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diff --git a/doc/libstls/index.html b/doc/libstls/index.html index fcd839a..f81396c 100644 --- a/doc/libstls/index.html +++ b/doc/libstls/index.html @@ -52,30 +52,97 @@ sysdeps directory. </li> <h2> Programming </h2> -<h3> Running the TLS/SSL engine </h3> +<h3> Utilities </h3> -<h4> <code> int stls_run (struct tls *ctx, int *fds, pid_t pid, unsigned int verbosity, uint32_t options, tain_t const *tto) </code> </h4> +<h4> <code> void stls_drop () </code> </h4> + +<p> + If the process is running as root, then this function drops its privileges +(else it does nothing). +The gid to drop to is read from the TLS_GID environment variable; the uid to +drop to is read from the TLS_UID environment variable. If those variables +are not given, then the uid, or gid, or both, are not changed. If they +contain something else than numerical uid/gids, the process exits 111 with +an error message. +</p> + +<h3> Initializing the TLS engine </h3> + +<h4> <code> struct tls *stls_client_init_and_handshake (int const *fds, uint32_t preoptions, char const *servername) </code> </h4> + +<p> + This function initializes a TLS context for a client-side connection, +then performs a TLS handshake. +It then returns a non-null pointer to a <tt>struct tls</tt> context for the +application to pass to the <tt>stls_run</tt> function when it wants to +run the engine. +If the context cannot be initialized or the handshake cannot be performed, +the process exits (96 for configuration issues, 97 for context and handshake +issues) with an appropriate error message. +</p> + +<p> + If the <tt>CADIR</tt> environment variable is set, then it must contain +the path of a directory containing the hashed names of the public +certificates identifying the trust anchors. Else, if the <tt>CAFILE</tt> +environment variable is set, then it must contain the path to a PEM file +containing all the certificates for the trust anchors. Else, the process +exits 100 with an error message. +</p> + +<p> + The arguments are as follows: +</p> + +<ul> + <li> <tt>fds</tt> : an array of 4 file descriptors, that are in this +order: the fd reading from the application (cleartext), the fd writing to the +application (cleartext), the fd reading from the network, the fd writing to +the network. </li> + <li> <tt>preoptions : a bitfield. + <ul> + <li> Bit 0: if clear, no client authentication is performed. If set, +the <tt>CERTFILE</tt> and <tt>KEYFILE</tt> environment variables are read, +they must contain the path to a valid client certificate and private key +(else the process exits 96); this certificate is then provided to the +server for client authentication. </li> + </ul> </li> + <li> <tt>servername</tt> : the server name used for SNI. If NULL, then +no SNI is performed, which may be a security risk. </li> +</ul> + +<h4> <code> struct tls *stls_server_init_and_handshake (int const *fds, uint32_t preoptions) </code> </h4> + +<p> + Same as the previous function, but on the server side. No <em>servername</em> +argument is required. The <tt>CERTFILE</tt> and <tt>KEYFILE</tt> environment +variables are mandatory, they point to the server's certificate and private +key. It is only necessary to set <tt>CADIR</tt> or <tt>CAFILE</tt> when bit +0 of <em>preoptions</em> is set, in which case client authentication will be +requested, and a list of trust anchors (read from either the directory +in <tt>CADIR</tt> or the PEM file in <tt>CAFILE</tt>) will be used to verify +the client certificate. +</p> + +<h3> Running the TLS engine </h3> + +<h4> <code> void stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t options, tain_t const *tto) </code> </h4> <p> This function runs a full-duplex TLS/SSL engine, reading/writing clear text from/to two file descriptors, and writing/reading ciphertext to/from two other file descriptors, until the connection is closed both ways (either with a SSL close, or -with EOF) or a given subprocess dies. +with EOF). It does not return. </p> <ul> <li> <em>ctx</em> is a pointer to a fully initialized context, connected to <em>fds</em>[2] and <em>fds</em>[3]. The TLS handshake must already be completed. </li> - <li> <em>fds</em> is an array of 5 file descriptors, in this + <li> <em>fds</em> is an array of 4 file descriptors, in this order: fd reading clear text, fd writing clear text, fd reading -ciphertext, fd writing ciphertext, selfpipe. </li> - <li> <em>pid</em> is the pid of the application subprocess. -When a SIGCHLD is detected on the selfpipe, the newly deceased -process is reaped, and if it was <em>pid</em>, then the function -returns as soon as it doesn't have anything left to write to -the network peer. </li> +ciphertext, fd writing ciphertext. </li> <li> <em>verbosity</em> defines the engine's verbosity: the higher the more verbose. This parameter is currently ignored. </li> <li> <em>options</em> is a bitfield. @@ -106,29 +173,8 @@ if you don't want the engine to ever timeout. </li> <p> <tt>stls_run</tt> will make the process die with an appropriate error -message if it encounters an unrecoverable error. If there were no problems and the -SSL/TLS connection closed cleanly, it returns -1. If the application -subprocess dies early, <tt>stls_run</tt> returns the <em>wstat</em> -for that subprocess, i.e. the integer containing the information about -its exit code or crash signal. No matter how <tt>stls_run</tt> returns, -the first four descriptors in <em>fds</em> are closed, but the -selfpipe is untouched and the caller should free <em>ctx</em> itself. -</p> - -<h4> <code> int stls_s6tlsc (char const *const *argv, char const *const *envp, tain_t const *tto, uint32_t preoptions, uint32_t options, uid_t uid, gid_t gid, unsigned int verbosity, char const *servername, int *sfd) </code> </h4> - -<p> - This function implements <a href="../s6-tlsc.html">s6-tlsc</a> on top of LibreSSL. -It has no other practical purpose; you're better off directly invoking -<a href="../s6-tlsc.html">s6-tlsc</a>. -</p> - -<h4> <code> int stls_s6tlsd (char const *const *argv, char const *const *envp, tain_t const *tto, uint32_t preoptions, uint32_t options, uid_t uid, gid_t gid, unsigned int verbosity) </code> </h4> - -<p> - This function implements <a href="../s6-tlsd.html">s6-tlsd</a> on top of LibreSSL. -It has no other practical purpose; you're better off directly invoking -<a href="../s6-tlsd.html">s6-tlsd</a>. +message and exit code if it encounters an unrecoverable error. If there were +no problems and the SSL/TLS connection closed cleanly, the process exits 0. </p> </body> |