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-rw-r--r--arch/riscv/crypto/Kconfig4
-rw-r--r--arch/riscv/crypto/aes-riscv64-glue.c93
-rw-r--r--arch/riscv/crypto/aes-riscv64-zvkned.S153
3 files changed, 245 insertions, 5 deletions
diff --git a/arch/riscv/crypto/Kconfig b/arch/riscv/crypto/Kconfig
index 2ad44e1d464afd..ad58dad9a58076 100644
--- a/arch/riscv/crypto/Kconfig
+++ b/arch/riscv/crypto/Kconfig
@@ -3,14 +3,14 @@
menu "Accelerated Cryptographic Algorithms for CPU (riscv)"
config CRYPTO_AES_RISCV64
- tristate "Ciphers: AES, modes: ECB, CBC, CTR, XTS"
+ tristate "Ciphers: AES, modes: ECB, CBC, CTS, CTR, XTS"
depends on 64BIT && RISCV_ISA_V && TOOLCHAIN_HAS_VECTOR_CRYPTO
select CRYPTO_ALGAPI
select CRYPTO_LIB_AES
select CRYPTO_SKCIPHER
help
Block cipher: AES cipher algorithms
- Length-preserving ciphers: AES with ECB, CBC, CTR, XTS
+ Length-preserving ciphers: AES with ECB, CBC, CTS, CTR, XTS
Architecture: riscv64 using:
- Zvkned vector crypto extension
diff --git a/arch/riscv/crypto/aes-riscv64-glue.c b/arch/riscv/crypto/aes-riscv64-glue.c
index 37bc6ef0be40e5..f814ee048555b1 100644
--- a/arch/riscv/crypto/aes-riscv64-glue.c
+++ b/arch/riscv/crypto/aes-riscv64-glue.c
@@ -1,13 +1,15 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* AES using the RISC-V vector crypto extensions. Includes the bare block
- * cipher and the ECB, CBC, CTR, and XTS modes.
+ * cipher and the ECB, CBC, CBC-CTS, CTR, and XTS modes.
*
* Copyright (C) 2023 VRULL GmbH
* Author: Heiko Stuebner <heiko.stuebner@vrull.eu>
*
* Copyright (C) 2023 SiFive, Inc.
* Author: Jerry Shih <jerry.shih@sifive.com>
+ *
+ * Copyright 2024 Google LLC
*/
#include <asm/simd.h>
@@ -40,6 +42,10 @@ asmlinkage void aes_cbc_decrypt_zvkned(const struct crypto_aes_ctx *key,
const u8 *in, u8 *out, size_t len,
u8 iv[AES_BLOCK_SIZE]);
+asmlinkage void aes_cbc_cts_crypt_zvkned(const struct crypto_aes_ctx *key,
+ const u8 *in, u8 *out, size_t len,
+ const u8 iv[AES_BLOCK_SIZE], bool enc);
+
asmlinkage void aes_ctr32_crypt_zvkned_zvkb(const struct crypto_aes_ctx *key,
const u8 *in, u8 *out, size_t len,
u8 iv[AES_BLOCK_SIZE]);
@@ -164,7 +170,7 @@ static int riscv64_aes_ecb_decrypt(struct skcipher_request *req)
/* AES-CBC */
-static inline int riscv64_aes_cbc_crypt(struct skcipher_request *req, bool enc)
+static int riscv64_aes_cbc_crypt(struct skcipher_request *req, bool enc)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
const struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -202,6 +208,70 @@ static int riscv64_aes_cbc_decrypt(struct skcipher_request *req)
return riscv64_aes_cbc_crypt(req, false);
}
+/* AES-CBC-CTS */
+
+static int riscv64_aes_cbc_cts_crypt(struct skcipher_request *req, bool enc)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ const struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct scatterlist sg_src[2], sg_dst[2];
+ struct skcipher_request subreq;
+ struct scatterlist *src, *dst;
+ struct skcipher_walk walk;
+ unsigned int cbc_len;
+ int err;
+
+ if (req->cryptlen < AES_BLOCK_SIZE)
+ return -EINVAL;
+
+ err = skcipher_walk_virt(&walk, req, false);
+ if (err)
+ return err;
+ /*
+ * If the full message is available in one step, decrypt it in one call
+ * to the CBC-CTS assembly function. This reduces overhead, especially
+ * on short messages. Otherwise, fall back to doing CBC up to the last
+ * two blocks, then invoke CTS just for the ciphertext stealing.
