Commit 652a3017 authored by Cheng-Yang Chou's avatar Cheng-Yang Chou Committed by Eric Biggers
Browse files

crypto: arm64/aes-neonbs - Move key expansion off the stack 



aesbs_setkey() and aesbs_cbc_ctr_setkey() allocate struct crypto_aes_ctx
on the stack. On arm64, the kernel-mode NEON context is also stored on
the stack, causing the combined frame size to exceed 1024 bytes and
triggering -Wframe-larger-than= warnings.

Allocate struct crypto_aes_ctx on the heap instead and use
kfree_sensitive() to ensure the key material is zeroed on free.
Use a goto-based cleanup path to ensure kfree_sensitive() is always
called.

Signed-off-by: default avatarCheng-Yang Chou <yphbchou0911@gmail.com>
Fixes: 4fa617cc ("arm64/fpsimd: Allocate kernel mode FP/SIMD buffers on the stack")
Link: https://lore.kernel.org/r/20260306064254.2079274-1-yphbchou0911@gmail.com


Signed-off-by: default avatarEric Biggers <ebiggers@kernel.org>
parent 1f318b96

arch/arm64/crypto/aes-neonbs-glue.c

+23 −14
Original line number Diff line number Diff line
@@ -76,19 +76,24 @@ static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key, 
			unsigned int key_len)

{

	struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);

	struct crypto_aes_ctx rk;

	struct crypto_aes_ctx *rk;

	int err;



	err = aes_expandkey(&rk, in_key, key_len);

	rk = kmalloc(sizeof(*rk), GFP_KERNEL);

	if (!rk)

		return -ENOMEM;



	err = aes_expandkey(rk, in_key, key_len);

	if (err)

		return err;

		goto out;



	ctx->rounds = 6 + key_len / 4;



	scoped_ksimd()

		aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds);



	return 0;

		aesbs_convert_key(ctx->rk, rk->key_enc, ctx->rounds);

out:

	kfree_sensitive(rk);

	return err;

}



static int __ecb_crypt(struct skcipher_request *req,
@@ -133,22 +138,26 @@ static int aesbs_cbc_ctr_setkey(struct crypto_skcipher *tfm, const u8 *in_key, 
			    unsigned int key_len)

{

	struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);

	struct crypto_aes_ctx rk;

	struct crypto_aes_ctx *rk;

	int err;



	err = aes_expandkey(&rk, in_key, key_len);

	rk = kmalloc(sizeof(*rk), GFP_KERNEL);

	if (!rk)

		return -ENOMEM;



	err = aes_expandkey(rk, in_key, key_len);

	if (err)

		return err;

		goto out;



	ctx->key.rounds = 6 + key_len / 4;



	memcpy(ctx->enc, rk.key_enc, sizeof(ctx->enc));

	memcpy(ctx->enc, rk->key_enc, sizeof(ctx->enc));



	scoped_ksimd()

		aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);

	memzero_explicit(&rk, sizeof(rk));



	return 0;

		aesbs_convert_key(ctx->key.rk, rk->key_enc, ctx->key.rounds);

out:

	kfree_sensitive(rk);

	return err;

}



static int cbc_encrypt(struct skcipher_request *req)