Commit | Line | Data |
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3b72c814 SM |
1 | Code Examples |
2 | ============= | |
3 | ||
4 | Code Example For Symmetric Key Cipher Operation | |
5 | ----------------------------------------------- | |
6 | ||
7 | :: | |
8 | ||
9 | ||
3b72c814 SM |
10 | /* tie all data structures together */ |
11 | struct skcipher_def { | |
12 | struct scatterlist sg; | |
13 | struct crypto_skcipher *tfm; | |
14 | struct skcipher_request *req; | |
aba973c6 | 15 | struct crypto_wait wait; |
3b72c814 SM |
16 | }; |
17 | ||
3b72c814 SM |
18 | /* Perform cipher operation */ |
19 | static unsigned int test_skcipher_encdec(struct skcipher_def *sk, | |
20 | int enc) | |
21 | { | |
aba973c6 | 22 | int rc; |
3b72c814 SM |
23 | |
24 | if (enc) | |
aba973c6 | 25 | rc = crypto_wait_req(crypto_skcipher_encrypt(sk->req), &sk->wait); |
3b72c814 | 26 | else |
aba973c6 GBY |
27 | rc = crypto_wait_req(crypto_skcipher_decrypt(sk->req), &sk->wait); |
28 | ||
29 | if (rc) | |
30 | pr_info("skcipher encrypt returned with result %d\n", rc); | |
3b72c814 SM |
31 | |
32 | return rc; | |
33 | } | |
34 | ||
35 | /* Initialize and trigger cipher operation */ | |
36 | static int test_skcipher(void) | |
37 | { | |
38 | struct skcipher_def sk; | |
39 | struct crypto_skcipher *skcipher = NULL; | |
40 | struct skcipher_request *req = NULL; | |
41 | char *scratchpad = NULL; | |
42 | char *ivdata = NULL; | |
43 | unsigned char key[32]; | |
44 | int ret = -EFAULT; | |
45 | ||
46 | skcipher = crypto_alloc_skcipher("cbc-aes-aesni", 0, 0); | |
47 | if (IS_ERR(skcipher)) { | |
48 | pr_info("could not allocate skcipher handle\n"); | |
49 | return PTR_ERR(skcipher); | |
50 | } | |
51 | ||
52 | req = skcipher_request_alloc(skcipher, GFP_KERNEL); | |
53 | if (!req) { | |
54 | pr_info("could not allocate skcipher request\n"); | |
55 | ret = -ENOMEM; | |
56 | goto out; | |
57 | } | |
58 | ||
59 | skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, | |
aba973c6 GBY |
60 | crypto_req_done, |
61 | &sk.wait); | |
3b72c814 SM |
62 | |
63 | /* AES 256 with random key */ | |
64 | get_random_bytes(&key, 32); | |
65 | if (crypto_skcipher_setkey(skcipher, key, 32)) { | |
66 | pr_info("key could not be set\n"); | |
67 | ret = -EAGAIN; | |
68 | goto out; | |
69 | } | |
70 | ||
71 | /* IV will be random */ | |
72 | ivdata = kmalloc(16, GFP_KERNEL); | |
73 | if (!ivdata) { | |
74 | pr_info("could not allocate ivdata\n"); | |
75 | goto out; | |
76 | } | |
77 | get_random_bytes(ivdata, 16); | |
78 | ||
79 | /* Input data will be random */ | |
80 | scratchpad = kmalloc(16, GFP_KERNEL); | |
81 | if (!scratchpad) { | |
82 | pr_info("could not allocate scratchpad\n"); | |
83 | goto out; | |
84 | } | |
85 | get_random_bytes(scratchpad, 16); | |
86 | ||
87 | sk.tfm = skcipher; | |
88 | sk.req = req; | |
89 | ||
90 | /* We encrypt one block */ | |
91 | sg_init_one(&sk.sg, scratchpad, 16); | |
92 | skcipher_request_set_crypt(req, &sk.sg, &sk.sg, 16, ivdata); | |
aba973c6 | 93 | crypto_init_wait(&sk.wait); |
3b72c814 SM |
94 | |
95 | /* encrypt data */ | |
96 | ret = test_skcipher_encdec(&sk, 1); | |
97 | if (ret) | |
98 | goto out; | |
99 | ||
100 | pr_info("Encryption triggered successfully\n"); | |
101 | ||
102 | out: | |
103 | if (skcipher) | |
