1 /* Copyright (c) 2015, 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/ssl.h> 16 17 #include <assert.h> 18 #include <limits.h> 19 #include <stdlib.h> 20 #include <string.h> 21 22 #include <openssl/bio.h> 23 #include <openssl/err.h> 24 #include <openssl/mem.h> 25 26 #include "../crypto/internal.h" 27 #include "internal.h" 28 29 30 BSSL_NAMESPACE_BEGIN 31 32 // BIO uses int instead of size_t. No lengths will exceed uint16_t, so this will 33 // not overflow. 34 static_assert(0xffff <= INT_MAX, "uint16_t does not fit in int"); 35 36 static_assert((SSL3_ALIGN_PAYLOAD & (SSL3_ALIGN_PAYLOAD - 1)) == 0, 37 "SSL3_ALIGN_PAYLOAD must be a power of 2"); 38 39 void SSLBuffer::Clear() { 40 free(buf_); // Allocated with malloc(). 41 buf_ = nullptr; 42 offset_ = 0; 43 size_ = 0; 44 cap_ = 0; 45 } 46 47 bool SSLBuffer::EnsureCap(size_t header_len, size_t new_cap) { 48 if (new_cap > 0xffff) { 49 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 50 return false; 51 } 52 53 if (cap_ >= new_cap) { 54 return true; 55 } 56 57 // Add up to |SSL3_ALIGN_PAYLOAD| - 1 bytes of slack for alignment. 58 // 59 // Since this buffer gets allocated quite frequently and doesn't contain any 60 // sensitive data, we allocate with malloc rather than |OPENSSL_malloc| and 61 // avoid zeroing on free. 62 uint8_t *new_buf = (uint8_t *)malloc(new_cap + SSL3_ALIGN_PAYLOAD - 1); 63 if (new_buf == NULL) { 64 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); 65 return false; 66 } 67 68 // Offset the buffer such that the record body is aligned. 69 size_t new_offset = 70 (0 - header_len - (uintptr_t)new_buf) & (SSL3_ALIGN_PAYLOAD - 1); 71 72 if (buf_ != NULL) { 73 OPENSSL_memcpy(new_buf + new_offset, buf_ + offset_, size_); 74 free(buf_); // Allocated with malloc(). 75 } 76 77 buf_ = new_buf; 78 offset_ = new_offset; 79 cap_ = new_cap; 80 return true; 81 } 82 83 void SSLBuffer::DidWrite(size_t new_size) { 84 if (new_size > cap() - size()) { 85 abort(); 86 } 87 size_ += new_size; 88 } 89 90 void SSLBuffer::Consume(size_t len) { 91 if (len > size_) { 92 abort(); 93 } 94 offset_ += (uint16_t)len; 95 size_ -= (uint16_t)len; 96 cap_ -= (uint16_t)len; 97 } 98 99 void SSLBuffer::DiscardConsumed() { 100 if (size_ == 0) { 101 Clear(); 102 } 103 } 104 105 static int dtls_read_buffer_next_packet(SSL *ssl) { 106 SSLBuffer *buf = &ssl->s3->read_buffer; 107 108 if (!buf->empty()) { 109 // It is an error to call |dtls_read_buffer_extend| when the read buffer is 110 // not empty. 111 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 112 return -1; 113 } 114 115 // Read a single packet from |ssl->rbio|. |buf->cap()| must fit in an int. 116 int ret = 117 BIO_read(ssl->rbio.get(), buf->data(), static_cast<int>(buf->cap())); 118 if (ret <= 0) { 119 ssl->s3->rwstate = SSL_READING; 120 return ret; 121 } 122 buf->DidWrite(static_cast<size_t>(ret)); 123 return 1; 124 } 125 126 static int tls_read_buffer_extend_to(SSL *ssl, size_t len) { 127 SSLBuffer *buf = &ssl->s3->read_buffer; 128 129 if (len > buf->cap()) { 130 OPENSSL_PUT_ERROR(SSL, SSL_R_BUFFER_TOO_SMALL); 131 return -1; 132 } 133 134 // Read until the target length is reached. 