[lld] r191403 - [ELF] Fix use after free.

[Michael Spencer]

On Thu, Sep 26, 2013 at 4:08 PM, Sean Silva <silvas at purdue.edu> wrote:

> asan?
>

Nope, just Windows debug allocator clearing memory on free.

- Michael Spencer


>
>
> On Wed, Sep 25, 2013 at 6:12 PM, Michael J. Spencer <bigcheesegs at gmail.com
> > wrote:
>
>> Author: mspencer
>> Date: Wed Sep 25 17:12:14 2013
>> New Revision: 191403
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=191403&view=rev
>> Log:
>> [ELF] Fix use after free.
>>
>> Modified:
>>     lld/trunk/include/lld/ReaderWriter/ELFLinkingContext.h
>>     lld/trunk/lib/ReaderWriter/ELF/ELFLinkingContext.cpp
>>
>> Modified: lld/trunk/include/lld/ReaderWriter/ELFLinkingContext.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/include/lld/ReaderWriter/ELFLinkingContext.h?rev=191403&r1=191402&r2=191403&view=diff
>>
>> ==============================================================================
>> --- lld/trunk/include/lld/ReaderWriter/ELFLinkingContext.h (original)
>> +++ lld/trunk/include/lld/ReaderWriter/ELFLinkingContext.h Wed Sep 25
>> 17:12:14 2013
>> @@ -156,7 +156,7 @@ public:
>>    virtual void setNoAllowDynamicLibraries() { _noAllowDynamicLibraries =
>> true; }
>>
>>    /// Searches directories for a match on the input File
>> -  llvm::ErrorOr<std::string>
>> +  llvm::ErrorOr<StringRef>
>>    searchLibrary(StringRef libName,
>>                  const std::vector<StringRef> &searchPath) const;
>>
>>
>> Modified: lld/trunk/lib/ReaderWriter/ELF/ELFLinkingContext.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/ELFLinkingContext.cpp?rev=191403&r1=191402&r2=191403&view=diff
>>
>> ==============================================================================
>> --- lld/trunk/lib/ReaderWriter/ELF/ELFLinkingContext.cpp (original)
>> +++ lld/trunk/lib/ReaderWriter/ELF/ELFLinkingContext.cpp Wed Sep 25
>> 17:12:14 2013
>> @@ -149,48 +149,49 @@ ELFLinkingContext::create(llvm::Triple t
>>    }
>>  }
>>
>> -llvm::ErrorOr<std::string> ELFLinkingContext::searchLibrary(
>> +llvm::ErrorOr<StringRef> ELFLinkingContext::searchLibrary(
>>      StringRef libName, const std::vector<StringRef> &searchPath) const {
>>    bool foundFile = false;
>>    StringRef pathref;
>> +  SmallString<128> path;
>>    for (StringRef dir : searchPath) {
>>      // Search for dynamic library
>>      if (!_isStaticExecutable) {
>> -      SmallString<128> dynlibPath;
>> +      path.clear();
>>        if (dir.startswith("=/")) {
>> -        dynlibPath.assign(_sysrootPath);
>> -        dynlibPath.append(dir.substr(1));
>> +        path.assign(_sysrootPath);
>> +        path.append(dir.substr(1));
>>        } else {
>> -        dynlibPath.assign(dir);
>> +        path.assign(dir);
>>        }
>> -      llvm::sys::path::append(dynlibPath, Twine("lib") + libName +
>> ".so");
>> -      pathref = dynlibPath.str();
>> +      llvm::sys::path::append(path, Twine("lib") + libName + ".so");
>> +      pathref = path.str();
>>        if (llvm::sys::fs::exists(pathref)) {
>>          foundFile = true;
>>        }
>>      }
>>      // Search for static libraries too
>>      if (!foundFile) {
>> -      SmallString<128> archivefullPath;
>> +      path.clear();
>>        if (dir.startswith("=/")) {
>> -        archivefullPath.assign(_sysrootPath);
>> -        archivefullPath.append(dir.substr(1));
>> +        path.assign(_sysrootPath);
>> +        path.append(dir.substr(1));
>>        } else {
>> -        archivefullPath.assign(dir);
>> +        path.assign(dir);
>>        }
>> -      llvm::sys::path::append(archivefullPath, Twine("lib") + libName +
>> ".a");
>> -      pathref = archivefullPath.str();
>> +      llvm::sys::path::append(path, Twine("lib") + libName + ".a");
>> +      pathref = path.str();
>>        if (llvm::sys::fs::exists(pathref)) {
>>          foundFile = true;
>>        }
>>      }
>>      if (foundFile)
>> -      return (*(new (_alloc) std::string(pathref.str())));
>> +      return StringRef(*new (_alloc) std::string(pathref));
>>    }
>>    if (!llvm::sys::fs::exists(libName))
>>      return llvm::make_error_code(llvm::errc::no_such_file_or_directory);
>>
>> -  return std::string(libName);
>> +  return libName;
>>  }
>>
>>  std::unique_ptr<File> ELFLinkingContext::createUndefinedSymbolFile() {
>>
>>
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>>
>
>
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