes &= AES_BLOCK_SIZE - 1;
>> ret = blkcipher_walk_done(desc, &walk, nbytes);
>> }
>> -
>> - disable_kernel_vsx();
>> - pagefault_enable();
>> - preempt_enable();
>> }
>>
>> return ret;
>> @@ -147,24 +146,23 @@ static int p8_aes_cbc_decrypt(struct
>> blkcipher_desc *desc,
>> ret = crypto_skcipher_decrypt(req);
>> skcipher_request_zero(req);
>> } else {
>> - preempt_disable();
>> - pagefault_disable();
>> - 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();
>> aes_p8_cbc_encrypt(walk.src.virt.addr,
>> walk.dst.virt.addr,
>> nbytes & AES_BLOCK_MASK,
>> &ctx->dec_key, walk.iv, 0);
>> + disable_kernel_vsx();
>> + pagefault_enable();
>> + preempt_enable();
>> +
>> nbytes &= AES_BLOCK_SIZE - 1;
>> ret = blkcipher_walk_done(desc, &walk, nbytes);
>> }
>> -
>> - disable_kernel_vsx();
>> - pagefault_enable();
>> - preempt_enable();
>> }
>>
>> return ret;
>> diff --git a/drivers/crypto/vmx/aes_xts.c
>> b/drivers/crypto/vmx/aes_xts.c
>> index 8bd9aff0f55f..e9954a7d4694 100644
>> --- a/drivers/crypto/vmx/aes_xts.c
>> +++ b/drivers/crypto/vmx/aes_xts.c
>> @@ -116,32 +116,39 @@ static int p8_aes_xts_crypt(struct
>> blkcipher_desc *desc,
>> ret = enc? crypto_skcipher_encrypt(req) :
>> crypto_skcipher_decrypt(req);
>> skcipher_request_zero(req);
>> } else {
>> + blkcipher_walk_init(&walk, dst, src, nbytes);
>> +
>> + ret = blkcipher_walk_virt(desc, &walk);
>> +
>> preempt_disable();
>> pagefault_disable();
>> enable_kernel_vsx();
>>
>> - blkcipher_walk_init(&walk, dst, src, nbytes);
>> -
>> - ret = blkcipher_walk_virt(desc, &walk);
>> iv = walk.iv;
>> memset(tweak, 0, AES_BLOCK_SIZE);
>> aes_p8_encrypt(iv, tweak, &ctx->tweak_key);
>>
>> + disable_kernel_vsx();
>> + pagefault_enable();
>> + preempt_enable();
>> +
>> while ((nbytes = walk.nbytes)) {
>> + preempt_disable();
>> + pagefault_disable();
>> + enable_kernel_vsx();
>> if (enc)
>> aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
>> nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak);
>> else
>> aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
>> nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak);
>> + disable_kernel_vsx();
>> + pagefault_enable();
>> + preempt_enable();
>>
>> nbytes &= AES_BLOCK_SIZE - 1;
>> ret = blkcipher_walk_done(desc, &walk, nbytes);
>> }
>> -
>> - disable_kernel_vsx();
>> - pagefault_enable();
>> - preempt_enable();
>> }
>> return ret;
>> }
>> --
>> 2.17.1
>>
Sure thing. I'll test it later today. Thanks Ondrej for the fix.
--
Paulo Flabiano Smorigo
IBM Linux Technology Center
On 2018-08-23 17:34, Paulo Flabiano Smorigo wrote:
> On 2018-08-22 21:04, Marcelo Henrique Cerri wrote:
>> That looks good to me. Maybe Paulo can help testing it.
>>
>> --
>> Regards,
>> Marcelo
>>
>> On Wed, Aug 22, 2018 at 08:26:31AM +0200, Ondrej Mosnacek wrote:
>>> 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: [email protected]
>>> Signed-off-by: Ondrej Mosnacek <[email protected]>
>>> ---
>>> Still untested, please test and review if possible.
