Subject: [PATCH 32/36] lib/crypto: aescfb: Use new AES library API

From: Eric Biggers <[email-masked]>
Date: Sun, 4 Jan 2026 21:13:05 -0800

Switch from the old AES library functions (which use struct
crypto_aes_ctx) to the new ones (which use struct aes_enckey).  This
eliminates the unnecessary computation and caching of the decryption
round keys.  The new AES en/decryption functions are also much faster
and use AES instructions when supported by the CPU.

Note: aes_encrypt_new() will be renamed to aes_encrypt() once all
callers of the old aes_encrypt() have been updated.

Signed-off-by: Eric Biggers <[email-masked]>
---
 drivers/char/tpm/tpm2-sessions.c | 10 +++++-----
 include/crypto/aes.h             |  4 ++--
 lib/crypto/aescfb.c              | 30 +++++++++++++++---------------
 3 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 4149379665c4..09df6353ef04 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -124,11 +124,11 @@ struct tpm2_auth {
 	 * session_key and passphrase.
 	 */
 	u8 session_key[SHA256_DIGEST_SIZE];
 	u8 passphrase[SHA256_DIGEST_SIZE];
 	int passphrase_len;
-	struct crypto_aes_ctx aes_ctx;
+	struct aes_enckey aes_key;
 	/* saved session attributes: */
 	u8 attrs;
 	__be32 ordinal;
 
 	/*
@@ -675,12 +675,12 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 			  + auth->passphrase_len, "CFB", auth->our_nonce,
 			  auth->tpm_nonce, AES_KEY_BYTES + AES_BLOCK_SIZE,
 			  auth->scratch);
 
 		len = tpm_buf_read_u16(buf, &offset_p);
-		aes_expandkey(&auth->aes_ctx, auth->scratch, AES_KEY_BYTES);
-		aescfb_encrypt(&auth->aes_ctx, &buf->data[offset_p],
+		aes_prepareenckey(&auth->aes_key, auth->scratch, AES_KEY_BYTES);
+		aescfb_encrypt(&auth->aes_key, &buf->data[offset_p],
 			       &buf->data[offset_p], len,
 			       auth->scratch + AES_KEY_BYTES);
 		/* reset p to beginning of parameters for HMAC */
 		offset_p -= 2;
 	}
@@ -856,12 +856,12 @@ int tpm_buf_check_hmac_response(struct tpm_chip *chip, struct tpm_buf *buf,
 			  + auth->passphrase_len, "CFB", auth->tpm_nonce,
 			  auth->our_nonce, AES_KEY_BYTES + AES_BLOCK_SIZE,
 			  auth->scratch);
 
 		len = tpm_buf_read_u16(buf, &offset_p);
-		aes_expandkey(&auth->aes_ctx, auth->scratch, AES_KEY_BYTES);
-		aescfb_decrypt(&auth->aes_ctx, &buf->data[offset_p],
+		aes_prepareenckey(&auth->aes_key, auth->scratch, AES_KEY_BYTES);
+		aescfb_decrypt(&auth->aes_key, &buf->data[offset_p],
 			       &buf->data[offset_p], len,
 			       auth->scratch + AES_KEY_BYTES);
 	}
 
  out:
diff --git a/include/crypto/aes.h b/include/crypto/aes.h
index e4b5f60e7a0b..18a5f518e914 100644
--- a/include/crypto/aes.h
+++ b/include/crypto/aes.h
@@ -342,11 +342,11 @@ void aes_decrypt_new(const struct aes_key *key, u8 out[at_least AES_BLOCK_SIZE],
 extern const u8 crypto_aes_sbox[];
 extern const u8 crypto_aes_inv_sbox[];
 extern const u32 __cacheline_aligned aes_enc_tab[256];
 extern const u32 __cacheline_aligned aes_dec_tab[256];
 
-void aescfb_encrypt(const struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src,
+void aescfb_encrypt(const struct aes_enckey *key, u8 *dst, const u8 *src,
 		    int len, const u8 iv[AES_BLOCK_SIZE]);
-void aescfb_decrypt(const struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src,
+void aescfb_decrypt(const struct aes_enckey *key, u8 *dst, const u8 *src,
 		    int len, const u8 iv[AES_BLOCK_SIZE]);
 
 #endif
diff --git a/lib/crypto/aescfb.c b/lib/crypto/aescfb.c
index 0f294c8cbf3c..3149d688c4e0 100644
--- a/lib/crypto/aescfb.c
+++ b/lib/crypto/aescfb.c
@@ -9,11 +9,11 @@
 #include <crypto/algapi.h>
 #include <linux/export.h>
 #include <linux/module.h>
 #include <asm/irqflags.h>
 
-static void aescfb_encrypt_block(const struct crypto_aes_ctx *ctx, void *dst,
+static void aescfb_encrypt_block(const struct aes_enckey *key, void *dst,
 				 const void *src)
 {
 	unsigned long flags;
 
 	/*
@@ -23,31 +23,31 @@ static void aescfb_encrypt_block(const struct crypto_aes_ctx *ctx, void *dst,
 	 * extent by pulling the entire S-box into the caches before doing any
 	 * substitutions, but this strategy is more effective when running with
 	 * interrupts disabled.
 	 */
 	local_irq_save(flags);
-	aes_encrypt(ctx, dst, src);
+	aes_encrypt_new(key, dst, src);
 	local_irq_restore(flags);
 }
 
