1 files changed, 220 insertions, 0 deletions
diff --git a/libexec/popa3d/pop_root.c b/libexec/popa3d/pop_root.c
new file mode 100644
index 00000000000..b109e47973d
--- /dev/null
+++ b/libexec/popa3d/pop_root.c
@@ -0,0 +1,220 @@
+/*
+ * Main daemon code: invokes the actual POP handling routines. Most calls
+ * to functions in other source files are done as a non-root user (either
+ * POP_USER or the authenticated user). Depending on compile-time options
+ * in params.h, the following files may contain code executed as root:
+ *
+ * standalone.c		if not running via an inetd clone (POP_STANDALONE)
+ * virtual.c		if supporting virtual domains (POP_VIRTUAL)
+ * auth_passwd.c	if using passwd or *BSD (AUTH_PASSWD && !VIRTUAL_ONLY)
+ * auth_shadow.c	if using shadow (AUTH_SHADOW && !VIRTUAL_ONLY)
+ * auth_pam.c		if using PAM (AUTH_PAM || AUTH_PAM_USERPASS)
+ */
+
+#include <unistd.h>
+#include <signal.h>
+#include <string.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <errno.h>
+#include <grp.h>
+#include <pwd.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+
+#include "params.h"
+#include "protocol.h"
+#include "pop_auth.h"
+#include "pop_trans.h"
+#if POP_VIRTUAL
+#include "virtual.h"
+#endif
+
+#if !VIRTUAL_ONLY
+extern struct passwd *auth_userpass(char *user, char *pass, char **mailbox);
+#endif
+
+static struct passwd pop_pw;
+static char *mailbox;
+
+int log_error(char *s)
+{
+	syslog(SYSLOG_PRIORITY, "%s: %m", s);
+	return 1;
+}
+
+static int set_user(struct passwd *pw)
+{
+	gid_t groups[2];
+
+	if (!pw->pw_uid) return 1;
+
+	groups[0] = groups[1] = pw->pw_gid;
+	if (setgroups(1, groups)) return log_error("setgroups");
+	if (setgid(pw->pw_gid)) return log_error("setgid");
+	if (setuid(pw->pw_uid)) return log_error("setuid");
+
+	return 0;
+}
+
+/*
+ * Attempts to read until EOF, and returns the number of bytes read.
+ * We don't expect any signals, so even EINTR is considered an error.
+ */
+static int read_loop(int fd, char *buffer, int count)
+{
+	int offset, block;
+
+	offset = 0;
+	while (count > 0) {
+		block = read(fd, &buffer[offset], count);
+
+		if (block < 0) return block;
+		if (!block) return offset;
+
+		offset += block;
+		count -= block;
+	}
+
+	return offset;
+}
+
+/*
+ * The root-privileged part of the AUTHORIZATION state handling: reads
+ * the authentication data obtained over POP from its end of the pipe,
+ * attempts authentication, and, if successful, drops privilege to the
+ * authenticated user. Returns one of the AUTH_* result codes.
+ */
+static int do_root_auth(int channel)
+{
+	static char auth[AUTH_BUFFER_SIZE + 2];
+	char *user, *pass;
+	struct passwd *pw;
+
+	mailbox = NULL;
+#if POP_VIRTUAL
+	virtual_domain = NULL;
+#endif
+
+/* The POP client could have sent extra commands without waiting for
+ * successful authentication. We're passing them into the TRANSACTION
+ * state if we ever get there. */
+	if (read_loop(channel, (char *)&pop_buffer, sizeof(pop_buffer)) !=
+	    sizeof(pop_buffer)) return AUTH_NONE;
+
+/* Now, the authentication data. */
+	memset(auth, 0, sizeof(auth));	/* Ensure the NUL termination */
+	if (read_loop(channel, auth, AUTH_BUFFER_SIZE) < 0) return AUTH_NONE;
+
+	user = auth;
+	pass = &user[strlen(user) + 1];
+
+	pw = NULL;
+#if POP_VIRTUAL
+	if (!(pw = virtual_userpass(user, pass, &mailbox)) && virtual_domain)
+		return AUTH_FAILED;
+#endif
+#if VIRTUAL_ONLY
+	if (!pw)
+		return AUTH_FAILED;
+#else
+	if (!pw && !(pw = auth_userpass(user, pass, &mailbox)))
+		return AUTH_FAILED;
+#endif
+	if (!*user || !*pass) return AUTH_FAILED;
+
+	memset(pass, 0, strlen(pass));
+
+	if (set_user(pw)) return AUTH_FAILED;
+
+	return AUTH_OK;
+}
+
+int do_pop_startup(void)
+{
+	struct passwd *pw;
+
+	umask(077);
+	signal(SIGPIPE, SIG_IGN);
+
+	openlog(SYSLOG_IDENT, SYSLOG_OPTIONS, SYSLOG_FACILITY);
+
+	errno = 0;
+	if (!(pw = getpwnam(POP_USER))) {
+		syslog(SYSLOG_PRIORITY, "getpwnam(\"" POP_USER "\"): %s",
+			errno ? strerror(errno) : "No such user");
+		return 1;
+	}
+	memcpy(&pop_pw, pw, sizeof(pop_pw));
+
+#if POP_VIRTUAL
+	if (virtual_startup()) return 1;
+#endif
+
+	return 0;
+}
+
+int do_pop_session(void)
+{
+	int channel[2];
+	int result, status;
+
+	signal(SIGCHLD, SIG_IGN);
+
+	if (pipe(channel)) return log_error("pipe");
+
+	switch (fork()) {
+	case -1:
+		return log_error("fork");
+
+	case 0:
+		if (close(channel[0])) return log_error("close");
+		if (set_user(&pop_pw)) return 1;
+		return do_pop_auth(channel[1]);
+	}
+
+	if (close(channel[1]))
+		result = AUTH_NONE;
+	else
+		result = do_root_auth(channel[0]);
+
+	if (wait(&status) < 0)
+		status = 1;
+	else
+	if (WIFEXITED(status))
+		status = WEXITSTATUS(status);
+	else
+		status = 1;
+
+	if (result == AUTH_OK) {
+		if (close(channel[0])) return log_error("close");
+		log_pop_auth(result, mailbox);
+#if POP_VIRTUAL
+		if (virtual_domain)
+			return do_pop_trans(virtual_spool, mailbox);
+#endif
+#if !VIRTUAL_ONLY
+		return do_pop_trans(MAIL_SPOOL_PATH, mailbox);
+#endif
+	}
+
+	if (set_user(&pop_pw)) return 1;
+	log_pop_auth(result, mailbox);
+
+#ifdef AUTH_FAILED_MESSAGE
+	if (result == AUTH_FAILED) pop_reply("-ERR %s", AUTH_FAILED_MESSAGE);
+#else
+	if (result == AUTH_FAILED) pop_reply_error();
+#endif
+
+	return status;
+}
+
+#if !POP_STANDALONE
+int main(void)
+{
+	if (do_pop_startup()) return 1;
+	return do_pop_session();
+}
+#endif