_ Git - BearSSL/blob - src/ssl/ssl_io.c

   1 /*
   2  * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining
   5  * a copy of this software and associated documentation files (the
   6  * "Software"), to deal in the Software without restriction, including
   7  * without limitation the rights to use, copy, modify, merge, publish,
   8  * distribute, sublicense, and/or sell copies of the Software, and to
   9  * permit persons to whom the Software is furnished to do so, subject to
  10  * the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 #include "inner.h"
  26
  27 /* see bearssl_ssl.h */
  28 void
  29 br_sslio_init(br_sslio_context *ctx,
  30         br_ssl_engine_context *engine,
  31         int (*low_read)(void *read_context,
  32                 unsigned char *data, size_t len),
  33         void *read_context,
  34         int (*low_write)(void *write_context,
  35                 const unsigned char *data, size_t len),
  36         void *write_context)
  37 {
  38         ctx->engine = engine;
  39         ctx->low_read = low_read;
  40         ctx->read_context = read_context;
  41         ctx->low_write = low_write;
  42         ctx->write_context = write_context;
  43 }
  44
  45 /*
  46  * Run the engine, until the specified target state is achieved, or
  47  * an error occurs. The target state is SENDAPP, RECVAPP, or the
  48  * combination of both (the combination matches either). When a match is
  49  * achieved, this function returns 0. On error, it returns -1.
  50  */
  51 static int
  52 run_until(br_sslio_context *ctx, unsigned target)
  53 {
  54         for (;;) {
  55                 unsigned state;
  56
  57                 state = br_ssl_engine_current_state(ctx->engine);
  58                 if (state & BR_SSL_CLOSED) {
  59                         return -1;
  60                 }
  61
  62                 /*
  63                  * If there is some record data to send, do it. This takes
  64                  * precedence over everything else.
  65                  */
  66                 if (state & BR_SSL_SENDREC) {
  67                         unsigned char *buf;
  68                         size_t len;
  69                         int wlen;
  70
  71                         buf = br_ssl_engine_sendrec_buf(ctx->engine, &len);
  72                         wlen = ctx->low_write(ctx->write_context, buf, len);
  73                         if (wlen < 0) {
  74                                 /*
  75                                  * If we received a close_notify and we
  76                                  * still send something, then we have our
  77                                  * own response close_notify to send, and
  78                                  * the peer is allowed by RFC 5246 not to
  79                                  * wait for it.
  80                                  */
  81                                 if (!ctx->engine->shutdown_recv) {
  82                                         br_ssl_engine_fail(
  83                                                 ctx->engine, BR_ERR_IO);
  84                                 }
  85                                 return -1;
  86                         }
  87                         if (wlen > 0) {
  88                                 br_ssl_engine_sendrec_ack(ctx->engine, wlen);
  89                         }
  90                         continue;
  91                 }
  92
  93                 /*
  94                  * If we reached our target, then we are finished.
  95                  */
  96                 if (state & target) {
  97                         return 0;
  98                 }
  99
 100                 /*
 101                  * If some application data must be read, and we did not
 102                  * exit, then this means that we are trying to write data,
 103                  * and that's not possible until the application data is
 104                  * read. This may happen if using a shared in/out buffer,
 105                  * and the underlying protocol is not strictly half-duplex.
 106                  * This is unrecoverable here, so we report an error.
 107                  */
 108                 if (state & BR_SSL_RECVAPP) {
 109                         return -1;
 110                 }
 111
 112                 /*
 113                  * If we reached that point, then either we are trying
 114                  * to read data and there is some, or the engine is stuck
 115                  * until a new record is obtained.
 116                  */
 117                 if (state & BR_SSL_RECVREC) {
 118                         unsigned char *buf;
 119                         size_t len;
 120                         int rlen;
 121
 122                         buf = br_ssl_engine_recvrec_buf(ctx->engine, &len);
 123                         rlen = ctx->low_read(ctx->read_context, buf, len);
 124                         if (rlen < 0) {
 125                                 br_ssl_engine_fail(ctx->engine, BR_ERR_IO);
 126                                 return -1;
 127                         }
 128                         if (rlen > 0) {
 129                                 br_ssl_engine_recvrec_ack(ctx->engine, rlen);
 130                         }
 131                         continue;
 132                 }
 133
 134                 /*
 135                  * We can reach that point if the target RECVAPP, and
 136                  * the state contains SENDAPP only. This may happen with
 137                  * a shared in/out buffer. In that case, we must flush
 138                  * the buffered data to "make room" for a new incoming
 139                  * record.