>>>
>>> Changes in v2:
>>> - fix leaving preemtption, etc. disabled when leaving the function
>>> (I switched to the more obvious and less efficient variant for the
>>> sake of clarity.)
>>>
>>> drivers/crypto/vmx/aes_cbc.c | 30 ++++++++++++++----------------
>>> drivers/crypto/vmx/aes_xts.c | 21 ++++++++++++++-------
>>> 2 files changed, 28 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/drivers/crypto/vmx/aes_cbc.c
>>> b/drivers/crypto/vmx/aes_cbc.c
>>> index 5285ece4f33a..b71895871be3 100644
>>> --- a/drivers/crypto/vmx/aes_cbc.c
>>> +++ b/drivers/crypto/vmx/aes_cbc.c
>>> @@ -107,24 +107,23 @@ static int p8_aes_cbc_encrypt(struct
>>> blkcipher_desc *desc,
>>> ret = crypto_skcipher_encrypt(req);
>>> skcipher_request_zero(req);
>>> } else {
>>> - preempt_disable();
>>> - pagefault_disable();
>>> - 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();
>>> aes_p8_cbc_encrypt(walk.src.virt.addr,
>>> walk.dst.virt.addr,
>>> nbytes & AES_BLOCK_MASK,
>>> &ctx->enc_key, walk.iv, 1);
>>> + disable_kernel_vsx();
>>> + pagefault_enable();
>>> + preempt_enable();
>>> +
>>> nbytes &= AES_BLOCK_SIZE - 1;
>>> ret = blkcipher_walk_done(desc, &walk, nbytes);
>>> }
>>> -
>>> - disable_kernel_vsx();
>>> - pagefault_enable();
>>> - preempt_enable();
>>> }
>>>
>>> return ret;
>>> @@ -147,24 +146,23 @@ static int p8_aes_cbc_decrypt(struct
>>> blkcipher_desc *desc,
>>> ret = crypto_skcipher_decrypt(req);
>>> skcipher_request_zero(req);
>>> } else {
>>> - preempt_disable();
>>> - pagefault_disable();
>>> - 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();
>>> aes_p8_cbc_encrypt(walk.src.virt.addr,
>>> walk.dst.virt.addr,
>>> nbytes & AES_BLOCK_MASK,
>>> &ctx->dec_key, walk.iv, 0);
>>> + disable_kernel_vsx();
>>> + pagefault_enable();
>>> + preempt_enable();
>>> +
>>> nbytes &= AES_BLOCK_SIZE - 1;
>>> ret = blkcipher_walk_done(desc, &walk, nbytes);
>>> }
>>> -
>>> - disable_kernel_vsx();
>>> - pagefault_enable();
>>> - preempt_enable();
>>> }
>>>
>>> return ret;
>>> diff --git a/drivers/crypto/vmx/aes_xts.c
>>> b/drivers/crypto/vmx/aes_xts.c
>>> index 8bd9aff0f55f..e9954a7d4694 100644
>>> --- a/drivers/crypto/vmx/aes_xts.c
>>> +++ b/drivers/crypto/vmx/aes_xts.c
>>> @@ -116,32 +116,39 @@ static int p8_aes_xts_crypt(struct
>>> blkcipher_desc *desc,
>>> ret = enc? crypto_skcipher_encrypt(req) :
>>> crypto_skcipher_decrypt(req);
>>> skcipher_request_zero(req);
>>> } else {
>>> + blkcipher_walk_init(&walk, dst, src, nbytes);
>>> +
>>> + ret = blkcipher_walk_virt(desc, &walk);
>>> +
>>> preempt_disable();
>>> pagefault_disable();
>>> enable_kernel_vsx();
>>>
>>> - blkcipher_walk_init(&walk, dst, src, nbytes);
>>> -
>>> - ret = blkcipher_walk_virt(desc, &walk);
>>> iv = walk.iv;
>>> memset(tweak, 0, AES_BLOCK_SIZE);
>>> aes_p8_encrypt(iv, tweak, &ctx->tweak_key);
>>>
>>> + disable_kernel_vsx();
>>> + pagefault_enable();
>>> + preempt_enable();
>>> +
>>> while ((nbytes = walk.nbytes)) {
>>> + preempt_disable();
>>> + pagefault_disable();
>>> + enable_kernel_vsx();
>>> if (enc)
>>> aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
>>> nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak);
>>> else
>>> aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
>>> nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak);
>>> + disable_kernel_vsx();
>>> + pagefault_enable();
>>> + preempt_enable();
>>>
>>> nbytes &= AES_BLOCK_SIZE - 1;
>>> ret = blkcipher_walk_done(desc, &walk, nbytes);
>>> }
>>> -
>>> - disable_kernel_vsx();
>>> - pagefault_enable();
>>> - preempt_enable();
>>> }
>>> return ret;
>>> }
>>> --
>>> 2.17.1
>>>
>
> Sure thing. I'll test it later today. Thanks Ondrej for the fix.
