Check for dup2() failure.

plugins/sudoers/logging.c

@@ -463,7 +463,7 @@ send_mail(const char *fmt, ...)
     }
 # endif
 #endif
-    chdir("/");
+    (void) chdir("/");
     if ((fd = open(_PATH_DEVNULL, O_RDWR, 0644)) != -1) {
 	(void) dup2(fd, STDIN_FILENO);
 	(void) dup2(fd, STDOUT_FILENO);
@@ -501,12 +501,15 @@ send_mail(const char *fmt, ...)
 
 		/* Child, set stdin to output side of the pipe */
 		if (pfd[0] != STDIN_FILENO) {
-		    (void) dup2(pfd[0], STDIN_FILENO);
+		    if (dup2(pfd[0], STDIN_FILENO) != -1) {
+			mysyslog(LOG_ERR, "cannot dup stdin: %m");
+			_exit(127);
+		    }
 		    (void) close(pfd[0]);
 		}
 		(void) close(pfd[1]);
 
-		/* Build up an argv based the mailer path and flags */
+		/* Build up an argv based on the mailer path and flags */
 		mflags = estrdup(def_mailerflags);
 		mpath = estrdup(def_mailerpath);
 		if ((argv[0] = strrchr(mpath, ' ')))

src/exec_pty.c

@@ -1096,9 +1096,10 @@ exec_pty(struct command_details *details, char *argv[], char *envp[])
     setpgid(0, self);
 
     /* Wire up standard fds, note that stdout/stderr may be pipes. */
-    dup2(io_fds[SFD_STDIN], STDIN_FILENO);
-    dup2(io_fds[SFD_STDOUT], STDOUT_FILENO);
-    dup2(io_fds[SFD_STDERR], STDERR_FILENO);
+    if (dup2(io_fds[SFD_STDIN], STDIN_FILENO) == -1 ||
+	dup2(io_fds[SFD_STDOUT], STDOUT_FILENO) == -1 ||
+	dup2(io_fds[SFD_STDERR], STDERR_FILENO) == -1)
+	error(1, "dup2");
 
     /* Wait for parent to grant us the tty if we are foreground. */
     if (foreground) {

src/selinux.c

@@ -114,6 +114,7 @@ relabel_tty(const char *ttyn, int ptyfd)
 {
     security_context_t tty_con = NULL;
     security_context_t new_tty_con = NULL;
+    int fd;
 
     se_state.ttyfd = ptyfd;
 
@@ -162,22 +163,26 @@ relabel_tty(const char *ttyn, int ptyfd)
 	    if (se_state.enforcing)
 		goto bad;
 	}
-	dup2(se_state.ttyfd, ptyfd);
+	if (dup2(se_state.ttyfd, ptyfd) == -1) {
+	    warning("dup2");
+	    goto bad;
+	}
     } else {
 	/* Re-open tty to get new label and reset std{in,out,err} */
 	close(se_state.ttyfd);
 	se_state.ttyfd = open(ttyn, O_RDWR|O_NONBLOCK);
-	if (se_state.ttyfd == -1)
+	if (se_state.ttyfd == -1) {
 	    warning("unable to open %s", ttyn);
-	else
-	    (void)fcntl(se_state.ttyfd, F_SETFL,
-		fcntl(se_state.ttyfd, F_GETFL, 0) & ~O_NONBLOCK);
-	if (isatty(STDIN_FILENO))
-	    dup2(se_state.ttyfd, STDIN_FILENO);
-	if (isatty(STDOUT_FILENO))
-	    dup2(se_state.ttyfd, STDOUT_FILENO);
-	if (isatty(STDERR_FILENO))
-	    dup2(se_state.ttyfd, STDERR_FILENO);
+	    goto bad;
+	}
+	(void)fcntl(se_state.ttyfd, F_SETFL,
+	    fcntl(se_state.ttyfd, F_GETFL, 0) & ~O_NONBLOCK);
+	for (fd = STDIN_FILENO; fd <= STDERR_FILENO; fd++) {
+	    if (isatty(fd) && dup2(se_state.ttyfd, fd) == -1) {
+		warning("dup2");
+		goto bad;
+	    }
+	}
     }
     /* Retain se_state.ttyfd so we can restore label when command finishes. */
     (void)fcntl(se_state.ttyfd, F_SETFD, FD_CLOEXEC);

src/sudo.c

@@ -271,16 +271,16 @@ fix_fds(void)
     miss[STDOUT_FILENO] = fcntl(STDOUT_FILENO, F_GETFL, 0) == -1;
     miss[STDERR_FILENO] = fcntl(STDERR_FILENO, F_GETFL, 0) == -1;
     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);
-	    if (devnull > STDERR_FILENO)
-		close(devnull);
-	}
+	if ((devnull = open(_PATH_DEVNULL, O_RDWR, 0644)) == -1)
+	    error(1, "unable to open %s", _PATH_DEVNULL);
+	if (miss[STDIN_FILENO] && dup2(devnull, STDIN_FILENO) == -1)
+	    error(1, "dup2");
+	if (miss[STDOUT_FILENO] && dup2(devnull, STDOUT_FILENO) == -1)
+	    error(1, "dup2");
+	if (miss[STDERR_FILENO] && dup2(devnull, STDERR_FILENO) == -1)
+	    error(1, "dup2");
+	if (devnull > STDERR_FILENO)
+	    close(devnull);
     }
 }
 

src/tgetpass.c

@@ -222,7 +222,10 @@ sudo_askpass(const char *askpass, const char *prompt)
 
     if (pid == 0) {
 	/* child, point stdout to output side of the pipe and exec askpass */
-	(void) dup2(pfd[1], STDOUT_FILENO);
+	if (dup2(pfd[1], STDOUT_FILENO) == -1) {
+	    warning("dup2");
+	    _exit(255);
+	}
 	(void) setuid(ROOT_UID);
 	if (setgid(user_details.gid)) {
 	    warning("unable to set gid to %u", (unsigned int)user_details.gid);