Index: sudo-1.7.4p4/exec.c
===================================================================
--- sudo-1.7.4p4.orig/exec.c	2011-06-06 07:55:23.000000000 +0300
+++ sudo-1.7.4p4/exec.c	2011-06-06 09:17:17.000000000 +0300
@@ -58,6 +58,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
+#include <setjmp.h>
 #ifdef HAVE_SELINUX
 # include <selinux/selinux.h>
 #endif
@@ -69,6 +70,9 @@
 sig_atomic_t recvsig[NSIG];
 void handler __P((int s));
 
+static sigjmp_buf jmpbuf;
+static void handler_jmp __P((int s));
+
 /*
  * Like execve(2) but falls back to running through /bin/sh
  * ala execvp(3) if we get ENOEXEC.
@@ -212,10 +216,16 @@
 
     zero_bytes(&sa, sizeof(sa));
     sigemptyset(&sa.sa_mask);
+    sigaddset(&sa.sa_mask, SIGCHLD);
+    sigaddset(&sa.sa_mask, SIGHUP);
+    sigaddset(&sa.sa_mask, SIGINT);
+    sigaddset(&sa.sa_mask, SIGPIPE);
+    sigaddset(&sa.sa_mask, SIGQUIT);
+    sigaddset(&sa.sa_mask, SIGTERM);
 
     /* Note: HP-UX select() will not be interrupted if SA_RESTART set */
     sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */
-    sa.sa_handler = handler;
+    sa.sa_handler = handler_jmp;
     sigaction(SIGCHLD, &sa, NULL);
     sigaction(SIGHUP, &sa, NULL);
     sigaction(SIGINT, &sa, NULL);
@@ -253,6 +263,7 @@
     fdsr = (fd_set *)emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
     fdsw = (fd_set *)emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
     for (;;) {
+	sigsetjmp(jmpbuf, 0);
 	if (recvsig[SIGCHLD]) {
 	    pid_t pid;
 
@@ -305,8 +316,7 @@
 	    }
 	}
 
-	if (recvsig[SIGCHLD])
-	    continue;
+	sigprocmask(SIG_UNBLOCK, &sa.sa_mask, NULL);
 	nready = select(maxfd + 1, fdsr, fdsw, NULL, NULL);
 	if (nready == -1) {
 	    if (errno == EINTR)
@@ -402,3 +412,11 @@
 {
     recvsig[s] = TRUE;
 }
+
+void
+handler_jmp(s)
+    int s;
+{
+    recvsig[s] = TRUE;
+    siglongjmp(jmpbuf, 1);
+}