Clang-11.0.0 Miscompiled SQLite

栏目: IT技术 · 发布时间: 6年前

内容简介:It appears that the clang-11.0.0 compiler mis-compiles sqlite3.c version 3.32.1. I havechecked in a change to SQLite that appears to work around the problem. But there might be other bugs. Therefore, use clang-11.0.0 with caution and test your applicatio

It appears that the clang-11.0.0 compiler mis-compiles sqlite3.c version 3.32.1. I havechecked in a change to SQLite that appears to work around the problem. But there might be other bugs. Therefore, use clang-11.0.0 with caution and test your applications carefully!

Details:

OSSFuzz has been reported bug 23003 against SQLite. I could not reproduce the problem on my desktop (Ubuntu with gcc-5.4.0) so I followed the OSSFuzz bug replication procedures and discovered what appears to be a problem with Clang-11.0.0 currently used by OSSFuzz.

The code that is miscompiled is lines 345-347 of the src/utf.c source file , shown below:

c = pMem->flags;
      sqlite3VdbeMemRelease(pMem);
      pMem->flags = MEM_Str|MEM_Term|(c&(MEM_AffMask|MEM_Subtype));

From the -S output, it looks like Clang-11.0.0 is compiling these three lines as if there were written as:

sqlite3VdbeMemRelease(pMem);
      pMem->flags = MEM_Str|MEM_Term|(pMem->flags&(MEM_AffMask|MEM_Subtype));

In other words, Clang seems to be assuming that the sqlite3VdbeMemRelease() function does not change the value of pMem->flags. But it does. My work-around is to do the bit-twiddling of pMem->flags before the function call instead of afterwards:

c = MEM_Str|MEM_Term|(pMem->flags&(MEM_AffMask|MEM_Subtype));
      sqlite3VdbeMemRelease(pMem);
      pMem->flags = c;

Compiler Version And Build Details:

OSSFuzz reports the compiler used as:

clang version 11.0.0 (https://github.com/llvm/llvm-project.git a6ae333a0c23fc9b0783ca45e2676abac00c6723)
    Target: x86_64-unknown-linux-gnu
    Thread model: posix

The build script compiles SQLite thusly:

clang -O1 -fno-omit-frame-pointer -gline-tables-only -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -fsanitize=address -fsanitize-address-use-after-scope -fsanitize=fuzzer-no-link -DSQLITE_MAX_LENGTH=128000000 -DSQLITE_MAX_SQL_LENGTH=128000000 -DSQLITE_MAX_MEMORY=25000000 -DSQLITE_PRINTF_PRECISION_LIMIT=1048576 -DSQLITE_DEBUG=1 -DSQLITE_MAX_PAGE_COUNT=16384 -O1 -g -I. -c -O1 -g ./sqlite3.c -o sqlite3.o


以上就是本文的全部内容,希望本文的内容对大家的学习或者工作能带来一定的帮助,也希望大家多多支持 码农网

查看所有标签

本站部分资源来源于网络,本站转载出于传递更多信息之目的,版权归原作者或者来源机构所有,如转载稿涉及版权问题,请联系我们。

正当法律程序简史

正当法律程序简史

(美)约翰·V.奥尔特 / 杨明成、陈霜玲 / 商务印书馆 / 2006-8 / 14.00元

本书的主题——正当法律程序,是英美法的核心概念,它使诸如法治、经济自由、个人自治以及免于政府专断行为的侵害等价值观念具体化,因而是法学领域一个永恒的主题,数百年以来一直是法学家、法官及律师关注的重点。本书以极为简洁、精确的语言总结了五百年法律发展的恢弘历史,为人们描述了正当法律程序观念发展演变的清晰轨迹。而沿着这条轨迹,人们可以准确地了解正当法律程序这一重要概念所包含的广泛的问题。 作为一本......一起来看看 《正当法律程序简史》 这本书的介绍吧!

随机密码生成器
随机密码生成器

多种字符组合密码

HEX HSV 转换工具
HEX HSV 转换工具

HEX HSV 互换工具

HSV CMYK 转换工具
HSV CMYK 转换工具

HSV CMYK互换工具