Wire up SIGALRM handler

Set close on exec flag for child side of the socketpair
Fix signal handling when not doing I/O logging

diff --git a/src/script.c b/src/script.c
index 287138ec3583be3a297a01684b5d3fd7dc12144d..747c7f864bc0d155ca81f354cd136d2e98df8f22 100644 (file)
--- a/src/script.c
+++ b/src/script.c
@@ -111,6 +111,7 @@ static void script_run(const char *path, char *argv[], char *envp[], int);
 static void sigchild(int s);
 static void sigwinch(int s);
 static void sync_winsize(int src, int dst);
+static void deliver_signal(pid_t pid, int signo);
 
 /* sudo.c */
 extern struct plugin_container_list io_plugins;
@@ -339,6 +340,10 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
     sa.sa_handler = sigchild;
     sigaction(SIGCHLD, &sa, NULL);
 
+    /* Catch SIGALRM for command timeout */
+    sa.sa_handler = handler;
+    sigaction(SIGALRM, &sa, NULL);
+
     /* Ignore SIGPIPE from other end of socketpair. */
     sa.sa_handler = SIG_IGN;
     sigaction(SIGPIPE, &sa, NULL);
@@ -392,6 +397,10 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
            error(1, "Can't set terminal to raw mode");
     }
 
+    /* Set command timeout if specified. */
+    if (ISSET(details->flags, CD_SET_TIMEOUT))
+           alarm(details->timeout);
+
     /*
      * Child will run the command in the pty, parent will pass data
      * to and from pty.
@@ -404,6 +413,7 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
     case 0:
        /* child */
        close(sv[0]);
+       fcntl(sv[1], F_SETFD, FD_CLOEXEC);
        if (exec_setup(details) == 0) {
            /* headed for execve() */
            if (log_io)
@@ -459,7 +469,7 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
     zero_bytes(&input, sizeof(input));
     zero_bytes(&output, sizeof(output));
     for (;;) {
-       /* XXX - racey */
+       /* XXX - racey */
        if (!relaysig && recvsig != SIGCHLD) {
            relaysig = recvsig;
            recvsig = 0;
@@ -491,8 +501,14 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
                FD_SET(script_fds[SFD_MASTER], fdsw);
        }
        FD_SET(sv[0], fdsr);
-       if (relaysig)
-           FD_SET(sv[0], fdsw);
+       if (relaysig) {
+           if (log_io) {
+               FD_SET(sv[0], fdsw);
+           } else {
+               /* nothing listening on sv[0], send directly */
+               deliver_signal(child, relaysig);
+           }
+       }
 
        nready = select(maxfd + 1, fdsr, fdsw, NULL, NULL);
        if (nready == -1) {
@@ -506,7 +522,7 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
            if (n == -1) {
                if (errno == EINTR)
                    continue;
-               if (errno != EAGAIN) {
+               if (log_io && errno != EAGAIN) {
                    /* Did the other end of the pipe go away? */
                    cstat->type = CMD_ERRNO;
                    cstat->val = errno;
@@ -629,14 +645,61 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
     return cstat->type == CMD_ERRNO ? -1 : 0;
 }
 
