int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw,
u64 lblk_num, struct page *src_page,
struct page *dest_page, unsigned int len,
unsigned int offs, gfp_t gfp_flags)
{
union fscrypt_iv iv;
struct skcipher_request *req = NULL;
DECLARE_CRYPTO_WAIT(wait);
struct scatterlist dst, src;
struct fscrypt_info *ci = inode->i_crypt_info;
struct crypto_skcipher *tfm = ci->ci_ctfm;
int res = 0;
BUG_ON(len == 0);
fscrypt_generate_iv(&iv, lblk_num, ci);
req = skcipher_request_alloc(tfm, gfp_flags);
if (!req)
return -ENOMEM;
skcipher_request_set_callback(
req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &wait);
sg_init_table(&dst, 1);
sg_set_page(&dst, dest_page, len, offs);
sg_init_table(&src, 1);
sg_set_page(&src, src_page, len, offs);
skcipher_request_set_crypt(req, &src, &dst, len, &iv);
if (rw == FS_DECRYPT)
res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait);
else
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
skcipher_request_free(req);
if (res) {
fscrypt_err(inode->i_sb,
"%scryption failed for inode %lu, block %llu: %d",
(rw == FS_DECRYPT ? "de" : "en"),
inode->i_ino, lblk_num, res);
return res;
}
return 0;
}
static inline int ahash_wait(int err, struct crypto_wait *wait)
{
err = crypto_wait_req(err, wait);
if (err)
pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
return err;
}
/*
* Encryption operation is performed with the public key. Hence it is done
* in software
*/
static int tpm_key_encrypt(struct tpm_key *tk,
struct kernel_pkey_params *params,
const void *in, void *out)
{
char alg_name[CRYPTO_MAX_ALG_NAME];
struct crypto_akcipher *tfm;
struct akcipher_request *req;
struct crypto_wait cwait;
struct scatterlist in_sg, out_sg;
uint8_t der_pub_key[PUB_KEY_BUF_SIZE];
uint32_t der_pub_key_len;
int ret;
pr_devel("==>%s()\n", __func__);
ret = determine_akcipher(params->encoding, params->hash_algo, alg_name);
if (ret < 0)
return ret;
tfm = crypto_alloc_akcipher(alg_name, 0, 0);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
der_pub_key_len = derive_pub_key(tk->pub_key, tk->pub_key_len,
der_pub_key);
ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len);
if (ret < 0)
goto error_free_tfm;
req = akcipher_request_alloc(tfm, GFP_KERNEL);
if (!req)
goto error_free_tfm;
sg_init_one(&in_sg, in, params->in_len);
sg_init_one(&out_sg, out, params->out_len);
akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len,
params->out_len);
crypto_init_wait(&cwait);
akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &cwait);
ret = crypto_akcipher_encrypt(req);
ret = crypto_wait_req(ret, &cwait);
if (ret == 0)
ret = req->dst_len;
akcipher_request_free(req);
error_free_tfm:
crypto_free_akcipher(tfm);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
/**
* fname_encrypt() - encrypt a filename
*
* The output buffer must be at least as large as the input buffer.
* Any extra space is filled with NUL padding before encryption.
*
* Return: 0 on success, -errno on failure
*/
int fname_encrypt(struct inode *inode, const struct qstr *iname,
u8 *out, unsigned int olen)
{
struct skcipher_request *req = NULL;
DECLARE_CRYPTO_WAIT(wait);
struct fscrypt_info *ci = inode->i_crypt_info;
struct crypto_skcipher *tfm = ci->ci_ctfm;
union fscrypt_iv iv;
struct scatterlist sg;
int res;
/*
* Copy the filename to the output buffer for encrypting in-place and
* pad it with the needed number of NUL bytes.
