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 data 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-data-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 b20209c91e23a9bbad9cac2f80bc16b3c259e10e Mon Sep 17 00:00:00 2001

From: Junaid Shahid junaids@google.com Date: Wed, 20 Dec 2017 17:08:37 -0800 Subject: crypto: aesni - Fix out-of-bounds access of the data buffer in generic-gcm-aesni

From: Junaid Shahid junaids@google.com

commit b20209c91e23a9bbad9cac2f80bc16b3c259e10e upstream.

The aesni_gcm_enc/dec functions can access memory before the start of the data buffer if the length of the data buffer is less than 16 bytes. This is because they perform the read via a single 16-byte load. 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 partial block byte-by-byte and optionally an via 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 | 87 +++++++++++++++++++------------------- 1 file changed, 45 insertions(+), 42 deletions(-)

--- a/arch/x86/crypto/aesni-intel_asm.S +++ b/arch/x86/crypto/aesni-intel_asm.S @@ -257,6 +257,37 @@ aad_shift_arr: pxor \TMP1, \GH # result is in TMP1 .endm

+# Reads DLEN bytes starting at DPTR and stores in XMMDst +# where 0 < DLEN < 16 +# Clobbers %rax, DLEN and XMM1 +.macro READ_PARTIAL_BLOCK DPTR DLEN XMM1 XMMDst + cmp $8, \DLEN + jl _read_lt8_@ + mov (\DPTR), %rax + MOVQ_R64_XMM %rax, \XMMDst + sub $8, \DLEN + jz _done_read_partial_block_@ + xor %eax, %eax +_read_next_byte_@: + shl $8, %rax + mov 7(\DPTR, \DLEN, 1), %al + dec \DLEN + jnz _read_next_byte_@ + MOVQ_R64_XMM %rax, \XMM1 + pslldq $8, \XMM1 + por \XMM1, \XMMDst + jmp _done_read_partial_block_@ +_read_lt8_@: + xor %eax, %eax +_read_next_byte_lt8_@: + shl $8, %rax + mov -1(\DPTR, \DLEN, 1), %al + dec \DLEN + jnz _read_next_byte_lt8_@ + MOVQ_R64_XMM %rax, \XMMDst +_done_read_partial_block_@: +.endm + /* * if a = number of total plaintext bytes * b = floor(a/16) @@ -1386,14 +1417,6 @@ _esb_loop_@: * * AAD Format with 64-bit Extended Sequence Number * -* aadLen: -* from the definition of the spec, aadLen can only be 8 or 12 bytes. -* The code supports 16 too but for other sizes, the code will fail. -* -* TLen: -* from the definition of the spec, TLen can only be 8, 12 or 16 bytes. -* For other sizes, the code will fail. -* * poly = x^128 + x^127 + x^126 + x^121 + 1 * *****************************************************************************/ @@ -1487,19 +1510,16 @@ _zero_cipher_left_decrypt: PSHUFB_XMM %xmm10, %xmm0

ENCRYPT_SINGLE_BLOCK %xmm0, %xmm1 # E(K, Yn) - sub $16, %r11 - add %r13, %r11 - movdqu (%arg3,%r11,1), %xmm1 # receive the last <16 byte block - lea SHIFT_MASK+16(%rip), %r12 - sub %r13, %r12 -# adjust the shuffle mask pointer to be able to shift 16-%r13 bytes -# (%r13 is the number of bytes in plaintext mod 16) - movdqu (%r12), %xmm2 # get the appropriate shuffle mask - PSHUFB_XMM %xmm2, %xmm1 # right shift 16-%r13 butes

+ lea (%arg3,%r11,1), %r10 + mov %r13, %r12 + READ_PARTIAL_BLOCK %r10 %r12 %xmm2 %xmm1 + + lea ALL_F+16(%rip), %r12 + sub %r13, %r12 movdqa %xmm1, %xmm2 pxor %xmm1, %xmm0 # Ciphertext XOR E(K, Yn) - movdqu ALL_F-SHIFT_MASK(%r12), %xmm1 + movdqu (%r12), %xmm1 # get the appropriate mask to mask out top 16-%r13 bytes of %xmm0 pand %xmm1, %xmm0 # mask out top 16-%r13 bytes of %xmm0 pand %xmm1, %xmm2 @@ -1508,9 +1528,6 @@ _zero_cipher_left_decrypt:

pxor %xmm2, %xmm8 GHASH_MUL %xmm8, %xmm13, %xmm9, %xmm10, %xmm11, %xmm5, %xmm6 - # GHASH computation for the last <16 byte block - sub %r13, %r11 - add $16, %r11

# output %r13 bytes MOVQ_R64_XMM %xmm0, %rax @@ -1664,14 +1681,6 @@ ENDPROC(aesni_gcm_dec) * * AAD Format with 64-bit Extended Sequence Number * -* aadLen: -* from the definition of the spec, aadLen can only be 8 or 12 bytes. -* The code supports 16 too but for other sizes, the code will fail. -* -* TLen: -* from the definition of the spec, TLen can only be 8, 12 or 16 bytes. -* For other sizes, the code will fail. -* * poly = x^128 + x^127 + x^126 + x^121 + 1 ***************************************************************************/ ENTRY(aesni_gcm_enc) @@ -1764,19 +1773,16 @@ _zero_cipher_left_encrypt: movdqa SHUF_MASK(%rip), %xmm10 PSHUFB_XMM %xmm10, %xmm0

- ENCRYPT_SINGLE_BLOCK %xmm0, %xmm1 # Encrypt(K, Yn) - sub $16, %r11 - add %r13, %r11 - movdqu (%arg3,%r11,1), %xmm1 # receive the last <16 byte blocks - lea SHIFT_MASK+16(%rip), %r12 + + lea (%arg3,%r11,1), %r10 + mov %r13, %r12 + READ_PARTIAL_BLOCK %r10 %r12 %xmm2 %xmm1 + + lea ALL_F+16(%rip), %r12 sub %r13, %r12 - # adjust the shuffle mask pointer to be able to shift 16-r13 bytes - # (%r13 is the number of bytes in plaintext mod 16) - movdqu (%r12), %xmm2 # get the appropriate shuffle mask - PSHUFB_XMM %xmm2, %xmm1 # shift right 16-r13 byte pxor %xmm1, %xmm0 # Plaintext XOR Encrypt(K, Yn) - movdqu ALL_F-SHIFT_MASK(%r12), %xmm1 + movdqu (%r12), %xmm1 # get the appropriate mask to mask out top 16-r13 bytes of xmm0 pand %xmm1, %xmm0 # mask out top 16-r13 bytes of xmm0 movdqa SHUF_MASK(%rip), %xmm10 @@ -1785,9 +1791,6 @@ _zero_cipher_left_encrypt: pxor %xmm0, %xmm8 GHASH_MUL %xmm8, %xmm13, %xmm9, %xmm10, %xmm11, %xmm5, %xmm6 # GHASH computation for the last <16 byte block - sub %r13, %r11 - add $16, %r11 - movdqa SHUF_MASK(%rip), %xmm10 PSHUFB_XMM %xmm10, %xmm0

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