104 | crypto_free_skcipher(skcipher); | |
105 | if (req) | |
106 | skcipher_request_free(req); | |
107 | if (ivdata) | |
108 | kfree(ivdata); | |
109 | if (scratchpad) | |
110 | kfree(scratchpad); | |
111 | return ret; | |
112 | } | |
113 | ||
114 | ||
115 | Code Example For Use of Operational State Memory With SHASH | |
116 | ----------------------------------------------------------- | |
117 | ||
118 | :: | |
119 | ||
120 | ||
121 | struct sdesc { | |
122 | struct shash_desc shash; | |
123 | char ctx[]; | |
124 | }; | |
125 | ||
ea644b8c | 126 | static struct sdesc *init_sdesc(struct crypto_shash *alg) |
3b72c814 | 127 | { |
ea644b8c | 128 | struct sdesc *sdesc; |
3b72c814 SM |
129 | int size; |
130 | ||
131 | size = sizeof(struct shash_desc) + crypto_shash_descsize(alg); | |
132 | sdesc = kmalloc(size, GFP_KERNEL); | |
133 | if (!sdesc) | |
134 | return ERR_PTR(-ENOMEM); | |
135 | sdesc->shash.tfm = alg; | |
136 | sdesc->shash.flags = 0x0; | |
137 | return sdesc; | |
138 | } | |
139 | ||
ea644b8c KK |
140 | static int calc_hash(struct crypto_shash *alg, |
141 | const unsigned char *data, unsigned int datalen, | |
142 | unsigned char *digest) | |
143 | { | |
144 | struct sdesc *sdesc; | |
3b72c814 SM |
145 | int ret; |
146 | ||
147 | sdesc = init_sdesc(alg); | |
148 | if (IS_ERR(sdesc)) { | |
ea644b8c | 149 | pr_info("can't alloc sdesc\n"); |
3b72c814 SM |
150 | return PTR_ERR(sdesc); |
151 | } | |
152 | ||
153 | ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest); | |
154 | kfree(sdesc); | |
155 | return ret; | |
156 | } | |
157 | ||
ea644b8c KK |
158 | static int test_hash(const unsigned char *data, unsigned int datalen, |
159 | unsigned char *digest) | |
160 | { | |
161 | struct crypto_shash *alg; | |
162 | char *hash_alg_name = "sha1-padlock-nano"; | |
163 | int ret; | |
164 | ||
165 | alg = crypto_alloc_shash(hash_alg_name, CRYPTO_ALG_TYPE_SHASH, 0); | |
166 | if (IS_ERR(alg)) { | |
167 | pr_info("can't alloc alg %s\n", hash_alg_name); | |
168 | return PTR_ERR(alg); | |
169 | } | |
170 | ret = calc_hash(alg, data, datalen, digest); | |
171 | crypto_free_shash(alg); | |
172 | return ret; | |
173 | } | |
174 | ||
3b72c814 SM |
175 | |
176 | Code Example For Random Number Generator Usage | |
177 | ---------------------------------------------- | |
178 | ||
179 | :: | |
180 | ||
181 | ||
182 | static int get_random_numbers(u8 *buf, unsigned int len) | |
183 | { | |
ea644b8c KK |
184 | struct crypto_rng *rng = NULL; |
185 | char *drbg = "drbg_nopr_sha256"; /* Hash DRBG with SHA-256, no PR */ | |
3b72c814 SM |
186 | int ret; |
187 | ||
188 | if (!buf || !len) { | |
189 | pr_debug("No output buffer provided\n"); | |
190 | return -EINVAL; | |
191 | } | |
192 | ||
193 | rng = crypto_alloc_rng(drbg, 0, 0); | |
194 | if (IS_ERR(rng)) { | |
195 | pr_debug("could not allocate RNG handle for %s\n", drbg); | |
ea644b8c | 196 | return PTR_ERR(rng); |
3b72c814 SM |
197 | } |
198 | ||
199 | ret = crypto_rng_get_bytes(rng, buf, len); | |
200 | if (ret < 0) | |
201 | pr_debug("generation of random numbers failed\n"); | |
202 | else if (ret == 0) | |
203 | pr_debug("RNG returned no data"); | |
204 | else | |
205 | pr_debug("RNG returned %d bytes of data\n", ret); | |
206 | ||
207 | out: | |
208 | crypto_free_rng(rng); | |
209 | return ret; | |
210 | } |