在python扩展上解决Sanitizer

问题描述

我正在尝试使用Address Sanitizer编译python扩展。加载扩展程序时，我得到

I am trying to compile a python extension with Address Sanitizer. When I load the extension, I get

Traceback (most recent call last):
  File "test.py", line 2, in <module>
    from extension import package
  File "/tmp/python_test/extension/package.py", line 28, in <module>
    from extension._ext import *
ImportError: /tmp/python_test/extension/_ext.so: undefined symbol: __asan_version_mismatch_check_v8

编译器调用为

clang -g -o _ext.so code.ll -fsanitize=address -lrt -lpthread -ldl -lstdc++ -lm -fPIC -shared

无法正确地从asan加载符号。我尝试使用 -static-libsan ，但结果是相同的。

So, it does not load symbols from asan correctly. I've tried using -static-libsan, but the result was the same.

我已经看到有些人使用 LD_PRELOAD 来使Asan进入共享对象，但是，似乎我系统上的 libasan.so 来自不同版本的Address Sanitizer（是从Debian的libasan3软件包安装的，而我从deb llvm-toolchain-stretch-8 main）。

I've seen that some people use LD_PRELOAD to get Asan into shared objects, however, it seems that the libasan.so on my system is from a different version of Address Sanitizer (Installed from Debian's libasan3 package, while I got clang from deb http://apt.llvm.org/stretch/ llvm-toolchain-stretch-8 main).

那么，如何使Address Sanitizer与共享库一起工作？
要么，我需要 libasan.so 的正确版本（似乎不在deb llvm-toolchain-stretch-8 main，或者我需要一种方法来静态地建立clang链接）。

So, how can I make Address Sanitizer work with a shared object library?Either, I need the correct version of libasan.so (which does not seem to be in deb http://apt.llvm.org/stretch/ llvm-toolchain-stretch-8 main, or I need a way to have clang link that statically).

我的clang版本：

$ clang -v
clang version 8.0.0-svn356034-1~exp1~20190313094216.53 (branches/release_80)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6.3.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.3.0
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6.3.0
Candidate multilib: .;@m64
Selected multilib: .;@m64

推荐答案

要消毒单个您应该使用Clang库（不对主要的 python 可执行文件进行消毒）

To sanitize a single library (without sanitizing main python executable) with Clang you should

• 添加 -shared-libasan 到 LDFLAGS （Clang默认为 -static-libasan ，与GCC不同）


• 运行 LD_PRELOAD = $（clang -print-file-name = libclang_rt.asan-x86_64.so）（应该

• add -shared-libasan to LDFLAGS (Clang defaults to -static-libasan, unlike GCC)
• run with LD_PRELOAD=$(clang -print-file-name=libclang_rt.asan-x86_64.so) (it should be somewhere with standard Clang libs)

（请参见）。

另一种方法是使用GCC，在这种情况下共享-libasan 不需要，并且 LD_PRELOAD 的值变为 libasan.so.N （ N 取决于GCC版本，请使用 $（gcc -print-file-name = libasan.so）查找）。

Another option is using GCC, in which case -shared-libasan is not needed and LD_PRELOAD value becomes libasan.so.N (N depends on GCC version, use $(gcc -print-file-name=libasan.so) to locate it).

有关GCC和Clang在shlibs消毒方面的区别的更多详细信息，请参见。

For more details on differences between GCC and Clang with respect to sanitization of shlibs see this answer.

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