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1 /*
2  * libwebsockets - small server side websockets and web server implementation
3  *
4  * Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to
8  * deal in the Software without restriction, including without limitation the
9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10  * sell copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22  * IN THE SOFTWARE.
23  */
24 
25 /*! \defgroup jwk JSON Web Keys
26  * ## JSON Web Keys API
27  *
28  * Lws provides an API to parse JSON Web Keys into a struct lws_gencrypto_keyelem.
29  *
30  * "oct" and "RSA" type keys are supported.  For "oct" keys, they are held in
31  * the "e" member of the struct lws_gencrypto_keyelem.
32  *
33  * Keys elements are allocated on the heap.  You must destroy the allocations
34  * in the struct lws_gencrypto_keyelem by calling
35  * lws_genrsa_destroy_elements() when you are finished with it.
36  */
37 ///@{
38 
39 enum enum_jwk_meta_tok {
40 	JWK_META_KTY,
41 	JWK_META_KID,
42 	JWK_META_USE,
43 	JWK_META_KEY_OPS,
44 	JWK_META_X5C,
45 	JWK_META_ALG,
46 
47 	LWS_COUNT_JWK_ELEMENTS
48 };
49 
50 struct lws_jwk {
51 	/* key data elements */
52 	struct lws_gencrypto_keyelem e[LWS_GENCRYPTO_MAX_KEYEL_COUNT];
53 	/* generic meta key elements, like KID */
54 	struct lws_gencrypto_keyelem meta[LWS_COUNT_JWK_ELEMENTS];
55 	int kty;			/**< one of LWS_GENCRYPTO_KTY_ */
56 	char private_key; /* nonzero = has private key elements */
57 };
58 
59 typedef int (*lws_jwk_key_import_callback)(struct lws_jwk *s, void *user);
60 
61 struct lws_jwk_parse_state {
62 	struct lws_jwk *jwk;
63 	char b64[(((8192 / 8) * 4) / 3) + 1]; /* enough for 8Kb key */
64 	lws_jwk_key_import_callback per_key_cb;
65 	void *user;
66 	int pos;
67 	int cose_state;
68 	int seen;
69 	unsigned short possible;
70 };
71 
72 /** lws_jwk_import() - Create a JSON Web key from the textual representation
73  *
74  * \param jwk: the JWK object to create
75  * \param cb: callback for each jwk-processed key, or NULL if importing a single
76  *	      key with no parent "keys" JSON
77  * \param user: pointer to be passed to the callback, otherwise ignored by lws.
78  *		NULL if importing a single key with no parent "keys" JSON
79  * \param in: a single JWK JSON stanza in utf-8
80  * \param len: the length of the JWK JSON stanza in bytes
81  *
82  * Creates an lws_jwk struct filled with data from the JSON representation.
83  *
84  * There are two ways to use this... with some protocols a single jwk is
85  * delivered with no parent "keys": [] array.  If you call this with cb and
86  * user as NULL, then the input will be interpreted like that and the results
87  * placed in s.
88  *
89  * The second case is that you are dealing with a "keys":[] array with one or
90  * more keys in it.  In this case, the function iterates through the keys using
91  * s as a temporary jwk, and calls the user-provided callback for each key in
92  * turn while it return 0 (nonzero return from the callback terminates the
93  * iteration through any further keys).
94  */
95 LWS_VISIBLE LWS_EXTERN int
96 lws_jwk_import(struct lws_jwk *jwk, lws_jwk_key_import_callback cb, void *user,
97 	       const char *in, size_t len);
98 
99 /** lws_jwk_destroy() - Destroy a JSON Web key
100  *
101  * \param jwk: the JWK object to destroy
102  *
103  * All allocations in the lws_jwk are destroyed
104  */
105 LWS_VISIBLE LWS_EXTERN void
106 lws_jwk_destroy(struct lws_jwk *jwk);
107 
108 /** lws_jwk_dup_oct() - Set a jwk to a dup'd binary OCT key
109  *
110  * \param jwk: the JWK object to set
111  * \param key: the JWK object to destroy
112  * \param len: the JWK object to destroy
113  *
114  * Sets the kty to OCT, allocates len bytes for K and copies len bytes of key
115  * into the allocation.
