1 /* Copyright (c) 2014, Google Inc.
2 *
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
6 *
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14
15 #include <openssl/aead.h>
16
17 #include <string.h>
18
19 #include <openssl/cipher.h>
20 #include <openssl/err.h>
21
22 #include "internal.h"
23
24
EVP_AEAD_key_length(const EVP_AEAD * aead)25 size_t EVP_AEAD_key_length(const EVP_AEAD *aead) { return aead->key_len; }
26
EVP_AEAD_nonce_length(const EVP_AEAD * aead)27 size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead) { return aead->nonce_len; }
28
EVP_AEAD_max_overhead(const EVP_AEAD * aead)29 size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead) { return aead->overhead; }
30
EVP_AEAD_max_tag_len(const EVP_AEAD * aead)31 size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead) { return aead->max_tag_len; }
32
EVP_AEAD_CTX_init(EVP_AEAD_CTX * ctx,const EVP_AEAD * aead,const uint8_t * key,size_t key_len,size_t tag_len,ENGINE * impl)33 int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
34 const uint8_t *key, size_t key_len, size_t tag_len,
35 ENGINE *impl) {
36 if (!aead->init) {
37 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_init, CIPHER_R_NO_DIRECTION_SET);
38 ctx->aead = NULL;
39 return 0;
40 }
41 return EVP_AEAD_CTX_init_with_direction(ctx, aead, key, key_len, tag_len,
42 evp_aead_open);
43 }
44
EVP_AEAD_CTX_init_with_direction(EVP_AEAD_CTX * ctx,const EVP_AEAD * aead,const uint8_t * key,size_t key_len,size_t tag_len,enum evp_aead_direction_t dir)45 int EVP_AEAD_CTX_init_with_direction(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
46 const uint8_t *key, size_t key_len,
47 size_t tag_len,
48 enum evp_aead_direction_t dir) {
49 if (key_len != aead->key_len) {
50 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_init_with_direction,
51 CIPHER_R_UNSUPPORTED_KEY_SIZE);
52 ctx->aead = NULL;
53 return 0;
54 }
55
56 ctx->aead = aead;
57
58 int ok;
59 if (aead->init) {
60 ok = aead->init(ctx, key, key_len, tag_len);
61 } else {
62 ok = aead->init_with_direction(ctx, key, key_len, tag_len, dir);
63 }
64
65 if (!ok) {
66 ctx->aead = NULL;
67 }
68
69 return ok;
70 }
71
EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX * ctx)72 void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx) {
73 if (ctx->aead == NULL) {
74 return;
75 }
76 ctx->aead->cleanup(ctx);
77 ctx->aead = NULL;
78 }
79
80 /* check_alias returns 0 if |out| points within the buffer determined by |in|
81 * and |in_len| and 1 otherwise.
82 *
83 * When processing, there's only an issue if |out| points within in[:in_len]
84 * and isn't equal to |in|. If that's the case then writing the output will
85 * stomp input that hasn't been read yet.
86 *
87 * This function checks for that case. */
check_alias(const uint8_t * in,size_t in_len,const uint8_t * out)88 static int check_alias(const uint8_t *in, size_t in_len, const uint8_t *out) {
89 if (out <= in) {
90 return 1;
91 } else if (in + in_len <= out) {
92 return 1;
93 }
94 return 0;
95 }
96
EVP_AEAD_CTX_seal(const EVP_AEAD_CTX * ctx,uint8_t * out,size_t * out_len,size_t max_out_len,const uint8_t * nonce,size_t nonce_len,const uint8_t * in,size_t in_len,const uint8_t * ad,size_t ad_len)97 int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len,
98 size_t max_out_len, const uint8_t *nonce,
99 size_t nonce_len, const uint8_t *in, size_t in_len,
100 const uint8_t *ad, size_t ad_len) {
101 size_t possible_out_len = in_len + ctx->aead->overhead;
102
103 if (possible_out_len < in_len /* overflow */) {
104 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_seal, CIPHER_R_TOO_LARGE);
105 goto error;
106 }
107
108 if (!check_alias(in, in_len, out)) {
109 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_seal, CIPHER_R_OUTPUT_ALIASES_INPUT);
110 goto error;
111 }
112
113 if (ctx->aead->seal(ctx, out, out_len, max_out_len, nonce, nonce_len, in,
114 in_len, ad, ad_len)) {
115 return 1;
116 }
117
118 error:
119 /* In the event of an error, clear the output buffer so that a caller
120 * that doesn't check the return value doesn't send raw data. */
121 memset(out, 0, max_out_len);
122 *out_len = 0;
123 return 0;
124 }
125
EVP_AEAD_CTX_open(const EVP_AEAD_CTX * ctx,uint8_t * out,size_t * out_len,size_t max_out_len,const uint8_t * nonce,size_t nonce_len,const uint8_t * in,size_t in_len,const uint8_t * ad,size_t ad_len)126 int EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len,
127 size_t max_out_len, const uint8_t *nonce,
128 size_t nonce_len, const uint8_t *in, size_t in_len,
129 const uint8_t *ad, size_t ad_len) {
130 if (!check_alias(in, in_len, out)) {
131 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_open, CIPHER_R_OUTPUT_ALIASES_INPUT);
132 goto error;
133 }
134
135 if (ctx->aead->open(ctx, out, out_len, max_out_len, nonce, nonce_len, in,
136 in_len, ad, ad_len)) {
137 return 1;
138 }
139
140 error:
141 /* In the event of an error, clear the output buffer so that a caller
142 * that doesn't check the return value doesn't try and process bad
143 * data. */
144 memset(out, 0, max_out_len);
145 *out_len = 0;
146 return 0;
147 }
148
EVP_AEAD_CTX_get_rc4_state(const EVP_AEAD_CTX * ctx,const RC4_KEY ** out_key)149 int EVP_AEAD_CTX_get_rc4_state(const EVP_AEAD_CTX *ctx, const RC4_KEY **out_key) {
150 if (ctx->aead->get_rc4_state == NULL) {
151 return 0;
152 }
153
154 return ctx->aead->get_rc4_state(ctx, out_key);
155 }
156