+static void
+deliver_signal(pid_t pid, int signo)
+{
+    int status;
+
+    /* Handle signal from parent. */
+    sudo_debug(8, "signal %d from parent", signo);
+    switch (signo) {
+    case SIGKILL:
+       _exit(1); /* XXX */
+       /* NOTREACHED */
+    case SIGHUP:
+    case SIGTERM:
+    case SIGINT:
+    case SIGQUIT:
+    case SIGTSTP:
+       /* relay signal to child */
+       killpg(pid, signo);
+       break;
+    case SIGALRM:
+       /* command time out, kill child with increasing urgency */
+       killpg(pid, SIGHUP);
+       sleep(1);
+       killpg(pid, SIGTERM);
+       sleep(1);
+       killpg(pid, SIGKILL);
+       break;
+    case SIGUSR1:
+       /* foreground process, grant it controlling tty. */
+       do {
+           status = tcsetpgrp(script_fds[SFD_SLAVE], pid);
+       } while (status == -1 && errno == EINTR);
+       killpg(pid, SIGCONT);
+       break;
+    case SIGUSR2:
+       /* background process, I take controlling tty. */
+       do {
+           status = tcsetpgrp(script_fds[SFD_SLAVE], getpid());
+       } while (status == -1 && errno == EINTR);
+       killpg(pid, SIGCONT);
+       break;
+    default:
+       warningx("unexpected signal from child: %d", signo);
+       break;
+    }
+}
+
 int
 script_child(const char *path, char *argv[], char *envp[], int backchannel, int rbac)
 {
     struct command_status cstat;
     fd_set *fdsr;
     sigaction_t sa;
-    pid_t pid, self = getpid();
-    int n, signo, status;
+    pid_t pid;
+    int n, status;
 
     recvsig = 0;
 
@@ -649,8 +712,8 @@ script_child(const char *path, char *argv[], char *envp[], int backchannel, int
     sigemptyset(&sa.sa_mask);
     sa.sa_flags = SA_RESTART;
     sa.sa_handler = SIG_DFL;
-    sigaction(SIGCONT, &sa, NULL);
     sigaction(SIGWINCH, &sa, NULL);
+    sigaction(SIGALRM, &sa, NULL);
 
     /* Ignore any SIGTT{IN,OU} or SIGPIPE we get. */
     sa.sa_handler = SIG_IGN;
@@ -774,7 +837,7 @@ script_child(const char *path, char *argv[], char *envp[], int backchannel, int
            error(1, "select failed");
        }
 
-       /* read child status */
+       /* read command from backchannel, should be a signal */
        n = recv(backchannel, &cstat, sizeof(cstat), 0);
        if (n == -1) {
            if (errno == EINTR)
@@ -786,40 +849,7 @@ script_child(const char *path, char *argv[], char *envp[], int backchannel, int
            warningx("unexpected reply type on backchannel: %d", cstat.type);
            continue;
        }
-       signo = cstat.val;
-
-       /* Handle signal from parent. */
-       sudo_debug(8, "signal %d from parent", signo);
-       switch (signo) {
-       case SIGKILL:
-           _exit(1); /* XXX */
-           /* NOTREACHED */
-       case SIGHUP:
-       case SIGTERM:
-       case SIGINT:
-       case SIGQUIT:
-       case SIGTSTP:
-           /* relay signal to child */
-           killpg(child, signo);
-           break;
-       case SIGUSR1:
-           /* foreground process, grant it controlling tty. */
-           do {
-               status = tcsetpgrp(script_fds[SFD_SLAVE], child);
-           } while (status == -1 && errno == EINTR);
-           killpg(child, SIGCONT);
-           break;
-       case SIGUSR2:
-           /* background process, I take controlling tty. */
-           do {
-               status = tcsetpgrp(script_fds[SFD_SLAVE], self);
-           } while (status == -1 && errno == EINTR);
-           killpg(child, SIGCONT);
-           break;
-       default:
-           warningx("unexpected signal from child: %d", signo);
-           break;
-       }
+       deliver_signal(child, cstat.val);
     }
 
     _exit(1); /* XXX */

diff --git a/src/sudo.c b/src/sudo.c
index 71cf4a9a76246b208fee47390815ecb9ea9d6748..8529499cf650c54d996e048ab135270b5dd27332 100644 (file)
--- a/src/sudo.c
+++ b/src/sudo.c
@@ -689,8 +689,6 @@ exec_setup(struct command_details *details)
     }
     if (ISSET(details->flags, CD_SET_UMASK))
        (void) umask(details->umask);
-    if (ISSET(details->flags, CD_SET_TIMEOUT))
-       alarm(details->timeout);
     if (details->chroot) {
        if (chroot(details->chroot) != 0 || chdir("/") != 0) {
            warning("unable to change root to %s", details->chroot);