135 while (buf->size() < len) { 136 // The amount of data to read is bounded by |buf->cap|, which must fit in an 137 // int. 138 int ret = BIO_read(ssl->rbio.get(), buf->data() + buf->size(), 139 static_cast<int>(len - buf->size())); 140 if (ret <= 0) { 141 ssl->s3->rwstate = SSL_READING; 142 return ret; 143 } 144 buf->DidWrite(static_cast<size_t>(ret)); 145 } 146 147 return 1; 148 } 149 150 int ssl_read_buffer_extend_to(SSL *ssl, size_t len) { 151 // |ssl_read_buffer_extend_to| implicitly discards any consumed data. 152 ssl->s3->read_buffer.DiscardConsumed(); 153 154 if (SSL_is_dtls(ssl)) { 155 static_assert( 156 DTLS1_RT_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH <= 0xffff, 157 "DTLS read buffer is too large"); 158 159 // The |len| parameter is ignored in DTLS. 160 len = DTLS1_RT_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH; 161 } 162 163 if (!ssl->s3->read_buffer.EnsureCap(ssl_record_prefix_len(ssl), len)) { 164 return -1; 165 } 166 167 if (ssl->rbio == nullptr) { 168 OPENSSL_PUT_ERROR(SSL, SSL_R_BIO_NOT_SET); 169 return -1; 170 } 171 172 int ret; 173 if (SSL_is_dtls(ssl)) { 174 // |len| is ignored for a datagram transport. 175 ret = dtls_read_buffer_next_packet(ssl); 176 } else { 177 ret = tls_read_buffer_extend_to(ssl, len); 178 } 179 180 if (ret <= 0) { 181 // If the buffer was empty originally and remained empty after attempting to 182 // extend it, release the buffer until the next attempt. 183 ssl->s3->read_buffer.DiscardConsumed(); 184 } 185 return ret; 186 } 187 188 int ssl_handle_open_record(SSL *ssl, bool *out_retry, ssl_open_record_t ret, 189 size_t consumed, uint8_t alert) { 190 *out_retry = false; 191 if (ret != ssl_open_record_partial) { 192 ssl->s3->read_buffer.Consume(consumed); 193 } 194 if (ret != ssl_open_record_success) { 195 // Nothing was returned to the caller, so discard anything marked consumed. 196 ssl->s3->read_buffer.DiscardConsumed(); 197 } 198 switch (ret) { 199 case ssl_open_record_success: 200 return 1; 201 202 case ssl_open_record_partial: { 203 int read_ret = ssl_read_buffer_extend_to(ssl, consumed); 204 if (read_ret <= 0) { 205 return read_ret; 206 } 207 *out_retry = true; 208 return 1; 209 } 210 211 case ssl_open_record_discard: 212 *out_retry = true; 213 return 1; 214 215 case ssl_open_record_close_notify: 216 return 0; 217 218 case ssl_open_record_error: 219 if (alert != 0) { 220 ssl_send_alert(ssl, SSL3_AL_FATAL, alert); 221 } 222 return -1; 223 } 224 assert(0); 225 return -1; 226 } 227 228 229 static_assert(SSL3_RT_HEADER_LENGTH * 2 + 230 SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD * 2 + 231 SSL3_RT_MAX_PLAIN_LENGTH <= 232 0xffff, 233 "maximum TLS write buffer is too large"); 234 235 static_assert(DTLS1_RT_HEADER_LENGTH + SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD + 236 SSL3_RT_MAX_PLAIN_LENGTH <= 237 0xffff, 238 "maximum DTLS write buffer is too large"); 239 240 static int tls_write_buffer_flush(SSL *ssl) { 241 SSLBuffer *buf = &ssl->s3->write_buffer; 242 243 while (!buf->empty()) { 244 int ret = BIO_write(ssl->wbio.get(), buf->data(), buf->size()); 245 if (ret <= 0) { 246 ssl->s3->rwstate = SSL_WRITING; 247 return ret; 248 } 249 buf->Consume(static_cast<size_t>(ret)); 250 } 251 buf->Clear(); 252 return 1; 253 } 254 255 static int dtls_write_buffer_flush(SSL *ssl) { 256 SSLBuffer *buf = &ssl->s3->write_buffer; 257 if (buf->empty()) { 258 return 1; 259 } 260 261 int ret = BIO_write(ssl->wbio.get(), buf->data(), buf->size()); 262 if (ret <= 0) { 263 ssl->s3->rwstate = SSL_WRITING; 264 // If the write failed, drop the write buffer anyway. Datagram transports 265 // can't write half a packet, so the caller is expected to retry from the 266 // top. 267 buf->Clear(); 268 return ret; 269 } 270 buf->Clear(); 271 return 1; 272 } 273 274 int ssl_write_buffer_flush(SSL *ssl) { 275 if (ssl->wbio == nullptr) { 276 OPENSSL_PUT_ERROR(SSL, SSL_R_BIO_NOT_SET); 277 return -1; 278 } 279 280 if (SSL_is_dtls(ssl)) { 281 return dtls_write_buffer_flush(ssl); 282 } else { 283 return tls_write_buffer_flush(ssl); 284 } 285 } 286 287 BSSL_NAMESPACE_END 288
