Adding upstream version 3.8.5.upstream/3.8.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 373 insertions, 0 deletions

diff --git a/src/spawn/spawn.c b/src/spawn/spawn.c
new file mode 100644
index 0000000..686b0da
--- /dev/null
+++ b/src/spawn/spawn.c
@@ -0,0 +1,373 @@
+/*++
+/* NAME
+/*	spawn 8
+/* SUMMARY
+/*	Postfix external command spawner
+/* SYNOPSIS
+/*	\fBspawn\fR [generic Postfix daemon options] command_attributes...
+/* DESCRIPTION
+/*	The \fBspawn\fR(8) daemon provides the Postfix equivalent
+/*	of \fBinetd\fR.
+/*	It listens on a port as specified in the Postfix \fBmaster.cf\fR file
+/*	and spawns an external command whenever a connection is established.
+/*	The connection can be made over local IPC (such as UNIX-domain
+/*	sockets) or over non-local IPC (such as TCP sockets).
+/*	The command's standard input, output and error streams are connected
+/*	directly to the communication endpoint.
+/*
+/*	This daemon expects to be run from the \fBmaster\fR(8) process
+/*	manager.
+/* COMMAND ATTRIBUTE SYNTAX
+/* .ad
+/* .fi
+/*	The external command attributes are given in the \fBmaster.cf\fR
+/*	file at the end of a service definition.  The syntax is as follows:
+/* .IP "\fBuser\fR=\fIusername\fR (required)"
+/* .IP "\fBuser\fR=\fIusername\fR:\fIgroupname\fR"
+/*	The external command is executed with the rights of the
+/*	specified \fIusername\fR.  The software refuses to execute
+/*	commands with root privileges, or with the privileges of the
+/*	mail system owner. If \fIgroupname\fR is specified, the
+/*	corresponding group ID is used instead of the group ID
+/*	of \fIusername\fR.
+/* .IP "\fBargv\fR=\fIcommand\fR... (required)"
+/*	The command to be executed. This must be specified as the
+/*	last command attribute.
+/*	The command is executed directly, i.e. without interpretation of
+/*	shell meta characters by a shell command interpreter.
+/* BUGS
+/*	In order to enforce standard Postfix process resource controls,
+/*	the \fBspawn\fR(8) daemon runs only one external command at a time.
+/*	As such, it presents a noticeable overhead by wasting precious
+/*	process resources. The \fBspawn\fR(8) daemon is expected to be
+/*	replaced by a more structural solution.
+/* DIAGNOSTICS
+/*	The \fBspawn\fR(8) daemon reports abnormal child exits.
+/*	Problems are logged to \fBsyslogd\fR(8) or \fBpostlogd\fR(8).
+/* SECURITY
+/* .fi
+/* .ad
+/*	This program needs root privilege in order to execute external
+/*	commands as the specified user. It is therefore security sensitive.
+/*	However the \fBspawn\fR(8) daemon does not talk to the external command
+/*	and thus is not vulnerable to data-driven attacks.
+/* CONFIGURATION PARAMETERS
+/* .ad
+/* .fi
+/*	Changes to \fBmain.cf\fR are picked up automatically as \fBspawn\fR(8)
+/*	processes run for only a limited amount of time. Use the command
+/*	"\fBpostfix reload\fR" to speed up a change.
+/*
+/*	The text below provides only a parameter summary. See
+/*	\fBpostconf\fR(5) for more details including examples.
+/*
+/*	In the text below, \fItransport\fR is the first field of the entry
+/*	in the \fBmaster.cf\fR file.
+/* RESOURCE AND RATE CONTROL
+/* .ad
+/* .fi
+/* .IP "\fBtransport_time_limit ($command_time_limit)\fR"
+/*	A transport-specific override for the command_time_limit parameter
+/*	value, where \fItransport\fR is the master.cf name of the message
+/*	delivery transport.
+/* MISCELLANEOUS
+/* .ad
+/* .fi
+/* .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
+/*	The default location of the Postfix main.cf and master.cf
+/*	configuration files.
+/* .IP "\fBdaemon_timeout (18000s)\fR"
+/*	How much time a Postfix daemon process may take to handle a
+/*	request before it is terminated by a built-in watchdog timer.
+/* .IP "\fBexport_environment (see 'postconf -d' output)\fR"
+/*	The list of environment variables that a Postfix process will export
+/*	to non-Postfix processes.
+/* .IP "\fBipc_timeout (3600s)\fR"
+/*	The time limit for sending or receiving information over an internal
+/*	communication channel.
+/* .IP "\fBmail_owner (postfix)\fR"
+/*	The UNIX system account that owns the Postfix queue and most Postfix
+/*	daemon processes.
