Adding upstream version 3.4.23.upstream/3.4.23upstream

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

1 files changed, 530 insertions, 0 deletions

diff --git a/src/postdrop/postdrop.c b/src/postdrop/postdrop.c
new file mode 100644
index 0000000..5e35d1d
--- /dev/null
+++ b/src/postdrop/postdrop.c
@@ -0,0 +1,530 @@
+/*++
+/* NAME
+/*	postdrop 1
+/* SUMMARY
+/*	Postfix mail posting utility
+/* SYNOPSIS
+/*	\fBpostdrop\fR [\fB-rv\fR] [\fB-c \fIconfig_dir\fR]
+/* DESCRIPTION
+/*	The \fBpostdrop\fR(1) command creates a file in the \fBmaildrop\fR
+/*	directory and copies its standard input to the file.
+/*
+/*	Options:
+/* .IP "\fB-c \fIconfig_dir\fR"
+/*	The \fBmain.cf\fR configuration file is in the named directory
+/*	instead of the default configuration directory. See also the
+/*	MAIL_CONFIG environment setting below.
+/* .IP \fB-r\fR
+/*	Use a Postfix-internal protocol for reading the message from
+/*	standard input, and for reporting status information on standard
+/*	output. This is currently the only supported method.
+/* .IP \fB-v\fR
+/*	Enable verbose logging for debugging purposes. Multiple \fB-v\fR
+/*	options make the software increasingly verbose. As of Postfix 2.3,
+/*	this option is available for the super-user only.
+/* SECURITY
+/* .ad
+/* .fi
+/*	The command is designed to run with set-group ID privileges, so
+/*	that it can write to the \fBmaildrop\fR queue directory and so that
+/*	it can connect to Postfix daemon processes.
+/* DIAGNOSTICS
+/*	Fatal errors: malformed input, I/O error, out of memory. Problems
+/*	are logged to \fBsyslogd\fR(8) or \fBpostlogd\fR(8) and to
+/*	the standard error stream.
+/*	When the input is incomplete, or when the process receives a HUP,
+/*	INT, QUIT or TERM signal, the queue file is deleted.
+/* ENVIRONMENT
+/* .ad
+/* .fi
+/* .IP MAIL_CONFIG
+/*	Directory with the \fBmain.cf\fR file. In order to avoid exploitation
+/*	of set-group ID privileges, a non-standard directory is allowed only
+/*	if:
+/* .RS
+/* .IP \(bu
+/*	The name is listed in the standard \fBmain.cf\fR file with the
+/*	\fBalternate_config_directories\fR configuration parameter.
+/* .IP \(bu
+/*	The command is invoked by the super-user.
+/* .RE
+/* CONFIGURATION PARAMETERS
+/* .ad
+/* .fi
+/*	The following \fBmain.cf\fR parameters are especially relevant to
+/*	this program.
+/*	The text below provides only a parameter summary. See
+/*	\fBpostconf\fR(5) for more details including examples.
+/* .IP "\fBalternate_config_directories (empty)\fR"
+/*	A list of non-default Postfix configuration directories that may
+/*	be specified with "-c config_directory" on the command line (in the
+/*	case of \fBsendmail\fR(1), with the "-C" option), or via the MAIL_CONFIG
+/*	environment parameter.
+/* .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
+/*	The default location of the Postfix main.cf and master.cf
+/*	configuration files.
+/* .IP "\fBimport_environment (see 'postconf -d' output)\fR"
+/*	The list of environment parameters that a privileged Postfix
+/*	process will import from a non-Postfix parent process, or name=value
+/*	environment overrides.
+/* .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".
+/* .IP "\fBtrigger_timeout (10s)\fR"
+/*	The time limit for sending a trigger to a Postfix daemon (for
+/*	example, the \fBpickup\fR(8) or \fBqmgr\fR(8) daemon).
+/* .PP
+/*	Available in Postfix version 2.2 and later:
+/* .IP "\fBauthorized_submit_users (static:anyone)\fR"
+/*	List of users who are authorized to submit mail with the \fBsendmail\fR(1)
+/*	command (and with the privileged \fBpostdrop\fR(1) helper command).
+/* FILES
+/*	/var/spool/postfix/maildrop, maildrop queue
+/* SEE ALSO
+/*	sendmail(1), compatibility interface
+/*	postconf(5), configuration parameters
+/*	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/stat.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>			/* remove() */
+#include <string.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <errno.h>
+#include <warn_stat.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <vstream.h>
+#include <vstring.h>
+#include <msg_vstream.h>
+#include <argv.h>
+#include <iostuff.h>
+#include <stringops.h>
+
+/* Global library. */
+
+#include <mail_proto.h>
+#include <mail_queue.h>
+#include <mail_params.h>
+#include <mail_version.h>
+#include <mail_conf.h>
+#include <mail_task.h>
+#include <clean_env.h>
+#include <mail_stream.h>
+#include <cleanup_user.h>
+#include <record.h>
+#include <rec_type.h>
+#include <mail_dict.h>
+#include <user_acl.h>
+#include <rec_attr_map.h>
+#include <mail_parm_split.h>
+#include <maillog_client.h>
+
+/* Application-specific. */
+
+ /*
+  * WARNING WARNING WARNING
+  * 
+  * This software is designed to run set-gid. In order to avoid exploitation of
+  * privilege, this software should not run any external commands, nor should
+  * it take any information from the user unless that information can be
+  * properly sanitized. To get an idea of how much information a process can
+  * inherit from a potentially hostile user, examine all the members of the
+  * process structure (typically, in /usr/include/sys/proc.h): the current
+  * directory, open files, timers, signals, environment, command line, umask,
+  * and so on.
+  */
+
+ /*
+  * Local mail submission access list.
+  */
+char   *var_submit_acl;
+
+static const CONFIG_STR_TABLE str_table[] = {
+    VAR_SUBMIT_ACL, DEF_SUBMIT_ACL, &var_submit_acl, 0, 0,
+    0,
+};
+
+ /*
+  * Queue file name. Global, so that the cleanup routine can find it when
+  * called by the run-time error handler.
+  */
+static char *postdrop_path;
+
+/* postdrop_sig - catch signal and clean up */
+
+static void postdrop_sig(int sig)
+{
+
+    /*
+     * This is the fatal error handler. Don't try to do anything fancy.
+     * 
+     * To avoid privilege escalation in a set-gid program, Postfix logging
+     * functions must not be called from a user-triggered signal handler,
+     * because Postfix logging functions may allocate memory on the fly (as
+     * does the syslog() library function), and the memory allocator is not
+     * reentrant.
+     * 
+     * Assume atomic signal() updates, even when emulated with sigaction(). We
+     * use the in-kernel SIGINT handler address as an atomic variable to
+     * prevent nested postdrop_sig() calls. For this reason, main() must
+     * configure postdrop_sig() as SIGINT handler before other signal
+     * handlers are allowed to invoke postdrop_sig().
+     */
+    if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
+	(void) signal(SIGQUIT, SIG_IGN);
+	(void) signal(SIGTERM, SIG_IGN);
+	(void) signal(SIGHUP, SIG_IGN);
+	if (postdrop_path) {
+	    (void) remove(postdrop_path);
+	    postdrop_path = 0;
+	}
+	/* Future proofing. If you need exit() here then you broke Postfix. */
+	if (sig)
+	    _exit(sig);
+    }
+}
+
+/* postdrop_cleanup - callback for the runtime error handler */
+
+static void postdrop_cleanup(void)
+{
+    postdrop_sig(0);
+}
+
+MAIL_VERSION_STAMP_DECLARE;
+
+/* main - the main program */
+
+int     main(int argc, char **argv)
+{
+    struct stat st;
+    int     fd;
+    int     c;
+    VSTRING *buf;
+    int     status;
+    MAIL_STREAM *dst;
+    int     rec_type;
+    static char *segment_info[] = {
+	REC_TYPE_POST_ENVELOPE, REC_TYPE_POST_CONTENT, REC_TYPE_POST_EXTRACT, ""
+    };
+    char  **expected;
+    uid_t   uid = getuid();
+    ARGV   *import_env;
+    const char *error_text;
+    char   *attr_name;
+    char   *attr_value;
+    const char *errstr;
+    char   *junk;
+    struct timeval start;
+    int     saved_errno;
+    int     from_count = 0;
+    int     rcpt_count = 0;
+    int     validate_input = 1;
+
+    /*
+     * Fingerprint executables and core dumps.
