svn commit: r325755 - head/sys/kern

[Xin LI]

Author: delphij
Date: Mon Nov 13 07:47:43 2017
New Revision: 325755
URL: https://svnweb.freebsd.org/changeset/base/325755

Log:
  Be more careful when doing calculation with request from userland.
  
  MFC after:	2 weeks

Modified:
  head/sys/kern/kern_proc.c

Modified: head/sys/kern/kern_proc.c
==============================================================================
--- head/sys/kern/kern_proc.c	Mon Nov 13 03:41:50 2017	(r325754)
+++ head/sys/kern/kern_proc.c	Mon Nov 13 07:47:43 2017	(r325755)
@@ -1956,7 +1956,7 @@ sysctl_kern_proc_args(SYSCTL_HANDLER_ARGS)
 	if (error != 0 || req->newptr == NULL)
 		return (error);
 
-	if (req->newlen + sizeof(struct pargs) > ps_arg_cache_limit)
+	if (req->newlen > ps_arg_cache_limit - sizeof(struct pargs))
 		return (ENOMEM);
 	newpa = pargs_alloc(req->newlen);
 	error = SYSCTL_IN(req, newpa->ar_args, req->newlen);