+/* .IP "\fBmax_idle (100s)\fR"
+/*	The maximum amount of time that an idle Postfix daemon process waits
+/*	for an incoming connection before terminating voluntarily.
+/* .IP "\fBmax_use (100)\fR"
+/*	The maximal number of incoming connections that a Postfix daemon
+/*	process will service before terminating voluntarily.
+/* .IP "\fBprocess_id (read-only)\fR"
+/*	The process ID of a Postfix command or daemon process.
+/* .IP "\fBprocess_name (read-only)\fR"
+/*	The process name of a Postfix command or daemon process.
+/* .IP "\fBqueue_directory (see 'postconf -d' output)\fR"
+/*	The location of the Postfix top-level queue directory.
+/* .IP "\fBsyslog_facility (mail)\fR"
+/*	The syslog facility of Postfix logging.
+/* .IP "\fBsyslog_name (see 'postconf -d' output)\fR"
+/*	A prefix that is prepended to the process name in syslog
+/*	records, so that, for example, "smtpd" becomes "prefix/smtpd".
+/* .PP
+/*	Available in Postfix 3.3 and later:
+/* .IP "\fBservice_name (read-only)\fR"
+/*	The master.cf service name of a Postfix daemon process.
+/* SEE ALSO
+/*	postconf(5), configuration parameters
+/*	master(8), process manager
+/*	postlogd(8), Postfix logging
+/*	syslogd(8), system logging
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pwd.h>
+#include <grp.h>
+#include <fcntl.h>
+#ifdef STRCASECMP_IN_STRINGS_H
+#include <strings.h>
+#endif
+
+/* Utility library. */
+
+#include <msg.h>
+#include <argv.h>
+#include <dict.h>
+#include <mymalloc.h>
+#include <spawn_command.h>
+#include <split_at.h>
+#include <timed_wait.h>
+#include <set_eugid.h>
+
+/* Global library. */
+
+#include <mail_version.h>
+
+/* Single server skeleton. */
+
+#include <mail_params.h>
+#include <mail_server.h>
+#include <mail_conf.h>
+#include <mail_parm_split.h>
+
+/* Application-specific. */
+
+ /*
+  * Tunable parameters. Values are taken from the config file, after
+  * prepending the service name to _name, and so on.
+  */
+int     var_command_maxtime;		/* system-wide */
+
+ /*
+  * For convenience. Instead of passing around lists of parameters, bundle
+  * them up in convenient structures.
+  */
+typedef struct {
+    char  **argv;			/* argument vector */
+    uid_t   uid;			/* command privileges */
+    gid_t   gid;			/* command privileges */
+    int     time_limit;			/* per-service time limit */
+} SPAWN_ATTR;
+
+/* get_service_attr - get service attributes */
+
+static void get_service_attr(SPAWN_ATTR *attr, char *service, char **argv)
+{
+    const char *myname = "get_service_attr";
+    struct passwd *pwd;
+    struct group *grp;
+    char   *user;			/* user name */
+    char   *group;			/* group name */
+
+    /*
+     * Initialize.
+     */
+    user = 0;
+    group = 0;
+    attr->argv = 0;
+
+    /*
+     * Figure out the command time limit for this transport.
+     */
+    attr->time_limit =
+	get_mail_conf_time2(service, _MAXTIME, var_command_maxtime, 's', 1, 0);
+
+    /*
+     * Iterate over the command-line attribute list.
+     */
+    for ( /* void */ ; *argv != 0; argv++) {
+
+	/*
+	 * user=username[:groupname]
+	 */
+	if (strncasecmp("user=", *argv, sizeof("user=") - 1) == 0) {
+	    user = *argv + sizeof("user=") - 1;
+	    if ((group = split_at(user, ':')) != 0)	/* XXX clobbers argv */
+		if (*group == 0)
+		    group = 0;
+	    if ((pwd = getpwnam(user)) == 0)
+		msg_fatal("unknown user name: %s", user);
+	    attr->uid = pwd->pw_uid;
+	    if (group != 0) {
+		if ((grp = getgrnam(group)) == 0)
+		    msg_fatal("unknown group name: %s", group);
+		attr->gid = grp->gr_gid;
+	    } else {
+		attr->gid = pwd->pw_gid;
+	    }
+	}
+
+	/*
+	 * argv=command...
+	 */
+	else if (strncasecmp("argv=", *argv, sizeof("argv=") - 1) == 0) {
+	    *argv += sizeof("argv=") - 1;	/* XXX clobbers argv */
+	    attr->argv = argv;
+	    break;
+	}
+
+	/*
+	 * Bad.
