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Avoid double-dispatch with AES_* vs aes_nohw_*.

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In particular, consistently pair bsaes with aes_nohw.

Ideally the aes_nohw_* calls in bsaes-*.pl would be patched out and
bsaes grows its own constant-time key setup
(https://crbug.com/boringssl/256), but I'll sort that out separately. In
the meantime, avoid going through AES_* which now dispatch. This avoids
several nuisances:

1. If we were to add, say, a vpaes-armv7.pl the ABI tests would break.
   Fundamentally, we cannot assume that an AES_KEY has one and only one
   representation and must keep everything matching up.

2. AES_* functions should enable vpaes. This makes AES_* faster and
   constant-time for vector-capable CPUs
   (https://crbug.com/boringssl/263), relevant for QUIC packet number
   encryption, allowing us to add vpaes-armv8.pl
   (https://crbug.com/boringssl/246) without carrying a (likely) mostly
   unused AES implementation.

3. It's silly to double-dispatch when the EVP layer has already
   dispatched.

4. We should avoid asm calling into C. Otherwise, we need to test asm
   for ABI compliance as both caller and callee. Currently we only test
   it for callee compliance. When asm calls into asm, it *should* comply
   with the ABI as caller too, but mistakes don't matter as long as the
   called function triggers it. If the function is asm, this is fixed.
   If it is C, we must care about arbitrary C compiler output.

Bug: 263
Change-Id: Ic85af5c765fd57cbffeaf301c3872bad6c5bbf78
Reviewed-on: https://boringssl-review.googlesource.com/c/34874
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
This commit is contained in:
David Benjamin 2019-02-10 04:05:43 +00:00 committed by Adam Langley
parent c18353d214
commit 3c19830f6f
2 changed files with 40 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
crypto/fipsmodule/aes/asm/bsaes-armv7.pl
View File

@ -1113,8 +1113,8 @@ my ($inp,$out,$len,$key, $ivp,$fp,$rounds)=map("r$_",(0..3,8..10));
my ($keysched)=("sp");
$code.=<<___;
.extern AES_cbc_encrypt
.extern AES_decrypt
.extern aes_nohw_cbc_encrypt
.extern aes_nohw_decrypt
.global bsaes_cbc_encrypt
.type bsaes_cbc_encrypt,%function
@ -1123,10 +1123,10 @@ bsaes_cbc_encrypt:
#ifndef __KERNEL__
cmp $len, #128
#ifndef __thumb__
blo AES_cbc_encrypt
blo aes_nohw_cbc_encrypt
#else
bhs 1f
b AES_cbc_encrypt
b aes_nohw_cbc_encrypt
1:
#endif
#endif
@ -1360,7 +1360,7 @@ bsaes_cbc_encrypt:
mov r2, $key
vmov @XMM[4],@XMM[15] @ just in case ensure that IV
vmov @XMM[5],@XMM[0] @ and input are preserved
bl AES_decrypt
bl aes_nohw_decrypt
vld1.8 {@XMM[0]}, [$fp] @ load result
veor @XMM[0], @XMM[0], @XMM[4] @ ^= IV
vmov @XMM[15], @XMM[5] @ @XMM[5] holds input
@ -1390,7 +1390,7 @@ my $const = "r6"; # shared with _bsaes_encrypt8_alt
my $keysched = "sp";
$code.=<<___;
.extern AES_encrypt
.extern aes_nohw_encrypt
.global bsaes_ctr32_encrypt_blocks
.type bsaes_ctr32_encrypt_blocks,%function
.align 5
@ -1596,7 +1596,7 @@ bsaes_ctr32_encrypt_blocks:
mov r1, sp @ output on the stack
mov r2, r7 @ key
bl AES_encrypt
bl aes_nohw_encrypt
vld1.8 {@XMM[0]}, [r4]! @ load input
vld1.8 {@XMM[1]}, [sp] @ load encrypted counter
@ -1658,7 +1658,7 @@ bsaes_xts_encrypt:
ldr r0, [ip, #4] @ iv[]
mov r1, sp
ldr r2, [ip, #0] @ key2
bl AES_encrypt
bl aes_nohw_encrypt
mov r0,sp @ pointer to initial tweak
#endif
@ -1976,7 +1976,7 @@ $code.=<<___;
mov r2, $key
mov r4, $fp @ preserve fp
bl AES_encrypt
bl aes_nohw_encrypt
vld1.8 {@XMM[0]}, [sp,:128]
veor @XMM[0], @XMM[0], @XMM[8]
@ -2008,7 +2008,7 @@ $code.=<<___;
mov r2, $key
mov r4, $fp @ preserve fp
bl AES_encrypt
bl aes_nohw_encrypt
vld1.8 {@XMM[0]}, [sp,:128]
veor @XMM[0], @XMM[0], @XMM[8]
@ -2062,7 +2062,7 @@ bsaes_xts_decrypt:
ldr r0, [ip, #4] @ iv[]
mov r1, sp
ldr r2, [ip, #0] @ key2
bl AES_encrypt
bl aes_nohw_encrypt
mov r0, sp @ pointer to initial tweak
#endif
@ -2388,7 +2388,7 @@ $code.=<<___;
mov r2, $key
mov r4, $fp @ preserve fp
bl AES_decrypt
bl aes_nohw_decrypt
vld1.8 {@XMM[0]}, [sp,:128]
veor @XMM[0], @XMM[0], @XMM[8]
@ -2420,7 +2420,7 @@ $code.=<<___;
mov r2, $key
mov r4, $fp @ preserve fp
bl AES_decrypt
bl aes_nohw_decrypt
vld1.8 {@XMM[0]}, [sp,:128]
veor @XMM[0], @XMM[0], @XMM[9]
@ -2443,7 +2443,7 @@ $code.=<<___;
vst1.8 {@XMM[0]}, [sp,:128]
mov r2, $key
bl AES_decrypt
bl aes_nohw_decrypt
vld1.8 {@XMM[0]}, [sp,:128]
veor @XMM[0], @XMM[0], @XMM[8]

