Make the AES-GCM library use the GHASH library instead of directly calling gf128mul_lle(). This allows the architecture-optimized GHASH implementations to be used, or the improved generic implementation if no architecture-optimized implementation is usable.
Note: this means that <crypto/gcm.h> no longer needs to include <crypto/gf128mul.h>. Remove that inclusion, and include <crypto/gf128mul.h> explicitly from arch/x86/crypto/aesni-intel_glue.c which previously was relying on the transitive inclusion. Signed-off-by: Eric Biggers <[email protected]> --- arch/x86/crypto/aesni-intel_glue.c | 1 + include/crypto/gcm.h | 4 +-- lib/crypto/Kconfig | 2 +- lib/crypto/aesgcm.c | 55 +++++++++++++++--------------- 4 files changed, 32 insertions(+), 30 deletions(-) diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c index e6c38d1d8a92..f522fff9231e 100644 --- a/arch/x86/crypto/aesni-intel_glue.c +++ b/arch/x86/crypto/aesni-intel_glue.c @@ -23,10 +23,11 @@ #include <linux/err.h> #include <crypto/algapi.h> #include <crypto/aes.h> #include <crypto/b128ops.h> #include <crypto/gcm.h> +#include <crypto/gf128mul.h> #include <crypto/xts.h> #include <asm/cpu_device_id.h> #include <asm/simd.h> #include <crypto/scatterwalk.h> #include <crypto/internal/aead.h> diff --git a/include/crypto/gcm.h b/include/crypto/gcm.h index b524e47bd4d0..1d5f39ff1dc4 100644 --- a/include/crypto/gcm.h +++ b/include/crypto/gcm.h @@ -2,11 +2,11 @@ #define _CRYPTO_GCM_H #include <linux/errno.h> #include <crypto/aes.h> -#include <crypto/gf128mul.h> +#include <crypto/gf128hash.h> #define GCM_AES_IV_SIZE 12 #define GCM_RFC4106_IV_SIZE 8 #define GCM_RFC4543_IV_SIZE 8 @@ -63,11 +63,11 @@ static inline int crypto_ipsec_check_assoclen(unsigned int assoclen) return 0; } struct aesgcm_ctx { - be128 ghash_key; + struct ghash_key ghash_key; struct aes_enckey aes_key; unsigned int authsize; }; int aesgcm_expandkey(struct aesgcm_ctx *ctx, const u8 *key, diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig index a39e7707e9ee..32fafe245f47 100644 --- a/lib/crypto/Kconfig +++ b/lib/crypto/Kconfig @@ -39,11 +39,11 @@ config CRYPTO_LIB_AES_CBC_MACS <crypto/aes-cbc-macs.h>. config CRYPTO_LIB_AESGCM tristate select CRYPTO_LIB_AES - select CRYPTO_LIB_GF128MUL + select CRYPTO_LIB_GF128HASH select CRYPTO_LIB_UTILS config CRYPTO_LIB_ARC4 tristate diff --git a/lib/crypto/aesgcm.c b/lib/crypto/aesgcm.c index 02f5b5f32c76..8c7e74d2d147 100644 --- a/lib/crypto/aesgcm.c +++ b/lib/crypto/aesgcm.c @@ -3,13 +3,12 @@ * Minimal library implementation of GCM * * Copyright 2022 Google LLC */ -#include <crypto/algapi.h> #include <crypto/gcm.h> -#include <crypto/ghash.h> +#include <crypto/utils.h> #include <linux/export.h> #include <linux/module.h> #include <asm/irqflags.h> static void aesgcm_encrypt_block(const struct aes_enckey *key, void *dst, @@ -43,37 +42,26 @@ static void aesgcm_encrypt_block(const struct aes_enckey *key, void *dst, * that are not permitted by the GCM specification. */ int aesgcm_expandkey(struct aesgcm_ctx *ctx, const u8 *key, unsigned int keysize, unsigned int authsize) { - u8 kin[AES_BLOCK_SIZE] = {}; + u8 h[AES_BLOCK_SIZE] = {}; int ret; ret = crypto_gcm_check_authsize(authsize) ?: aes_prepareenckey(&ctx->aes_key, key, keysize); if (ret) return ret; ctx->authsize = authsize; - aesgcm_encrypt_block(&ctx->aes_key, &ctx->ghash_key, kin); - + aesgcm_encrypt_block(&ctx->aes_key, h, h); + ghash_preparekey(&ctx->ghash_key, h); + memzero_explicit(h, sizeof(h)); return 0; } EXPORT_SYMBOL(aesgcm_expandkey); -static void aesgcm_ghash(be128 *ghash, const be128 *key, const void *src, - int len) -{ - while (len > 0) { - crypto_xor((u8 *)ghash, src, min(len, GHASH_BLOCK_SIZE)); - gf128mul_lle(ghash, key); - - src += GHASH_BLOCK_SIZE; - len -= GHASH_BLOCK_SIZE; - } -} - /** * aesgcm_mac - Generates the authentication tag using AES-GCM algorithm. * @ctx: The data structure that will hold the AES-GCM key schedule * @src: The input source data. * @src_len: Length of the source data. @@ -86,24 +74,37 @@ static void aesgcm_ghash(be128 *ghash, const be128 *key, const void *src, * and an output buffer for the authentication tag. */ static void aesgcm_mac(const struct aesgcm_ctx *ctx, const u8 *src, int src_len, const u8 *assoc, int assoc_len, __be32 *ctr, u8 *authtag) { - be128 tail = { cpu_to_be64(assoc_len * 8), cpu_to_be64(src_len * 8) }; - u8 buf[AES_BLOCK_SIZE]; - be128 ghash = {}; + static const u8 zeroes[GHASH_BLOCK_SIZE]; + __be64 tail[2] = { + cpu_to_be64((u64)assoc_len * 8), + cpu_to_be64((u64)src_len * 8), + }; + struct ghash_ctx ghash; + u8 ghash_out[AES_BLOCK_SIZE]; + u8 enc_ctr[AES_BLOCK_SIZE]; + + ghash_init(&ghash, &ctx->ghash_key); + + ghash_update(&ghash, assoc, assoc_len); + ghash_update(&ghash, zeroes, -assoc_len & (GHASH_BLOCK_SIZE - 1)); - aesgcm_ghash(&ghash, &ctx->ghash_key, assoc, assoc_len); - aesgcm_ghash(&ghash, &ctx->ghash_key, src, src_len); - aesgcm_ghash(&ghash, &ctx->ghash_key, &tail, sizeof(tail)); + ghash_update(&ghash, src, src_len); + ghash_update(&ghash, zeroes, -src_len & (GHASH_BLOCK_SIZE - 1)); + + ghash_update(&ghash, (const u8 *)&tail, sizeof(tail)); + + ghash_final(&ghash, ghash_out); ctr[3] = cpu_to_be32(1); - aesgcm_encrypt_block(&ctx->aes_key, buf, ctr); - crypto_xor_cpy(authtag, buf, (u8 *)&ghash, ctx->authsize); + aesgcm_encrypt_block(&ctx->aes_key, enc_ctr, ctr); + crypto_xor_cpy(authtag, ghash_out, enc_ctr, ctx->authsize); - memzero_explicit(&ghash, sizeof(ghash)); - memzero_explicit(buf, sizeof(buf)); + memzero_explicit(ghash_out, sizeof(ghash_out)); + memzero_explicit(enc_ctr, sizeof(enc_ctr)); } static void aesgcm_crypt(const struct aesgcm_ctx *ctx, u8 *dst, const u8 *src, int len, __be32 *ctr) { -- 2.53.0
