// SPDX-License-Identifier: GPL-2.0-or-later/* Crypto operations using stored keys * * Copyright (c) 2016, Intel Corporation */ #include <linux/slab.h>#include <linux/uaccess.h>#include <linux/scatterlist.h>#include <linux/crypto.h>#include <crypto/hash.h>#include <crypto/kpp.h>#include <crypto/dh.h>#include <crypto/kdf_sp800108.h>#include <keys/user-type.h>#include "internal.h" static ssize_t dh_data_from_key(key_serial_t keyid, const void **data){	struct key *key;	key_ref_t key_ref;	long status;	ssize_t ret; 	key_ref = lookup_user_key(keyid, 0, KEY_NEED_READ);	if (IS_ERR(key_ref)) {		ret = -ENOKEY;		goto error;	} 	key = key_ref_to_ptr(key_ref); 	ret = -EOPNOTSUPP;	if (key->type == &key_type_user) {		down_read(&key->sem);		status = key_validate(key);		if (status == 0) {			const struct user_key_payload *payload;			uint8_t *duplicate; 			payload = user_key_payload_locked(key); 			duplicate = kmemdup(payload->data, payload->datalen,					    GFP_KERNEL);			if (duplicate) {				*data = duplicate;				ret = payload->datalen;			} else {				ret = -ENOMEM;			}		}		up_read(&key->sem);	} 	key_put(key);error:	return ret;} static void dh_free_data(struct dh *dh){	kfree_sensitive(dh->key);	kfree_sensitive(dh->p);	kfree_sensitive(dh->g);} static int kdf_alloc(struct crypto_shash **hash, char *hashname){	struct crypto_shash *tfm; 	/* allocate synchronous hash */	tfm = crypto_alloc_shash(hashname, 0, 0);	if (IS_ERR(tfm)) {		pr_info("could not allocate digest TFM handle %s\n", hashname);		return PTR_ERR(tfm);	} 	if (crypto_shash_digestsize(tfm) == 0) {		crypto_free_shash(tfm);		return -EINVAL;	} 	*hash = tfm; 	return 0;} static void kdf_dealloc(struct crypto_shash *hash){	if (hash)		crypto_free_shash(hash);} static int keyctl_dh_compute_kdf(struct crypto_shash *hash,				 char __user *buffer, size_t buflen,				 uint8_t *kbuf, size_t kbuflen){	struct kvec kbuf_iov = { .iov_base = kbuf, .iov_len = kbuflen };	uint8_t *outbuf = NULL;	int ret;	size_t outbuf_len = roundup(buflen, crypto_shash_digestsize(hash)); 	outbuf = kmalloc(outbuf_len, GFP_KERNEL);	if (!outbuf) {		ret = -ENOMEM;		goto err;	} 	ret = crypto_kdf108_ctr_generate(hash, &kbuf_iov, 1, outbuf, outbuf_len);	if (ret)		goto err; 	ret = buflen;	if (copy_to_user(buffer, outbuf, buflen) != 0)		ret = -EFAULT; err:	kfree_sensitive(outbuf);	return ret;} long __keyctl_dh_compute(struct keyctl_dh_params __user *params,			 char __user *buffer, size_t buflen,			 struct keyctl_kdf_params *kdfcopy){	long ret;	ssize_t dlen;	int secretlen;	int outlen;	struct keyctl_dh_params pcopy;	struct dh dh_inputs;	struct scatterlist outsg;	DECLARE_CRYPTO_WAIT(compl);	struct crypto_kpp *tfm;	struct kpp_request *req;	uint8_t *secret;	uint8_t *outbuf;	struct crypto_shash *hash = NULL; 	if (!params || (!buffer && buflen)) {		ret = -EINVAL;		goto out1;	}	if (copy_from_user(&pcopy, params, sizeof(pcopy)) != 0) {		ret = -EFAULT;		goto out1;	} 	if (kdfcopy) {		char *hashname; 		if (memchr_inv(kdfcopy->__spare, 0, sizeof(kdfcopy->__spare))) {			ret = -EINVAL;			goto out1;		} 		if (buflen > KEYCTL_KDF_MAX_OUTPUT_LEN ||		    kdfcopy->otherinfolen > KEYCTL_KDF_MAX_OI_LEN) {			ret = -EMSGSIZE;			goto out1;		} 		/* get KDF name string */		hashname = strndup_user(kdfcopy->hashname, CRYPTO_MAX_ALG_NAME);		if (IS_ERR(hashname)) {			ret = PTR_ERR(hashname);			goto out1;		} 		/* allocate KDF from the kernel crypto API */		ret = kdf_alloc(&hash, hashname);		kfree(hashname);		if (ret)			goto out1;	} 	memset(&dh_inputs, 0, sizeof(dh_inputs)); 	dlen = dh_data_from_key(pcopy.prime, &dh_inputs.p);	if (dlen < 0) {		ret = dlen;		goto out1;	}	dh_inputs.p_size = dlen; 	dlen = dh_data_from_key(pcopy.base, &dh_inputs.g);	if (dlen < 0) {		ret = dlen;		goto out2;	}	dh_inputs.g_size = dlen; 	dlen = dh_data_from_key(pcopy.private, &dh_inputs.key);	if (dlen < 0) {		ret = dlen;		goto out2;	}	dh_inputs.key_size = dlen; 	secretlen = crypto_dh_key_len(&dh_inputs);	secret = kmalloc(secretlen, GFP_KERNEL);	if (!secret) {		ret = -ENOMEM;		goto out2;	}	ret = crypto_dh_encode_key(secret, secretlen, &dh_inputs);	if (ret)		goto out3; 	tfm = crypto_alloc_kpp("dh", 0, 0);	if (IS_ERR(tfm)) {		ret = PTR_ERR(tfm);		goto out3;	} 	ret = crypto_kpp_set_secret(tfm, secret, secretlen);	if (ret)		goto out4; 	outlen = crypto_kpp_maxsize(tfm); 	if (!kdfcopy) {		/*		 * When not using a KDF, buflen 0 is used to read the		 * required buffer length		 */		if (buflen == 0) {			ret = outlen;			goto out4;		} else if (outlen > buflen) {			ret = -EOVERFLOW;			goto out4;		}	} 	outbuf = kzalloc(kdfcopy ? (outlen + kdfcopy->otherinfolen) : outlen,			 GFP_KERNEL);	if (!outbuf) {		ret = -ENOMEM;		goto out4;	} 	sg_init_one(&outsg, outbuf, outlen); 	req = kpp_request_alloc(tfm, GFP_KERNEL);	if (!req) {		ret = -ENOMEM;		goto out5;	} 	kpp_request_set_input(req, NULL, 0);	kpp_request_set_output(req, &outsg, outlen);	kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |				 CRYPTO_TFM_REQ_MAY_SLEEP,				 crypto_req_done, &compl); 	/*	 * For DH, generate_public_key and generate_shared_secret are	 * the same calculation	 */	ret = crypto_kpp_generate_public_key(req);	ret = crypto_wait_req(ret, &compl);	if (ret)		goto out6; 	if (kdfcopy) {		/*		 * Concatenate SP800-56A otherinfo past DH shared secret -- the		 * input to the KDF is (DH shared secret || otherinfo)		 */		if (copy_from_user(outbuf + req->dst_len, kdfcopy->otherinfo,				   kdfcopy->otherinfolen) != 0) {			ret = -EFAULT;			goto out6;		} 		ret = keyctl_dh_compute_kdf(hash, buffer, buflen, outbuf,					    req->dst_len + kdfcopy->otherinfolen);	} else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) {		ret = req->dst_len;	} else {		ret = -EFAULT;	} out6:	kpp_request_free(req);out5:	kfree_sensitive(outbuf);out4:	crypto_free_kpp(tfm);out3:	kfree_sensitive(secret);out2:	dh_free_data(&dh_inputs);out1:	kdf_dealloc(hash);	return ret;} long keyctl_dh_compute(struct keyctl_dh_params __user *params,		       char __user *buffer, size_t buflen,		       struct keyctl_kdf_params __user *kdf){	struct keyctl_kdf_params kdfcopy; 	if (!kdf)		return __keyctl_dh_compute(params, buffer, buflen, NULL); 	if (copy_from_user(&kdfcopy, kdf, sizeof(kdfcopy)) != 0)		return -EFAULT; 	return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy);}