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crypto: x86/sha1 - Fix reads beyond the number of blocks passed 

It was reported that the sha1 AVX2 function(sha1_transform_avx2) is
reading ahead beyond its intended data, and causing a crash if the next
block is beyond page boundary:
http://marc.info/?l=linux-crypto-vger&m=149373371023377

This patch makes sure that there is no overflow for any buffer length.

It passes the tests written by Jan Stancek that revealed this problem:
https://github.com/jstancek/sha1-avx2-crash

I have re-enabled sha1-avx2 by reverting commit
b82ce24426

Cc: <stable@vger.kernel.org>
Fixes: b82ce24426 ("crypto: sha1-ssse3 - Disable avx2")
Originally-by: Ilya Albrekht <ilya.albrekht@intel.com>
Tested-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Megha Dey <megha.dey@linux.intel.com>
Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
megha.dey@linux.intel.com 2017-08-02 13:49:09 -07:00 committed by Herbert Xu
parent 28389575a8
commit 8861249c74
2 changed files with 37 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

67
arch/x86/crypto/sha1_avx2_x86_64_asm.S
View File

@ -117,11 +117,10 @@
.set T1, REG_T1
.endm
#define K_BASE %r8
#define HASH_PTR %r9
#define BLOCKS_CTR %r8
#define BUFFER_PTR %r10
#define BUFFER_PTR2 %r13
#define BUFFER_END %r11
#define PRECALC_BUF %r14
#define WK_BUF %r15
@ -205,14 +204,14 @@
* blended AVX2 and ALU instruction scheduling
* 1 vector iteration per 8 rounds
*/
vmovdqu ((i * 2) + PRECALC_OFFSET)(BUFFER_PTR), W_TMP
vmovdqu (i * 2)(BUFFER_PTR), W_TMP
.elseif ((i & 7) == 1)
vinsertf128 $1, (((i-1) * 2)+PRECALC_OFFSET)(BUFFER_PTR2),\
vinsertf128 $1, ((i-1) * 2)(BUFFER_PTR2),\
WY_TMP, WY_TMP
.elseif ((i & 7) == 2)
vpshufb YMM_SHUFB_BSWAP, WY_TMP, WY
.elseif ((i & 7) == 4)
vpaddd K_XMM(K_BASE), WY, WY_TMP
vpaddd K_XMM + K_XMM_AR(%rip), WY, WY_TMP
.elseif ((i & 7) == 7)
vmovdqu WY_TMP, PRECALC_WK(i&~7)
@ -255,7 +254,7 @@
vpxor WY, WY_TMP, WY_TMP
.elseif ((i & 7) == 7)
vpxor WY_TMP2, WY_TMP, WY
vpaddd K_XMM(K_BASE), WY, WY_TMP
vpaddd K_XMM + K_XMM_AR(%rip), WY, WY_TMP
vmovdqu WY_TMP, PRECALC_WK(i&~7)
PRECALC_ROTATE_WY
@ -291,7 +290,7 @@
vpsrld $30, WY, WY
vpor WY, WY_TMP, WY
.elseif ((i & 7) == 7)
vpaddd K_XMM(K_BASE), WY, WY_TMP
vpaddd K_XMM + K_XMM_AR(%rip), WY, WY_TMP
vmovdqu WY_TMP, PRECALC_WK(i&~7)
PRECALC_ROTATE_WY
@ -446,6 +445,16 @@
.endm
/* Add constant only if (%2 > %3) condition met (uses RTA as temp)
* %1 + %2 >= %3 ? %4 : 0
*/
.macro ADD_IF_GE a, b, c, d
mov \a, RTA
add $\d, RTA
cmp $\c, \b
cmovge RTA, \a
.endm
/*
* macro implements 80 rounds of SHA-1, for multiple blocks with s/w pipelining
*/
@ -463,13 +472,16 @@
lea (2*4*80+32)(%rsp), WK_BUF
# Precalc WK for first 2 blocks
PRECALC_OFFSET = 0
ADD_IF_GE BUFFER_PTR2, BLOCKS_CTR, 2, 64
.set i, 0
.rept 160
PRECALC i
.set i, i + 1
.endr
PRECALC_OFFSET = 128
/* Go to next block if needed */
ADD_IF_GE BUFFER_PTR, BLOCKS_CTR, 3, 128
ADD_IF_GE BUFFER_PTR2, BLOCKS_CTR, 4, 128
xchg WK_BUF, PRECALC_BUF
.align 32
@ -479,8 +491,8 @@ _loop:
* we use K_BASE value as a signal of a last block,
* it is set below by: cmovae BUFFER_PTR, K_BASE
*/
cmp K_BASE, BUFFER_PTR
jne _begin
test BLOCKS_CTR, BLOCKS_CTR
jnz _begin
.align 32
jmp _end
.align 32
@ -512,10 +524,10 @@ _loop0:
.set j, j+2
.endr
add $(2*64), BUFFER_PTR /* move to next odd-64-byte block */
cmp BUFFER_END, BUFFER_PTR /* is current block the last one? */
cmovae K_BASE, BUFFER_PTR /* signal the last iteration smartly */
/* Update Counter */
sub $1, BLOCKS_CTR
/* Move to the next block only if needed*/
ADD_IF_GE BUFFER_PTR, BLOCKS_CTR, 4, 128
/*
* rounds
* 60,62,64,66,68
@ -532,8 +544,8 @@ _loop0:
UPDATE_HASH 12(HASH_PTR), D
UPDATE_HASH 16(HASH_PTR), E
cmp K_BASE, BUFFER_PTR /* is current block the last one? */
je _loop
test BLOCKS_CTR, BLOCKS_CTR
jz _loop
mov TB, B
@ -575,10 +587,10 @@ _loop2:
.set j, j+2
.endr
add $(2*64), BUFFER_PTR2 /* move to next even-64-byte block */
cmp BUFFER_END, BUFFER_PTR2 /* is current block the last one */
cmovae K_BASE, BUFFER_PTR /* signal the last iteration smartly */
/* update counter */
sub $1, BLOCKS_CTR
/* Move to the next block only if needed*/
ADD_IF_GE BUFFER_PTR2, BLOCKS_CTR, 4, 128
jmp _loop3
_loop3:
@ -641,19 +653,12 @@ _loop3:
avx2_zeroupper
lea K_XMM_AR(%rip), K_BASE
/* Setup initial values */
mov CTX, HASH_PTR
mov BUF, BUFFER_PTR
lea 64(BUF), BUFFER_PTR2
shl $6, CNT /* mul by 64 */
add BUF, CNT
add $64, CNT
mov CNT, BUFFER_END
cmp BUFFER_END, BUFFER_PTR2
cmovae K_BASE, BUFFER_PTR2
mov BUF, BUFFER_PTR2
mov CNT, BLOCKS_CTR
xmm_mov BSWAP_SHUFB_CTL(%rip), YMM_SHUFB_BSWAP

2
arch/x86/crypto/sha1_ssse3_glue.c
View File

@ -201,7 +201,7 @@ asmlinkage void sha1_transform_avx2(u32 *digest, const char *data,
static bool avx2_usable(void)
{
if (false && avx_usable() && boot_cpu_has(X86_FEATURE_AVX2)
if (avx_usable() && boot_cpu_has(X86_FEATURE_AVX2)
&& boot_cpu_has(X86_FEATURE_BMI1)
&& boot_cpu_has(X86_FEATURE_BMI2))
return true;