From: Alan Cox <alan@linux.intel.com>
Date: Sat, 19 Jan 2019 19:14:56 +0000 (+0000)
Subject: usermem: fix dumb error where some out of range addresses were not errorred
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=9a3b936aee427652849705ed9e820aa7cb3045ab;p=FUZIX.git

usermem: fix dumb error where some out of range addresses were not errorred
---

diff --git a/Kernel/usermem.c b/Kernel/usermem.c
index 6a966645..4490247b 100644
--- a/Kernel/usermem.c
+++ b/Kernel/usermem.c
@@ -16,7 +16,8 @@
 /* This checks to see if a user-supplied address is legitimate */
 usize_t valaddr(const char *base, usize_t size)
 {
-	if (!base || base < (const char *)PROGBASE || base + size < base)
+	if (!base || base < (const char *)PROGBASE || base + size < base ||
+		base > (const char *)(size_t)udata.u_top)
 		size = 0;
 	else if (base + size > (const char *)(size_t)udata.u_top)
 		size = (char *)(size_t)udata.u_top - base;