+ */
+ if (unlikely(walk.nbytes != req->cryptlen)) {
+ cbc_len = round_down(req->cryptlen - AES_BLOCK_SIZE - 1,
+ AES_BLOCK_SIZE);
+ skcipher_walk_abort(&walk);
+ skcipher_request_set_tfm(&subreq, tfm);
+ skcipher_request_set_callback(&subreq,
+ skcipher_request_flags(req),
+ NULL, NULL);
+ skcipher_request_set_crypt(&subreq, req->src, req->dst,
+ cbc_len, req->iv);
+ err = riscv64_aes_cbc_crypt(&subreq, enc);
+ if (err)
+ return err;
+ dst = src = scatterwalk_ffwd(sg_src, req->src, cbc_len);
+ if (req->dst != req->src)
+ dst = scatterwalk_ffwd(sg_dst, req->dst, cbc_len);
+ skcipher_request_set_crypt(&subreq, src, dst,
+ req->cryptlen - cbc_len, req->iv);
+ err = skcipher_walk_virt(&walk, &subreq, false);
+ if (err)
+ return err;
+ }
+ kernel_vector_begin();
+ aes_cbc_cts_crypt_zvkned(ctx, walk.src.virt.addr, walk.dst.virt.addr,
+ walk.nbytes, req->iv, enc);
+ kernel_vector_end();
+ return skcipher_walk_done(&walk, 0);
+}
+
+static int riscv64_aes_cbc_cts_encrypt(struct skcipher_request *req)
+{
+ return riscv64_aes_cbc_cts_crypt(req, true);
+}
+
+static int riscv64_aes_cbc_cts_decrypt(struct skcipher_request *req)
+{
+ return riscv64_aes_cbc_cts_crypt(req, false);
+}
+
/* AES-CTR */
static int riscv64_aes_ctr_crypt(struct skcipher_request *req)
@@ -434,6 +504,22 @@ static struct skcipher_alg riscv64_zvkned_aes_skcipher_algs[] = {
.cra_driver_name = "cbc-aes-riscv64-zvkned",
.cra_module = THIS_MODULE,
},
+ }, {
+ .setkey = riscv64_aes_setkey_skcipher,
+ .encrypt = riscv64_aes_cbc_cts_encrypt,
+ .decrypt = riscv64_aes_cbc_cts_decrypt,
+ .min_keysize = AES_MIN_KEY_SIZE,
+ .max_keysize = AES_MAX_KEY_SIZE,
+ .ivsize = AES_BLOCK_SIZE,
+ .walksize = 4 * AES_BLOCK_SIZE, /* matches LMUL=4 */
+ .base = {
+ .cra_blocksize = AES_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct crypto_aes_ctx),
+ .cra_priority = 300,
+ .cra_name = "cts(cbc(aes))",
+ .cra_driver_name = "cts-cbc-aes-riscv64-zvkned",
+ .cra_module = THIS_MODULE,
+ },
}
};
@@ -540,11 +626,12 @@ static void __exit riscv64_aes_mod_exit(void)
module_init(riscv64_aes_mod_init);
module_exit(riscv64_aes_mod_exit);
-MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS (RISC-V accelerated)");
+MODULE_DESCRIPTION("AES-ECB/CBC/CTS/CTR/XTS (RISC-V accelerated)");
MODULE_AUTHOR("Jerry Shih <jerry.shih@sifive.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CRYPTO("aes");
MODULE_ALIAS_CRYPTO("ecb(aes)");
MODULE_ALIAS_CRYPTO("cbc(aes)");
+MODULE_ALIAS_CRYPTO("cts(cbc(aes))");
MODULE_ALIAS_CRYPTO("ctr(aes)");
MODULE_ALIAS_CRYPTO("xts(aes)");
diff --git a/arch/riscv/crypto/aes-riscv64-zvkned.S b/arch/riscv/crypto/aes-riscv64-zvkned.S
index 43541aad6386cc..23d063f94ce61d 100644
--- a/arch/riscv/crypto/aes-riscv64-zvkned.S
+++ b/arch/riscv/crypto/aes-riscv64-zvkned.S
@@ -184,3 +184,156 @@ SYM_FUNC_START(aes_cbc_decrypt_zvkned)
192:
aes_cbc_decrypt 192
SYM_FUNC_END(aes_cbc_decrypt_zvkned)
+
+.macro aes_cbc_cts_encrypt keylen
+
+ // CBC-encrypt all blocks except the last. But don't store the
+ // second-to-last block to the output buffer yet, since it will be
+ // handled specially in the ciphertext stealing step. Exception: if the
+ // message is single-block, still encrypt the last (and only) block.
