Kernel: When validating a string read, validate the pointer first.

Calling strlen() on an invalid pointer is just gonna crash the process.
luteresa · Feb 7, 2019 · f4bce03 · f4bce03
1 parent 887b4a7
commit f4bce03
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Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
@@ -1643,6 +1643,13 @@ bool Process::validate_read_from_kernel(LinearAddress laddr) const
  return validate_read(laddr.as_ptr(), 1);
 }
 
+bool Process::validate_read_str(const char* str)
+{
+ if (!validate_read(str, 1))
+ return false;
+ return validate_read(str, strlen(str) + 1);
+}
+
 bool Process::validate_read(const void* address, size_t size) const
 {
  if (is_ring0()) {

diff --git a/Kernel/Process.h b/Kernel/Process.h
@@ -267,7 +267,7 @@ class Process : public InlineLinkedListNode<Process>, public Weakable<Process> {
 
  bool validate_read(const void*, size_t) const;
  bool validate_write(void*, size_t) const;
- bool validate_read_str(const char* str) { return validate_read(str, strlen(str) + 1); }
+ bool validate_read_str(const char* str);
  template<typename T> bool validate_read_typed(T* value, size_t count = 1) { return validate_read(value, sizeof(T) * count); }
  template<typename T> bool validate_write_typed(T* value, size_t count = 1) { return validate_write(value, sizeof(T) * count); }