diff options
author | Ard Biesheuvel <ardb@kernel.org> | 2023-01-16 14:01:48 +0300 |
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committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2023-01-18 18:04:51 +0300 |
commit | b575b5a1e625b589ba1b1eb36c05fcca588cbc85 (patch) | |
tree | 6f6fe162d68873370effbe60f51494837e63bc3a /arch/arm/crypto/ghash-ce-glue.c | |
parent | cdc3116f191ad4250f992d750b2d6f72fb98afde (diff) | |
download | linux-b575b5a1e625b589ba1b1eb36c05fcca588cbc85.tar.xz |
ARM: 9286/1: crypto: Implement fused AES-CTR/GHASH version of GCM
On 32-bit ARM, AES in GCM mode takes full advantage of the ARMv8 Crypto
Extensions when available, resulting in a performance of 6-7 cycles per
byte for typical IPsec frames on cores such as Cortex-A53, using the
generic GCM template encapsulating the accelerated AES-CTR and GHASH
implementations.
At such high rates, any time spent copying data or doing other poorly
optimized work in the generic layer hurts disproportionately, and we can
get a significant performance improvement by combining the optimized
AES-CTR and GHASH implementations into a single GCM driver.
On Cortex-A53, this results in a performance improvement of around 75%,
and AES-256-GCM-128 with RFC4106 encapsulation runs in 4 cycles per
byte.
Note that this code takes advantage of the fact that kernel mode NEON is
now supported in softirq context as well, and therefore does not provide
a non-NEON fallback path at all. (AEADs are only callable in process or
softirq context)
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/crypto/ghash-ce-glue.c')
-rw-r--r-- | arch/arm/crypto/ghash-ce-glue.c | 423 |
1 files changed, 419 insertions, 4 deletions
diff --git a/arch/arm/crypto/ghash-ce-glue.c b/arch/arm/crypto/ghash-ce-glue.c index f13401f3e669..3ddf05b4234d 100644 --- a/arch/arm/crypto/ghash-ce-glue.c +++ b/arch/arm/crypto/ghash-ce-glue.c @@ -2,36 +2,53 @@ /* * Accelerated GHASH implementation with ARMv8 vmull.p64 instructions. * - * Copyright (C) 2015 - 2018 Linaro Ltd. <ard.biesheuvel@linaro.org> + * Copyright (C) 2015 - 2018 Linaro Ltd. + * Copyright (C) 2023 Google LLC. */ #include <asm/hwcap.h> #include <asm/neon.h> #include <asm/simd.h> #include <asm/unaligned.h> +#include <crypto/aes.h> +#include <crypto/gcm.h> #include <crypto/b128ops.h> #include <crypto/cryptd.h> +#include <crypto/internal/aead.h> #include <crypto/internal/hash.h> #include <crypto/internal/simd.h> +#include <crypto/internal/skcipher.h> #include <crypto/gf128mul.h> +#include <crypto/scatterwalk.h> #include <linux/cpufeature.h> #include <linux/crypto.h> #include <linux/jump_label.h> #include <linux/module.h> MODULE_DESCRIPTION("GHASH hash function using ARMv8 Crypto Extensions"); -MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>"); -MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Ard Biesheuvel <ardb@kernel.org>"); +MODULE_LICENSE("GPL"); MODULE_ALIAS_CRYPTO("ghash"); +MODULE_ALIAS_CRYPTO("gcm(aes)"); +MODULE_ALIAS_CRYPTO("rfc4106(gcm(aes))"); #define GHASH_BLOCK_SIZE 16 #define GHASH_DIGEST_SIZE 16 +#define RFC4106_NONCE_SIZE 4 + struct ghash_key { be128 k; u64 h[][2]; }; +struct gcm_key { + u64 h[4][2]; + u32 rk[AES_MAX_KEYLENGTH_U32]; + int rounds; + u8 nonce[]; // for RFC4106 nonce +}; + struct ghash_desc_ctx { u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)]; u8 buf[GHASH_BLOCK_SIZE]; @@ -344,6 +361,393 @@ static struct ahash_alg ghash_async_alg = { }, }; + +void pmull_gcm_encrypt(int blocks, u64 dg[], const char *src, + struct