*/
if (WARN_ON(olen < iname->len))
return -ENOBUFS;
memcpy(out, iname->name, iname->len);
memset(out + iname->len, 0, olen - iname->len);
/* Initialize the IV */
fscrypt_generate_iv(&iv, 0, ci);
/* Set up the encryption request */
req = skcipher_request_alloc(tfm, GFP_NOFS);
if (!req)
return -ENOMEM;
skcipher_request_set_callback(req,
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &wait);
sg_init_one(&sg, out, olen);
skcipher_request_set_crypt(req, &sg, &sg, olen, &iv);
/* Do the encryption */
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
skcipher_request_free(req);
if (res < 0) {
fscrypt_err(inode->i_sb,
"Filename encryption failed for inode %lu: %d",
inode->i_ino, res);
return res;
}
return 0;
}
/**
* fname_decrypt() - decrypt a filename
*
* The caller must have allocated sufficient memory for the @oname string.
*
* Return: 0 on success, -errno on failure
*/
static int fname_decrypt(struct inode *inode,
const struct fscrypt_str *iname,
struct fscrypt_str *oname)
{
struct skcipher_request *req = NULL;
DECLARE_CRYPTO_WAIT(wait);
struct scatterlist src_sg, dst_sg;
struct fscrypt_info *ci = inode->i_crypt_info;
struct crypto_skcipher *tfm = ci->ci_ctfm;
union fscrypt_iv iv;
int res;
/* Allocate request */
req = skcipher_request_alloc(tfm, GFP_NOFS);
if (!req)
return -ENOMEM;
skcipher_request_set_callback(req,
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &wait);
/* Initialize IV */
fscrypt_generate_iv(&iv, 0, ci);
/* Create decryption request */
sg_init_one(&src_sg, iname->name, iname->len);
sg_init_one(&dst_sg, oname->name, oname->len);
skcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, &iv);
res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait);
skcipher_request_free(req);
if (res < 0) {
fscrypt_err(inode->i_sb,
"Filename decryption failed for inode %lu: %d",
inode->i_ino, res);
return res;
}
oname->len = strnlen(oname->name, iname->len);
return 0;
}
/*
* Verify a signature using a public key.
*/
static int tpm_key_verify_signature(const struct key *key,
const struct public_key_signature *sig)
{
const struct tpm_key *tk = key->payload.data[asym_crypto];
struct crypto_wait cwait;
struct crypto_akcipher *tfm;
struct akcipher_request *req;
struct scatterlist sig_sg, digest_sg;
char alg_name[CRYPTO_MAX_ALG_NAME];
uint8_t der_pub_key[PUB_KEY_BUF_SIZE];
uint32_t der_pub_key_len;
void *output;
unsigned int outlen;
int ret;
pr_devel("==>%s()\n", __func__);
BUG_ON(!tk);
BUG_ON(!sig);
BUG_ON(!sig->s);
if (!sig->digest)
return -ENOPKG;
ret = determine_akcipher(sig->encoding, sig->hash_algo, alg_name);
if (ret < 0)
return ret;
tfm = crypto_alloc_akcipher(alg_name, 0, 0);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
der_pub_key_len = derive_pub_key(tk->pub_key, tk->pub_key_len,
der_pub_key);
ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len);
if (ret < 0)
goto error_free_tfm;
ret = -ENOMEM;
req = akcipher_request_alloc(tfm, GFP_KERNEL);
if (!req)
goto error_free_tfm;
ret = -ENOMEM;
outlen = crypto_akcipher_maxsize(tfm);
output = kmalloc(outlen, GFP_KERNEL);
if (!output)
goto error_free_req;
sg_init_one(&sig_sg, sig->s, sig->s_size);
sg_init_one(&digest_sg, output, outlen);
akcipher_request_set_crypt(req, &sig_sg, &digest_sg, sig->s_size,
outlen);
crypto_init_wait(&cwait);
akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &cwait);
/* Perform the verification calculation. This doesn't actually do the
* verification, but rather calculates the hash expected by the
* signature and returns that to us.
*/
ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
if (ret)
goto out_free_output;
/* Do the actual verification step. */
if (req->dst_len != sig->digest_size ||
memcmp(sig->digest, output, sig->digest_size) != 0)
ret = -EKEYREJECTED;
out_free_output:
kfree(output);
error_free_req:
akcipher_request_free(req);
error_free_tfm:
crypto_free_akcipher(tfm);
pr_devel("<==%s() = %d\n", __func__, ret);
if (WARN_ON_ONCE(ret > 0))
ret = -EINVAL;
return ret;
}