+     */
+    MAIL_VERSION_STAMP_ALLOCATE;
+
+    /*
+     * Be consistent with file permissions.
+     */
+    umask(022);
+
+    /*
+     * To minimize confusion, make sure that the standard file descriptors
+     * are open before opening anything else. XXX Work around for 44BSD where
+     * fstat can return EBADF on an open file descriptor.
+     */
+    for (fd = 0; fd < 3; fd++)
+	if (fstat(fd, &st) == -1
+	    && (close(fd), open("/dev/null", O_RDWR, 0)) != fd)
+	    msg_fatal("open /dev/null: %m");
+
+    /*
+     * Set up logging. Censor the process name: it is provided by the user.
+     */
+    argv[0] = "postdrop";
+    msg_vstream_init(argv[0], VSTREAM_ERR);
+    maillog_client_init(mail_task("postdrop"), MAILLOG_CLIENT_FLAG_NONE);
+    set_mail_conf_str(VAR_PROCNAME, var_procname = mystrdup(argv[0]));
+
+    /*
+     * Check the Postfix library version as soon as we enable logging.
+     */
+    MAIL_VERSION_CHECK;
+
+    /*
+     * Parse JCL. This program is set-gid and must sanitize all command-line
+     * arguments. The configuration directory argument is validated by the
+     * mail configuration read routine. Don't do complex things until we have
+     * completed initializations.
+     */
+    while ((c = GETOPT(argc, argv, "c:rv")) > 0) {
+	switch (c) {
+	case 'c':
+	    if (setenv(CONF_ENV_PATH, optarg, 1) < 0)
+		msg_fatal("out of memory");
+	    break;
+	case 'r':				/* forward compatibility */
+	    break;
+	case 'v':
+	    if (geteuid() == 0)
+		msg_verbose++;
+	    break;
+	default:
+	    msg_fatal("usage: %s [-c config_dir] [-v]", argv[0]);
+	}
+    }
+
+    /*
+     * Read the global configuration file and extract configuration
+     * information.
+     */
+    mail_conf_read();
+    /* Re-evaluate mail_task() after reading main.cf. */
+    maillog_client_init(mail_task("postdrop"), MAILLOG_CLIENT_FLAG_NONE);
+    get_mail_conf_str_table(str_table);
+
+    /*
+     * Mail submission access control. Should this be in the user-land gate,
+     * or in the daemon process?
+     */
+    mail_dict_init();
+    if ((errstr = check_user_acl_byuid(VAR_SUBMIT_ACL, var_submit_acl,
+				       uid)) != 0)
+	msg_fatal("User %s(%ld) is not allowed to submit mail",
+		  errstr, (long) uid);
+
+    /*
+     * Stop run-away process accidents by limiting the queue file size. This
+     * is not a defense against DOS attack.
+     */
+    if (var_message_limit > 0 && get_file_limit() > var_message_limit)
+	set_file_limit((off_t) var_message_limit);
+
+    /*
+     * This program is installed with setgid privileges. Strip the process
+     * environment so that we don't have to trust the C library.
+     */
+    import_env = mail_parm_split(VAR_IMPORT_ENVIRON, var_import_environ);
+    clean_env(import_env->argv);
+    argv_free(import_env);
+
+    if (chdir(var_queue_dir))
+	msg_fatal("chdir %s: %m", var_queue_dir);
+    if (msg_verbose)
+	msg_info("chdir %s", var_queue_dir);
+
+    /*
+     * Set up signal handlers and a runtime error handler so that we can
+     * clean up incomplete output.
+     * 
+     * postdrop_sig() uses the in-kernel SIGINT handler address as an atomic
+     * variable to prevent nested postdrop_sig() calls. For this reason, the
+     * SIGINT handler must be configured before other signal handlers are
+     * allowed to invoke postdrop_sig().
