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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Undefined behavior- and address sanitizer fails to detect invalid vptr and use-after-free"
href="https://bugs.llvm.org/show_bug.cgi?id=39805">39805</a>
</td>
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<th>Summary</th>
<td>Undefined behavior- and address sanitizer fails to detect invalid vptr and use-after-free
</td>
</tr>
<tr>
<th>Product</th>
<td>compiler-rt
</td>
</tr>
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<th>Version</th>
<td>7.0
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>ubsan
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>idart@hotmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>The undefined address sanitizer fails to detect the invalid vptr in the example
below.
In addition, the address sanitizer fails to detect the use-after-free.
This holds even if the interface and classes are in different translation
units.
//-----
#include <iostream>
#include <memory>
#include <string>
namespace {
class StatusIntf
{
public:
virtual ~StatusIntf() = default;
virtual void updateStatus(const std::string& status) = 0;
};
class StatusImpl : public StatusIntf
{
public:
~StatusImpl() override
{
std::cout << "Status Implementation deleted" << std::endl;
}
void updateStatus(const std::string& status) override
{
status_ = status;
std::cout << "Status is: " << status_ << std::flush << std::endl;
}
private:
std::string status_;
};
class User
{
public:
User(StatusIntf& statusUpdater) : statusUpdater_(statusUpdater) {}
~User()
{
statusUpdater_.updateStatus("Ending");
}
private:
StatusIntf& statusUpdater_;
};
class Keeper
{
public:
Keeper()
{
user_ = std::make_unique<User>(statusUpdater_);
}
private:
// Note the declaration order:
// 'statusUpdater_' will be deleted before 'user_'.
std::unique_ptr<User> user_;
StatusImpl statusUpdater_;
};
}
int main()
{
Keeper keeper;
return 0;
}
//-----
Compiled with:
clang++ -std=c++14 -stdlib=libc++ -fsanitize=undefined,address
-fno-sanitize-recover=undefined -fPIC -fno-omit-frame-pointer -O2 -g
Tried Clang 6.0.1 and 7.0.0 on Linux (x86-64) and the version that ships with
Xcode 10.1 on macOS (identifying itself as clang-1000.11.45.5).
g++-8 detects the vptr issue and issues a "object has invalid vptr" error. But
its address sanitizer also fails to detect the use-after-free.</pre>
</div>
</p>
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