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Commit ee618b46 authored by Eric Biggers's avatar Eric Biggers Committed by James Morris
Browse files

KEYS: trusted: sanitize all key material 



As the previous patch did for encrypted-keys, zero sensitive any
potentially sensitive data related to the "trusted" key type before it
is freed.  Notably, we were not zeroing the tpm_buf structures in which
the actual key is stored for TPM seal and unseal, nor were we zeroing
the trusted_key_payload in certain error paths.

Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: David Safford <safford@us.ibm.com>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
parent a9dd74b2

security/keys/trusted.c

+22 −28
Original line number Diff line number Diff line
@@ -70,7 +70,7 @@ static int TSS_sha1(const unsigned char *data, unsigned int datalen, 
	}



	ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest);

	kfree(sdesc);

	kzfree(sdesc);

	return ret;

}
@@ -114,7 +114,7 @@ static int TSS_rawhmac(unsigned char *digest, const unsigned char *key, 
	if (!ret)

		ret = crypto_shash_final(&sdesc->shash, digest);

out:

	kfree(sdesc);

	kzfree(sdesc);

	return ret;

}
@@ -165,7 +165,7 @@ static int TSS_authhmac(unsigned char *digest, const unsigned char *key, 
				  paramdigest, TPM_NONCE_SIZE, h1,

				  TPM_NONCE_SIZE, h2, 1, &c, 0, 0);

out:

	kfree(sdesc);

	kzfree(sdesc);

	return ret;

}
@@ -246,7 +246,7 @@ static int TSS_checkhmac1(unsigned char *buffer, 
	if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE))

		ret = -EINVAL;

out:

	kfree(sdesc);

	kzfree(sdesc);

	return ret;

}
@@ -347,7 +347,7 @@ static int TSS_checkhmac2(unsigned char *buffer, 
	if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE))

		ret = -EINVAL;

out:

	kfree(sdesc);

	kzfree(sdesc);

	return ret;

}
@@ -564,7 +564,7 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, 
		*bloblen = storedsize;

	}

out:

	kfree(td);

	kzfree(td);

	return ret;

}
@@ -678,7 +678,7 @@ static int key_seal(struct trusted_key_payload *p, 
	if (ret < 0)

		pr_info("trusted_key: srkseal failed (%d)\n", ret);



	kfree(tb);

	kzfree(tb);

	return ret;

}
@@ -703,7 +703,7 @@ static int key_unseal(struct trusted_key_payload *p, 
		/* pull migratable flag out of sealed key */

		p->migratable = p->key[--p->key_len];



	kfree(tb);

	kzfree(tb);

	return ret;

}
@@ -1037,12 +1037,12 @@ static int trusted_instantiate(struct key *key, 
	if (!ret && options->pcrlock)

		ret = pcrlock(options->pcrlock);

out:

	kfree(datablob);

	kfree(options);

	kzfree(datablob);

	kzfree(options);

	if (!ret)

		rcu_assign_keypointer(key, payload);

	else

		kfree(payload);

		kzfree(payload);

	return ret;

}
@@ -1051,8 +1051,7 @@ static void trusted_rcu_free(struct rcu_head *rcu) 
	struct trusted_key_payload *p;



	p = container_of(rcu, struct trusted_key_payload, rcu);

	memset(p->key, 0, p->key_len);

	kfree(p);

	kzfree(p);

}



/*
@@ -1094,13 +1093,13 @@ static int trusted_update(struct key *key, struct key_preparsed_payload *prep) 
	ret = datablob_parse(datablob, new_p, new_o);

	if (ret != Opt_update) {

		ret = -EINVAL;

		kfree(new_p);

		kzfree(new_p);

		goto out;

	}



	if (!new_o->keyhandle) {

		ret = -EINVAL;

		kfree(new_p);

		kzfree(new_p);

		goto out;

	}
@@ -1114,22 +1113,22 @@ static int trusted_update(struct key *key, struct key_preparsed_payload *prep) 
	ret = key_seal(new_p, new_o);

	if (ret < 0) {

		pr_info("trusted_key: key_seal failed (%d)\n", ret);

		kfree(new_p);

		kzfree(new_p);

		goto out;

	}

	if (new_o->pcrlock) {

		ret = pcrlock(new_o->pcrlock);

		if (ret < 0) {

			pr_info("trusted_key: pcrlock failed (%d)\n", ret);

			kfree(new_p);

			kzfree(new_p);

			goto out;

		}

	}

	rcu_assign_keypointer(key, new_p);

	call_rcu(&p->rcu, trusted_rcu_free);

out:

	kfree(datablob);

	kfree(new_o);

	kzfree(datablob);

	kzfree(new_o);

	return ret;

}
@@ -1158,24 +1157,19 @@ static long trusted_read(const struct key *key, char __user *buffer, 
	for (i = 0; i < p->blob_len; i++)

		bufp = hex_byte_pack(bufp, p->blob[i]);

	if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) {

		kfree(ascii_buf);

		kzfree(ascii_buf);

		return -EFAULT;

	}

	kfree(ascii_buf);

	kzfree(ascii_buf);

	return 2 * p->blob_len;

}



/*

 * trusted_destroy - before freeing the key, clear the decrypted data

 * trusted_destroy - clear and free the key's payload

 */

static void trusted_destroy(struct key *key)

{

	struct trusted_key_payload *p = key->payload.data[0];



	if (!p)

		return;

	memset(p->key, 0, p->key_len);

	kfree(key->payload.data[0]);

	kzfree(key->payload.data[0]);

}



struct key_type key_type_trusted = {