svn commit: r359943 - head/lib/libc/sys

[Kyle Evans]

Author: kevans
Date: Tue Apr 14 23:24:24 2020
New Revision: 359943
URL: https://svnweb.freebsd.org/changeset/base/359943

Log:
  closefrom: clamp lowfd to >= 0; close_range's parameters are unsigned.
  
  Pointy hat:	kevans
  Reported by:	CI (lwhsu)

Modified:
  head/lib/libc/sys/closefrom.c

Modified: head/lib/libc/sys/closefrom.c
==============================================================================
--- head/lib/libc/sys/closefrom.c	Tue Apr 14 23:06:25 2020	(r359942)
+++ head/lib/libc/sys/closefrom.c	Tue Apr 14 23:24:24 2020	(r359943)
@@ -28,6 +28,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <sys/param.h>
 #include <sys/syscall.h>
 #include <unistd.h>
 
@@ -40,7 +41,7 @@ closefrom(int lowfd)
 {
 
 	if (__getosreldate() >= CLOSE_RANGE_OSREL)
-		__sys_close_range(lowfd, ~0U, 0);
+		__sys_close_range(MAX(0, lowfd), ~0U, 0);
 	else
 		/* Fallback to closefrom(2) on older kernels. */
 		syscall(SYS_freebsd12_closefrom, lowfd);