[PATCH 7/7] crypto: aesni: add generic gcm(aes)

From: Sabrina Dubroca
Date: Fri Apr 28 2017 - 12:13:41 EST

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Now that the asm side of things can support all the valid lengths of ICV
and all lengths of associated data, provide the glue code to expose a
generic gcm(aes) crypto algorithm.

Signed-off-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
---
arch/x86/crypto/aesni-intel_glue.c | 208 ++++++++++++++++++++++++++++---------
1 file changed, 158 insertions(+), 50 deletions(-)

diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index 93de8ea51548..4a55cdcdc008 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -61,6 +61,11 @@ struct aesni_rfc4106_gcm_ctx {
u8 nonce[4];
};

+struct generic_gcmaes_ctx {
+ u8 hash_subkey[16] AESNI_ALIGN_ATTR;
+ struct crypto_aes_ctx aes_key_expanded AESNI_ALIGN_ATTR;
+};
+
struct aesni_xts_ctx {
u8 raw_tweak_ctx[sizeof(struct crypto_aes_ctx)] AESNI_ALIGN_ATTR;
u8 raw_crypt_ctx[sizeof(struct crypto_aes_ctx)] AESNI_ALIGN_ATTR;
@@ -102,13 +107,11 @@ asmlinkage void aesni_xts_crypt8(struct crypto_aes_ctx *ctx, u8 *out,
* u8 *out, Ciphertext output. Encrypt in-place is allowed.
* const u8 *in, Plaintext input
* unsigned long plaintext_len, Length of data in bytes for encryption.
- * u8 *iv, Pre-counter block j0: 4 byte salt (from Security Association)
- * concatenated with 8 byte Initialisation Vector (from IPSec ESP
- * Payload) concatenated with 0x00000001. 16-byte aligned pointer.
+ * u8 *iv, Pre-counter block j0: 12 byte IV concatenated with 0x00000001.
+ * 16-byte aligned pointer.
* u8 *hash_subkey, the Hash sub key input. Data starts on a 16-byte boundary.
* const u8 *aad, Additional Authentication Data (AAD)
- * unsigned long aad_len, Length of AAD in bytes. With RFC4106 this
- * is going to be 8 or 12 bytes
+ * unsigned long aad_len, Length of AAD in bytes.
* u8 *auth_tag, Authenticated Tag output.
* unsigned long auth_tag_len), Authenticated Tag Length in bytes.
* Valid values are 16 (most likely), 12 or 8.
@@ -123,9 +126,8 @@ asmlinkage void aesni_gcm_enc(void *ctx, u8 *out,
* u8 *out, Plaintext output. Decrypt in-place is allowed.
* const u8 *in, Ciphertext input
* unsigned long ciphertext_len, Length of data in bytes for decryption.
- * u8 *iv, Pre-counter block j0: 4 byte salt (from Security Association)
- * concatenated with 8 byte Initialisation Vector (from IPSec ESP
- * Payload) concatenated with 0x00000001. 16-byte aligned pointer.
+ * u8 *iv, Pre-counter block j0: 12 byte IV concatenated with 0x00000001.
+ * 16-byte aligned pointer.
* u8 *hash_subkey, the Hash sub key input. Data starts on a 16-byte boundary.
* const u8 *aad, Additional Authentication Data (AAD)
* unsigned long aad_len, Length of AAD in bytes. With RFC4106 this is going
@@ -275,6 +277,16 @@ aesni_rfc4106_gcm_ctx *aesni_rfc4106_gcm_ctx_get(struct crypto_aead *tfm)
align = 1;
return PTR_ALIGN(crypto_aead_ctx(tfm), align);
}
+
+static inline struct
+generic_gcmaes_ctx *generic_gcmaes_ctx_get(struct crypto_aead *tfm)
+{
+ unsigned long align = AESNI_ALIGN;
+
+ if (align <= crypto_tfm_ctx_alignment())
+ align = 1;
+ return PTR_ALIGN(crypto_aead_ctx(tfm), align);
+}
#endif

static inline struct crypto_aes_ctx *aes_ctx(void *raw_ctx)
@@ -712,32 +724,34 @@ static int rfc4106_set_authsize(struct crypto_aead *parent,
return crypto_aead_setauthsize(&cryptd_tfm->base, authsize);
}