 140                  */
 141                 br_ssl_engine_flush(ctx->engine, 0);
 142         }
 143 }
 144
 145 /* see bearssl_ssl.h */
 146 int
 147 br_sslio_read(br_sslio_context *ctx, void *dst, size_t len)
 148 {
 149         unsigned char *buf;
 150         size_t alen;
 151
 152         if (len == 0) {
 153                 return 0;
 154         }
 155         if (run_until(ctx, BR_SSL_RECVAPP) < 0) {
 156                 return -1;
 157         }
 158         buf = br_ssl_engine_recvapp_buf(ctx->engine, &alen);
 159         if (alen > len) {
 160                 alen = len;
 161         }
 162         memcpy(dst, buf, alen);
 163         br_ssl_engine_recvapp_ack(ctx->engine, alen);
 164         return (int)alen;
 165 }
 166
 167 /* see bearssl_ssl.h */
 168 int
 169 br_sslio_read_all(br_sslio_context *ctx, void *dst, size_t len)
 170 {
 171         unsigned char *buf;
 172
 173         buf = dst;
 174         while (len > 0) {
 175                 int rlen;
 176
 177                 rlen = br_sslio_read(ctx, buf, len);
 178                 if (rlen < 0) {
 179                         return -1;
 180                 }
 181                 buf += rlen;
 182                 len -= (size_t)rlen;
 183         }
 184         return 0;
 185 }
 186
 187 /* see bearssl_ssl.h */
 188 int
 189 br_sslio_write(br_sslio_context *ctx, const void *src, size_t len)
 190 {
 191         unsigned char *buf;
 192         size_t alen;
 193
 194         if (len == 0) {
 195                 return 0;
 196         }
 197         if (run_until(ctx, BR_SSL_SENDAPP) < 0) {
 198                 return -1;
 199         }
 200         buf = br_ssl_engine_sendapp_buf(ctx->engine, &alen);
 201         if (alen > len) {
 202                 alen = len;
 203         }
 204         memcpy(buf, src, alen);
 205         br_ssl_engine_sendapp_ack(ctx->engine, alen);
 206         return (int)alen;
 207 }
 208
 209 /* see bearssl_ssl.h */
 210 int
 211 br_sslio_write_all(br_sslio_context *ctx, const void *src, size_t len)
 212 {
 213         const unsigned char *buf;
 214
 215         buf = src;
 216         while (len > 0) {
 217                 int wlen;
 218
 219                 wlen = br_sslio_write(ctx, buf, len);
 220                 if (wlen < 0) {
 221                         return -1;
 222                 }
 223                 buf += wlen;
 224                 len -= (size_t)wlen;
 225         }
 226         return 0;
 227 }
 228
 229 /* see bearssl_ssl.h */
 230 int
 231 br_sslio_flush(br_sslio_context *ctx)
 232 {
 233         /*
 234          * We trigger a flush. We know the data is gone when there is
 235          * no longer any record data to send, and we can either read
 236          * or write application data. The call to run_until() does the
 237          * job because it ensures that any assembled record data is
 238          * first sent down the wire before considering anything else.
 239          */
 240         br_ssl_engine_flush(ctx->engine, 0);
 241         return run_until(ctx, BR_SSL_SENDAPP | BR_SSL_RECVAPP);
 242 }
 243
 244 /* see bearssl_ssl.h */
 245 int
 246 br_sslio_close(br_sslio_context *ctx)
 247 {
 248         br_ssl_engine_close(ctx->engine);
 249         while (br_ssl_engine_current_state(ctx->engine) != BR_SSL_CLOSED) {
 250                 /*
 251                  * Discard any incoming application data.
 252                  */
 253                 size_t len;
 254
 255                 run_until(ctx, BR_SSL_RECVAPP);
 256                 if (br_ssl_engine_recvapp_buf(ctx->engine, &len) != NULL) {
 257                         br_ssl_engine_recvapp_ack(ctx->engine, len);
 258                 }
 259         }
 260         return br_ssl_engine_last_error(ctx->engine) == BR_ERR_OK;
 261 }