gcm_key const *k, char *dst, + const char *iv, int rounds, u32 counter); + +void pmull_gcm_enc_final(int blocks, u64 dg[], char *tag, + struct gcm_key const *k, char *head, + const char *iv, int rounds, u32 counter); + +void pmull_gcm_decrypt(int bytes, u64 dg[], const char *src, + struct gcm_key const *k, char *dst, + const char *iv, int rounds, u32 counter); + +int pmull_gcm_dec_final(int bytes, u64 dg[], char *tag, + struct gcm_key const *k, char *head, + const char *iv, int rounds, u32 counter, + const char *otag, int authsize); + +static int gcm_aes_setkey(struct crypto_aead *tfm, const u8 *inkey, + unsigned int keylen) +{ + struct gcm_key *ctx = crypto_aead_ctx(tfm); + struct crypto_aes_ctx aes_ctx; + be128 h, k; + int ret; + + ret = aes_expandkey(&aes_ctx, inkey, keylen); + if (ret) + return -EINVAL; + + aes_encrypt(&aes_ctx, (u8 *)&k, (u8[AES_BLOCK_SIZE]){}); + + memcpy(ctx->rk, aes_ctx.key_enc, sizeof(ctx->rk)); + ctx->rounds = 6 + keylen / 4; + + memzero_explicit(&aes_ctx, sizeof(aes_ctx)); + + ghash_reflect(ctx->h[0], &k); + + h = k; + gf128mul_lle(&h, &k); + ghash_reflect(ctx->h[1], &h); + + gf128mul_lle(&h, &k); + ghash_reflect(ctx->h[2], &h); + + gf128mul_lle(&h, &k); + ghash_reflect(ctx->h[3], &h); + + return 0; +} + +static int gcm_aes_setauthsize(struct crypto_aead *tfm, unsigned int authsize) +{ + return crypto_gcm_check_authsize(authsize); +} + +static void gcm_update_mac(u64 dg[], const u8 *src, int count, u8 buf[], + int *buf_count, struct gcm_key *ctx) +{ + if (*buf_count > 0) { + int buf_added = min(count, GHASH_BLOCK_SIZE - *buf_count); + + memcpy(&buf[*buf_count], src, buf_added); + + *buf_count += buf_added; + src += buf_added; + count -= buf_added; + } + + if (count >= GHASH_BLOCK_SIZE || *buf_count == GHASH_BLOCK_SIZE) { + int blocks = count / GHASH_BLOCK_SIZE; + + pmull_ghash_update_p64(blocks, dg, src, ctx->h, + *buf_count ? buf : NULL); + + src += blocks * GHASH_BLOCK_SIZE; + count %= GHASH_BLOCK_SIZE; + *buf_count = 0; + } + + if (count > 0) { + memcpy(buf, src, count); + *buf_count = count; + } +} + +static void gcm_calculate_auth_mac(struct aead_request *req, u64 dg[], u32 len) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + struct gcm_key *ctx = crypto_aead_ctx(aead); + u8 buf[GHASH_BLOCK_SIZE]; + struct scatter_walk walk; + int buf_count = 0; + + scatterwalk_start(&walk, req->src); + + do { + u32 n = scatterwalk_clamp(&walk, len); + u8 *p; + + if (!n) { + scatterwalk_start(&walk, sg_next(walk.sg)); + n = scatterwalk_clamp(&walk, len); + } + + p = scatterwalk_map(&walk); + gcm_update_mac(dg, p, n, buf, &buf_count, ctx); + scatterwalk_unmap(p); + + if (unlikely(len / SZ_4K > (len - n) / SZ_4K)) { + kernel_neon_end(); + kernel_neon_begin(); + } + + len -= n; + scatterwalk_advance(&walk, n); + scatterwalk_done(&walk, 0, len); + } while (len); + + if (buf_count) { + memset(&buf[buf_count], 0, GHASH_BLOCK_SIZE - buf_count); + pmull_ghash_update_p64(1, dg, buf, ctx->h, NULL); + } +} + +static int gcm_encrypt(struct aead_request *req, const u8 *iv, u32 assoclen) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + struct gcm_key *ctx = crypto_aead_ctx(aead); + struct skcipher_walk walk; + u8 buf[AES_BLOCK_SIZE]; + u32 counter = 2; + u64 dg[2] = {}; + be128 lengths; + const u8 *src; + u8 *tag, *dst; + int tail, err; + + if (WARN_ON_ONCE(!may_use_simd())) + return -EBUSY; + + err = skcipher_walk_aead_encrypt(&walk, req, false); + + kernel_neon_begin(); + + if (assoclen) + gcm_calculate_auth_mac(req, dg, assoclen); + + src = walk.src.virt.addr; + dst = walk.dst.virt.addr; + + while (walk.nbytes >= AES_BLOCK_SIZE) { + int nblocks = walk.nbytes / AES_BLOCK_SIZE; + + pmull_gcm_encrypt(nblocks, dg, src, ctx, dst, iv, + ctx->rounds, counter); + counter += nblocks; + + if (walk.nbytes == walk.total) { + src += nblocks * AES_BLOCK_SIZE; + dst += nblocks * AES_BLOCK_SIZE; + break; + } + + kernel_neon_end(); + + err = skcipher_walk_done(&walk, + walk.nbytes % AES_BLOCK_SIZE); + if (err) + return err; + + src = walk.src.virt.addr; + dst = walk.dst.virt.addr; + + kernel_neon_begin(); + } + + + lengths.a = cpu_to_be64(assoclen * 8); + lengths.b = cpu_to_be64(req->cryptlen * 8); + + tag = (u8 *)&lengths; + tail = walk.nbytes % AES_BLOCK_SIZE; + + /* + * Bounce via a buffer unless we are encrypting in place and src/dst + * are not pointing to the start of the walk buffer. In that case, we + * can do a NEON load/xor/store sequence in place as long as we move + * the plain/ciphertext and keystream to the start of the register. If + * not, do a memcpy() to the end of the buffer so we can reuse the same + * logic. + */ + if (unlikely(tail && (tail == walk.nbytes || src != dst))) + src = memcpy(buf + sizeof(buf) - tail, src, tail); + + pmull_gcm_enc_final(tail, dg, tag, ctx, (u8 *)src, iv, + ctx->rounds, counter); + kernel_neon_end(); + + if (unlikely(tail && src != dst)) + memcpy(dst, src, tail); + + if (walk.nbytes) { + err = skcipher_walk_done(&walk, 0); + if (err) + return err; + } + + /* copy authtag to end of dst */ + scatterwalk_map_and_copy(tag, req->dst, req->assoclen + req->cryptlen, + crypto_aead_authsize(aead), 1); + + return 0; +} + +static int gcm_decrypt(struct aead_request *req, const u8 *iv, u32 assoclen) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + struct gcm_key *ctx = crypto_aead_ctx(aead); + int authsize = crypto_aead_authsize(aead); + struct skcipher_walk walk; + u8 otag[AES_BLOCK_SIZE]; + u8 buf[AES_BLOCK_SIZE]; + u32 counter = 2; + u64 dg[2] = {}; + be128 lengths; + const u8 *src; + u8 *tag, *dst; + int tail, err, ret; + + if (WARN_ON_ONCE(!may_use_simd())) + return -EBUSY; + + scatterwalk_map_and_copy(otag, req->src, + req->assoclen + req->cryptlen - authsize, + authsize, 0); + + err = skcipher_walk_aead_decrypt(&walk, req, false); + + kernel_neon_begin(); + + if (assoclen) + gcm_calculate_auth_mac(req, dg, assoclen); + + src = walk.src.virt.addr; + dst = walk.dst.virt.addr; + + while (walk.nbytes >= AES_BLOCK_SIZE) { + int nblocks = walk.nbytes / AES_BLOCK_SIZE; + + pmull_gcm_decrypt(nblocks, dg, src, ctx, dst, iv, + ctx->rounds, counter); + counter += nblocks; + + if (walk.nbytes == walk.total) { + src += nblocks * AES_BLOCK_SIZE; + dst += nblocks * AES_BLOCK_SIZE; + break; + } + + kernel_neon_end(); + + err = skcipher_walk_done(&walk, + walk.nbytes % AES_BLOCK_SIZE); + if (err) + return err; + + src = walk.src.virt.addr; + dst = walk.dst.virt.addr; + + kernel_neon_begin(); + } + + lengths.a = cpu_to_be64(assoclen * 8); + lengths.b = cpu_to_be64((req->cryptlen - authsize) * 8); + + tag = (u8 *)&lengths; + tail = walk.nbytes % AES_BLOCK_SIZE; + + if (unlikely(tail && (tail == walk.nbytes || src != dst))) + src = memcpy(buf + sizeof(buf) - tail, src, tail); + + ret = pmull_gcm_dec_final(tail, dg, tag, ctx, (u8 *)src, iv, + ctx->rounds, counter, otag, authsize); + kernel_neon_end(); + + if (unlikely(tail && src != dst)) + memcpy(dst, src, tail); + + if (walk.nbytes) { + err = skcipher_walk_done(&walk, 0); + if (err) + return err; + } + + return ret ? -EBADMSG : 0; +} + +static int gcm_aes_encrypt(struct aead_request *req) +{ + return gcm_encrypt(req, req->iv, req->assoclen); +} + +static int gcm_aes_decrypt(struct aead_request *req) +{ + return gcm_decrypt(req, req->iv, req->assoclen); +} + +static int rfc4106_setkey(struct crypto_aead *tfm, const u8 *inkey, + unsigned int keylen) +{ + struct gcm_key *ctx = crypto_aead_ctx(tfm); + int err; + + keylen -= RFC4106_NONCE_SIZE; + err = gcm_aes_setkey(tfm, inkey, keylen); + if (err) + return err; + + memcpy(ctx->nonce, inkey + keylen, RFC4106_NONCE_SIZE); + return 0; +} + +static int rfc4106_setauthsize(struct crypto_aead *tfm, unsigned int authsize) +{ + return crypto_rfc4106_check_authsize(authsize); +} + +static int rfc4106_encrypt(struct aead_request *req) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + struct gcm_key *ctx = crypto_aead_ctx(aead); + u8 iv[GCM_AES_IV_SIZE]; + + memcpy(iv, ctx->nonce, RFC4106_NONCE_SIZE); + memcpy(iv + RFC4106_NONCE_SIZE, req->iv, GCM_RFC4106_IV_SIZE); + + return crypto_ipsec_check_assoclen(req->assoclen) ?: + gcm_encrypt(req, iv, req->assoclen - GCM_RFC4106_IV_SIZE); +} + +static int rfc4106_decrypt(struct aead_request *req) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + struct gcm_key *ctx = crypto_aead_ctx(aead); + u8 iv[GCM_AES_IV_SIZE]; + + memcpy(iv, ctx->nonce, RFC4106_NONCE_SIZE); + memcpy(iv + RFC4106_NONCE_SIZE, req->iv, GCM_RFC4106_IV_SIZE); + + return crypto_ipsec_check_assoclen(req->assoclen) ?: + gcm_decrypt(req, iv, req->assoclen - GCM_RFC4106_IV_SIZE); +} + +static struct aead_alg gcm_aes_algs[] = {{ + .ivsize = GCM_AES_IV_SIZE, + .chunksize = AES_BLOCK_SIZE, + .maxauthsize = AES_BLOCK_SIZE, + .setkey = gcm_aes_setkey, + .setauthsize = gcm_aes_setauthsize, + .encrypt = gcm_aes_encrypt, + .decrypt = gcm_aes_decrypt, + + .base.cra_name = "gcm(aes)", + .base.cra_driver_name = "gcm-aes-ce", + .base.cra_priority = 400, + .base.cra_blocksize = 1, + .base.cra_ctxsize = sizeof(struct gcm_key), + .base.cra_module = THIS_MODULE, +}, { + .ivsize = GCM_RFC4106_IV_SIZE, + .chunksize = AES_BLOCK_SIZE, + .maxauthsize = AES_BLOCK_SIZE, + .setkey = rfc4106_setkey, + .setauthsize = rfc4106_setauthsize, + .encrypt = rfc4106_encrypt, + .decrypt = rfc4106_decrypt, + + .base.cra_name = "rfc4106(gcm(aes))", + .base.cra_driver_name = "rfc4106-gcm-aes-ce", + .base.cra_priority = 400, + .base.cra_blocksize = 1, + .base.cra_ctxsize = sizeof(struct gcm_key) + RFC4106_NONCE_SIZE, + .base.cra_module = THIS_MODULE, +}}; + static int __init ghash_ce_mod_init(void) { int err; @@ -352,13 +756,17 @@ static int __init ghash_ce_mod_init(void) return -ENODEV; if (elf_hwcap2 & HWCAP2_PMULL) { + err = crypto_register_aeads(gcm_aes_algs, + ARRAY_SIZE(gcm_aes_algs)); + if (err) + return err; ghash_alg.base.cra_ctxsize += 3 * sizeof(u64[2]); static_branch_enable(&use_p64); } err = crypto_register_shash(&ghash_alg); if (err) - return err; + goto err_aead; err = crypto_register_ahash(&ghash_async_alg); if (err) goto err_shash; @@ -367,6 +775,10 @@ static int __init ghash_ce_mod_init(void) err_shash: crypto_unregister_shash(&ghash_alg); +err_aead: + if (elf_hwcap2 & HWCAP2_PMULL) + crypto_unregister_aeads(gcm_aes_algs, + ARRAY_SIZE(gcm_aes_algs)); return err; } @@ -374,6 +786,9 @@ static void __exit ghash_ce_mod_exit(void) { crypto_unregister_ahash(&ghash_async_alg); crypto_unregister_shash(&ghash_alg); + if (elf_hwcap2 & HWCAP2_PMULL) + crypto_unregister_aeads(gcm_aes_algs, + ARRAY_SIZE(gcm_aes_algs)); } module_init(ghash_ce_mod_init); |