-static int helper_rfc4106_encrypt(struct aead_request *req)
+static int generic_gcmaes_set_authsize(struct crypto_aead *tfm,
+ unsigned int authsize)
+{
+ switch (authsize) {
+ case 4:
+ case 8:
+ case 12:
+ case 13:
+ case 14:
+ case 15:
+ case 16:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int gcmaes_encrypt(struct aead_request *req, unsigned int assoclen,
+ u8 *hash_subkey, u8 *iv, void *aes_ctx)
{
u8 one_entry_in_sg = 0;
u8 *src, *dst, *assoc;
- __be32 counter = cpu_to_be32(1);
struct crypto_aead *tfm = crypto_aead_reqtfm(req);
- struct aesni_rfc4106_gcm_ctx *ctx = aesni_rfc4106_gcm_ctx_get(tfm);
- void *aes_ctx = &(ctx->aes_key_expanded);
unsigned long auth_tag_len = crypto_aead_authsize(tfm);
- u8 iv[16] __attribute__ ((__aligned__(AESNI_ALIGN)));
struct scatter_walk src_sg_walk;
struct scatter_walk dst_sg_walk = {};
- unsigned int i;
-
- /* Assuming we are supporting rfc4106 64-bit extended */
- /* sequence numbers We need to have the AAD length equal */
- /* to 16 or 20 bytes */
- if (unlikely(req->assoclen != 16 && req->assoclen != 20))
- return -EINVAL;
-
- /* IV below built */
- for (i = 0; i < 4; i++)
- *(iv+i) = ctx->nonce[i];
- for (i = 0; i < 8; i++)
- *(iv+4+i) = req->iv[i];
- *((__be32 *)(iv+12)) = counter;

if (sg_is_last(req->src) &&
(!PageHighMem(sg_page(req->src)) ||
@@ -768,7 +782,7 @@ static int helper_rfc4106_encrypt(struct aead_request *req)

kernel_fpu_begin();
aesni_gcm_enc_tfm(aes_ctx, dst, src, req->cryptlen, iv,
- ctx->hash_subkey, assoc, req->assoclen - 8,
+ hash_subkey, assoc, assoclen,
dst + req->cryptlen, auth_tag_len);
kernel_fpu_end();

@@ -791,37 +805,20 @@ static int helper_rfc4106_encrypt(struct aead_request *req)
return 0;
}

-static int helper_rfc4106_decrypt(struct aead_request *req)
+static int gcmaes_decrypt(struct aead_request *req, unsigned int assoclen,
+ u8 *hash_subkey, u8 *iv, void *aes_ctx)
{
u8 one_entry_in_sg = 0;
u8 *src, *dst, *assoc;
unsigned long tempCipherLen = 0;
- __be32 counter = cpu_to_be32(1);
- int retval = 0;
struct crypto_aead *tfm = crypto_aead_reqtfm(req);
- struct aesni_rfc4106_gcm_ctx *ctx = aesni_rfc4106_gcm_ctx_get(tfm);
- void *aes_ctx = &(ctx->aes_key_expanded);
unsigned long auth_tag_len = crypto_aead_authsize(tfm);
- u8 iv[16] __attribute__ ((__aligned__(AESNI_ALIGN)));
u8 authTag[16];
struct scatter_walk src_sg_walk;
struct scatter_walk dst_sg_walk = {};
- unsigned int i;
-
- if (unlikely(req->assoclen != 16 && req->assoclen != 20))
- return -EINVAL;
-
- /* Assuming we are supporting rfc4106 64-bit extended */
- /* sequence numbers We need to have the AAD length */
- /* equal to 16 or 20 bytes */
+ int retval = 0;

