When not logging I/O, put command in its own pgrp and make that the

controlling pgrp if the command is in the foreground. Fixes a race
in the non-I/O logging path where the command may receive two
keyboard-generated signals; one from the kernel and one from the
sudo process.

--HG--
branch : 1.7

diff --git a/exec.c b/exec.c
index 8235829cfb2904d4bb9c82e61df446936897b56f..dd936cfa8d215072a572ddcfaa29a2d4dd7cae43 100644 (file)
--- a/exec.c
+++ b/exec.c
@@ -118,6 +118,7 @@ static int fork_cmnd(path, argv, envp, sv, rbac_enabled)
     int sv[2];
     int rbac_enabled;
 {
+    int ttyfd, foreground = 0;
     struct command_status cstat;
     sigaction_t sa;
     pid_t child;
@@ -128,6 +129,12 @@ static int fork_cmnd(path, argv, envp, sv, rbac_enabled)
     sa.sa_handler = handler;
     sigaction(SIGCONT, &sa, NULL);
 
+    ttyfd = open(_PATH_TTY, O_RDWR|O_NOCTTY, 0);
+    if (ttyfd != -1) {
+       foreground = (tcgetpgrp(ttyfd) == getpgrp());
+       (void)fcntl(ttyfd, F_SETFD, FD_CLOEXEC);
+    }
+
     child = fork();
     switch (child) {
     case -1:
@@ -141,6 +148,16 @@ static int fork_cmnd(path, argv, envp, sv, rbac_enabled)
        fcntl(sv[1], F_SETFD, FD_CLOEXEC);
        restore_signals();
        if (exec_setup(rbac_enabled, user_ttypath, -1) == TRUE) {
+           /* Set child process group here too to avoid a race. */
+           child = getpid();
+           setpgid(0, child);
+
+           /* Wait for parent to grant us the tty if we are foreground. */
+           if (foreground) {
+               while (tcgetpgrp(ttyfd) != child)
+                   ; /* spin */
+           }
+
            /* headed for execve() */
            int maxfd = def_closefrom;
            dup2(sv[1], maxfd);
@@ -159,6 +176,19 @@ static int fork_cmnd(path, argv, envp, sv, rbac_enabled)
        send(sv[1], &cstat, sizeof(cstat), 0);
        _exit(1);
     }
+
+    /*
+     * Put child in its own process group.  If we are starting the command
+     * in the foreground, assign its pgrp to the tty.
+     */
+    setpgid(child, child);
+    if (foreground) {
+       while (tcsetpgrp(ttyfd, child) == -1 && errno == EINTR)
+           continue;
+    }
+    if (ttyfd != -1)
+       close(ttyfd);
+
     return child;
 }
 
@@ -522,17 +552,17 @@ handle_signals(fd, child, cstat)
                         */
 #ifdef HAVE_TCSETPGRP
                        pid_t saved_pgrp = (pid_t)-1;
-                       int fd = open(_PATH_TTY, O_RDWR|O_NOCTTY, 0);
-                       if (fd != -1)
-                           saved_pgrp = tcgetpgrp(fd);
+                       int ttyfd = open(_PATH_TTY, O_RDWR|O_NOCTTY, 0);
+                       if (ttyfd != -1)
+                           saved_pgrp = tcgetpgrp(ttyfd);
 #endif /* HAVE_TCSETPGRP */
                        if (kill(getpid(), WSTOPSIG(status)) != 0)
                            warning("kill(%d, %d)", getpid(), WSTOPSIG(status));
 #ifdef HAVE_TCSETPGRP
-                       if (fd != -1) {
+                       if (ttyfd != -1) {
                            if (saved_pgrp != (pid_t)-1)
-                               (void)tcsetpgrp(fd, saved_pgrp);
-                           close(fd);
+                               (void)tcsetpgrp(ttyfd, saved_pgrp);
+                           close(ttyfd);
                        }
 #endif /* HAVE_TCSETPGRP */
                    } else {