Re: [PATCH 1/2] x86/crypto/sha256-mb: fix panic due to unaligned access

[Herbert Xu]

On Mon, Oct 16, 2017 at 06:51:30PM +0300, Andrey Ryabinin wrote:
> struct sha256_ctx_mgr allocated in sha256_mb_mod_init() via kzalloc()
> and later passed in sha256_mb_flusher_mgr_flush_avx2() function where
> instructions vmovdqa used to access the struct. vmovdqa requires
> 16-bytes aligned argument, but nothing guarantees that struct
> sha256_ctx_mgr will have that alignment. Unaligned vmovdqa will
> generate GP fault.
> 
> Fix this by replacing vmovdqa with vmovdqu which doesn't have alignment
> requirements.
> 
> Fixes: a377c6b1876e ("crypto: sha256-mb - submit/flush routines for AVX2")
> Reported-by: Josh Poimboeuf 
> Signed-off-by: Andrey Ryabinin 
> Cc: 

Both patches applied.  Thanks.
-- 
Email: Herbert Xu 
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 1/2] x86/crypto/sha256-mb: fix panic due to unaligned access

[Tim Chen]

On 10/16/2017 08:51 AM, Andrey Ryabinin wrote:
> struct sha256_ctx_mgr allocated in sha256_mb_mod_init() via kzalloc()
> and later passed in sha256_mb_flusher_mgr_flush_avx2() function where
> instructions vmovdqa used to access the struct. vmovdqa requires
> 16-bytes aligned argument, but nothing guarantees that struct
> sha256_ctx_mgr will have that alignment. Unaligned vmovdqa will
> generate GP fault.
> 
> Fix this by replacing vmovdqa with vmovdqu which doesn't have alignment
> requirements.

Using vmovdqu will be a bit slower if the structure is unaligned.
However, flush is done on the non performance critical path so
I don't expect this will be an issue to performance.  

Thanks.

Tim

Acked-by: Tim Chen 

> 
> Fixes: a377c6b1876e ("crypto: sha256-mb - submit/flush routines for AVX2")
> Reported-by: Josh Poimboeuf 
> Signed-off-by: Andrey Ryabinin 
> Cc: 
> ---
>  arch/x86/crypto/sha256-mb/sha256_mb_mgr_flush_avx2.S | 12 ++--
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/crypto/sha256-mb/sha256_mb_mgr_flush_avx2.S 
> b/arch/x86/crypto/sha256-mb/sha256_mb_mgr_flush_avx2.S
> index 8fe6338bcc84..16c4ccb1f154 100644
> --- a/arch/x86/crypto/sha256-mb/sha256_mb_mgr_flush_avx2.S
> +++ b/arch/x86/crypto/sha256-mb/sha256_mb_mgr_flush_avx2.S
> @@ -155,8 +155,8 @@ LABEL skip_ %I
>  .endr
>  
>   # Find min length
> - vmovdqa _lens+0*16(state), %xmm0
> - vmovdqa _lens+1*16(state), %xmm1
> + vmovdqu _lens+0*16(state), %xmm0
> + vmovdqu _lens+1*16(state), %xmm1
>  
>   vpminud %xmm1, %xmm0, %xmm2 # xmm2 has {D,C,B,A}
>   vpalignr $8, %xmm2, %xmm3, %xmm3# xmm3 has {x,x,D,C}
> @@ -176,8 +176,8 @@ LABEL skip_ %I
>   vpsubd  %xmm2, %xmm0, %xmm0
>   vpsubd  %xmm2, %xmm1, %xmm1
>  
> - vmovdqa %xmm0, _lens+0*16(state)
> - vmovdqa %xmm1, _lens+1*16(state)
> + vmovdqu %xmm0, _lens+0*16(state)
> + vmovdqu %xmm1, _lens+1*16(state)
>  
>   # "state" and "args" are the same address, arg1
>   # len is arg2
> @@ -234,8 +234,8 @@ ENTRY(sha256_mb_mgr_get_comp_job_avx2)
>   jc  .return_null
>  
>   # Find min length
> - vmovdqa _lens(state), %xmm0
> - vmovdqa _lens+1*16(state), %xmm1
> + vmovdqu _lens(state), %xmm0
> + vmovdqu _lens+1*16(state), %xmm1
>  
>   vpminud %xmm1, %xmm0, %xmm2 # xmm2 has {D,C,B,A}
>   vpalignr $8, %xmm2, %xmm3, %xmm3# xmm3 has {x,x,D,C}
> 

[PATCH 1/2] x86/crypto/sha256-mb: fix panic due to unaligned access

[Andrey Ryabinin]

struct sha256_ctx_mgr allocated in sha256_mb_mod_init() via kzalloc()
and later passed in sha256_mb_flusher_mgr_flush_avx2() function where
instructions vmovdqa used to access the struct. vmovdqa requires
16-bytes aligned argument, but nothing guarantees that struct
sha256_ctx_mgr will have that alignment. Unaligned vmovdqa will
generate GP fault.

Fix this by replacing vmovdqa with vmovdqu which doesn't have alignment
requirements.

Fixes: a377c6b1876e ("crypto: sha256-mb - submit/flush routines for AVX2")
Reported-by: Josh Poimboeuf 
Signed-off-by: Andrey Ryabinin 
Cc: 
---
 arch/x86/crypto/sha256-mb/sha256_mb_mgr_flush_avx2.S | 12 ++--
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/crypto/sha256-mb/sha256_mb_mgr_flush_avx2.S 
b/arch/x86/crypto/sha256-mb/sha256_mb_mgr_flush_avx2.S
index 8fe6338bcc84..16c4ccb1f154 100644
--- a/arch/x86/crypto/sha256-mb/sha256_mb_mgr_flush_avx2.S
+++ b/arch/x86/crypto/sha256-mb/sha256_mb_mgr_flush_avx2.S
@@ -155,8 +155,8 @@ LABEL skip_ %I
 .endr
 
# Find min length
-   vmovdqa _lens+0*16(state), %xmm0
-   vmovdqa _lens+1*16(state), %xmm1
+   vmovdqu _lens+0*16(state), %xmm0
+   vmovdqu _lens+1*16(state), %xmm1
 
vpminud %xmm1, %xmm0, %xmm2 # xmm2 has {D,C,B,A}
vpalignr $8, %xmm2, %xmm3, %xmm3# xmm3 has {x,x,D,C}
@@ -176,8 +176,8 @@ LABEL skip_ %I
vpsubd  %xmm2, %xmm0, %xmm0
vpsubd  %xmm2, %xmm1, %xmm1
 
-   vmovdqa %xmm0, _lens+0*16(state)
-   vmovdqa %xmm1, _lens+1*16(state)
+   vmovdqu %xmm0, _lens+0*16(state)
+   vmovdqu %xmm1, _lens+1*16(state)
 
# "state" and "args" are the same address, arg1
# len is arg2
@@ -234,8 +234,8 @@ ENTRY(sha256_mb_mgr_get_comp_job_avx2)
jc  .return_null
 
# Find min length
-   vmovdqa _lens(state), %xmm0
-   vmovdqa _lens+1*16(state), %xmm1
+   vmovdqu _lens(state), %xmm0
+   vmovdqu _lens+1*16(state), %xmm1
 
vpminud %xmm1, %xmm0, %xmm2 # xmm2 has {D,C,B,A}
vpalignr $8, %xmm2, %xmm3, %xmm3# xmm3 has {x,x,D,C}
-- 
2.13.6