From 535018ae7247ede06606e4d8aced2d12c761f28f Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Sat, 20 Mar 2021 21:55:52 +0100
Subject: Reimplemented memory range validation

---
 kernel/features/mm.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

(limited to 'kernel/features/mm.c')

diff --git a/kernel/features/mm.c b/kernel/features/mm.c
index b804076..d14bd81 100644
--- a/kernel/features/mm.c
+++ b/kernel/features/mm.c
@@ -412,24 +412,27 @@ void memory_backup_dir(struct page_dir **backup)
 	*backup = dir;
 }
 
-// TODO: Verify that this isn't a huge security risk
 static u8 memory_bypass_validity = 0;
 void memory_bypass_enable(void)
 {
-	/* memory_bypass_validity = 1; */
+	memory_bypass_validity = 1;
 }
 
 void memory_bypass_disable(void)
 {
-	/* memory_bypass_validity = 0; */
+	memory_bypass_validity = 0;
+}
+
+u8 memory_is_user(u32 addr)
+{
+	return PDI(addr) >= PAGE_KERNEL_COUNT;
 }
 
 // TODO: Limit by proc stack and data range
 u8 memory_valid(const void *addr)
 {
-	/* return ((u32)addr) / PAGE_SIZE / PAGE_COUNT >= PAGE_KERNEL_COUNT; */
 	if (proc_current() && !memory_bypass_validity)
-		return (u32)addr >= 0x100000;
+		return memory_is_user((u32)addr);
 	else
 		return 1;
 }
-- 
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