--- /dev/null
+=pod
+
+=head1 NAME
+
+BIO_f_ssl, BIO_set_ssl, BIO_get_ssl, BIO_set_ssl_mode, BIO_set_ssl_renegotiate_bytes,
+BIO_get_num_renegotiates, BIO_set_ssl_renegotiate_timeout, BIO_new_ssl,
+BIO_new_ssl_connect, BIO_new_buffer_ssl_connect, BIO_ssl_copy_session_id,
+BIO_ssl_shutdown - SSL BIO
+
+=head1 SYNOPSIS
+
+ #include <openssl/bio.h>
+ #include <openssl/ssl.h>
+
+ BIO_METHOD *BIO_f_ssl(void);
+
+ #define BIO_set_ssl(b,ssl,c) BIO_ctrl(b,BIO_C_SET_SSL,c,(char *)ssl)
+ #define BIO_get_ssl(b,sslp) BIO_ctrl(b,BIO_C_GET_SSL,0,(char *)sslp)
+ #define BIO_set_ssl_mode(b,client) BIO_ctrl(b,BIO_C_SSL_MODE,client,NULL)
+ #define BIO_set_ssl_renegotiate_bytes(b,num) \
+ BIO_ctrl(b,BIO_C_SET_SSL_RENEGOTIATE_BYTES,num,NULL);
+ #define BIO_set_ssl_renegotiate_timeout(b,seconds) \
+ BIO_ctrl(b,BIO_C_SET_SSL_RENEGOTIATE_TIMEOUT,seconds,NULL);
+ #define BIO_get_num_renegotiates(b) \
+ BIO_ctrl(b,BIO_C_SET_SSL_NUM_RENEGOTIATES,0,NULL);
+
+ BIO *BIO_new_ssl(SSL_CTX *ctx,int client);
+ BIO *BIO_new_ssl_connect(SSL_CTX *ctx);
+ BIO *BIO_new_buffer_ssl_connect(SSL_CTX *ctx);
+ int BIO_ssl_copy_session_id(BIO *to,BIO *from);
+ void BIO_ssl_shutdown(BIO *bio);
+
+ #define BIO_do_handshake(b) BIO_ctrl(b,BIO_C_DO_STATE_MACHINE,0,NULL)
+
+=head1 DESCRIPTION
+
+BIO_f_ssl() returns the SSL BIO method. This is a filter BIO which
+is a wrapper round the OpenSSL SSL routines adding a BIO "flavour" to
+SSL I/O.
+
+I/O performed on an SSL BIO communicates using the SSL protocol with
+the SSLs read and write BIOs. If an SSL connection is not established
+then an attempt is made to establish one on the first I/O call.
+
+If a BIO is appended to an SSL BIO using BIO_push() it is automatically
+used as the SSL BIOs read and write BIOs.
+
+Calling BIO_reset() on an SSL BIO closes down any current SSL connection
+by calling SSL_shutdown(). BIO_reset() is then sent to the next BIO in
+the chain: this will typically disconnect the underlying transport.
+The SSL BIO is then reset to the initial accept or connect state.
+
+If the close flag is set when an SSL BIO is freed then the internal
+SSL structure is also freed using SSL_free().
+
+BIO_set_ssl() sets the internal SSL pointer of BIO B<b> to B<ssl> using
+the close flag B<c>.
+
+BIO_get_ssl() retrieves the SSL pointer of BIO B<b>, it can then be
+manipulated using the standard SSL library functions.
+
+BIO_set_ssl_mode() sets the SSL BIO mode to B<client>. If B<client>
+is 1 client mode is set. If B<client> is 0 server mode is set.
+
+BIO_set_ssl_renegotiate_bytes() sets the renegotiate byte count
+to B<num>. When set after every B<num> bytes of I/O (read and write)
+the SSL session is automatically renegotiated. B<num> must be at
+least 512 bytes.
+
+BIO_set_ssl_renegotiate_timeout() sets the renegotiate timeout to
+B<seconds>. When the renegotiate timeout elapses the session is
+automatically renegotiated.
+
+BIO_get_num_renegotiates() returns the total number of session
+renegotiations due to I/O or timeout.
+
+BIO_new_ssl() allocates an SSL BIO using SSL_CTX B<ctx> and using
+client mode if B<client> is non zero.
+
+BIO_new_ssl_connect() creates a new BIO chain consisting of an
+SSL BIO (using B<ctx>) followed by a connect BIO.
