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@xxxxxxxxxx>
---
arch/x86/crypto/aesni-intel_asm.S | 80 +++++----------------------------------
1 file changed, 10 insertions(+), 70 deletions(-)
diff --git a/arch/x86/crypto/aesni-intel_asm.S b/arch/x86/crypto/aesni-intel_asm.S
index 4b16f31cb359..03846f2d32c9 100644
--- a/arch/x86/crypto/aesni-intel_asm.S
+++ b/arch/x86/crypto/aesni-intel_asm.S
@@ -309,7 +309,7 @@ XMM2 XMM3 XMM4 XMMDst TMP6 TMP7 i i_seq operation
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
@@ -322,43 +322,13 @@ _get_AAD_blocks\num_initial_blocks\operation:
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, %r12, %r11, \TMP1, \TMP2, %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
@@ -568,7 +538,7 @@ XMM2 XMM3 XMM4 XMMDst TMP6 TMP7 i i_seq operation
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
@@ -581,43 +551,13 @@ _get_AAD_blocks\num_initial_blocks\operation:
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, %r12, %r11, \TMP1, \TMP2, %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
--
2.15.1.620.gb9897f4670-goog
