thunderbolt: Use HMAC-SHA256 library instead of crypto_shash

Use the hmac_sha256_usingrawkey() library function instead of the
"hmac(sha256)" crypto_shash.  This is simpler and faster.

As a cleanup, change the input data parameters from "challenge,
sizeof(hmac)" to "challenge, sizeof(challenge)", so that the size is
being taken of the correct buffer.  This is not a functional change,
since it happens that sizeof(hmac) == sizeof(challenge).

Replace the selection of CRYPTO and CRYPTO_HASH with CRYPTO_LIB_SHA256
and CRYPTO_LIB_UTILS.  The latter is needed for crypto_memneq() which
was previously being pulled in via CRYPTO.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig
index 0abdb69ee9f437b41b463112910a7b2b61dd0dfa..db3b0bef48f4c30be6b27e11a2ff9d1ba072c3fe 100644 (file)
--- a/drivers/thunderbolt/Kconfig
+++ b/drivers/thunderbolt/Kconfig
@@ -4,8 +4,8 @@ menuconfig USB4
        depends on PCI
        select APPLE_PROPERTIES if EFI_STUB && X86
        select CRC32
-       select CRYPTO
-       select CRYPTO_HASH
+       select CRYPTO_LIB_SHA256
+       select CRYPTO_LIB_UTILS
        select NVMEM
        help
          USB4 and Thunderbolt driver. USB4 is the public specification

diff --git a/drivers/thunderbolt/domain.c b/drivers/thunderbolt/domain.c
index 7e0eb3c07f1c71f5c8e4877dcd993a4e9ec24b8e..5272c255e046d5c99e518912f66530cb6a7a6abf 100644 (file)
--- a/drivers/thunderbolt/domain.c
+++ b/drivers/thunderbolt/domain.c
@@ -12,7 +12,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/random.h>
-#include <crypto/hash.h>
+#include <crypto/sha2.h>
 #include <crypto/utils.h>
 
 #include "tb.h"
@@ -709,8 +709,6 @@ int tb_domain_challenge_switch_key(struct tb *tb, struct tb_switch *sw)
        u8 response[TB_SWITCH_KEY_SIZE];
        u8 hmac[TB_SWITCH_KEY_SIZE];
        struct tb_switch *parent_sw;
-       struct crypto_shash *tfm;
-       struct shash_desc *shash;
        int ret;
 
        if (!tb->cm_ops->approve_switch || !tb->cm_ops->challenge_switch_key)
@@ -726,45 +724,15 @@ int tb_domain_challenge_switch_key(struct tb *tb, struct tb_switch *sw)
        if (ret)
                return ret;
 
-       tfm = crypto_alloc_shash("hmac(sha256)", 0, 0);
-       if (IS_ERR(tfm))
-               return PTR_ERR(tfm);
-
-       ret = crypto_shash_setkey(tfm, sw->key, TB_SWITCH_KEY_SIZE);
-       if (ret)
-               goto err_free_tfm;
-
-       shash = kzalloc(sizeof(*shash) + crypto_shash_descsize(tfm),
-                       GFP_KERNEL);
-       if (!shash) {
-               ret = -ENOMEM;
-               goto err_free_tfm;
-       }
-
-       shash->tfm = tfm;
-
-       memset(hmac, 0, sizeof(hmac));
-       ret = crypto_shash_digest(shash, challenge, sizeof(hmac), hmac);
-       if (ret)
-               goto err_free_shash;
+       static_assert(sizeof(hmac) == SHA256_DIGEST_SIZE);
+       hmac_sha256_usingrawkey(sw->key, TB_SWITCH_KEY_SIZE,
+                               challenge, sizeof(challenge), hmac);
 
        /* The returned HMAC must match the one we calculated */
-       if (crypto_memneq(response, hmac, sizeof(hmac))) {
-               ret = -EKEYREJECTED;
-               goto err_free_shash;
-       }
-
-       crypto_free_shash(tfm);
-       kfree(shash);
+       if (crypto_memneq(response, hmac, sizeof(hmac)))
+               return -EKEYREJECTED;
 
        return tb->cm_ops->approve_switch(tb, sw);
-
-err_free_shash:
-       kfree(shash);
-err_free_tfm:
-       crypto_free_shash(tfm);
-
-       return ret;
 }
 
 /**