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1// SPDX-License-Identifier: GPL-2.0-or-later2/* PKCS#8 Private Key parser [RFC 5208].3 *4 * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.5 * Written by David Howells (dhowells@redhat.com)6 */7 8#define pr_fmt(fmt) "PKCS8: "fmt9#include <linux/module.h>10#include <linux/kernel.h>11#include <linux/export.h>12#include <linux/slab.h>13#include <linux/err.h>14#include <linux/oid_registry.h>15#include <keys/asymmetric-subtype.h>16#include <keys/asymmetric-parser.h>17#include <crypto/public_key.h>18#include "pkcs8.asn1.h"19 20struct pkcs8_parse_context {21 struct public_key *pub;22 unsigned long data; /* Start of data */23 enum OID last_oid; /* Last OID encountered */24 enum OID algo_oid; /* Algorithm OID */25 u32 key_size;26 const void *key;27};28 29/*30 * Note an OID when we find one for later processing when we know how to31 * interpret it.32 */33int pkcs8_note_OID(void *context, size_t hdrlen,34 unsigned char tag,35 const void *value, size_t vlen)36{37 struct pkcs8_parse_context *ctx = context;38 39 ctx->last_oid = look_up_OID(value, vlen);40 if (ctx->last_oid == OID__NR) {41 char buffer[50];42 43 sprint_oid(value, vlen, buffer, sizeof(buffer));44 pr_info("Unknown OID: [%lu] %s\n",45 (unsigned long)value - ctx->data, buffer);46 }47 return 0;48}49 50/*51 * Note the version number of the ASN.1 blob.52 */53int pkcs8_note_version(void *context, size_t hdrlen,54 unsigned char tag,55 const void *value, size_t vlen)56{57 if (vlen != 1 || ((const u8 *)value)[0] != 0) {58 pr_warn("Unsupported PKCS#8 version\n");59 return -EBADMSG;60 }61 return 0;62}63 64/*65 * Note the public algorithm.66 */67int pkcs8_note_algo(void *context, size_t hdrlen,68 unsigned char tag,69 const void *value, size_t vlen)70{71 struct pkcs8_parse_context *ctx = context;72 73 if (ctx->last_oid != OID_rsaEncryption)74 return -ENOPKG;75 76 ctx->pub->pkey_algo = "rsa";77 return 0;78}79 80/*81 * Note the key data of the ASN.1 blob.82 */83int pkcs8_note_key(void *context, size_t hdrlen,84 unsigned char tag,85 const void *value, size_t vlen)86{87 struct pkcs8_parse_context *ctx = context;88 89 ctx->key = value;90 ctx->key_size = vlen;91 return 0;92}93 94/*95 * Parse a PKCS#8 private key blob.96 */97static struct public_key *pkcs8_parse(const void *data, size_t datalen)98{99 struct pkcs8_parse_context ctx;100 struct public_key *pub;101 long ret;102 103 memset(&ctx, 0, sizeof(ctx));104 105 ret = -ENOMEM;106 ctx.pub = kzalloc(sizeof(struct public_key), GFP_KERNEL);107 if (!ctx.pub)108 goto error;109 110 ctx.data = (unsigned long)data;111 112 /* Attempt to decode the private key */113 ret = asn1_ber_decoder(&pkcs8_decoder, &ctx, data, datalen);114 if (ret < 0)115 goto error_decode;116 117 ret = -ENOMEM;118 pub = ctx.pub;119 pub->key = kmemdup(ctx.key, ctx.key_size, GFP_KERNEL);120 if (!pub->key)121 goto error_decode;122 123 pub->keylen = ctx.key_size;124 pub->key_is_private = true;125 return pub;126 127error_decode:128 kfree(ctx.pub);129error:130 return ERR_PTR(ret);131}132 133/*134 * Attempt to parse a data blob for a key as a PKCS#8 private key.135 */136static int pkcs8_key_preparse(struct key_preparsed_payload *prep)137{138 struct public_key *pub;139 140 pub = pkcs8_parse(prep->data, prep->datalen);141 if (IS_ERR(pub))142 return PTR_ERR(pub);143 144 pr_devel("Cert Key Algo: %s\n", pub->pkey_algo);145 pub->id_type = "PKCS8";146 147 /* We're pinning the module by being linked against it */148 __module_get(public_key_subtype.owner);149 prep->payload.data[asym_subtype] = &public_key_subtype;150 prep->payload.data[asym_key_ids] = NULL;151 prep->payload.data[asym_crypto] = pub;152 prep->payload.data[asym_auth] = NULL;153 prep->quotalen = 100;154 return 0;155}156 157static struct asymmetric_key_parser pkcs8_key_parser = {158 .owner = THIS_MODULE,159 .name = "pkcs8",160 .parse = pkcs8_key_preparse,161};162 163/*164 * Module stuff165 */166static int __init pkcs8_key_init(void)167{168 return register_asymmetric_key_parser(&pkcs8_key_parser);169}170 171static void __exit pkcs8_key_exit(void)172{173 unregister_asymmetric_key_parser(&pkcs8_key_parser);174}175 176module_init(pkcs8_key_init);177module_exit(pkcs8_key_exit);178 179MODULE_DESCRIPTION("PKCS#8 certificate parser");180MODULE_LICENSE("GPL");181