tempCipherLen = (unsigned long)(req->cryptlen - auth_tag_len);
- /* IV below built */
- for (i = 0; i < 4; i++)
- *(iv+i) = ctx->nonce[i];
- for (i = 0; i < 8; i++)
- *(iv+4+i) = req->iv[i];
- *((__be32 *)(iv+12)) = counter;

if (sg_is_last(req->src) &&
(!PageHighMem(sg_page(req->src)) ||
@@ -838,7 +835,6 @@ static int helper_rfc4106_decrypt(struct aead_request *req)
scatterwalk_start(&dst_sg_walk, req->dst);
dst = scatterwalk_map(&dst_sg_walk) + req->assoclen;
}
-
} else {
/* Allocate memory for src, dst, assoc */
assoc = kmalloc(req->cryptlen + req->assoclen, GFP_ATOMIC);
@@ -850,9 +846,10 @@ static int helper_rfc4106_decrypt(struct aead_request *req)
dst = src;
}

+
kernel_fpu_begin();
aesni_gcm_dec_tfm(aes_ctx, dst, src, tempCipherLen, iv,
- ctx->hash_subkey, assoc, req->assoclen - 8,
+ hash_subkey, assoc, assoclen,
authTag, auth_tag_len);
kernel_fpu_end();

@@ -875,6 +872,60 @@ static int helper_rfc4106_decrypt(struct aead_request *req)
kfree(assoc);
}
return retval;
+
+}
+
+static int helper_rfc4106_encrypt(struct aead_request *req)
+{
+ struct crypto_aead *tfm = crypto_aead_reqtfm(req);
+ struct aesni_rfc4106_gcm_ctx *ctx = aesni_rfc4106_gcm_ctx_get(tfm);
+ void *aes_ctx = &(ctx->aes_key_expanded);
+ u8 iv[16] __attribute__ ((__aligned__(AESNI_ALIGN)));
+ unsigned int i;
+ __be32 counter = cpu_to_be32(1);
+
+ /* Assuming we are supporting rfc4106 64-bit extended */
+ /* sequence numbers We need to have the AAD length equal */
+ /* to 16 or 20 bytes */
+ if (unlikely(req->assoclen != 16 && req->assoclen != 20))
+ return -EINVAL;
+
+ /* IV below built */
+ for (i = 0; i < 4; i++)
+ *(iv+i) = ctx->nonce[i];
+ for (i = 0; i < 8; i++)
+ *(iv+4+i) = req->iv[i];
+ *((__be32 *)(iv+12)) = counter;
+
+ return gcmaes_encrypt(req, req->assoclen - 8, ctx->hash_subkey, iv,
+ aes_ctx);
+}
+
+static int helper_rfc4106_decrypt(struct aead_request *req)
+{
+ __be32 counter = cpu_to_be32(1);
+ struct crypto_aead *tfm = crypto_aead_reqtfm(req);
+ struct aesni_rfc4106_gcm_ctx *ctx = aesni_rfc4106_gcm_ctx_get(tfm);
+ void *aes_ctx = &(ctx->aes_key_expanded);
+ u8 iv[16] __attribute__ ((__aligned__(AESNI_ALIGN)));
+ unsigned int i;
+
+ if (unlikely(req->assoclen != 16 && req->assoclen != 20))
+ return -EINVAL;
+
+ /* Assuming we are supporting rfc4106 64-bit extended */
+ /* sequence numbers We need to have the AAD length */
+ /* equal to 16 or 20 bytes */
+
+ /* IV below built */
+ for (i = 0; i < 4; i++)
+ *(iv+i) = ctx->nonce[i];
+ for (i = 0; i < 8; i++)
+ *(iv+4+i) = req->iv[i];
+ *((__be32 *)(iv+12)) = counter;
+
+ return gcmaes_decrypt(req, req->assoclen - 8, ctx->hash_subkey, iv,
+ aes_ctx);
}

static int rfc4106_encrypt(struct aead_request *req)
@@ -1035,6 +1086,46 @@ struct {
};