+
+BIO_new_buffer_ssl_connect() creates a new BIO chain consisting
+of a buffering BIO, an SSL BIO (using B<ctx>) and a connect
+BIO.
+
+BIO_ssl_copy_session_id() copies an SSL session id between
+BIO chains B<from> and B<to>. It does this by locating the
+SSL BIOs in each chain and calling SSL_copy_session_id() on
+the internal SSL pointer.
+
+BIO_ssl_shutdown() closes down an SSL connection on BIO
+chain B<bio>. It does this by locating the SSL BIO in the
+chain and calling SSL_shutdown() on its internal SSL
+pointer.
+
+BIO_do_handshake() attempts to complete an SSL handshake on the
+supplied BIO and establish the SSL connection. It returns 1
+if the connection was established successfully. A zero or negative
+value is returned if the connection could not be established, the
+call BIO_should_retry() should be used for non blocking connect BIOs
+to determine if the call should be retried. If an SSL connection has
+already been established this call has no effect.
+
+=head1 NOTES
+
+SSL BIOs are exceptional in that if the underlying transport
+is non blocking they can still request a retry in exceptional
+circumstances. Specifically this will happen if a session
+renegotiation takes place during a BIO_read() operation, one
+case where this happens is when SGC or step up occurs.
+
+In OpenSSL 0.9.6 and later the SSL flag SSL_AUTO_RETRY can be
+set to disable this behaviour. That is when this flag is set
+an SSL BIO using a blocking transport will never request a
+retry.
+
+Since unknown BIO_ctrl() operations are sent through filter
+BIOs the servers name and port can be set using BIO_set_host()
+on the BIO returned by BIO_new_ssl_connect() without having
+to locate the connect BIO first.
+
+Applications do not have to call BIO_do_handshake() but may wish
+to do so to separate the handshake process from other I/O
+processing.
+
+=head1 RETURN VALUES
+
+TBA
+
+=head1 EXAMPLE
+
+This SSL/TLS client example, attempts to retrieve a page from an
+SSL/TLS web server. The I/O routines are identical to those of the
+unencrypted example in L<BIO_s_connect(3)|BIO_s_connect(3)>.
+
+ BIO *sbio, *out;
+ int len;
+ char tmpbuf[1024];
+ SSL_CTX *ctx;
+ SSL *ssl;
+
+ ERR_load_crypto_strings();
+ ERR_load_SSL_strings();
+ OpenSSL_add_all_algorithms();
+
+ /* We would seed the PRNG here if the platform didn't
+ * do it automatically
+ */
+
+ ctx = SSL_CTX_new(SSLv23_client_method());
+
+ /* We'd normally set some stuff like the verify paths and
+ * mode here because as things stand this will connect to
+ * any server whose certificate is signed by any CA.
+ */
+
+ sbio = BIO_new_ssl_connect(ctx);
+
+ BIO_get_ssl(sbio, &ssl);
+
+ if(!ssl) {
+ fprintf(stderr, "Can't locate SSL pointer\n");
+ /* whatever ... */
+ }
+
+ /* Don't want any retries */
+ SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY);
+
+ /* We might want to do other things with ssl here */
+
+ BIO_set_conn_hostname(sbio, "localhost:https");
+
+ out = BIO_new_fp(stdout, BIO_NOCLOSE);
+ if(BIO_do_connect(sbio) <= 0) {
+ fprintf(stderr, "Error connecting to server\n");
+ ERR_print_errors_fp(stderr);
+ /* whatever ... */
+ }
+
+ if(BIO_do_handshake(sbio) <= 0) {
+ fprintf(stderr, "Error establishing SSL connection\n");
+ ERR_print_errors_fp(stderr);
+ /* whatever ... */
+ }
+
+ /* Could examine ssl here to get connection info */
+
+ BIO_puts(sbio, "GET / HTTP/1.0\n\n");
+ for(;;) {
+ len = BIO_read(sbio, tmpbuf, 1024);
+ if(len <= 0) break;
+ BIO_write(out, tmpbuf, len);
+ }
+ BIO_free_all(sbio);
+ BIO_free(out);
+
+Here is a simple server example. It makes use of a buffering
+BIO to allow lines to be read from the SSL BIO using BIO_gets.
+It creates a pseudo web page containing the actual request from
+a client and also echoes the request to standard output.