+	 */
+	else
+	    msg_fatal("unknown attribute name: %s", *argv);
+    }
+
+    /*
+     * Sanity checks. Verify that every member has an acceptable value.
+     */
+    if (user == 0)
+	msg_fatal("missing user= attribute");
+    if (attr->argv == 0)
+	msg_fatal("missing argv= attribute");
+    if (attr->uid == 0)
+	msg_fatal("request to deliver as root");
+    if (attr->uid == var_owner_uid)
+	msg_fatal("request to deliver as mail system owner");
+    if (attr->gid == 0)
+	msg_fatal("request to use privileged group id %ld", (long) attr->gid);
+    if (attr->gid == var_owner_gid)
+	msg_fatal("request to use mail system owner group id %ld", (long) attr->gid);
+    if (attr->uid == (uid_t) (-1))
+	msg_fatal("user must not have user ID -1");
+    if (attr->gid == (gid_t) (-1))
+	msg_fatal("user must not have group ID -1");
+
+    /*
+     * Give the poor tester a clue of what is going on.
+     */
+    if (msg_verbose)
+	msg_info("%s: uid %ld, gid %ld; time %d",
+	      myname, (long) attr->uid, (long) attr->gid, attr->time_limit);
+}
+
+/* spawn_service - perform service for client */
+
+static void spawn_service(VSTREAM *client_stream, char *service, char **argv)
+{
+    const char *myname = "spawn_service";
+    static SPAWN_ATTR attr;
+    WAIT_STATUS_T status;
+    ARGV   *export_env;
+
+    /*
+     * This routine runs whenever a client connects to the UNIX-domain socket
+     * dedicated to running an external command.
+     */
+    if (msg_verbose)
+	msg_info("%s: service=%s, command=%s...", myname, service, argv[0]);
+
+    /*
+     * Look up service attributes and config information only once. This is
+     * safe since the information comes from a trusted source.
+     */
+    if (attr.argv == 0) {
+	get_service_attr(&attr, service, argv);
+    }
+
+    /*
+     * Execute the command.
+     */
+    export_env = mail_parm_split(VAR_EXPORT_ENVIRON, var_export_environ);
+    status = spawn_command(CA_SPAWN_CMD_STDIN(vstream_fileno(client_stream)),
+			 CA_SPAWN_CMD_STDOUT(vstream_fileno(client_stream)),
+			 CA_SPAWN_CMD_STDERR(vstream_fileno(client_stream)),
+			   CA_SPAWN_CMD_UID(attr.uid),
+			   CA_SPAWN_CMD_GID(attr.gid),
+			   CA_SPAWN_CMD_ARGV(attr.argv),
+			   CA_SPAWN_CMD_TIME_LIMIT(attr.time_limit),
+			   CA_SPAWN_CMD_EXPORT(export_env->argv),
+			   CA_SPAWN_CMD_END);
+    argv_free(export_env);
+
+    /*
+     * Warn about unsuccessful completion.
+     */
+    if (!NORMAL_EXIT_STATUS(status)) {
+	if (WIFEXITED(status))
+	    msg_warn("command %s exit status %d",
+		     attr.argv[0], WEXITSTATUS(status));
+	if (WIFSIGNALED(status))
+	    msg_warn("command %s killed by signal %d",
+		     attr.argv[0], WTERMSIG(status));
+    }
+}
+
+/* pre_accept - see if tables have changed */
+
+static void pre_accept(char *unused_name, char **unused_argv)
+{
+    const char *table;
+
+    if ((table = dict_changed_name()) != 0) {
+	msg_info("table %s has changed -- restarting", table);
+	exit(0);
+    }
+}
+
+/* drop_privileges - drop privileges most of the time */
+
+static void drop_privileges(char *unused_name, char **unused_argv)
+{
+    set_eugid(var_owner_uid, var_owner_gid);
+}
+
+MAIL_VERSION_STAMP_DECLARE;
+
+/* main - pass control to the single-threaded skeleton */
+
+int     main(int argc, char **argv)
+{
+    static const CONFIG_TIME_TABLE time_table[] = {
+	VAR_COMMAND_MAXTIME, DEF_COMMAND_MAXTIME, &var_command_maxtime, 1, 0,
+	0,
+    };
+
+    /*
+     * Fingerprint executables and core dumps.
+     */
+    MAIL_VERSION_STAMP_ALLOCATE;
+
+    single_server_main(argc, argv, spawn_service,
+		       CA_MAIL_SERVER_TIME_TABLE(time_table),
+		       CA_MAIL_SERVER_POST_INIT(drop_privileges),
+		       CA_MAIL_SERVER_PRE_ACCEPT(pre_accept),
+		       CA_MAIL_SERVER_PRIVILEGED,
+		       0);
+}