#ifdef CONFIG_X86_64
+static int generic_gcmaes_set_key(struct crypto_aead *aead, const u8 *key,
+ unsigned int key_len)
+{
+ struct generic_gcmaes_ctx *ctx = generic_gcmaes_ctx_get(aead);
+
+ return aes_set_key_common(crypto_aead_tfm(aead),
+ &ctx->aes_key_expanded, key, key_len) ?:
+ rfc4106_set_hash_subkey(ctx->hash_subkey, key, key_len);
+}
+
+static int generic_gcmaes_encrypt(struct aead_request *req)
+{
+ struct crypto_aead *tfm = crypto_aead_reqtfm(req);
+ struct generic_gcmaes_ctx *ctx = generic_gcmaes_ctx_get(tfm);
+ void *aes_ctx = &(ctx->aes_key_expanded);
+ u8 iv[16] __attribute__ ((__aligned__(AESNI_ALIGN)));
+ __be32 counter = cpu_to_be32(1);
+
+ memcpy(iv, req->iv, 12);
+ *((__be32 *)(iv+12)) = counter;
+
+ return gcmaes_encrypt(req, req->assoclen, ctx->hash_subkey, iv,
+ aes_ctx);
+}
+
+static int generic_gcmaes_decrypt(struct aead_request *req)
+{
+ __be32 counter = cpu_to_be32(1);
+ struct crypto_aead *tfm = crypto_aead_reqtfm(req);
+ struct aesni_rfc4106_gcm_ctx *ctx = aesni_rfc4106_gcm_ctx_get(tfm);
+ void *aes_ctx = &(ctx->aes_key_expanded);
+ u8 iv[16] __attribute__ ((__aligned__(AESNI_ALIGN)));
+
+ memcpy(iv, req->iv, 12);
+ *((__be32 *)(iv+12)) = counter;
+
+ return gcmaes_decrypt(req, req->assoclen, ctx->hash_subkey, iv,
+ aes_ctx);
+}
+
static struct aead_alg aesni_aead_algs[] = { {
.setkey = common_rfc4106_set_key,
.setauthsize = common_rfc4106_set_authsize,
@@ -1069,6 +1160,23 @@ static struct aead_alg aesni_aead_algs[] = { {
.cra_ctxsize = sizeof(struct cryptd_aead *),
.cra_module = THIS_MODULE,
},
+}, {
+ .setkey = generic_gcmaes_set_key,
+ .setauthsize = generic_gcmaes_set_authsize,
+ .encrypt = generic_gcmaes_encrypt,
+ .decrypt = generic_gcmaes_decrypt,
+ .ivsize = 12,
+ .maxauthsize = 16,
+ .base = {
+ .cra_name = "gcm(aes)",
+ .cra_driver_name = "generic-gcm-aesni",
+ .cra_priority = 400,
+ .cra_flags = CRYPTO_ALG_ASYNC,
+ .cra_blocksize = 1,
+ .cra_ctxsize = sizeof(struct generic_gcmaes_ctx),
+ .cra_alignmask = AESNI_ALIGN - 1,
+ .cra_module = THIS_MODULE,
+ },
} };
#else
static struct aead_alg aesni_aead_algs[0];
--
2.12.2

Next message: Geert Uytterhoeven: "Re: [PATCH v4 2/2] of: Add unit tests for applying overlays"
Previous message: Sabrina Dubroca: "[PATCH 5/7] crypto: aesni: make AVX2 AES-GCM work with any aadlen"
In reply to: Sabrina Dubroca: "[PATCH 5/7] crypto: aesni: make AVX2 AES-GCM work with any aadlen"
Next in thread: Sabrina Dubroca: "[PATCH 4/7] crypto: aesni: make AVX AES-GCM work with all valid auth_tag_len"
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