 /**
  * aescfb_encrypt - Perform AES-CFB encryption on a block of data
  *
- * @ctx:	The AES-CFB key schedule
+ * @key:	The AES-CFB key schedule
  * @dst:	Pointer to the ciphertext output buffer
  * @src:	Pointer the plaintext (may equal @dst for encryption in place)
  * @len:	The size in bytes of the plaintext and ciphertext.
  * @iv:		The initialization vector (IV) to use for this block of data
  */
-void aescfb_encrypt(const struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src,
+void aescfb_encrypt(const struct aes_enckey *key, u8 *dst, const u8 *src,
 		    int len, const u8 iv[AES_BLOCK_SIZE])
 {
 	u8 ks[AES_BLOCK_SIZE];
 	const u8 *v = iv;
 
 	while (len > 0) {
-		aescfb_encrypt_block(ctx, ks, v);
+		aescfb_encrypt_block(key, ks, v);
 		crypto_xor_cpy(dst, src, ks, min(len, AES_BLOCK_SIZE));
 		v = dst;
 
 		dst += AES_BLOCK_SIZE;
 		src += AES_BLOCK_SIZE;
@@ -59,31 +59,31 @@ void aescfb_encrypt(const struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src,
 EXPORT_SYMBOL(aescfb_encrypt);
 
 /**
  * aescfb_decrypt - Perform AES-CFB decryption on a block of data
  *
- * @ctx:	The AES-CFB key schedule
+ * @key:	The AES-CFB key schedule
  * @dst:	Pointer to the plaintext output buffer
  * @src:	Pointer the ciphertext (may equal @dst for decryption in place)
  * @len:	The size in bytes of the plaintext and ciphertext.
  * @iv:		The initialization vector (IV) to use for this block of data
  */
-void aescfb_decrypt(const struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src,
+void aescfb_decrypt(const struct aes_enckey *key, u8 *dst, const u8 *src,
 		    int len, const u8 iv[AES_BLOCK_SIZE])
 {
 	u8 ks[2][AES_BLOCK_SIZE];
 
-	aescfb_encrypt_block(ctx, ks[0], iv);
+	aescfb_encrypt_block(key, ks[0], iv);
 
 	for (int i = 0; len > 0; i ^= 1) {
 		if (len > AES_BLOCK_SIZE)
 			/*
 			 * Generate the keystream for the next block before
 			 * performing the XOR, as that may update in place and
 			 * overwrite the ciphertext.
 			 */
-			aescfb_encrypt_block(ctx, ks[!i], src);
+			aescfb_encrypt_block(key, ks[!i], src);
 
 		crypto_xor_cpy(dst, src, ks[i], min(len, AES_BLOCK_SIZE));
 
 		dst += AES_BLOCK_SIZE;
 		src += AES_BLOCK_SIZE;
@@ -212,34 +212,34 @@ static struct {
 };
 
 static int __init libaescfb_init(void)
 {
 	for (int i = 0; i < ARRAY_SIZE(aescfb_tv); i++) {
-		struct crypto_aes_ctx ctx;
+		struct aes_enckey key;
 		u8 buf[64];
 
-		if (aes_expandkey(&ctx, aescfb_tv[i].key, aescfb_tv[i].klen)) {
-			pr_err("aes_expandkey() failed on vector %d\n", i);
+		if (aes_prepareenckey(&key, aescfb_tv[i].key, aescfb_tv[i].klen)) {
+			pr_err("aes_prepareenckey() failed on vector %d\n", i);
 			return -ENODEV;
 		}
 
-		aescfb_encrypt(&ctx, buf, aescfb_tv[i].ptext, aescfb_tv[i].len,
+		aescfb_encrypt(&key, buf, aescfb_tv[i].ptext, aescfb_tv[i].len,
 			       aescfb_tv[i].iv);
 		if (memcmp(buf, aescfb_tv[i].ctext, aescfb_tv[i].len)) {
 			pr_err("aescfb_encrypt() #1 failed on vector %d\n", i);
 			return -ENODEV;
 		}
 
 		/* decrypt in place */
-		aescfb_decrypt(&ctx, buf, buf, aescfb_tv[i].len, aescfb_tv[i].iv);
+		aescfb_decrypt(&key, buf, buf, aescfb_tv[i].len, aescfb_tv[i].iv);
 		if (memcmp(buf, aescfb_tv[i].ptext, aescfb_tv[i].len)) {
 			pr_err("aescfb_decrypt() failed on vector %d\n", i);
 			return -ENODEV;
 		}
 
 		/* encrypt in place */
-		aescfb_encrypt(&ctx, buf, buf, aescfb_tv[i].len, aescfb_tv[i].iv);
+		aescfb_encrypt(&key, buf, buf, aescfb_tv[i].len, aescfb_tv[i].iv);
 		if (memcmp(buf, aescfb_tv[i].ctext, aescfb_tv[i].len)) {
 			pr_err("aescfb_encrypt() #2 failed on vector %d\n", i);
 
 			return -ENODEV;
 		}
-- 
2.52.0