[Lldb-commits] [lldb] be556d5 - [lldb/Commands] Fix heap-use-after-free error in CommandObjectProcess

[Med Ismail Bennani via lldb-commits]

Author: Med Ismail Bennani
Date: 2021-08-11T17:03:20+01:00
New Revision: be556d5131d56f285e55b0548f3b953d55d055c4

URL: https://github.com/llvm/llvm-project/commit/be556d5131d56f285e55b0548f3b953d55d055c4
DIFF: https://github.com/llvm/llvm-project/commit/be556d5131d56f285e55b0548f3b953d55d055c4.diff

LOG: [lldb/Commands] Fix heap-use-after-free error in CommandObjectProcess

This patch should fix the use-after-free error that was brought up by
the LLDB ASAN Green Dragon bot.

This is caused because the `StringRef` object was acquired too early
before being use and by the underlying memory was modified which caused
it to point to null memory.

Fetching back the string reference close to its usage location should
fix the issue.

Signed-off-by: Med Ismail Bennani <medismail.bennani at gmail.com>

Added: 
    

Modified: 
    lldb/source/Commands/CommandObjectProcess.cpp

Removed: 
    


################################################################################
diff  --git a/lldb/source/Commands/CommandObjectProcess.cpp b/lldb/source/Commands/CommandObjectProcess.cpp
index 7aaba37315000..1a8ed021b9f0e 100644
--- a/lldb/source/Commands/CommandObjectProcess.cpp
+++ b/lldb/source/Commands/CommandObjectProcess.cpp
@@ -170,8 +170,6 @@ class CommandObjectProcessLaunch : public CommandObjectProcessLaunchOrAttach {
     if (!StopProcessIfNecessary(m_exe_ctx.GetProcessPtr(), state, result))
       return false;
 
-    llvm::StringRef target_settings_argv0 = target->GetArg0();
-
     // Determine whether we will disable ASLR or leave it in the default state
     // (i.e. enabled if the platform supports it). First check if the process
     // launch options explicitly turn on/off
@@ -216,6 +214,8 @@ class CommandObjectProcessLaunch : public CommandObjectProcessLaunchOrAttach {
     m_options.launch_info.GetEnvironment().insert(target_env.begin(),
                                                   target_env.end());
 
+    llvm::StringRef target_settings_argv0 = target->GetArg0();
+
     if (!target_settings_argv0.empty()) {
       m_options.launch_info.GetArguments().AppendArgument(
           target_settings_argv0);