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bebc0c7d MC |
1 | /* |
2 | * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved. | |
3 | * | |
4 | * Licensed under the OpenSSL license (the "License"). You may not use | |
5 | * this file except in compliance with the License. You can obtain a copy | |
6 | * in the file LICENSE in the source distribution or at | |
7 | * https://www.openssl.org/source/license.html | |
8 | */ | |
9 | ||
18b3a80a | 10 | #include <assert.h> |
bebc0c7d MC |
11 | #include "../ssl_locl.h" |
12 | #include "record_locl.h" | |
13 | ||
14 | /*- | |
15 | * tls13_enc encrypts/decrypts |n_recs| in |recs|. | |
16 | * | |
17 | * Returns: | |
18 | * 0: (in non-constant time) if the record is publically invalid (i.e. too | |
19 | * short etc). | |
20 | * 1: if the record encryption was successful. | |
21 | * -1: if the record's AEAD-authenticator is invalid or, if sending, | |
22 | * an internal error occurred. | |
23 | */ | |
24 | int tls13_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int send) | |
25 | { | |
26 | EVP_CIPHER_CTX *ctx; | |
27 | unsigned char iv[EVP_MAX_IV_LENGTH]; | |
ec07b1d8 | 28 | size_t ivlen, taglen, offset, loop; |
bebc0c7d MC |
29 | unsigned char *staticiv; |
30 | unsigned char *seq; | |
31 | int lenu, lenf; | |
32 | SSL3_RECORD *rec = &recs[0]; | |
18b3a80a | 33 | uint32_t alg_enc; |
bebc0c7d MC |
34 | |
35 | if (n_recs != 1) { | |
36 | /* Should not happen */ | |
37 | /* TODO(TLS1.3): Support pipelining */ | |
38 | return -1; | |
39 | } | |
40 | ||
41 | if (send) { | |
42 | ctx = s->enc_write_ctx; | |
43 | staticiv = s->write_iv; | |
44 | seq = RECORD_LAYER_get_write_sequence(&s->rlayer); | |
45 | } else { | |
46 | ctx = s->enc_read_ctx; | |
47 | staticiv = s->read_iv; | |
48 | seq = RECORD_LAYER_get_read_sequence(&s->rlayer); | |
49 | } | |
50 | ||
51 | if (ctx == NULL) { | |
52 | memmove(rec->data, rec->input, rec->length); | |
53 | rec->input = rec->data; | |
54 | return 1; | |
55 | } | |
18b3a80a | 56 | |
bebc0c7d MC |
57 | ivlen = EVP_CIPHER_CTX_iv_length(ctx); |
58 | ||
49e7fe12 MC |
59 | if (s->early_data_state == SSL_EARLY_DATA_WRITING) { |
60 | alg_enc = s->session->cipher->algorithm_enc; | |
61 | } else { | |
62 | /* | |
63 | * To get here we must have selected a ciphersuite - otherwise ctx would | |
64 | * be NULL | |
65 | */ | |
66 | assert(s->s3->tmp.new_cipher != NULL); | |
67 | if (s->s3->tmp.new_cipher == NULL) | |
68 | return -1; | |
69 | alg_enc = s->s3->tmp.new_cipher->algorithm_enc; | |
70 | } | |
18b3a80a | 71 | |
20fc2051 DSH |
72 | if (alg_enc & SSL_AESCCM) { |
73 | if (alg_enc & (SSL_AES128CCM8 | SSL_AES256CCM8)) | |
ec07b1d8 DSH |
74 | taglen = EVP_CCM8_TLS_TAG_LEN; |
75 | else | |
76 | taglen = EVP_CCM_TLS_TAG_LEN; | |
77 | if (send && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, | |
78 | NULL) <= 0) | |
79 | return -1; | |
20fc2051 | 80 | } else if (alg_enc & SSL_AESGCM) { |
ec07b1d8 | 81 | taglen = EVP_GCM_TLS_TAG_LEN; |
20fc2051 DSH |
82 | } else if (alg_enc & SSL_CHACHA20) { |
83 | taglen = EVP_CHACHAPOLY_TLS_TAG_LEN; | |
84 | } else { | |
85 | return -1; | |
ec07b1d8 DSH |
86 | } |
87 | ||
bebc0c7d MC |
88 | if (!send) { |
89 | /* | |
90 | * Take off tag. There must be at least one byte of content type as | |
91 | * well as the tag | |
92 | */ | |
ec07b1d8 | 93 | if (rec->length < taglen + 1) |
bebc0c7d | 94 | return 0; |
ec07b1d8 | 95 | rec->length -= taglen; |
bebc0c7d MC |
96 | } |
97 | ||
98 | /* Set up IV */ | |
99 | if (ivlen < SEQ_NUM_SIZE) { | |
100 | /* Should not happen */ | |
101 | return -1; | |
102 | } | |
103 | offset = ivlen - SEQ_NUM_SIZE; | |
104 | memcpy(iv, staticiv, offset); | |
105 | for (loop = 0; loop < SEQ_NUM_SIZE; loop++) | |
106 | iv[offset + loop] = staticiv[offset + loop] ^ seq[loop]; | |
107 | ||
ac77aa9a MC |
108 | /* Increment the sequence counter */ |
109 | for (loop = SEQ_NUM_SIZE; loop > 0; loop--) { | |
110 | ++seq[loop - 1]; | |
111 | if (seq[loop - 1] != 0) | |
112 | break; | |
113 | } | |
114 | if (loop == 0) { | |
115 | /* Sequence has wrapped */ | |
116 | return -1; | |
117 | } | |
118 | ||
6606d600 | 119 | /* TODO(size_t): lenu/lenf should be a size_t but EVP doesn't support it */ |
bebc0c7d | 120 | if (EVP_CipherInit_ex(ctx, NULL, NULL, NULL, iv, send) <= 0 |
bebc0c7d | 121 | || (!send && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, |
ec07b1d8 | 122 | taglen, |
bebc0c7d | 123 | rec->data + rec->length) <= 0) |
ec07b1d8 DSH |
124 | || EVP_CipherUpdate(ctx, rec->data, &lenu, rec->input, |
125 | (unsigned int)rec->length) <= 0 | |
bebc0c7d MC |
126 | || EVP_CipherFinal_ex(ctx, rec->data + lenu, &lenf) <= 0 |
127 | || (size_t)(lenu + lenf) != rec->length) { | |
128 | return -1; | |
129 | } | |
bebc0c7d MC |
130 | if (send) { |
131 | /* Add the tag */ | |
ec07b1d8 | 132 | if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, |
bebc0c7d MC |
133 | rec->data + rec->length) <= 0) |
134 | return -1; | |
ec07b1d8 | 135 | rec->length += taglen; |
bebc0c7d MC |
136 | } |
137 | ||
138 | return 1; | |
139 | } |