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

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Date:   Mon, 16 Oct 2017 18:51:30 +0300
From:   Andrey Ryabinin <aryabinin@...tuozzo.com>
To:     Herbert Xu <herbert@...dor.apana.org.au>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Jeffrey Walton <noloader@...il.com>,
        Megha Dey <megha.dey@...ux.intel.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        stable@...r.kernel.org
Subject: [PATCH 1/2] x86/crypto/sha256-mb: fix panic due to unaligned access

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 <jpoimboe@...hat.com>
Signed-off-by: Andrey Ryabinin <aryabinin@...tuozzo.com>
Cc: <stable@...r.kernel.org>
---
 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