42
crypto/fipsmodule/cipher/e_aes.c
View File

@ -114,17 +114,22 @@ static int aes_init_key(EVP_CIPHER_CTX *ctx, const uint8_t *key,
dat->stream.cbc = aes_hw_cbc_encrypt;
}
} else if (bsaes_capable() && mode == EVP_CIPH_CBC_MODE) {
ret = AES_set_decrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
dat->block = AES_decrypt;
ret = aes_nohw_set_decrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
dat->block = aes_nohw_decrypt;
dat->stream.cbc = bsaes_cbc_encrypt;
} else if (vpaes_capable()) {
ret = vpaes_set_decrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
dat->block = vpaes_decrypt;
dat->stream.cbc = mode == EVP_CIPH_CBC_MODE ? vpaes_cbc_encrypt : NULL;
} else {
ret = AES_set_decrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
dat->block = AES_decrypt;
dat->stream.cbc = mode == EVP_CIPH_CBC_MODE ? AES_cbc_encrypt : NULL;
ret = aes_nohw_set_decrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
dat->block = aes_nohw_decrypt;
dat->stream.cbc = NULL;
#if defined(AES_NOHW_CBC)
if (mode == EVP_CIPH_CBC_MODE) {
dat->stream.cbc = aes_nohw_cbc_encrypt;
}
#endif
}
} else if (hwaes_capable()) {
ret = aes_hw_set_encrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
@ -136,17 +141,22 @@ static int aes_init_key(EVP_CIPHER_CTX *ctx, const uint8_t *key,
dat->stream.ctr = aes_hw_ctr32_encrypt_blocks;
}
} else if (bsaes_capable() && mode == EVP_CIPH_CTR_MODE) {
ret = AES_set_encrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
dat->block = AES_encrypt;
ret = aes_nohw_set_encrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
dat->block = aes_nohw_encrypt;
dat->stream.ctr = bsaes_ctr32_encrypt_blocks;
} else if (vpaes_capable()) {
ret = vpaes_set_encrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
dat->block = vpaes_encrypt;
dat->stream.cbc = mode == EVP_CIPH_CBC_MODE ? vpaes_cbc_encrypt : NULL;
} else {
ret = AES_set_encrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
dat->block = AES_encrypt;
dat->stream.cbc = mode == EVP_CIPH_CBC_MODE ? AES_cbc_encrypt : NULL;
ret = aes_nohw_set_encrypt_key(key, ctx->key_len * 8, &dat->ks.ks);
dat->block = aes_nohw_encrypt;
dat->stream.cbc = NULL;
#if defined(AES_NOHW_CBC)
if (mode == EVP_CIPH_CBC_MODE) {
dat->stream.cbc = aes_nohw_cbc_encrypt;
}
#endif
}
if (ret < 0) {
@ -229,12 +239,12 @@ ctr128_f aes_ctr_set_key(AES_KEY *aes_key, GCM128_KEY *gcm_key,
const int bsaes_ok = bsaes_capable();
const int vpaes_ok = vpaes_capable();
if (bsaes_ok && (large_inputs || !vpaes_ok)) {
AES_set_encrypt_key(key, key_bytes * 8, aes_key);
aes_nohw_set_encrypt_key(key, key_bytes * 8, aes_key);
if (gcm_key != NULL) {
CRYPTO_gcm128_init_key(gcm_key, aes_key, AES_encrypt, 0);
CRYPTO_gcm128_init_key(gcm_key, aes_key, aes_nohw_encrypt, 0);
}
if (out_block) {
*out_block = AES_encrypt;
*out_block = aes_nohw_encrypt;
}
return bsaes_ctr32_encrypt_blocks;
}
@ -250,12 +260,12 @@ ctr128_f aes_ctr_set_key(AES_KEY *aes_key, GCM128_KEY *gcm_key,
return NULL;
}
AES_set_encrypt_key(key, key_bytes * 8, aes_key);
aes_nohw_set_encrypt_key(key, key_bytes * 8, aes_key);
if (gcm_key != NULL) {
CRYPTO_gcm128_init_key(gcm_key, aes_key, AES_encrypt, 0);
CRYPTO_gcm128_init_key(gcm_key, aes_key, aes_nohw_encrypt, 0);
}
if (out_block) {
*out_block = AES_encrypt;
*out_block = aes_nohw_encrypt;
}
return NULL;
}