+
+ BIO *sbio, *bbio, *acpt, *out;
+ int len;
+ char tmpbuf[1024];
+ SSL_CTX *ctx;
+ SSL *ssl;
+
+ ERR_load_crypto_strings();
+ ERR_load_SSL_strings();
+ OpenSSL_add_all_algorithms();
+
+ /* Might seed PRNG here */
+
+ ctx = SSL_CTX_new(SSLv23_server_method());
+
+ if (!SSL_CTX_use_certificate_file(ctx,"server.pem",SSL_FILETYPE_PEM)
+ || !SSL_CTX_use_PrivateKey_file(ctx,"server.pem",SSL_FILETYPE_PEM)
+ || !SSL_CTX_check_private_key(ctx)) {
+
+ fprintf(stderr, "Error setting up SSL_CTX\n");
+ ERR_print_errors_fp(stderr);
+ return 0;
+ }
+
+ /* Might do other things here like setting verify locations and
+ * DH and/or RSA temporary key callbacks
+ */
+
+ /* New SSL BIO setup as server */
+ sbio=BIO_new_ssl(ctx,0);
+
+ BIO_get_ssl(sbio, &ssl);
+
+ if(!ssl) {
+ fprintf(stderr, "Can't locate SSL pointer\n");
+ /* whatever ... */
+ }
+
+ /* Don't want any retries */
+ SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY);
+
+ /* Create the buffering BIO */
+
+ bbio = BIO_new(BIO_f_buffer());
+
+ /* Add to chain */
+ sbio = BIO_push(bbio, sbio);
+
+ acpt=BIO_new_accept("4433");
+
+ /* By doing this when a new connection is established
+ * we automatically have sbio inserted into it. The
+ * BIO chain is now 'swallowed' by the accept BIO and
+ * will be freed when the accept BIO is freed.
+ */
+
+ BIO_set_accept_bios(acpt,sbio);
+
+ out = BIO_new_fp(stdout, BIO_NOCLOSE);
+
+ /* Setup accept BIO */
+ if(BIO_do_accept(acpt) <= 0) {
+ fprintf(stderr, "Error setting up accept BIO\n");
+ ERR_print_errors_fp(stderr);
+ return 0;
+ }
+
+ /* Now wait for incoming connection */
+ if(BIO_do_accept(acpt) <= 0) {
+ fprintf(stderr, "Error in connection\n");
+ ERR_print_errors_fp(stderr);
+ return 0;
+ }
+
+ /* We only want one connection so remove and free
+ * accept BIO
+ */
+
+ sbio = BIO_pop(acpt);
+
+ BIO_free_all(acpt);
+
+ if(BIO_do_handshake(sbio) <= 0) {
+ fprintf(stderr, "Error in SSL handshake\n");
+ ERR_print_errors_fp(stderr);
+ return 0;
+ }
+
+ BIO_puts(sbio, "HTTP/1.0 200 OK\r\nContent-type: text/plain\r\n\r\n");
+ BIO_puts(sbio, "\r\nConnection Established\r\nRequest headers:\r\n");
+ BIO_puts(sbio, "--------------------------------------------------\r\n");
+
+ for(;;) {
+ len = BIO_gets(sbio, tmpbuf, 1024);
+ if(len <= 0) break;
+ BIO_write(sbio, tmpbuf, len);
+ BIO_write(out, tmpbuf, len);
+ /* Look for blank line signifying end of headers*/
+ if((tmpbuf[0] == '\r') || (tmpbuf[0] == '\n')) break;
+ }
+
+ BIO_puts(sbio, "--------------------------------------------------\r\n");
+ BIO_puts(sbio, "\r\n");
+
+ /* Since there is a buffering BIO present we had better flush it */
+ BIO_flush(sbio);
+
+ BIO_free_all(sbio);
+
+=head1 BUGS
+
+In OpenSSL versions before 1.0.0 the BIO_pop() call was handled incorrectly,
+the I/O BIO reference count was incorrectly incremented (instead of
+decremented) and dissociated with the SSL BIO even if the SSL BIO was not
+explicitly being popped (e.g. a pop higher up the chain). Applications which
+included workarounds for this bug (e.g. freeing BIOs more than once) should
+be modified to handle this fix or they may free up an already freed BIO.
+
+=head1 SEE ALSO
+
+TBA
projects / cassiopeia.git / blobdiff