116  */
117 LWS_VISIBLE LWS_EXTERN int
118 lws_jwk_dup_oct(struct lws_jwk *jwk, const void *key, int len);
119 
120 #define LWSJWKF_EXPORT_PRIVATE				(1 << 0)
121 #define LWSJWKF_EXPORT_NOCRLF				(1 << 1)
122 
123 /** lws_jwk_export() - Export a JSON Web key to a textual representation
124  *
125  * \param jwk: the JWK object to export
126  * \param flags: control export options
127  * \param p: the buffer to write the exported JWK to
128  * \param len: the length of the buffer \p p in bytes... reduced by used amount
129  *
130  * Returns length of the used part of the buffer if OK, or -1 for error.
131  *
132  * \p flags can be OR-ed together
133  *
134  * LWSJWKF_EXPORT_PRIVATE: default is only public part, set this to also export
135  *			   the private part
136  *
137  * LWSJWKF_EXPORT_NOCRLF: normally adds a CRLF at the end of the export, if
138  *			  you need to suppress it, set this flag
139  *
140  * Serializes the content of the JWK into a char buffer.
141  */
142 LWS_VISIBLE LWS_EXTERN int
143 lws_jwk_export(struct lws_jwk *jwk, int flags, char *p, int *len);
144 
145 /** lws_jwk_load() - Import a JSON Web key from a file
146  *
147  * \param jwk: the JWK object to load into
148  * \param filename: filename to load from
149  * \param cb: optional callback for each key
150  * \param user: opaque user pointer passed to cb if given
151  *
152  * Returns 0 for OK or -1 for failure
153  *
154  * There are two ways to use this... with some protocols a single jwk is
155  * delivered with no parent "keys": [] array.  If you call this with cb and
156  * user as NULL, then the input will be interpreted like that and the results
157  * placed in s.
158  *
159  * The second case is that you are dealing with a "keys":[] array with one or
160  * more keys in it.  In this case, the function iterates through the keys using
161  * s as a temporary jwk, and calls the user-provided callback for each key in
162  * turn while it return 0 (nonzero return from the callback terminates the
163  * iteration through any further keys, leaving the last one in s).
164  */
165 LWS_VISIBLE LWS_EXTERN int
166 lws_jwk_load(struct lws_jwk *jwk, const char *filename,
167 	     lws_jwk_key_import_callback cb, void *user);
168 
169 /** lws_jwk_save() - Export a JSON Web key to a file
170  *
171  * \param jwk: the JWK object to save from
172  * \param filename: filename to save to
173  *
174  * Returns 0 for OK or -1 for failure
175  */
176 LWS_VISIBLE LWS_EXTERN int
177 lws_jwk_save(struct lws_jwk *jwk, const char *filename);
178 
179 /** lws_jwk_rfc7638_fingerprint() - jwk to RFC7638 compliant fingerprint
180  *
181  * \param jwk: the JWK object to fingerprint
182  * \param digest32: buffer to take 32-byte digest
183  *
184  * Returns 0 for OK or -1 for failure
185  */
186 LWS_VISIBLE LWS_EXTERN int
187 lws_jwk_rfc7638_fingerprint(struct lws_jwk *jwk, char *digest32);
188 
189 /** lws_jwk_strdup_meta() - allocate a duplicated string meta element
190  *
191  * \param jwk: the JWK object to fingerprint
192  * \param idx: JWK_META_ element index
193  * \param in: string to copy
194  * \param len: length of string to copy
195  *
196  * Returns 0 for OK or nonzero for failure
197  */
198 LWS_VISIBLE LWS_EXTERN int
199 lws_jwk_strdup_meta(struct lws_jwk *jwk, enum enum_jwk_meta_tok idx,
200 		    const char *in, int len);
201 
202 
203 LWS_VISIBLE LWS_EXTERN int
204 lws_jwk_dump(struct lws_jwk *jwk);
205 
206 /** lws_jwk_generate() - create a new key of given type and characteristics
207  *
208  * \param context: the struct lws_context used for RNG
209  * \param jwk: the JWK object to fingerprint
210  * \param kty: One of the LWS_GENCRYPTO_KTY_ key types
211  * \param bits: for OCT and RSA keys, the number of bits
212  * \param curve: for EC keys, the name of the curve
213  *
214  * Returns 0 for OK or nonzero for failure
215  */
216 LWS_VISIBLE int
217 lws_jwk_generate(struct lws_context *context, struct lws_jwk *jwk,
218 	         enum lws_gencrypto_kty kty, int bits, const char *curve);
219 
220 ///@}
221