From: Todd C. Miller <Todd.Miller@courtesan.com>
Date: Fri, 10 Dec 2004 00:26:22 +0000 (+0000)
Subject: Make sure stdin, stdout and stderr are open and dup them to /dev/null
X-Git-Tag: SUDO_1_7_0~770
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=07d74adfbadf39d432e0c66d474890b33218075b;p=sudo

Make sure stdin, stdout and stderr are open and dup them to /dev/null
if not.
---

diff --git a/sudo.c b/sudo.c
index 8bebd53ff..9f569894a 100644
--- a/sudo.c
+++ b/sudo.c
@@ -965,6 +965,7 @@ open_sudoers(sudoers, keepopen)
 static void
 initial_setup()
 {
+    int miss[3], devnull = -1;
 #if defined(RLIMIT_CORE) && !defined(SUDO_DEVEL)
     struct rlimit rl;
 
@@ -977,6 +978,23 @@ initial_setup()
     (void) setrlimit(RLIMIT_CORE, &rl);
 #endif /* RLIMIT_CORE && !SUDO_DEVEL */
 
+    /*
+     * stdin, stdout and stderr must be open; set them to /dev/null
+     * if they are closed and close all other fds.
+     */
+    miss[STDIN_FILENO] = fcntl(STDIN_FILENO, F_GETFL, 0) != 0;
+    miss[STDOUT_FILENO] = fcntl(STDOUT_FILENO, F_GETFL, 0) != 0;
+    miss[STDERR_FILENO] = fcntl(STDERR_FILENO, F_GETFL, 0) != 0;
+    if ((miss[STDIN_FILENO] || miss[STDOUT_FILENO] || miss[STDERR_FILENO])) {
+	if ((devnull = open(_PATH_DEVNULL, O_RDWR, 0644)) != -1) {
+	    if (miss[STDIN_FILENO])
+		(void) dup2(devnull, STDIN_FILENO);
+	    if (miss[STDOUT_FILENO])
+		(void) dup2(devnull, STDOUT_FILENO);
+	    if (miss[STDERR_FILENO])
+		(void) dup2(devnull, STDERR_FILENO);
+	}
+    }
     closefrom(STDERR_FILENO + 1);
 }