keyctl_pkey.c
// SPDX-License-Identifier: GPL-2.0-or-later
/* Public-key operation keyctls
*
* Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/key.h>
#include <linux/keyctl.h>
#include <linux/parser.h>
#include <linux/uaccess.h>
#include <keys/user-type.h>
#include "internal.h"
static void keyctl_pkey_params_free(struct kernel_pkey_params *params)
{
kfree(params->info);
key_put(params->key);
}
enum {
Opt_err,
Opt_enc, /* "enc=<encoding>" eg. "enc=oaep" */
Opt_hash, /* "hash=<digest-name>" eg. "hash=sha1" */
};
static const match_table_t param_keys = {
{ Opt_enc, "enc=%s" },
{ Opt_hash, "hash=%s" },
{ Opt_err, NULL }
};
/*
* Parse the information string which consists of key=val pairs.
*/
static int keyctl_pkey_params_parse(struct kernel_pkey_params *params)
{
unsigned long token_mask = 0;
substring_t args[MAX_OPT_ARGS];
char *c = params->info, *p, *q;
int token;
while ((p = strsep(&c, " \t"))) {
if (*p == '\0' || *p == ' ' || *p == '\t')
continue;
token = match_token(p, param_keys, args);
if (token == Opt_err)
return -EINVAL;
if (__test_and_set_bit(token, &token_mask))
return -EINVAL;
q = args[0].from;
if (!q[0])
return -EINVAL;
switch (token) {
case Opt_enc:
params->encoding = q;
break;
case Opt_hash:
params->hash_algo = q;
break;
default:
return -EINVAL;
}
}
return 0;
}
/*
* Interpret parameters. Callers must always call the free function
* on params, even if an error is returned.
*/
static int keyctl_pkey_params_get(key_serial_t id,
const char __user *_info,
struct kernel_pkey_params *params)
{
key_ref_t key_ref;
void *p;
int ret;
memset(params, 0, sizeof(*params));
params->encoding = "raw";
p = strndup_user(_info, PAGE_SIZE);
if (IS_ERR(p))
return PTR_ERR(p);
params->info = p;
ret = keyctl_pkey_params_parse(params);
if (ret < 0)
return ret;
key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
if (IS_ERR(key_ref))
return PTR_ERR(key_ref);
params->key = key_ref_to_ptr(key_ref);
if (!params->key->type->asym_query)
return -EOPNOTSUPP;
return 0;
}
/*
* Get parameters from userspace. Callers must always call the free function
* on params, even if an error is returned.
*/
static int keyctl_pkey_params_get_2(const struct keyctl_pkey_params __user *_params,
const char __user *_info,
int op,
struct kernel_pkey_params *params)
{
struct keyctl_pkey_params uparams;
struct kernel_pkey_query info;
int ret;
memset(params, 0, sizeof(*params));
params->encoding = "raw";
if (copy_from_user(&uparams, _params, sizeof(uparams)) != 0)
return -EFAULT;
ret = keyctl_pkey_params_get(uparams.key_id, _info, params);
if (ret < 0)
return ret;
ret = params->key->type->asym_query(params, &info);
if (ret < 0)
return ret;
switch (op) {
case KEYCTL_PKEY_ENCRYPT:
case KEYCTL_PKEY_DECRYPT:
if (uparams.in_len > info.max_enc_size ||
uparams.out_len > info.max_dec_size)
return -EINVAL;
break;
case KEYCTL_PKEY_SIGN:
case KEYCTL_PKEY_VERIFY:
if (uparams.in_len > info.max_sig_size ||
uparams.out_len > info.max_data_size)
return -EINVAL;
break;
default:
BUG();
}
params->in_len = uparams.in_len;
params->out_len = uparams.out_len;
return 0;
}
/*
* Query information about an asymmetric key.
