Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7f3bb75a authored by Roberto Sassu's avatar Roberto Sassu Committed by Greg Kroah-Hartman
Browse files

KEYS: asymmetric: Copy sig and digest in public_key_verify_signature() 

[ Upstream commit c3d03e8e35e005e1a614e51bb59053eeb5857f76 ]

Commit ac4e97ab ("scatterlist: sg_set_buf() argument must be in linear
mapping") checks that both the signature and the digest reside in the
linear mapping area.

However, more recently commit ba14a194 ("fork: Add generic vmalloced
stack support") made it possible to move the stack in the vmalloc area,
which is not contiguous, and thus not suitable for sg_set_buf() which needs
adjacent pages.

Always make a copy of the signature and digest in the same buffer used to
store the key and its parameters, and pass them to sg_init_one(). Prefer it
to conditionally doing the copy if necessary, to keep the code simple. The
buffer allocated with kmalloc() is in the linear mapping area.

Cc: stable@vger.kernel.org # 4.9.x
Fixes: ba14a194 ("fork: Add generic vmalloced stack support")
Link: https://lore.kernel.org/linux-integrity/Y4pIpxbjBdajymBJ@sol.localdomain/


Suggested-by: default avatarEric Biggers <ebiggers@kernel.org>
Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: default avatarEric Biggers <ebiggers@google.com>
Tested-by: default avatarStefan Berger <stefanb@linux.ibm.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 75d9e00f

crypto/asymmetric_keys/public_key.c

+20 −16
Original line number Diff line number Diff line
@@ -255,9 +255,10 @@ int public_key_verify_signature(const struct public_key *pkey, 
	struct crypto_wait cwait;

	struct crypto_akcipher *tfm;

	struct akcipher_request *req;

	struct scatterlist src_sg[2];

	struct scatterlist src_sg;

	char alg_name[CRYPTO_MAX_ALG_NAME];

	char *key, *ptr;

	char *buf, *ptr;

	size_t buf_len;

	int ret;



	pr_devel("==>%s()\n", __func__);
@@ -281,28 +282,31 @@ int public_key_verify_signature(const struct public_key *pkey, 
	if (!req)

		goto error_free_tfm;



	key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,

		      GFP_KERNEL);

	if (!key)

	buf_len = max_t(size_t, pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,

			sig->s_size + sig->digest_size);



	buf = kmalloc(buf_len, GFP_KERNEL);

	if (!buf)

		goto error_free_req;



	memcpy(key, pkey->key, pkey->keylen);

	ptr = key + pkey->keylen;

	memcpy(buf, pkey->key, pkey->keylen);

	ptr = buf + pkey->keylen;

	ptr = pkey_pack_u32(ptr, pkey->algo);

	ptr = pkey_pack_u32(ptr, pkey->paramlen);

	memcpy(ptr, pkey->params, pkey->paramlen);



	if (pkey->key_is_private)

		ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);

		ret = crypto_akcipher_set_priv_key(tfm, buf, pkey->keylen);

	else

		ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);

		ret = crypto_akcipher_set_pub_key(tfm, buf, pkey->keylen);

	if (ret)

		goto error_free_key;

		goto error_free_buf;



	sg_init_table(src_sg, 2);

	sg_set_buf(&src_sg[0], sig->s, sig->s_size);

	sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);

	akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,

	memcpy(buf, sig->s, sig->s_size);

	memcpy(buf + sig->s_size, sig->digest, sig->digest_size);



	sg_init_one(&src_sg, buf, sig->s_size + sig->digest_size);

	akcipher_request_set_crypt(req, &src_sg, NULL, sig->s_size,

				   sig->digest_size);

	crypto_init_wait(&cwait);

	akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
@@ -310,8 +314,8 @@ int public_key_verify_signature(const struct public_key *pkey, 
				      crypto_req_done, &cwait);

	ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);



error_free_key:

	kfree(key);

error_free_buf:

	kfree(buf);

error_free_req:

	akcipher_request_free(req);

error_free_tfm: