From 0e73aa36c8ed90d833656746182efb8ab636e1a5 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Sun, 27 Jan 2019 10:17:56 +0100
Subject: [PATCH] Kernel: Unbreak symbolication yet another time.

---
 Kernel/Process.cpp | 23 +++++++++++++++++------
 Kernel/kmalloc.cpp |  2 +-
 Kernel/kmalloc.h   |  2 +-
 3 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index 37fdd3a226..89fabe84ae 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -1597,14 +1597,19 @@ void sleep(dword ticks)
     sched_yield();
 }
 
+static bool is_inside_kernel_code(LinearAddress laddr)
+{
+    // FIXME: What if we're indexing into the ksym with the highest address though?
+    return laddr.get() >= ksym_lowest_address && laddr.get() <= ksym_highest_address;
+}
+
 bool Process::validate_read_from_kernel(LinearAddress laddr) const
 {
     // We check extra carefully here since the first 4MB of the address space is identity-mapped.
     // This code allows access outside of the known used address ranges to get caught.
 
     InterruptDisabler disabler;
-    // FIXME: What if we're indexing into the ksym with the highest address though?
-    if (laddr.get() >= ksym_lowest_address && laddr.get() <= ksym_highest_address)
+    if (is_inside_kernel_code(laddr))
         return true;
     if (is_kmalloc_address(laddr.as_ptr()))
         return true;
@@ -1613,8 +1618,12 @@ bool Process::validate_read_from_kernel(LinearAddress laddr) const
 
 bool Process::validate_read(const void* address, size_t size) const
 {
-    if (isRing0())
-        return true;
+    if (isRing0()) {
+        if (is_inside_kernel_code(LinearAddress((dword)address)))
+            return true;
+        if (is_kmalloc_address(address))
+            return true;
+    }
     ASSERT(size);
     if (!size)
         return false;
@@ -1629,8 +1638,10 @@ bool Process::validate_read(const void* address, size_t size) const
 
 bool Process::validate_write(void* address, size_t size) const
 {
-    if (isRing0())
-        return true;
+    if (isRing0()) {
+        if (is_kmalloc_address(address))
+            return true;
+    }
     ASSERT(size);
     if (!size)
         return false;
diff --git a/Kernel/kmalloc.cpp b/Kernel/kmalloc.cpp
index c22b7ca0ca..a61a1b48a0 100644
--- a/Kernel/kmalloc.cpp
+++ b/Kernel/kmalloc.cpp
@@ -38,7 +38,7 @@ volatile size_t kmalloc_sum_eternal = 0;
 static byte* s_next_eternal_ptr;
 static byte* s_end_of_eternal_range;
 
-bool is_kmalloc_address(void* ptr)
+bool is_kmalloc_address(const void* ptr)
 {
     if (ptr >= (byte*)ETERNAL_BASE_PHYSICAL && ptr < s_next_eternal_ptr)
         return true;
diff --git a/Kernel/kmalloc.h b/Kernel/kmalloc.h
index 8c4a1522eb..82c47e3354 100644
--- a/Kernel/kmalloc.h
+++ b/Kernel/kmalloc.h
@@ -10,7 +10,7 @@ void* kmalloc_aligned(size_t, size_t alignment) __attribute__ ((malloc));
 void kfree(void*);
 void kfree_aligned(void*);
 
-bool is_kmalloc_address(void*);
+bool is_kmalloc_address(const void*);
 
 extern volatile size_t sum_alloc;
 extern volatile size_t sum_free;