3c58b2362b
Implement PKCS#8 RSA Private Key format [RFC 5208] parser for the asymmetric key type. For the moment, this will only support unencrypted DER blobs. PEM and decryption can be added later. PKCS#8 keys can be loaded like this: openssl pkcs8 -in private_key.pem -topk8 -nocrypt -outform DER | \ keyctl padd asymmetric foo @s Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Denis Kenzior <denkenz@gmail.com> Tested-by: Denis Kenzior <denkenz@gmail.com> Signed-off-by: James Morris <james.morris@microsoft.com>
185 lines
4.1 KiB
C
185 lines
4.1 KiB
C
/* PKCS#8 Private Key parser [RFC 5208].
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*
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* Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#define pr_fmt(fmt) "PKCS8: "fmt
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <linux/oid_registry.h>
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#include <keys/asymmetric-subtype.h>
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#include <keys/asymmetric-parser.h>
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#include <crypto/public_key.h>
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#include "pkcs8.asn1.h"
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struct pkcs8_parse_context {
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struct public_key *pub;
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unsigned long data; /* Start of data */
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enum OID last_oid; /* Last OID encountered */
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enum OID algo_oid; /* Algorithm OID */
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u32 key_size;
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const void *key;
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};
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/*
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* Note an OID when we find one for later processing when we know how to
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* interpret it.
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*/
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int pkcs8_note_OID(void *context, size_t hdrlen,
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unsigned char tag,
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const void *value, size_t vlen)
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{
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struct pkcs8_parse_context *ctx = context;
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ctx->last_oid = look_up_OID(value, vlen);
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if (ctx->last_oid == OID__NR) {
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char buffer[50];
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sprint_oid(value, vlen, buffer, sizeof(buffer));
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pr_info("Unknown OID: [%lu] %s\n",
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(unsigned long)value - ctx->data, buffer);
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}
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return 0;
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}
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/*
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* Note the version number of the ASN.1 blob.
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*/
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int pkcs8_note_version(void *context, size_t hdrlen,
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unsigned char tag,
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const void *value, size_t vlen)
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{
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if (vlen != 1 || ((const u8 *)value)[0] != 0) {
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pr_warn("Unsupported PKCS#8 version\n");
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return -EBADMSG;
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}
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return 0;
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}
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/*
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* Note the public algorithm.
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*/
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int pkcs8_note_algo(void *context, size_t hdrlen,
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unsigned char tag,
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const void *value, size_t vlen)
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{
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struct pkcs8_parse_context *ctx = context;
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if (ctx->last_oid != OID_rsaEncryption)
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return -ENOPKG;
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ctx->pub->pkey_algo = "rsa";
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return 0;
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}
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/*
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* Note the key data of the ASN.1 blob.
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*/
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int pkcs8_note_key(void *context, size_t hdrlen,
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unsigned char tag,
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const void *value, size_t vlen)
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{
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struct pkcs8_parse_context *ctx = context;
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ctx->key = value;
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ctx->key_size = vlen;
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return 0;
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}
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/*
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* Parse a PKCS#8 private key blob.
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*/
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static struct public_key *pkcs8_parse(const void *data, size_t datalen)
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{
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struct pkcs8_parse_context ctx;
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struct public_key *pub;
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long ret;
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memset(&ctx, 0, sizeof(ctx));
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ret = -ENOMEM;
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ctx.pub = kzalloc(sizeof(struct public_key), GFP_KERNEL);
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if (!ctx.pub)
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goto error;
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ctx.data = (unsigned long)data;
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/* Attempt to decode the private key */
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ret = asn1_ber_decoder(&pkcs8_decoder, &ctx, data, datalen);
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if (ret < 0)
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goto error_decode;
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ret = -ENOMEM;
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pub = ctx.pub;
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pub->key = kmemdup(ctx.key, ctx.key_size, GFP_KERNEL);
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if (!pub->key)
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goto error_decode;
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pub->keylen = ctx.key_size;
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pub->key_is_private = true;
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return pub;
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error_decode:
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kfree(ctx.pub);
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error:
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return ERR_PTR(ret);
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}
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/*
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* Attempt to parse a data blob for a key as a PKCS#8 private key.
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*/
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static int pkcs8_key_preparse(struct key_preparsed_payload *prep)
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{
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struct public_key *pub;
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pub = pkcs8_parse(prep->data, prep->datalen);
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if (IS_ERR(pub))
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return PTR_ERR(pub);
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pr_devel("Cert Key Algo: %s\n", pub->pkey_algo);
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pub->id_type = "PKCS8";
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/* We're pinning the module by being linked against it */
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__module_get(public_key_subtype.owner);
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prep->payload.data[asym_subtype] = &public_key_subtype;
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prep->payload.data[asym_key_ids] = NULL;
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prep->payload.data[asym_crypto] = pub;
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prep->payload.data[asym_auth] = NULL;
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prep->quotalen = 100;
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return 0;
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}
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static struct asymmetric_key_parser pkcs8_key_parser = {
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.owner = THIS_MODULE,
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.name = "pkcs8",
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.parse = pkcs8_key_preparse,
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};
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/*
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* Module stuff
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*/
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static int __init pkcs8_key_init(void)
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{
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return register_asymmetric_key_parser(&pkcs8_key_parser);
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}
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static void __exit pkcs8_key_exit(void)
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{
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unregister_asymmetric_key_parser(&pkcs8_key_parser);
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}
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module_init(pkcs8_key_init);
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module_exit(pkcs8_key_exit);
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MODULE_DESCRIPTION("PKCS#8 certificate parser");
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MODULE_LICENSE("GPL");
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