Looks good to me. I made some tests here and no problem was found.
--
Paulo Flabiano Smorigo
IBM Linux Technology Center
On Fri, Aug 24, 2018 at 9:39 PM Paulo Flabiano Smorigo
<[email protected]> wrote:
> On 2018-08-23 17:34, Paulo Flabiano Smorigo wrote:
> > On 2018-08-22 21:04, Marcelo Henrique Cerri wrote:
> >> That looks good to me. Maybe Paulo can help testing it.
> >>
> >> --
> >> Regards,
> >> Marcelo
> >>
> >> On Wed, Aug 22, 2018 at 08:26:31AM +0200, Ondrej Mosnacek wrote:
> >>> 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: [email protected]
> >>> Signed-off-by: Ondrej Mosnacek <[email protected]>
> >>> ---
> >>> Still untested, please test and review if possible.
> >>>
> >>> Changes in v2:
> >>> - fix leaving preemtption, etc. disabled when leaving the function
> >>> (I switched to the more obvious and less efficient variant for the
> >>> sake of clarity.)
> >>>
> >>> drivers/crypto/vmx/aes_cbc.c | 30 ++++++++++++++----------------
> >>> drivers/crypto/vmx/aes_xts.c | 21 ++++++++++++++-------
> >>> 2 files changed, 28 insertions(+), 23 deletions(-)
> >>>
> >>> diff --git a/drivers/crypto/vmx/aes_cbc.c
> >>> b/drivers/crypto/vmx/aes_cbc.c
> >>> index 5285ece4f33a..b71895871be3 100644
> >>> --- a/drivers/crypto/vmx/aes_cbc.c
> >>> +++ b/drivers/crypto/vmx/aes_cbc.c
> >>> @@ -107,24 +107,23 @@ static int p8_aes_cbc_encrypt(struct
> >>> blkcipher_desc *desc,
> >>> ret = crypto_skcipher_encrypt(req);
> >>> skcipher_request_zero(req);
> >>> } else {
> >>> - preempt_disable();
> >>> - pagefault_disable();
> >>> - 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();
> >>> aes_p8_cbc_encrypt(walk.src.virt.addr,
> >>> walk.dst.virt.addr,
> >>> nbytes & AES_BLOCK_MASK,
> >>> &ctx->enc_key, walk.iv, 1);
> >>> + disable_kernel_vsx();
> >>> + pagefault_enable();
> >>> + preempt_enable();
> >>> +
> >>> nbytes &= AES_BLOCK_SIZE - 1;
> >>> ret = blkcipher_walk_done(desc, &walk, nbytes);
> >>> }
> >>> -
> >>> - disable_kernel_vsx();
> >>> - pagefault_enable();
> >>> - preempt_enable();
> >>> }
> >>>
> >>> return ret;
> >>> @@ -147,24 +146,23 @@ static int p8_aes_cbc_decrypt(struct
> >>> blkcipher_desc *desc,
> >>> ret = crypto_skcipher_decrypt(req);
> >>> skcipher_request_zero(req);
> >>> } else {
> >>> - preempt_disable();
> >>> - pagefault_disable();
> >>> - 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();
> >>> aes_p8_cbc_encrypt(walk.src.virt.addr,
> >>> walk.dst.virt.addr,
> >>> nbytes & AES_BLOCK_MASK,
> >>> &ctx->dec_key, walk.iv, 0);
> >>> + disable_kernel_vsx();
