1 /* $OpenBSD: tls_bio_cb.c,v 1.22 2024/03/26 06:24:52 joshua Exp $ */
2 /*
3 * Copyright (c) 2016 Tobias Pape <tobias@netshed.de>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include <fcntl.h>
19 #include <stdlib.h>
20 #include <string.h>
21 #include <unistd.h>
22
23 #include <openssl/bio.h>
24
25 #include <tls.h>
26 #include "tls_internal.h"
27
28 static int bio_cb_write(BIO *bio, const char *buf, int num);
29 static int bio_cb_read(BIO *bio, char *buf, int size);
30 static int bio_cb_puts(BIO *bio, const char *str);
31 static long bio_cb_ctrl(BIO *bio, int cmd, long num, void *ptr);
32
33 static BIO_METHOD *bio_cb_method;
34
35 static pthread_mutex_t bio_cb_method_lock = PTHREAD_MUTEX_INITIALIZER;
36
37 static void
bio_cb_method_init(void)38 bio_cb_method_init(void)
39 {
40 BIO_METHOD *bio_method;
41
42 if (bio_cb_method != NULL)
43 return;
44
45 bio_method = BIO_meth_new(BIO_TYPE_MEM, "libtls_callbacks");
46 if (bio_method == NULL)
47 return;
48
49 BIO_meth_set_write(bio_method, bio_cb_write);
50 BIO_meth_set_read(bio_method, bio_cb_read);
51 BIO_meth_set_puts(bio_method, bio_cb_puts);
52 BIO_meth_set_ctrl(bio_method, bio_cb_ctrl);
53
54 bio_cb_method = bio_method;
55 }
56
57 static BIO_METHOD *
bio_s_cb(void)58 bio_s_cb(void)
59 {
60 if (bio_cb_method != NULL)
61 return (bio_cb_method);
62
63 pthread_mutex_lock(&bio_cb_method_lock);
64 bio_cb_method_init();
65 pthread_mutex_unlock(&bio_cb_method_lock);
66
67 return (bio_cb_method);
68 }
69
70 static int
bio_cb_puts(BIO * bio,const char * str)71 bio_cb_puts(BIO *bio, const char *str)
72 {
73 return (bio_cb_write(bio, str, strlen(str)));
74 }
75
76 static long
bio_cb_ctrl(BIO * bio,int cmd,long num,void * ptr)77 bio_cb_ctrl(BIO *bio, int cmd, long num, void *ptr)
78 {
79 long ret = 1;
80
81 switch (cmd) {
82 case BIO_CTRL_GET_CLOSE:
83 ret = (long)BIO_get_shutdown(bio);
84 break;
85 case BIO_CTRL_SET_CLOSE:
86 BIO_set_shutdown(bio, (int)num);
87 break;
88 case BIO_CTRL_DUP:
89 case BIO_CTRL_FLUSH:
90 break;
91 case BIO_CTRL_INFO:
92 case BIO_CTRL_GET:
93 case BIO_CTRL_SET:
94 default:
95 ret = BIO_ctrl(BIO_next(bio), cmd, num, ptr);
96 }
97
98 return (ret);
99 }
100
101 static int
bio_cb_write(BIO * bio,const char * buf,int num)102 bio_cb_write(BIO *bio, const char *buf, int num)
103 {
104 struct tls *ctx = BIO_get_data(bio);
105 int rv;
106
107 BIO_clear_retry_flags(bio);
108 rv = (ctx->write_cb)(ctx, buf, num, ctx->cb_arg);
109 if (rv == TLS_WANT_POLLIN) {
110 BIO_set_retry_read(bio);
111 rv = -1;
112 } else if (rv == TLS_WANT_POLLOUT) {
113 BIO_set_retry_write(bio);
114 rv = -1;
115 }
116 return (rv);
117 }
118
119 static int
bio_cb_read(BIO * bio,char * buf,int size)120 bio_cb_read(BIO *bio, char *buf, int size)
121 {
122 struct tls *ctx = BIO_get_data(bio);
123 int rv;
124
125 BIO_clear_retry_flags(bio);
126 rv = (ctx->read_cb)(ctx, buf, size, ctx->cb_arg);
127 if (rv == TLS_WANT_POLLIN) {
128 BIO_set_retry_read(bio);
129 rv = -1;
130 } else if (rv == TLS_WANT_POLLOUT) {
131 BIO_set_retry_write(bio);
132 rv = -1;
133 }
134 return (rv);
135 }
136
137 int
tls_set_cbs(struct tls * ctx,tls_read_cb read_cb,tls_write_cb write_cb,void * cb_arg)138 tls_set_cbs(struct tls *ctx, tls_read_cb read_cb, tls_write_cb write_cb,
139 void *cb_arg)
140 {
141 const BIO_METHOD *bio_cb;
142 BIO *bio;
143 int rv = -1;
144
145 if (read_cb == NULL || write_cb == NULL) {
146 tls_set_errorx(ctx, TLS_ERROR_UNKNOWN, "no callbacks provided");
147 goto err;
148 }
149
150 ctx->read_cb = read_cb;
151 ctx->write_cb = write_cb;
152 ctx->cb_arg = cb_arg;
153
154 if ((bio_cb = bio_s_cb()) == NULL) {
155 tls_set_errorx(ctx, TLS_ERROR_UNKNOWN,
156 "failed to create callback method");
157 goto err;
158 }
159 if ((bio = BIO_new(bio_cb)) == NULL) {
160 tls_set_errorx(ctx, TLS_ERROR_UNKNOWN,
161 "failed to create callback i/o");
162 goto err;
163 }
164 BIO_set_data(bio, ctx);
165 BIO_set_init(bio, 1);
166
167 SSL_set_bio(ctx->ssl_conn, bio, bio);
168
169 rv = 0;
170
171 err:
172 return (rv);
173 }
174