Commit e9ed1eb8 authored by Eric Biggers's avatar Eric Biggers Committed by John Johansen
Browse files

apparmor: use SHA-256 library API instead of crypto_shash API 



This user of SHA-256 does not support any other algorithm, so the
crypto_shash abstraction provides no value.  Just use the SHA-256
library API instead, which is much simpler and easier to use.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarJohn Johansen <john.johansen@canonical.com>
parent 2b270e2f

security/apparmor/Kconfig

+1 −2
Original line number Diff line number Diff line
@@ -59,8 +59,7 @@ config SECURITY_APPARMOR_INTROSPECT_POLICY 
config SECURITY_APPARMOR_HASH

	bool "Enable introspection of sha256 hashes for loaded profiles"

	depends on SECURITY_APPARMOR_INTROSPECT_POLICY

	select CRYPTO

	select CRYPTO_SHA256

	select CRYPTO_LIB_SHA256

	default y

	help

	  This option selects whether introspection of loaded policy

security/apparmor/crypto.c

+12 −73
Original line number Diff line number Diff line
@@ -11,113 +11,52 @@ 
 * it should be.

 */



#include <crypto/hash.h>

#include <crypto/sha2.h>



#include "include/apparmor.h"

#include "include/crypto.h"



static unsigned int apparmor_hash_size;



static struct crypto_shash *apparmor_tfm;



unsigned int aa_hash_size(void)

{

	return apparmor_hash_size;

	return SHA256_DIGEST_SIZE;

}



char *aa_calc_hash(void *data, size_t len)

{

	SHASH_DESC_ON_STACK(desc, apparmor_tfm);

	char *hash;

	int error;



	if (!apparmor_tfm)

		return NULL;



	hash = kzalloc(apparmor_hash_size, GFP_KERNEL);

	hash = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);

	if (!hash)

		return ERR_PTR(-ENOMEM);



	desc->tfm = apparmor_tfm;



	error = crypto_shash_init(desc);

	if (error)

		goto fail;

	error = crypto_shash_update(desc, (u8 *) data, len);

	if (error)

		goto fail;

	error = crypto_shash_final(desc, hash);

	if (error)

		goto fail;



	sha256(data, len, hash);

	return hash;



fail:

	kfree(hash);



	return ERR_PTR(error);

}



int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,

			 size_t len)

{

	SHASH_DESC_ON_STACK(desc, apparmor_tfm);

	int error;

	struct sha256_state state;

	__le32 le32_version = cpu_to_le32(version);



	if (!aa_g_hash_policy)

		return 0;



	if (!apparmor_tfm)

		return 0;



	profile->hash = kzalloc(apparmor_hash_size, GFP_KERNEL);

	profile->hash = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);

	if (!profile->hash)

		return -ENOMEM;



	desc->tfm = apparmor_tfm;



	error = crypto_shash_init(desc);

	if (error)

		goto fail;

	error = crypto_shash_update(desc, (u8 *) &le32_version, 4);

	if (error)

		goto fail;

	error = crypto_shash_update(desc, (u8 *) start, len);

	if (error)

		goto fail;

	error = crypto_shash_final(desc, profile->hash);

	if (error)

		goto fail;



	sha256_init(&state);

	sha256_update(&state, (u8 *)&le32_version, 4);

	sha256_update(&state, (u8 *)start, len);

	sha256_final(&state, profile->hash);

	return 0;



fail:

	kfree(profile->hash);

	profile->hash = NULL;



	return error;

}



static int __init init_profile_hash(void)

{

	struct crypto_shash *tfm;



	if (!apparmor_initialized)

		return 0;



	tfm = crypto_alloc_shash("sha256", 0, 0);

	if (IS_ERR(tfm)) {

		int error = PTR_ERR(tfm);

		AA_ERROR("failed to setup profile sha256 hashing: %d\n", error);

		return error;

	}

	apparmor_tfm = tfm;

	apparmor_hash_size = crypto_shash_digestsize(apparmor_tfm);



	if (apparmor_initialized)

		aa_info_message("AppArmor sha256 policy hashing enabled");



	return 0;

}



late_initcall(init_profile_hash);