chanjarster / bash-5_1_8_long_var_corrupt

bash 5.1.8 long variable corrupt problem

bash-5_1_8_long_var_corrupt

bash 5.1.8 long variable corrupt problem

This is a project to reproduce bash 5.1.8 (alpine linux 3.15.0) long variable value corrupt issue.

Environment

OS: Alpine linux 3.15.0

Bash version: GNU bash, version 5.1.8(1)-release (x86_64-alpine-linux-musl)

Problem

A UTF-8 encoded file containing a lot of Chinese characters, file size ~35K.

file foo.txt
foo.txt: UTF-8 Unicode text, with very long lines, with no line terminators

A test script read content from foo.txt and assign the content to a variable, and then check md5sum for that variable. See test.sh

Sometimes, the md5sum check failed.

Output variable value to foo-corrupt.txt when check fail, compare it with foo.txt, found that a random byte are inserted into multiple positions.(I use "Hex friend" on Mac to do the compare work).

Reproduce step

build docker image:

./build.sh

run docker image:

./loop-run-docker.sh

output:

Docker run round 1
succeed

Docker run round 2
failed

Docker run round 3
succeed

Docker run round 4
succeed

Docker run round 5
failed

Fix

This bug is fixed at patch 14, see this, this and this.

Dockerfile-fix provide Bash 5.1.16, which solves the problem.

Run build-fix.sh to build the fixed docker image.

Run loop-run-docker-fix.sh to verify the fix.

Reference

相关文章：https://chanjarster.github.io/post/bash-long-var-corrupt/