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b4d0d230 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
3c58b236 DH |
2 | /* 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) | |
3c58b236 DH |
6 | */ |
7 | ||
8 | #define pr_fmt(fmt) "PKCS8: "fmt | |
9 | #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 | ||
20 | struct 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 to | |
31 | * interpret it. | |
32 | */ | |
33 | int 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 | */ | |
53 | int 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 | */ | |
67 | int 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 | */ | |
83 | int 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 | */ | |
97 | static 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 | ||
127 | error_decode: | |
128 | kfree(ctx.pub); | |
129 | error: | |
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 | */ | |
136 | static 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 | ||
157 | static struct asymmetric_key_parser pkcs8_key_parser = { | |
158 | .owner = THIS_MODULE, | |
159 | .name = "pkcs8", | |
160 | .parse = pkcs8_key_preparse, | |
161 | }; | |
162 | ||
163 | /* | |
164 | * Module stuff | |
165 | */ | |
166 | static int __init pkcs8_key_init(void) | |
167 | { | |
168 | return register_asymmetric_key_parser(&pkcs8_key_parser); | |
169 | } | |
170 | ||
171 | static void __exit pkcs8_key_exit(void) | |
172 | { | |
173 | unregister_asymmetric_key_parser(&pkcs8_key_parser); | |
174 | } | |
175 | ||
176 | module_init(pkcs8_key_init); | |
177 | module_exit(pkcs8_key_exit); | |
178 | ||
179 | MODULE_DESCRIPTION("PKCS#8 certificate parser"); | |
180 | MODULE_LICENSE("GPL"); |