+ li t0, 16
+ j 2f
+1:
+ vse32.v v16, (OUTP) // Store ciphertext block
+ addi OUTP, OUTP, 16
+2:
+ vle32.v v17, (INP) // Load plaintext block
+ vxor.vv v16, v16, v17 // XOR with IV or prev ciphertext block
+ aes_encrypt v16, \keylen // Encrypt
+ addi INP, INP, 16
+ addi LEN, LEN, -16
+ bgt LEN, t0, 1b // Repeat if more than one block remains
+
+ // Special case: if the message is a single block, just do CBC.
+ beqz LEN, .Lcts_encrypt_done\@
+
+ // Encrypt the last two blocks using ciphertext stealing as follows:
+ // C[n-1] = Encrypt(Encrypt(P[n-1] ^ C[n-2]) ^ P[n])
+ // C[n] = Encrypt(P[n-1] ^ C[n-2])[0..LEN]
+ //
+ // C[i] denotes the i'th ciphertext block, and likewise P[i] the i'th
+ // plaintext block. Block n, the last block, may be partial; its length
+ // is 1 <= LEN <= 16. If there are only 2 blocks, C[n-2] means the IV.
+ //
+ // v16 already contains Encrypt(P[n-1] ^ C[n-2]).
+ // INP points to P[n]. OUTP points to where C[n-1] should go.
+ // To support in-place encryption, load P[n] before storing C[n].
+ addi t0, OUTP, 16 // Get pointer to where C[n] should go
+ vsetvli zero, LEN, e8, m1, tu, ma
+ vle8.v v17, (INP) // Load P[n]
+ vse8.v v16, (t0) // Store C[n]
+ vxor.vv v16, v16, v17 // v16 = Encrypt(P[n-1] ^ C[n-2]) ^ P[n]
+ vsetivli zero, 4, e32, m1, ta, ma
+ aes_encrypt v16, \keylen
+.Lcts_encrypt_done\@:
+ vse32.v v16, (OUTP) // Store C[n-1] (or C[n] in single-block case)
+ ret
+.endm
+
+#define LEN32 t4 // Length of remaining full blocks in 32-bit words
+#define LEN_MOD16 t5 // Length of message in bytes mod 16
+
+.macro aes_cbc_cts_decrypt keylen
+ andi LEN32, LEN, ~15
+ srli LEN32, LEN32, 2
+ andi LEN_MOD16, LEN, 15
+
+ // Save C[n-2] in v28 so that it's available later during the ciphertext
+ // stealing step. If there are fewer than three blocks, C[n-2] means
+ // the IV, otherwise it means the third-to-last ciphertext block.
+ vmv.v.v v28, v16 // IV
+ add t0, LEN, -33
+ bltz t0, .Lcts_decrypt_loop\@
+ andi t0, t0, ~15
+ add t0, t0, INP
+ vle32.v v28, (t0)
+
+ // CBC-decrypt all full blocks. For the last full block, or the last 2
+ // full blocks if the message is block-aligned, this doesn't write the
+ // correct output blocks (unless the message is only a single block),
+ // because it XORs the wrong values with the raw AES plaintexts. But we
+ // fix this after this loop without redoing the AES decryptions. This
+ // approach allows more of the AES decryptions to be parallelized.
