privsep: Send signal from launcher to master over the socket

rather than using kill which is not permitted in capsicum.
This also allows us to drop the proc pledge.

diff --git a/src/dhcpcd.c b/src/dhcpcd.c
index 83161471e073dfcadecedbdec9f401ea9e977d3d..228f7497913a434cc46d9dfe5db52a1585c59c19 100644 (file)
--- a/src/dhcpcd.c
+++ b/src/dhcpcd.c
@@ -1417,8 +1417,9 @@ dhcpcd_signal_cb(int sig, void *arg)
        }
 
        if (sig != SIGCHLD && ctx->options & DHCPCD_FORKED) {
-               if (sig != SIGHUP && kill(ctx->fork_pid, sig) == -1)
-                       logerr("%s: kill", __func__);
+               if (sig != SIGHUP &&
+                   write(ctx->fork_fd, &sig, sizeof(sig)) == -1)
+                       logerr("%s: write", __func__);
                return;
        }
 
@@ -1760,16 +1761,9 @@ dhcpcd_fork_cb(void *arg)
 {
        struct dhcpcd_ctx *ctx = arg;
        int exit_code;
-       bool do_exit;
        ssize_t len;
 
-       if (ctx->fork_pid == 0) {
-               do_exit = false;
-               len = read(ctx->fork_fd, &ctx->fork_pid, sizeof(ctx->fork_pid));
-       } else {
-               do_exit = true;
-               len = read(ctx->fork_fd, &exit_code, sizeof(exit_code));
-       }
+       len = read(ctx->fork_fd, &exit_code, sizeof(exit_code));
        if (len == -1) {
                logerr(__func__);
                exit_code = EXIT_FAILURE;
@@ -1778,8 +1772,10 @@ dhcpcd_fork_cb(void *arg)
                    __func__, len, sizeof(exit_code));
                exit_code = EXIT_FAILURE;
        }
-       if (do_exit)
+       if (ctx->options & DHCPCD_FORKED)
                eloop_exit(ctx->eloop, exit_code);
+       else
+               dhcpcd_signal_cb(exit_code, ctx);
 }
 
 static void
@@ -2285,6 +2281,8 @@ printpidfile:
                        goto exit_failure;
                }
 #endif
+               eloop_event_add(ctx.eloop, ctx.fork_fd, dhcpcd_fork_cb, &ctx);
+
                /*
                 * Redirect stderr to the stderr socketpair.
                 * Redirect stdout as well.
@@ -2312,9 +2310,6 @@ printpidfile:
                        logerr("fork");
                        goto exit_failure;
                case 0:
-                       /* Inform the launcher of our pid as it's chrooted */
-                       pid = getpid();
-                       write(ctx.fork_fd, &pid, sizeof(pid));
                        break;
                default:
                        ctx.options |= DHCPCD_FORKED; /* A lie */
@@ -2324,7 +2319,7 @@ printpidfile:
                break;
        default:
                setproctitle("[launcher]");
-               ctx.options |= DHCPCD_FORKED; /* A lie */
+               ctx.options |= DHCPCD_FORKED;
                ctx.fork_fd = fork_fd[0];
                close(fork_fd[1]);
 #ifdef PRIVSEP_RIGHTS
@@ -2351,8 +2346,7 @@ printpidfile:
                                    dhcpcd_stderr_cb, &ctx);
                }
 #ifdef PRIVSEP
-               if (IN_PRIVSEP(&ctx) &&
-                   ps_mastersandbox(&ctx, "stdio proc") == -1)
+               if (IN_PRIVSEP(&ctx) && ps_mastersandbox(&ctx, NULL) == -1)
                        goto exit_failure;
 #endif
                goto run_loop;

diff --git a/src/dhcpcd.h b/src/dhcpcd.h
index a3a54b0655567e9375c0b5dfb8ccfa8e270b3154..03449e5846053d3255087762420ad14c2aa75d70 100644 (file)
--- a/src/dhcpcd.h
+++ b/src/dhcpcd.h
@@ -122,7 +122,6 @@ struct dhcpcd_ctx {
        bool stderr_valid;
        int stderr_fd;  /* FD for logging to stderr */
        int fork_fd;    /* FD for the fork init signal pipe */
-       pid_t fork_pid;
        const char *cffile;
        unsigned long long options;
        char *logfile;