[Lldb-commits] [lldb] 5f6c558 - Revert "[LLDB] Fix buffer overflow problem in DWARFExpression::Evaluate."

[Caroline Tice via lldb-commits]

Author: Caroline Tice
Date: 2023-07-10T16:24:31-07:00
New Revision: 5f6c55836fb4666f3160400dc273deefdac82e06

URL: https://github.com/llvm/llvm-project/commit/5f6c55836fb4666f3160400dc273deefdac82e06
DIFF: https://github.com/llvm/llvm-project/commit/5f6c55836fb4666f3160400dc273deefdac82e06.diff

LOG: Revert "[LLDB] Fix buffer overflow problem in DWARFExpression::Evaluate."

This reverts commit ee476996bec7f170928505a4c5b7715183cfbada.

That commit was not the right way to fix the issue (it could result in
reading too many bytes).  A better fix is in the works.

Original review: https://reviews.llvm.org/D153840

Added: 
    

Modified: 
    lldb/source/Expression/DWARFExpression.cpp

Removed: 
    


################################################################################
diff  --git a/lldb/source/Expression/DWARFExpression.cpp b/lldb/source/Expression/DWARFExpression.cpp
index c9524870f316f4..2e512bf7581e86 100644
--- a/lldb/source/Expression/DWARFExpression.cpp
+++ b/lldb/source/Expression/DWARFExpression.cpp
@@ -1127,16 +1127,15 @@ bool DWARFExpression::Evaluate(
 
         if (load_addr == LLDB_INVALID_ADDRESS && so_addr.IsSectionOffset()) {
           uint8_t addr_bytes[8];
-          size_t buf_size = sizeof(addr_bytes);
           Status error;
 
           if (target &&
-              target->ReadMemory(so_addr, &addr_bytes, buf_size, error,
-                                 /*force_live_memory=*/false) == buf_size) {
+              target->ReadMemory(so_addr, &addr_bytes, size, error,
+                                 /*force_live_memory=*/false) == size) {
             ObjectFile *objfile = module_sp->GetObjectFile();
 
             stack.back().GetScalar() = DerefSizeExtractDataHelper(
-                addr_bytes, size, objfile->GetByteOrder(), buf_size);
+                addr_bytes, size, objfile->GetByteOrder(), size);
             stack.back().ClearContext();
             break;
           } else {
@@ -1160,13 +1159,13 @@ bool DWARFExpression::Evaluate(
             lldb::addr_t pointer_addr =
                 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
             uint8_t addr_bytes[sizeof(lldb::addr_t)];
-            size_t buf_size = sizeof(addr_bytes);
             Status error;
-            if (process->ReadMemory(pointer_addr, &addr_bytes, buf_size, error)
-                == buf_size) {
+            if (process->ReadMemory(pointer_addr, &addr_bytes, size, error) ==
+                size) {
+
               stack.back().GetScalar() =
                   DerefSizeExtractDataHelper(addr_bytes, sizeof(addr_bytes),
-                                             process->GetByteOrder(), buf_size);
+                                             process->GetByteOrder(), size);
               stack.back().ClearContext();
             } else {
               if (error_ptr)