> >>> + pagefault_enable();
> >>> + preempt_enable();
> >>> +
> >>> nbytes &= AES_BLOCK_SIZE - 1;
> >>> ret = blkcipher_walk_done(desc, &walk, nbytes);
> >>> }
> >>> -
> >>> - disable_kernel_vsx();
> >>> - pagefault_enable();
> >>> - preempt_enable();
> >>> }
> >>>
> >>> return ret;
> >>> diff --git a/drivers/crypto/vmx/aes_xts.c
> >>> b/drivers/crypto/vmx/aes_xts.c
> >>> index 8bd9aff0f55f..e9954a7d4694 100644
> >>> --- a/drivers/crypto/vmx/aes_xts.c
> >>> +++ b/drivers/crypto/vmx/aes_xts.c
> >>> @@ -116,32 +116,39 @@ static int p8_aes_xts_crypt(struct
> >>> blkcipher_desc *desc,
> >>> ret = enc? crypto_skcipher_encrypt(req) :
> >>> crypto_skcipher_decrypt(req);
> >>> skcipher_request_zero(req);
> >>> } else {
> >>> + blkcipher_walk_init(&walk, dst, src, nbytes);
> >>> +
> >>> + ret = blkcipher_walk_virt(desc, &walk);
> >>> +
> >>> preempt_disable();
> >>> pagefault_disable();
> >>> enable_kernel_vsx();
> >>>
> >>> - blkcipher_walk_init(&walk, dst, src, nbytes);
> >>> -
> >>> - ret = blkcipher_walk_virt(desc, &walk);
> >>> iv = walk.iv;
> >>> memset(tweak, 0, AES_BLOCK_SIZE);
> >>> aes_p8_encrypt(iv, tweak, &ctx->tweak_key);
> >>>
> >>> + disable_kernel_vsx();
> >>> + pagefault_enable();
> >>> + preempt_enable();
> >>> +
> >>> while ((nbytes = walk.nbytes)) {
> >>> + preempt_disable();
> >>> + pagefault_disable();
> >>> + enable_kernel_vsx();
> >>> if (enc)
> >>> aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
> >>> nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak);
> >>> else
> >>> aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
> >>> nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak);
> >>> + disable_kernel_vsx();
> >>> + pagefault_enable();
> >>> + preempt_enable();
> >>>
> >>> nbytes &= AES_BLOCK_SIZE - 1;
> >>> ret = blkcipher_walk_done(desc, &walk, nbytes);
> >>> }
> >>> -
> >>> - disable_kernel_vsx();
> >>> - pagefault_enable();
> >>> - preempt_enable();
> >>> }
> >>> return ret;
> >>> }
> >>> --
> >>> 2.17.1
> >>>
> >
> > Sure thing. I'll test it later today. Thanks Ondrej for the fix.
>
> Looks good to me. I made some tests here and no problem was found.
Great, thanks!
--
Ondrej Mosnacek <omosnace at redhat dot com>
Associate Software Engineer, Security Technologies
Red Hat, Inc.
On Wed, Aug 22, 2018 at 08:26:31AM +0200, Ondrej Mosnacek wrote:
> 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: [email protected]
> Signed-off-by: Ondrej Mosnacek <[email protected]>
Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt