static int derived_key_decrypt(struct encrypted_key_payload *epayload,
const u8 *derived_key,
unsigned int derived_keylen)
{
struct scatterlist sg_in[1];
struct scatterlist sg_out[2];
struct blkcipher_desc desc;
unsigned int encrypted_datalen;
char pad[16];
int ret;
encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
ret = init_blkcipher_desc(&desc, derived_key, derived_keylen,
epayload->iv, ivsize);
if (ret < 0)
goto out;
dump_encrypted_data(epayload, encrypted_datalen);
memset(pad, 0, sizeof pad);
sg_init_table(sg_in, 1);
sg_init_table(sg_out, 2);
sg_set_buf(sg_in, epayload->encrypted_data, encrypted_datalen);
sg_set_buf(&sg_out[0], epayload->decrypted_data,
epayload->decrypted_datalen);
sg_set_buf(&sg_out[1], pad, sizeof pad);
ret = crypto_blkcipher_decrypt(&desc, sg_out, sg_in, encrypted_datalen);
crypto_free_blkcipher(desc.tfm);
if (ret < 0)
goto out;
dump_decrypted_data(epayload);
out:
return ret;
}
/* Before returning data to userspace, encrypt decrypted data. */
static int derived_key_encrypt(struct encrypted_key_payload *epayload,
const u8 *derived_key,
unsigned int derived_keylen)
{
struct scatterlist sg_in[2];
struct scatterlist sg_out[1];
struct crypto_skcipher *tfm;
struct skcipher_request *req;
unsigned int encrypted_datalen;
u8 iv[AES_BLOCK_SIZE];
unsigned int padlen;
char pad[16];
int ret;
encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
padlen = encrypted_datalen - epayload->decrypted_datalen;
req = init_skcipher_req(derived_key, derived_keylen);
ret = PTR_ERR(req);
if (IS_ERR(req))
goto out;
dump_decrypted_data(epayload);
memset(pad, 0, sizeof pad);
sg_init_table(sg_in, 2);
sg_set_buf(&sg_in[0], epayload->decrypted_data,
epayload->decrypted_datalen);
sg_set_buf(&sg_in[1], pad, padlen);
sg_init_table(sg_out, 1);
sg_set_buf(sg_out, epayload->encrypted_data, encrypted_datalen);
memcpy(iv, epayload->iv, sizeof(iv));
skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv);
ret = crypto_skcipher_encrypt(req);
tfm = crypto_skcipher_reqtfm(req);
skcipher_request_free(req);
crypto_free_skcipher(tfm);
if (ret < 0)
pr_err("encrypted_key: failed to encrypt (%d)\n", ret);
else
dump_encrypted_data(epayload, encrypted_datalen);
out:
return ret;
}
static int derived_key_decrypt(struct encrypted_key_payload *epayload,
const u8 *derived_key,
unsigned int derived_keylen)
{
struct scatterlist sg_in[1];
struct scatterlist sg_out[2];
struct crypto_skcipher *tfm;
struct skcipher_request *req;
unsigned int encrypted_datalen;
char pad[16];
int ret;
encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
req = init_skcipher_req(derived_key, derived_keylen);
ret = PTR_ERR(req);
if (IS_ERR(req))
goto out;
dump_encrypted_data(epayload, encrypted_datalen);
memset(pad, 0, sizeof pad);
sg_init_table(sg_in, 1);
sg_init_table(sg_out, 2);
sg_set_buf(sg_in, epayload->encrypted_data, encrypted_datalen);
sg_set_buf(&sg_out[0], epayload->decrypted_data,
epayload->decrypted_datalen);
sg_set_buf(&sg_out[1], pad, sizeof pad);
skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen,
epayload->iv);
ret = crypto_skcipher_decrypt(req);
tfm = crypto_skcipher_reqtfm(req);
skcipher_request_free(req);
crypto_free_skcipher(tfm);
if (ret < 0)
goto out;
dump_decrypted_data(epayload);
out:
return ret;
}