+.Lcts_decrypt_loop\@:
+ vsetvli t0, LEN32, e32, m4, ta, ma
+ addi t1, t0, -4
+ vle32.v v20, (INP) // Load next set of ciphertext blocks
+ vmv.v.v v24, v16 // Get IV or last ciphertext block of prev set
+ vslideup.vi v24, v20, 4 // Setup prev ciphertext blocks
+ vslidedown.vx v16, v20, t1 // Save last ciphertext block of this set
+ aes_decrypt v20, \keylen // Decrypt this set of blocks
+ vxor.vv v24, v24, v20 // XOR prev ciphertext blocks with decrypted blocks
+ vse32.v v24, (OUTP) // Store this set of plaintext blocks
+ sub LEN32, LEN32, t0
+ slli t0, t0, 2 // Words to bytes
+ add INP, INP, t0
+ add OUTP, OUTP, t0
+ bnez LEN32, .Lcts_decrypt_loop\@
+
+ vsetivli zero, 4, e32, m4, ta, ma
+ vslidedown.vx v20, v20, t1 // Extract raw plaintext of last full block
+ addi t0, OUTP, -16 // Get pointer to last full plaintext block
+ bnez LEN_MOD16, .Lcts_decrypt_non_block_aligned\@
+
+ // Special case: if the message is a single block, just do CBC.
+ li t1, 16
+ beq LEN, t1, .Lcts_decrypt_done\@
+
+ // Block-aligned message. Just fix up the last 2 blocks. We need:
+ //
+ // P[n-1] = Decrypt(C[n]) ^ C[n-2]
+ // P[n] = Decrypt(C[n-1]) ^ C[n]
+ //
+ // We have C[n] in v16, Decrypt(C[n]) in v20, and C[n-2] in v28.
+ // Together with Decrypt(C[n-1]) ^ C[n-2] from the output buffer, this
+ // is everything needed to fix the output without re-decrypting blocks.
+ addi t1, OUTP, -32 // Get pointer to where P[n-1] should go
+ vxor.vv v20, v20, v28 // Decrypt(C[n]) ^ C[n-2] == P[n-1]
+ vle32.v v24, (t1) // Decrypt(C[n-1]) ^ C[n-2]
+ vse32.v v20, (t1) // Store P[n-1]
+ vxor.vv v20, v24, v16 // Decrypt(C[n-1]) ^ C[n-2] ^ C[n] == P[n] ^ C[n-2]
+ j .Lcts_decrypt_finish\@
+
+.Lcts_decrypt_non_block_aligned\@:
+ // Decrypt the last two blocks using ciphertext stealing as follows:
+ //
+ // P[n-1] = Decrypt(C[n] || Decrypt(C[n-1])[LEN_MOD16..16]) ^ C[n-2]
+ // P[n] = (Decrypt(C[n-1]) ^ C[n])[0..LEN_MOD16]
+ //
+ // We already have Decrypt(C[n-1]) in v20 and C[n-2] in v28.
+ vmv.v.v v16, v20 // v16 = Decrypt(C[n-1])
+ vsetvli zero, LEN_MOD16, e8, m1, tu, ma
+ vle8.v v20, (INP) // v20 = C[n] || Decrypt(C[n-1])[LEN_MOD16..16]
+ vxor.vv v16, v16, v20 // v16 = Decrypt(C[n-1]) ^ C[n]
+ vse8.v v16, (OUTP) // Store P[n]
+ vsetivli zero, 4, e32, m1, ta, ma
+ aes_decrypt v20, \keylen // v20 = Decrypt(C[n] || Decrypt(C[n-1])[LEN_MOD16..16])
+.Lcts_decrypt_finish\@:
+ vxor.vv v20, v20, v28 // XOR with C[n-2]
+ vse32.v v20, (t0) // Store last full plaintext block
+.Lcts_decrypt_done\@:
+ ret
+.endm
+
+.macro aes_cbc_cts_crypt keylen
+ vle32.v v16, (IVP) // Load IV
+ beqz a5, .Lcts_decrypt\@
+ aes_cbc_cts_encrypt \keylen
+.Lcts_decrypt\@:
+ aes_cbc_cts_decrypt \keylen
+.endm
+
+// void aes_cbc_cts_crypt_zvkned(const struct crypto_aes_ctx *key,
+// const u8 *in, u8 *out, size_t len,
+// const u8 iv[16], bool enc);
+//
+// Encrypts or decrypts a message with the CS3 variant of AES-CBC-CTS.
+// This is the variant that unconditionally swaps the last two blocks.
+SYM_FUNC_START(aes_cbc_cts_crypt_zvkned)
+ aes_begin KEYP, 128f, 192f
+ aes_cbc_cts_crypt 256
+128:
+ aes_cbc_cts_crypt 128
+192:
+ aes_cbc_cts_crypt 192
+SYM_FUNC_END(aes_cbc_cts_crypt_zvkned)
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-05-11 11:48:14 +0000