*/
long keyctl_pkey_query(key_serial_t id,
const char __user *_info,
struct keyctl_pkey_query __user *_res)
{
struct kernel_pkey_params params;
struct kernel_pkey_query res;
long ret;
ret = keyctl_pkey_params_get(id, _info, ¶ms);
if (ret < 0)
goto error;
ret = params.key->type->asym_query(¶ms, &res);
if (ret < 0)
goto error;
ret = -EFAULT;
if (copy_to_user(_res, &res, sizeof(res)) == 0 &&
clear_user(_res->__spare, sizeof(_res->__spare)) == 0)
ret = 0;
error:
keyctl_pkey_params_free(¶ms);
return ret;
}
/*
* Encrypt/decrypt/sign
*
* Encrypt data, decrypt data or sign data using a public key.
*
* _info is a string of supplementary information in key=val format. For
* instance, it might contain:
*
* "enc=pkcs1 hash=sha256"
*
* where enc= specifies the encoding and hash= selects the OID to go in that
* particular encoding if required. If enc= isn't supplied, it's assumed that
* the caller is supplying raw values.
*
* If successful, the amount of data written into the output buffer is
* returned.
*/
long keyctl_pkey_e_d_s(int op,
const struct keyctl_pkey_params __user *_params,
const char __user *_info,
const void __user *_in,
void __user *_out)
{
struct kernel_pkey_params params;
void *in, *out;
long ret;
ret = keyctl_pkey_params_get_2(_params, _info, op, ¶ms);
if (ret < 0)
goto error_params;
ret = -EOPNOTSUPP;
if (!params.key->type->asym_eds_op)
goto error_params;
switch (op) {
case KEYCTL_PKEY_ENCRYPT:
params.op = kernel_pkey_encrypt;
break;
case KEYCTL_PKEY_DECRYPT:
params.op = kernel_pkey_decrypt;
break;
case KEYCTL_PKEY_SIGN:
params.op = kernel_pkey_sign;
break;
default:
BUG();
}
in = memdup_user(_in, params.in_len);
if (IS_ERR(in)) {
ret = PTR_ERR(in);
goto error_params;
}
ret = -ENOMEM;
out = kmalloc(params.out_len, GFP_KERNEL);
if (!out)
goto error_in;
ret = params.key->type->asym_eds_op(¶ms, in, out);
if (ret < 0)
goto error_out;
if (copy_to_user(_out, out, ret) != 0)
ret = -EFAULT;
error_out:
kfree(out);
error_in:
kfree(in);
error_params:
keyctl_pkey_params_free(¶ms);
return ret;
}
/*
* Verify a signature.
*
* Verify a public key signature using the given key, or if not given, search
* for a matching key.
*
* _info is a string of supplementary information in key=val format. For
* instance, it might contain:
*
* "enc=pkcs1 hash=sha256"
*
* where enc= specifies the signature blob encoding and hash= selects the OID
* to go in that particular encoding. If enc= isn't supplied, it's assumed
* that the caller is supplying raw values.
*
* If successful, 0 is returned.
*/
long keyctl_pkey_verify(const struct keyctl_pkey_params __user *_params,
const char __user *_info,
const void __user *_in,
const void __user *_in2)
{
struct kernel_pkey_params params;
void *in, *in2;
long ret;
ret = keyctl_pkey_params_get_2(_params, _info, KEYCTL_PKEY_VERIFY,
¶ms);
if (ret < 0)
goto error_params;
ret = -EOPNOTSUPP;
if (!params.key->type->asym_verify_signature)
goto error_params;
in = memdup_user(_in, params.in_len);
if (IS_ERR(in)) {
ret = PTR_ERR(in);
goto error_params;
}
in2 = memdup_user(_in2, params.in2_len);
if (IS_ERR(in2)) {
ret = PTR_ERR(in2);
goto error_in;
}
params.op = kernel_pkey_verify;
ret = params.key->type->asym_verify_signature(¶ms, in, in2);
kfree(in2);
error_in:
kfree(in);
error_params:
keyctl_pkey_params_free(¶ms);
return ret;
}