net: phy: mscc: avoid skcipher API for single block AES encryption (5a3235e5) · Commits · 戴 / test

The skcipher API dynamically instantiates the transformation object on request that implements the requested algorithm optimally on the given platform. This notion of optimality only matters for cases like bulk network or disk encryption, where performance can be a bottleneck, or in cases where the algorithm itself is not known at compile time. In the mscc case, we are dealing with AES encryption of a single block, and so neither concern applies, and we are better off using the AES library interface, which is lightweight and safe for this kind of use. Note that the scatterlist API does not permit references to buffers that are located on the stack, so the existing code is incorrect in any case, but avoiding the skcipher and scatterlist APIs entirely is the most straight-forward approach to fixing this. Cc: Antoine Tenart <antoine.tenart@bootlin.com> Cc: Andrew Lunn <andrew@lunn.ch> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Heiner Kallweit <hkallweit1@gmail.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Fixes: ("net: phy: mscc: macsec support") Reviewed-by:

Eric Biggers <ebiggers@google.com> Signed-off-by:

Ard Biesheuvel <ardb@kernel.org> Tested-by:

Antoine Tenart <antoine.tenart@bootlin.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/phy/Kconfig

+1 −2

Original line number	Diff line number	Diff line
		@@ -480,8 +480,7 @@ config MICROCHIP_T1_PHY
		config MICROSEMI_PHY
		tristate "Microsemi PHYs"
		depends on MACSEC \|\| MACSEC=n
		select CRYPTO_AES
		select CRYPTO_ECB
		select CRYPTO_LIB_AES if MACSEC
		help
		Currently supports VSC8514, VSC8530, VSC8531, VSC8540 and VSC8541 PHYs

drivers/net/phy/mscc/mscc_macsec.c

+9 −31

Original line number	Diff line number	Diff line
		@@ -10,7 +10,7 @@
		#include <linux/phy.h>
		#include <dt-bindings/net/mscc-phy-vsc8531.h>

		#include <crypto/skcipher.h>
		#include <crypto/aes.h>

		#include <net/macsec.h>

		@@ -500,39 +500,17 @@ static u32 vsc8584_macsec_flow_context_id(struct macsec_flow *flow)
		static int vsc8584_macsec_derive_key(const u8 key[MACSEC_KEYID_LEN],
		u16 key_len, u8 hkey[16])
		{
		struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
		struct skcipher_request *req = NULL;
		struct scatterlist src, dst;
		DECLARE_CRYPTO_WAIT(wait);
		u32 input[4] = {0};
		const u8 input[AES_BLOCK_SIZE] = {0};
		struct crypto_aes_ctx ctx;
		int ret;

		if (IS_ERR(tfm))
		return PTR_ERR(tfm);

		req = skcipher_request_alloc(tfm, GFP_KERNEL);
		if (!req) {
		ret = -ENOMEM;
		goto out;
		}

		skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG \|
		CRYPTO_TFM_REQ_MAY_SLEEP, crypto_req_done,
		&wait);
		ret = crypto_skcipher_setkey(tfm, key, key_len);
		if (ret < 0)
		goto out;

		sg_init_one(&src, input, 16);
		sg_init_one(&dst, hkey, 16);
		skcipher_request_set_crypt(req, &src, &dst, 16, NULL);

		ret = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);

		out:
		skcipher_request_free(req);
		crypto_free_skcipher(tfm);
		ret = aes_expandkey(&ctx, key, key_len);
		if (ret)
		return ret;

		aes_encrypt(&ctx, hkey, input);
		memzero_explicit(&ctx, sizeof(ctx));
		return 0;
		}

		static int vsc8584_macsec_transformation(struct phy_device *phydev,

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