[PATCH 11/12] x86/crypto: aesni: Introduce partial block macro
From: Dave Watson
Date: Mon Dec 10 2018 - 15:00:09 EST
Before this diff, multiple calls to GCM_ENC_DEC will
succeed, but only if all calls are a multiple of 16 bytes.
Handle partial blocks at the start of GCM_ENC_DEC, and update
aadhash as appropriate.
The data offset %r11 is also updated after the partial block.
Signed-off-by: Dave Watson <davejwatson@xxxxxx>
---
arch/x86/crypto/aesni-intel_avx-x86_64.S | 156 ++++++++++++++++++++++-
1 file changed, 150 insertions(+), 6 deletions(-)
diff --git a/arch/x86/crypto/aesni-intel_avx-x86_64.S b/arch/x86/crypto/aesni-intel_avx-x86_64.S
index ff00ad19064d..af45fc57db90 100644
--- a/arch/x86/crypto/aesni-intel_avx-x86_64.S
+++ b/arch/x86/crypto/aesni-intel_avx-x86_64.S
@@ -301,6 +301,12 @@ VARIABLE_OFFSET = 16*8
vmovdqu HashKey(arg2), %xmm13 # xmm13 = HashKey
add arg5, InLen(arg2)
+ # initialize the data pointer offset as zero
+ xor %r11d, %r11d
+
+ PARTIAL_BLOCK \GHASH_MUL, arg3, arg4, arg5, %r11, %xmm8, \ENC_DEC
+ sub %r11, arg5
+
mov arg5, %r13 # save the number of bytes of plaintext/ciphertext
and $-16, %r13 # r13 = r13 - (r13 mod 16)
@@ -737,6 +743,150 @@ _read_next_byte_lt8_\@:
_done_read_partial_block_\@:
.endm
+# PARTIAL_BLOCK: Handles encryption/decryption and the tag partial blocks
+# between update calls.
+# Requires the input data be at least 1 byte long due to READ_PARTIAL_BLOCK
+# Outputs encrypted bytes, and updates hash and partial info in gcm_data_context
+# Clobbers rax, r10, r12, r13, xmm0-6, xmm9-13
+.macro PARTIAL_BLOCK GHASH_MUL CYPH_PLAIN_OUT PLAIN_CYPH_IN PLAIN_CYPH_LEN DATA_OFFSET \
+ AAD_HASH ENC_DEC
+ mov PBlockLen(arg2), %r13
+ cmp $0, %r13
+ je _partial_block_done_\@ # Leave Macro if no partial blocks
+ # Read in input data without over reading
+ cmp $16, \PLAIN_CYPH_LEN
+ jl _fewer_than_16_bytes_\@
+ vmovdqu (\PLAIN_CYPH_IN), %xmm1 # If more than 16 bytes, just fill xmm
+ jmp _data_read_\@
+
+_fewer_than_16_bytes_\@:
+ lea (\PLAIN_CYPH_IN, \DATA_OFFSET, 1), %r10
+ mov \PLAIN_CYPH_LEN, %r12
+ READ_PARTIAL_BLOCK %r10 %r12 %xmm1
+
+ mov PBlockLen(arg2), %r13
+
+_data_read_\@: # Finished reading in data
+
+ vmovdqu PBlockEncKey(arg2), %xmm9
+ vmovdqu HashKey(arg2), %xmm13
+
+ lea SHIFT_MASK(%rip), %r12
+
+ # adjust the shuffle mask pointer to be able to shift r13 bytes
+ # r16-r13 is the number of bytes in plaintext mod 16)
+ add %r13, %r12
+ vmovdqu (%r12), %xmm2 # get the appropriate shuffle mask
+ vpshufb %xmm2, %xmm9, %xmm9 # shift right r13 bytes
+
+.if \ENC_DEC == DEC
+ vmovdqa %xmm1, %xmm3
+ pxor %xmm1, %xmm9 # Cyphertext XOR E(K, Yn)
+
+ mov \PLAIN_CYPH_LEN, %r10
+ add %r13, %r10
+ # Set r10 to be the amount of data left in CYPH_PLAIN_IN after filling
+ sub $16, %r10
+ # Determine if if partial block is not being filled and
+ # shift mask accordingly
+ jge _no_extra_mask_1_\@
+ sub %r10, %r12
+_no_extra_mask_1_\@:
+
+ vmovdqu ALL_F-SHIFT_MASK(%r12), %xmm1
+ # get the appropriate mask to mask out bottom r13 bytes of xmm9
