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 ctx->aead = aead;
37 if (key_len != aead->key_len) {
38 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_init, CIPHER_R_UNSUPPORTED_KEY_SIZE);
39 return 0;
40 }
41 return aead->init(ctx, key, key_len, tag_len);
42 }
43
EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX * ctx)44 void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx) {
45 if (ctx->aead == NULL) {
46 return;
47 }
48 ctx->aead->cleanup(ctx);
49 ctx->aead = NULL;
50 }
51
52 /* check_alias returns 0 if |out| points within the buffer determined by |in|
53 * and |in_len| and 1 otherwise.
54 *
55 * When processing, there's only an issue if |out| points within in[:in_len]
56 * and isn't equal to |in|. If that's the case then writing the output will
57 * stomp input that hasn't been read yet.
58 *
59 * This function checks for that case. */
check_alias(const uint8_t * in,size_t in_len,const uint8_t * out)60 static int check_alias(const uint8_t *in, size_t in_len, const uint8_t *out) {
61 if (out <= in) {
62 return 1;
63 } else if (in + in_len <= out) {
64 return 1;
65 }
66 return 0;
67 }
68
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)69 int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len,
70 size_t max_out_len, const uint8_t *nonce,
71 size_t nonce_len, const uint8_t *in, size_t in_len,
72 const uint8_t *ad, size_t ad_len) {
73 size_t possible_out_len = in_len + ctx->aead->overhead;
74
75 if (possible_out_len < in_len /* overflow */) {
76 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_seal, CIPHER_R_TOO_LARGE);
77 goto error;
78 }
79
80 if (!check_alias(in, in_len, out)) {
81 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_seal, CIPHER_R_OUTPUT_ALIASES_INPUT);
82 goto error;
83 }
84
85 if (ctx->aead->seal(ctx, out, out_len, max_out_len, nonce, nonce_len, in,
86 in_len, ad, ad_len)) {
87 return 1;
88 }
89
90 error:
91 /* In the event of an error, clear the output buffer so that a caller
92 * that doesn't check the return value doesn't send raw data. */
93 memset(out, 0, max_out_len);
94 *out_len = 0;
95 return 0;
96 }
97
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)98 int EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len,
99 size_t max_out_len, const uint8_t *nonce,
100 size_t nonce_len, const uint8_t *in, size_t in_len,
101 const uint8_t *ad, size_t ad_len) {
102 if (!check_alias(in, in_len, out)) {
103 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_open, CIPHER_R_OUTPUT_ALIASES_INPUT);
104 goto error;
105 }
106
107 if (ctx->aead->open(ctx, out, out_len, max_out_len, nonce, nonce_len, in,
108 in_len, ad, ad_len)) {
109 return 1;
110 }
111
112 error:
113 /* In the event of an error, clear the output buffer so that a caller
114 * that doesn't check the return value doesn't try and process bad
115 * data. */
116 memset(out, 0, max_out_len);
117 *out_len = 0;
118 return 0;
119 }
120