+     */
+    signal(SIGPIPE, SIG_IGN);
+    signal(SIGXFSZ, SIG_IGN);
+
+    signal(SIGINT, postdrop_sig);
+    signal(SIGQUIT, postdrop_sig);
+    if (signal(SIGTERM, SIG_IGN) == SIG_DFL)
+	signal(SIGTERM, postdrop_sig);
+    if (signal(SIGHUP, SIG_IGN) == SIG_DFL)
+	signal(SIGHUP, postdrop_sig);
+    msg_cleanup(postdrop_cleanup);
+
+    /* End of initializations. */
+
+    /*
+     * Don't trust the caller's time information.
+     */
+    GETTIMEOFDAY(&start);
+
+    /*
+     * Create queue file. mail_stream_file() never fails. Send the queue ID
+     * to the caller. Stash away a copy of the queue file name so we can
+     * clean up in case of a fatal error or an interrupt.
+     */
+    dst = mail_stream_file(MAIL_QUEUE_MAILDROP, MAIL_CLASS_PUBLIC,
+			   var_pickup_service, 0444);
+    attr_print(VSTREAM_OUT, ATTR_FLAG_NONE,
+	       SEND_ATTR_STR(MAIL_ATTR_QUEUEID, dst->id),
+	       ATTR_TYPE_END);
+    vstream_fflush(VSTREAM_OUT);
+    postdrop_path = mystrdup(VSTREAM_PATH(dst->stream));
+
+    /*
+     * Copy stdin to file. The format is checked so that we can recognize
+     * incomplete input and cancel the operation. With the sanity checks
+     * applied here, the pickup daemon could skip format checks and pass a
+     * file descriptor to the cleanup daemon. These are by no means all
+     * sanity checks - the cleanup service and queue manager services will
+     * reject messages that lack required information.
+     * 
+     * If something goes wrong, slurp up the input before responding to the
+     * client, otherwise the client will give up after detecting SIGPIPE.
+     * 
+     * Allow attribute records if the attribute specifies the MIME body type
+     * (sendmail -B).
+     */
+    vstream_control(VSTREAM_IN, CA_VSTREAM_CTL_PATH("stdin"), CA_VSTREAM_CTL_END);
+    buf = vstring_alloc(100);
+    expected = segment_info;
+    /* Override time information from the untrusted caller. */
+    rec_fprintf(dst->stream, REC_TYPE_TIME, REC_TYPE_TIME_FORMAT,
+		REC_TYPE_TIME_ARG(start));
+    for (;;) {
+	/* Don't allow PTR records. */
+	rec_type = rec_get_raw(VSTREAM_IN, buf, var_line_limit, REC_FLAG_NONE);
+	if (rec_type == REC_TYPE_EOF) {		/* request cancelled */
+	    mail_stream_cleanup(dst);
+	    if (remove(postdrop_path))
+		msg_warn("uid=%ld: remove %s: %m", (long) uid, postdrop_path);
+	    else if (msg_verbose)
+		msg_info("remove %s", postdrop_path);
+	    myfree(postdrop_path);
+	    postdrop_path = 0;
+	    exit(0);
+	}
+	if (rec_type == REC_TYPE_ERROR)
+	    msg_fatal("uid=%ld: malformed input", (long) uid);
+	if (strchr(*expected, rec_type) == 0)
+	    msg_fatal("uid=%ld: unexpected record type: %d", (long) uid, rec_type);
+	if (rec_type == **expected)
+	    expected++;
+	/* Override time information from the untrusted caller. */
+	if (rec_type == REC_TYPE_TIME)
+	    continue;
+	/* Check these at submission time instead of pickup time. */
+	if (rec_type == REC_TYPE_FROM)
+	    from_count++;
+	if (rec_type == REC_TYPE_RCPT)
+	    rcpt_count++;
+	/* Limit the attribute types that users may specify. */
+	if (rec_type == REC_TYPE_ATTR) {
+	    if ((error_text = split_nameval(vstring_str(buf), &attr_name,
+					    &attr_value)) != 0) {
+		msg_warn("uid=%ld: ignoring malformed record: %s: %.200s",
