[patch] bfilter-0.10.1-droppriv.patch

bfilter-0.10.1-droppriv.patch (text/plain), 3.56 KB, created by Alan Swanson on 2005-11-14 14:30:29 UTC

diff -ur bfilter-0.10.1/main/daemon/Daemon.cpp bfilter-0.10.1-droppriv/main/daemon/Daemon.cpp
--- bfilter-0.10.1/main/daemon/Daemon.cpp	2005-10-10 23:52:20.000000000 +0100
+++ bfilter-0.10.1-droppriv/main/daemon/Daemon.cpp	2005-11-14 20:05:40.000000000 +0000
@@ -52,6 +52,10 @@
 #include <deque>
 #include <list>
 #include <cstdlib>
+#include <sys/stat.h>
+#include <pwd.h>
+#include <grp.h>
+#include <netdb.h>
 
 namespace po = boost::program_options;
 using namespace std;
@@ -340,6 +344,69 @@
 }
 
 bool
+Daemon::droppriv(std::string const& chrootdir, std::string const& user, std::string const& group)
+{
+	uid_t uid = 0;
+	uid_t gid = 0;
+
+	if (!chrootdir.empty() || !user.empty() || !group.empty()) {
+		struct stat stat_r;
+		struct passwd *user_r;
+		struct group *group_r;
+
+		if (getuid()) {
+			std::cerr << "Cannot lower privileges, not running as root" << std::endl;
+			return false;
+		}
+		if (!chrootdir.empty() && stat(chrootdir.c_str(), &stat_r)) {
+			if (!S_ISDIR(stat_r.st_mode)) {
+				std::cerr << "Cannot lower privileges, chroot directory does not exist" << std::endl;
+				return false;
+			}
+		}
+		if (!user.empty()) {
+			user_r = getpwnam(user.c_str());
+			if (user_r) {
+				uid = user_r->pw_uid;
+			} else {
+				std::cerr << "Cannot lower privileges, unknown user" << std::endl;
+				return false;
+			}
+		}
+		if (!group.empty()) {
+			group_r = getgrnam(group.c_str());
+			if (group_r) {
+				gid = group_r->gr_gid;
+			} else {
+				std::cerr << "Cannot lower privileges, unknown group" << std::endl;
+				return false;
+			}
+		}
+	}
+
+	if (!chrootdir.empty()) {
+		// Using gethostbyname before chrooting means that the chroot
+		// directory can be empty (no etc/resolv.conf or dynamically
+		// loaded lib/libnss* libraries). Using localhost here to
+		// prevent remote name resolution does not work.
+		gethostbyname("slashdot.org");
+		if (chroot(chrootdir.c_str())) {
+			std::cerr << "Cannot lower privileges, chroot directory no longer exists" << std::endl;
+			return false;
+		}
+		chdir("/");
+	}
+	if (gid) {
+		setgroups(0, NULL);
+		setgid(gid);
+	}
+	if (uid) {
+		setuid(uid);
+	}
+	return true;
+}
+
+bool
 Daemon::run(bool nodaemon)
 {
 	if (!nodaemon) {
@@ -447,13 +514,19 @@
 {
 	bool nodaemon = false;
 	std::string confdir = string(SYSCONFDIR) + "/bfilter";
-	
+	std::string chrootdir;
+	std::string user;
+	std::string group;
+
 	try {
 		po::options_description desc("Allowed options");
 		desc.add_options()
 			("help,h", "Print help message")
 			("version,v", "Print version")
 			("confdir,c", po::value<string>(&confdir), "Set custom config directory")
+			("chroot,r", po::value<string>(&chrootdir), "Set chroot directory")
+			("user,u", po::value<string>(&user), "Set unprivileged user")
+			("group,g", po::value<string>(&group), "Set unprivileged group")
 			("nodaemon,n", po::bool_switch(&nodaemon), "Disable background daemon mode")
 		;
 		po::variables_map vm;
@@ -476,6 +549,9 @@
 	if (!daemon.init(confdir)) {
 		exit(EXIT_FAILURE);
 	}
+	if (!daemon.droppriv(chrootdir, user, group)) {
+		exit(EXIT_FAILURE);
+	}
 	if (!daemon.run(nodaemon)) {
 		exit(EXIT_FAILURE);
 	}
diff -ur bfilter-0.10.1/main/daemon/Daemon.h bfilter-0.10.1-droppriv/main/daemon/Daemon.h
--- bfilter-0.10.1/main/daemon/Daemon.h	2005-01-14 16:54:32.000000000 +0000
+++ bfilter-0.10.1-droppriv/main/daemon/Daemon.h	2005-11-14 18:22:58.000000000 +0000
@@ -33,7 +33,7 @@
 {
 public:
 	bool init(std::string const& confdir);
-	
+	bool droppriv(std::string const& chrootdir, std::string const& user, std::string const& group);
 	bool run(bool nodaemon);
 private:
 	class ConfigErrorHandler;