[hackers] [quark] Cleanup socket file at exit. || Quentin Rameau

From: <git_AT_suckless.org>
Date: Tue, 11 Jul 2017 15:03:02 +0200 (CEST)

commit 141bb88af14489c14bf47259b63098331f7c3076
Author: Quentin Rameau <quinq_AT_fifth.space>
AuthorDate: Sun Jul 9 14:36:46 2017 +0200
Commit: Laslo Hunhold <dev_AT_frign.de>
CommitDate: Tue Jul 11 14:09:27 2017 +0200

    Cleanup socket file at exit.
    
    We can't unlink the file if it's outside the chroot, so we need to keep
    a simple worker outside of it.

diff --git a/quark.1 b/quark.1
index 240a0e4..1c133fb 100644
--- a/quark.1
+++ b/quark.1
_AT_@ -55,6 +55,7 @@ when dropping privileges.
 Create the UNIX-domain socket file
 .Ar sockfile
 and listen on it for incoming connections.
+The file will be cleaned up at exit.
 .It Fl v
 Print version information to stdout and exit.
 .El
diff --git a/quark.c b/quark.c
index edf4103..8a9e936 100644
--- a/quark.c
+++ b/quark.c
_AT_@ -5,6 +5,7 @@
 #include <sys/time.h>
 #include <sys/types.h>
 #include <sys/un.h>
+#include <sys/wait.h>
 
 #include <arpa/inet.h>
 #include <ctype.h>
_AT_@ -28,6 +29,8 @@
 #include "arg.h"
 
 char *argv0;
+static int insock;
+static char *udsname;
 
 #include "config.h"
 
_AT_@ -824,7 +827,7 @@ serve(int insock)
         }
 }
 
-void
+static void
 die(const char *errstr, ...)
 {
         va_list ap;
_AT_@ -918,6 +921,23 @@ getusock(char *udsname, uid_t uid, gid_t gid)
 }
 
 static void
+cleanup(void)
+{
+ close(insock);
+ if (udsname) {
+ if (unlink(udsname) < 0)
+ fprintf(stderr, "unlink: %s\n", strerror(errno));
+ }
+}
+
+static void
+sigcleanup(int sig)
+{
+ cleanup();
+ _exit(1);
+}
+
+static void
 usage(void)
 {
         char *opts = "[-v] [-d dir] [-l] [-L] [-u user] [-g group]";
_AT_@ -932,8 +952,8 @@ main(int argc, char *argv[])
         struct passwd *pwd = NULL;
         struct group *grp = NULL;
         struct rlimit rlim;
- int i, insock;
- char *udsname = NULL;
+ pid_t cpid, wpid;
+ int i, status = 0;
 
         ARGBEGIN {
         case 'd':
_AT_@ -971,6 +991,13 @@ main(int argc, char *argv[])
                 usage();
         }
 
+ atexit(cleanup);
+ if (signal(SIGINT, sigcleanup) == SIG_ERR) {
+ fprintf(stderr, "%s: signal: Failed to handle SIGINT\n",
+ argv0);
+ return 1;
+ }
+
         /* compile and check the supplied vhost regexes */
         if (vhosts) {
                 for (i = 0; i < LEN(vhost); i++) {
_AT_@ -1011,35 +1038,52 @@ main(int argc, char *argv[])
         insock = udsname ? getusock(udsname, pwd->pw_uid, grp->gr_gid) :
                            getipsock();
 
- /* chroot */
- if (chdir(servedir) < 0) {
- die("%s: chdir %s: %s\n", argv0, servedir, strerror(errno));
- }
- if (chroot(".") < 0) {
- die("%s: chroot .: %s\n", argv0, strerror(errno));
- }
+ switch (cpid = fork()) {
+ case -1:
+ fprintf(stderr, "%s: fork: %s\n", argv0, strerror(errno));
+ break;
+ case 0:
+ /* reap children automatically */
+ if (signal(SIGINT, SIG_IGN) == SIG_ERR) {
+ fprintf(stderr, "%s: signal: Failed to set SIG_IGN on"
+ "SIGINT\n", argv0);
+ return 1;
+ }
 
- /* drop root */
- if (grp && setgroups(1, &(grp->gr_gid)) < 0) {
- die("%s: setgroups: %s\n", argv0, strerror(errno));
- }
- if (grp && setgid(grp->gr_gid) < 0) {
- die("%s: setgid: %s\n", argv0, strerror(errno));
- }
- if (pwd && setuid(pwd->pw_uid) < 0) {
- die("%s: setuid: %s\n", argv0, strerror(errno));
- }
- if (getuid() == 0) {
- die("%s: won't run as root user\n", argv0);
- }
- if (getgid() == 0) {
- die("%s: won't run as root group\n", argv0);
- }
+ /* chroot */
+ if (chdir(servedir) < 0) {
+ die("%s: chdir %s: %s\n", argv0, servedir, strerror(errno));
+ }
+ if (chroot(".") < 0) {
+ die("%s: chroot .: %s\n", argv0, strerror(errno));
+ }
 
- serve(insock);
- close(insock);
+ /* drop root */
+ if (grp && setgroups(1, &(grp->gr_gid)) < 0) {
+ die("%s: setgroups: %s\n", argv0, strerror(errno));
+ }
+ if (grp && setgid(grp->gr_gid) < 0) {
+ die("%s: setgid: %s\n", argv0, strerror(errno));
+ }
+ if (pwd && setuid(pwd->pw_uid) < 0) {
+ die("%s: setuid: %s\n", argv0, strerror(errno));
+ }
+ if (getuid() == 0) {
+ die("%s: won't run as root user\n", argv0);
+ }
+ if (getgid() == 0) {
+ die("%s: won't run as root group\n", argv0);
+ }
 
- return 0;
+ serve(insock);
+ _exit(0);
+ default:
+ while ((wpid = wait(&status)) > 0)
+ ;
+ }
+
+ cleanup();
+ return status;
 }
 
 /*
Received on Tue Jul 11 2017 - 15:03:02 CEST