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Commit 1ecdd37e authored by Junaid Shahid's avatar Junaid Shahid Committed by Herbert Xu
Browse files

crypto: aesni - Fix out-of-bounds access of the AAD buffer in generic-gcm-aesni 



The aesni_gcm_enc/dec functions can access memory after the end of
the AAD buffer if the AAD length is not a multiple of 4 bytes.
It didn't matter with rfc4106-gcm-aesni as in that case the AAD was
always followed by the 8 byte IV, but that is no longer the case with
generic-gcm-aesni. This can potentially result in accessing a page that
is not mapped and thus causing the machine to crash. This patch fixes
that by reading the last <16 byte block of the AAD byte-by-byte and
optionally via an 8-byte load if the block was at least 8 bytes.

Fixes: 0487ccac ("crypto: aesni - make non-AVX AES-GCM work with any aadlen")
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarJunaid Shahid <junaids@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent b20209c9

arch/x86/crypto/aesni-intel_asm.S

+12 −100
Original line number Diff line number Diff line
@@ -89,30 +89,6 @@ SHIFT_MASK: .octa 0x0f0e0d0c0b0a09080706050403020100 
ALL_F:      .octa 0xffffffffffffffffffffffffffffffff

            .octa 0x00000000000000000000000000000000



.section .rodata

.align 16

.type aad_shift_arr, @object

.size aad_shift_arr, 272

aad_shift_arr:

        .octa     0xffffffffffffffffffffffffffffffff

        .octa     0xffffffffffffffffffffffffffffff0C

        .octa     0xffffffffffffffffffffffffffff0D0C

        .octa     0xffffffffffffffffffffffffff0E0D0C

        .octa     0xffffffffffffffffffffffff0F0E0D0C

        .octa     0xffffffffffffffffffffff0C0B0A0908

        .octa     0xffffffffffffffffffff0D0C0B0A0908

        .octa     0xffffffffffffffffff0E0D0C0B0A0908

        .octa     0xffffffffffffffff0F0E0D0C0B0A0908

        .octa     0xffffffffffffff0C0B0A090807060504

        .octa     0xffffffffffff0D0C0B0A090807060504

        .octa     0xffffffffff0E0D0C0B0A090807060504

        .octa     0xffffffff0F0E0D0C0B0A090807060504

        .octa     0xffffff0C0B0A09080706050403020100

        .octa     0xffff0D0C0B0A09080706050403020100

        .octa     0xff0E0D0C0B0A09080706050403020100

        .octa     0x0F0E0D0C0B0A09080706050403020100





.text
@@ -303,62 +279,30 @@ _done_read_partial_block_\@: 
XMM2 XMM3 XMM4 XMMDst TMP6 TMP7 i i_seq operation

        MOVADQ     SHUF_MASK(%rip), %xmm14

	mov	   arg7, %r10           # %r10 = AAD

	mov	   arg8, %r12           # %r12 = aadLen

	mov	   %r12, %r11

	mov	   arg8, %r11           # %r11 = aadLen

	pxor	   %xmm\i, %xmm\i

	pxor       \XMM2, \XMM2



	cmp	   $16, %r11

	jl	   _get_AAD_rest8\num_initial_blocks\operation

	jl	   _get_AAD_rest\num_initial_blocks\operation

_get_AAD_blocks\num_initial_blocks\operation:

	movdqu	   (%r10), %xmm\i

	PSHUFB_XMM %xmm14, %xmm\i # byte-reflect the AAD data

	pxor	   %xmm\i, \XMM2

	GHASH_MUL  \XMM2, \TMP3, \TMP1, \TMP2, \TMP4, \TMP5, \XMM1

	add	   $16, %r10

	sub	   $16, %r12

	sub	   $16, %r11

	cmp	   $16, %r11

	jge	   _get_AAD_blocks\num_initial_blocks\operation



	movdqu	   \XMM2, %xmm\i



	/* read the last <16B of AAD */

_get_AAD_rest\num_initial_blocks\operation:

	cmp	   $0, %r11

	je	   _get_AAD_done\num_initial_blocks\operation



	pxor	   %xmm\i,%xmm\i



	/* read the last <16B of AAD. since we have at least 4B of

	data right after the AAD (the ICV, and maybe some CT), we can

	read 4B/8B blocks safely, and then get rid of the extra stuff */

_get_AAD_rest8\num_initial_blocks\operation:

	cmp	   $4, %r11

	jle	   _get_AAD_rest4\num_initial_blocks\operation

	movq	   (%r10), \TMP1

	add	   $8, %r10

	sub	   $8, %r11

	pslldq	   $8, \TMP1

	psrldq	   $8, %xmm\i

	pxor	   \TMP1, %xmm\i

	jmp	   _get_AAD_rest8\num_initial_blocks\operation

_get_AAD_rest4\num_initial_blocks\operation:

	cmp	   $0, %r11

	jle	   _get_AAD_rest0\num_initial_blocks\operation

	mov	   (%r10), %eax

	movq	   %rax, \TMP1

	add	   $4, %r10

	sub	   $4, %r10

	pslldq	   $12, \TMP1

	psrldq	   $4, %xmm\i

	pxor	   \TMP1, %xmm\i

_get_AAD_rest0\num_initial_blocks\operation:

	/* finalize: shift out the extra bytes we read, and align

	left. since pslldq can only shift by an immediate, we use

	vpshufb and an array of shuffle masks */

	movq	   %r12, %r11

	salq	   $4, %r11

	movdqu	   aad_shift_arr(%r11), \TMP1

	PSHUFB_XMM \TMP1, %xmm\i

_get_AAD_rest_final\num_initial_blocks\operation:

	READ_PARTIAL_BLOCK %r10, %r11, \TMP1, %xmm\i

	PSHUFB_XMM   %xmm14, %xmm\i # byte-reflect the AAD data

	pxor	   \XMM2, %xmm\i

	GHASH_MUL  %xmm\i, \TMP3, \TMP1, \TMP2, \TMP4, \TMP5, \XMM1
@@ -562,62 +506,30 @@ _initial_blocks_done\num_initial_blocks\operation: 
XMM2 XMM3 XMM4 XMMDst TMP6 TMP7 i i_seq operation

        MOVADQ     SHUF_MASK(%rip), %xmm14

	mov	   arg7, %r10           # %r10 = AAD

	mov	   arg8, %r12           # %r12 = aadLen

	mov	   %r12, %r11

	mov	   arg8, %r11           # %r11 = aadLen

	pxor	   %xmm\i, %xmm\i

	pxor	   \XMM2, \XMM2



	cmp	   $16, %r11

	jl	   _get_AAD_rest8\num_initial_blocks\operation

	jl	   _get_AAD_rest\num_initial_blocks\operation

_get_AAD_blocks\num_initial_blocks\operation:

	movdqu	   (%r10), %xmm\i

	PSHUFB_XMM   %xmm14, %xmm\i # byte-reflect the AAD data

	pxor	   %xmm\i, \XMM2

	GHASH_MUL  \XMM2, \TMP3, \TMP1, \TMP2, \TMP4, \TMP5, \XMM1

	add	   $16, %r10

	sub	   $16, %r12

	sub	   $16, %r11

	cmp	   $16, %r11

	jge	   _get_AAD_blocks\num_initial_blocks\operation



	movdqu	   \XMM2, %xmm\i



	/* read the last <16B of AAD */

_get_AAD_rest\num_initial_blocks\operation:

	cmp	   $0, %r11

	je	   _get_AAD_done\num_initial_blocks\operation



	pxor	   %xmm\i,%xmm\i



	/* read the last <16B of AAD. since we have at least 4B of

	data right after the AAD (the ICV, and maybe some PT), we can

	read 4B/8B blocks safely, and then get rid of the extra stuff */

_get_AAD_rest8\num_initial_blocks\operation:

	cmp	   $4, %r11

	jle	   _get_AAD_rest4\num_initial_blocks\operation

	movq	   (%r10), \TMP1

	add	   $8, %r10

	sub	   $8, %r11

	pslldq	   $8, \TMP1

	psrldq	   $8, %xmm\i

	pxor	   \TMP1, %xmm\i

	jmp	   _get_AAD_rest8\num_initial_blocks\operation

_get_AAD_rest4\num_initial_blocks\operation:

	cmp	   $0, %r11

	jle	   _get_AAD_rest0\num_initial_blocks\operation

	mov	   (%r10), %eax

	movq	   %rax, \TMP1

	add	   $4, %r10

	sub	   $4, %r10

	pslldq	   $12, \TMP1

	psrldq	   $4, %xmm\i

	pxor	   \TMP1, %xmm\i

_get_AAD_rest0\num_initial_blocks\operation:

	/* finalize: shift out the extra bytes we read, and align

	left. since pslldq can only shift by an immediate, we use

	vpshufb and an array of shuffle masks */

	movq	   %r12, %r11

	salq	   $4, %r11

	movdqu	   aad_shift_arr(%r11), \TMP1

	PSHUFB_XMM \TMP1, %xmm\i

_get_AAD_rest_final\num_initial_blocks\operation:

	READ_PARTIAL_BLOCK %r10, %r11, \TMP1, %xmm\i

	PSHUFB_XMM   %xmm14, %xmm\i # byte-reflect the AAD data

	pxor	   \XMM2, %xmm\i

	GHASH_MUL  %xmm\i, \TMP3, \TMP1, \TMP2, \TMP4, \TMP5, \XMM1