+ vpand %xmm1, %xmm9, %xmm9 # mask out bottom r13 bytes of xmm9
+
+ vpand %xmm1, %xmm3, %xmm3
+ vmovdqa SHUF_MASK(%rip), %xmm10
+ vpshufb %xmm10, %xmm3, %xmm3
+ vpshufb %xmm2, %xmm3, %xmm3
+ vpxor %xmm3, \AAD_HASH, \AAD_HASH
+
+ cmp $0, %r10
+ jl _partial_incomplete_1_\@
+
+ # GHASH computation for the last <16 Byte block
+ \GHASH_MUL \AAD_HASH, %xmm13, %xmm0, %xmm10, %xmm11, %xmm5, %xmm6
+ xor %eax,%eax
+
+ mov %rax, PBlockLen(arg2)
+ jmp _dec_done_\@
+_partial_incomplete_1_\@:
+ add \PLAIN_CYPH_LEN, PBlockLen(arg2)
+_dec_done_\@:
+ vmovdqu \AAD_HASH, AadHash(arg2)
+.else
+ vpxor %xmm1, %xmm9, %xmm9 # Plaintext XOR E(K, Yn)
+
+ mov \PLAIN_CYPH_LEN, %r10
+ add %r13, %r10
+ # Set r10 to be the amount of data left in CYPH_PLAIN_IN after filling
+ sub $16, %r10
+ # Determine if if partial block is not being filled and
+ # shift mask accordingly
+ jge _no_extra_mask_2_\@
+ sub %r10, %r12
+_no_extra_mask_2_\@:
+
+ vmovdqu ALL_F-SHIFT_MASK(%r12), %xmm1
+ # get the appropriate mask to mask out bottom r13 bytes of xmm9
+ vpand %xmm1, %xmm9, %xmm9
+
+ vmovdqa SHUF_MASK(%rip), %xmm1
+ vpshufb %xmm1, %xmm9, %xmm9
+ vpshufb %xmm2, %xmm9, %xmm9
+ vpxor %xmm9, \AAD_HASH, \AAD_HASH
+
+ cmp $0, %r10
+ jl _partial_incomplete_2_\@
+
+ # GHASH computation for the last <16 Byte block
+ \GHASH_MUL \AAD_HASH, %xmm13, %xmm0, %xmm10, %xmm11, %xmm5, %xmm6
+ xor %eax,%eax
+
+ mov %rax, PBlockLen(arg2)
+ jmp _encode_done_\@
+_partial_incomplete_2_\@:
+ add \PLAIN_CYPH_LEN, PBlockLen(arg2)
+_encode_done_\@:
+ vmovdqu \AAD_HASH, AadHash(arg2)
+
+ vmovdqa SHUF_MASK(%rip), %xmm10
+ # shuffle xmm9 back to output as ciphertext
+ vpshufb %xmm10, %xmm9, %xmm9
+ vpshufb %xmm2, %xmm9, %xmm9
+.endif
+ # output encrypted Bytes
+ cmp $0, %r10
+ jl _partial_fill_\@
+ mov %r13, %r12
+ mov $16, %r13
+ # Set r13 to be the number of bytes to write out
+ sub %r12, %r13
+ jmp _count_set_\@
+_partial_fill_\@:
+ mov \PLAIN_CYPH_LEN, %r13
+_count_set_\@:
+ vmovdqa %xmm9, %xmm0
+ vmovq %xmm0, %rax
+ cmp $8, %r13
+ jle _less_than_8_bytes_left_\@
+
+ mov %rax, (\CYPH_PLAIN_OUT, \DATA_OFFSET, 1)
+ add $8, \DATA_OFFSET
+ psrldq $8, %xmm0
+ vmovq %xmm0, %rax
+ sub $8, %r13
+_less_than_8_bytes_left_\@:
+ movb %al, (\CYPH_PLAIN_OUT, \DATA_OFFSET, 1)
+ add $1, \DATA_OFFSET
+ shr $8, %rax
+ sub $1, %r13
+ jne _less_than_8_bytes_left_\@
+_partial_block_done_\@:
+.endm # PARTIAL_BLOCK
+
#ifdef CONFIG_AS_AVX
###############################################################################
# GHASH_MUL MACRO to implement: Data*HashKey mod (128,127,126,121,0)
@@ -856,9 +1006,6 @@ _done_read_partial_block_\@:
setreg
vmovdqu AadHash(arg2), reg_i
- # initialize the data pointer offset as zero
- xor %r11d, %r11d
-
# start AES for num_initial_blocks blocks
vmovdqu CurCount(arg2), \CTR
@@ -1798,9 +1945,6 @@ ENDPROC(aesni_gcm_dec_avx_gen2)
setreg
vmovdqu AadHash(arg2), reg_i
- # initialize the data pointer offset as zero
- xor %r11d, %r11d
-
# start AES for num_initial_blocks blocks
vmovdqu CurCount(arg2), \CTR
--
2.17.1