+			 (long) uid, error_text, vstring_str(buf));
+		continue;
+	    }
+#define STREQ(x,y) (strcmp(x,y) == 0)
+
+	    if ((STREQ(attr_name, MAIL_ATTR_ENCODING)
+		 && (STREQ(attr_value, MAIL_ATTR_ENC_7BIT)
+		     || STREQ(attr_value, MAIL_ATTR_ENC_8BIT)
+		     || STREQ(attr_value, MAIL_ATTR_ENC_NONE)))
+		|| STREQ(attr_name, MAIL_ATTR_DSN_ENVID)
+		|| STREQ(attr_name, MAIL_ATTR_DSN_NOTIFY)
+		|| rec_attr_map(attr_name)
+		|| (STREQ(attr_name, MAIL_ATTR_RWR_CONTEXT)
+		    && (STREQ(attr_value, MAIL_ATTR_RWR_LOCAL)
+			|| STREQ(attr_value, MAIL_ATTR_RWR_REMOTE)))
+		|| STREQ(attr_name, MAIL_ATTR_TRACE_FLAGS)) {	/* XXX */
+		rec_fprintf(dst->stream, REC_TYPE_ATTR, "%s=%s",
+			    attr_name, attr_value);
+	    } else {
+		msg_warn("uid=%ld: ignoring attribute record: %.200s=%.200s",
+			 (long) uid, attr_name, attr_value);
+	    }
+	    continue;
+	}
+	if (REC_PUT_BUF(dst->stream, rec_type, buf) < 0) {
+	    /* rec_get() errors must not clobber errno. */
+	    saved_errno = errno;
+	    while ((rec_type = rec_get_raw(VSTREAM_IN, buf, var_line_limit,
+					   REC_FLAG_NONE)) != REC_TYPE_END
+		   && rec_type != REC_TYPE_EOF)
+		if (rec_type == REC_TYPE_ERROR)
+		    msg_fatal("uid=%ld: malformed input", (long) uid);
+	    validate_input = 0;
+	    errno = saved_errno;
+	    break;
+	}
+	if (rec_type == REC_TYPE_END)
+	    break;
+    }
+    vstring_free(buf);
+
+    /*
+     * As of Postfix 2.7 the pickup daemon discards mail without recipients.
+     * Such mail may enter the maildrop queue when "postsuper -r" is invoked
+     * before the queue manager deletes an already delivered message. Looking
+     * at file ownership is not a good way to make decisions on what mail to
+     * discard. Instead, the pickup server now requires that new submissions
+     * always have at least one recipient record.
+     * 
+     * The Postfix sendmail command already rejects mail without recipients.
+     * However, in the future postdrop may receive mail via other programs,
+     * so we add a redundant recipient check here for future proofing.
+     * 
+     * The test for the sender address is just for consistency of error
+     * reporting (report at submission time instead of pickup time). Besides
+     * the segment terminator records, there aren't any other mandatory
+     * records in a Postfix submission queue file.
+     */
+    if (validate_input && (from_count == 0 || rcpt_count == 0)) {
+	status = CLEANUP_STAT_BAD;
+	mail_stream_cleanup(dst);
+    }
+
+    /*
+     * Finish the file.
+     */
+    else if ((status = mail_stream_finish(dst, (VSTRING *) 0)) != 0) {
+	msg_warn("uid=%ld: %m", (long) uid);
+	postdrop_cleanup();
+    }
+
+    /*
+     * Disable deletion on fatal error before reporting success, so the file
+     * will not be deleted after we have taken responsibility for delivery.
+     */
+    if (postdrop_path) {
+	junk = postdrop_path;
+	postdrop_path = 0;
+	myfree(junk);
+    }
+
+    /*
+     * Send the completion status to the caller and terminate.
+     */
+    attr_print(VSTREAM_OUT, ATTR_FLAG_NONE,
+	       SEND_ATTR_INT(MAIL_ATTR_STATUS, status),
+	       SEND_ATTR_STR(MAIL_ATTR_WHY, ""),
+	       ATTR_TYPE_END);
+    vstream_fflush(VSTREAM_OUT);
+    exit(status);
+}