This is a note to let you know that I've just added the patch titled

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

to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: crypto-aesni-fix-out-of-bounds-access-of-the-aad-buffer-in-generic-gcm-aesni.patch and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 1ecdd37e308ca149dc378cce225068cbac54e3a6 Mon Sep 17 00:00:00 2001

From: Junaid Shahid junaids@google.com Date: Wed, 20 Dec 2017 17:08:38 -0800 Subject: crypto: aesni - Fix out-of-bounds access of the AAD buffer in generic-gcm-aesni

From: Junaid Shahid junaids@google.com

commit 1ecdd37e308ca149dc378cce225068cbac54e3a6 upstream.

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") Signed-off-by: Junaid Shahid junaids@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/x86/crypto/aesni-intel_asm.S | 112 ++++---------------------------------- 1 file changed, 12 insertions(+), 100 deletions(-)

--- a/arch/x86/crypto/aesni-intel_asm.S +++ b/arch/x86/crypto/aesni-intel_asm.S @@ -90,30 +90,6 @@ SHIFT_MASK: .octa 0x0f0e0d0c0b0a09080706 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

@@ -304,62 +280,30 @@ _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 @@ -563,62 +507,30 @@ _initial_blocks_done\num_initial_blocks\ 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

Patches currently in stable-queue which might be from junaids@google.com are

queue-4.15/crypto-aesni-fix-out-of-bounds-access-of-the-data-buffer-in-generic-gcm-aesni.patch queue-4.15/crypto-aesni-fix-out-of-bounds-access-of-the-aad-buffer-in-generic-gcm-aesni.patch