From cb9596484d37dc4ea3027851c88a048405cd35c0 Mon Sep 17 00:00:00 2001
From: Eric van Beurden <ericvb@transgaming.com>
Date: Thu, 17 Jan 2008 17:31:49 -0500
Subject: [PATCH] dbghelp: Prevent huge minidumps by ensuring the memory range
 is clamped.

---
 dlls/dbghelp/minidump.c | 42 +++++++++++++++++++++++++++++++++++------
 1 file changed, 36 insertions(+), 6 deletions(-)

diff --git a/dlls/dbghelp/minidump.c b/dlls/dbghelp/minidump.c
index 3dd69cf3c8a..9ae530745ce 100644
--- a/dlls/dbghelp/minidump.c
+++ b/dlls/dbghelp/minidump.c
@@ -119,20 +119,50 @@ static void fetch_thread_stack(struct dump_context* dc, const void* teb_addr,
     {
 #ifdef __i386__
         /* limiting the stack dumping to the size actually used */
-        if (ctx->Esp)
-            mmd->StartOfMemoryRange = (ctx->Esp - 4);
+        if (ctx->Esp){
+
+            /* make sure ESP is within the established range of the stack.  It could have
+               been clobbered by whatever caused the original exception. */
+            if (ctx->Esp - 4 < (ULONG_PTR)tib.StackLimit || ctx->Esp - 4 > (ULONG_PTR)tib.StackBase)
+                mmd->StartOfMemoryRange = (ULONG_PTR)tib.StackLimit;
+
+            else
+                mmd->StartOfMemoryRange = (ctx->Esp - 4);
+        }
+
         else
             mmd->StartOfMemoryRange = (ULONG_PTR)tib.StackLimit;
+
 #elif defined(__powerpc__)
-        if (ctx->Iar)
-            mmd->StartOfMemoryRange = ctx->Iar - 4;
+        if (ctx->Iar){
+
+            /* make sure IAR is within the established range of the stack.  It could have
+               been clobbered by whatever caused the original exception. */
+            if (ctx->Iar - 4 < (ULONG_PTR)tib.StackLimit || ctx->Iar - 4 > (ULONG_PTR)tib.StackBase)
+                mmd->StartOfMemoryRange = (ULONG_PTR)tib.StackLimit;
+
+            else
+                mmd->StartOfMemoryRange = (ctx->Iar - 4);
+        }
+
         else
             mmd->StartOfMemoryRange = (ULONG_PTR)tib.StackLimit;
+
 #elif defined(__x86_64__)
-        if (ctx->Rsp)
-            mmd->StartOfMemoryRange = (ctx->Rsp - 8);
+        if (ctx->Rsp){
+
+            /* make sure RSP is within the established range of the stack.  It could have
+               been clobbered by whatever caused the original exception. */
+            if (ctx->Rsp - 8 < (ULONG_PTR)tib.StackLimit || ctx->Rsp - 8 > (ULONG_PTR)tib.StackBase)
+                mmd->StartOfMemoryRange = (ULONG_PTR)tib.StackLimit;
+
+            else
+                mmd->StartOfMemoryRange = (ctx->Rsp - 8);
+        }
+
         else
             mmd->StartOfMemoryRange = (ULONG_PTR)tib.StackLimit;
+
 #else
 #error unsupported CPU
 #endif