Package: grep Version: 2.5.3~dfsg-6 Severity: normal Setting the (un-documented) environment variable GREP_USE_DFA to 0 causes grep to generate incorrect results.
Start with a three line text file:
$ cat file.txt
foo <= space
foo <= tab
sfoo
Now use grep with GREP_USE_DFA set to 1. Notice correct match:
$ GREP_USE_DFA=1 grep '^\s*foo' file.txt
sfoo
Now try with GREP_USE_DFA set to 0.
$ GREP_USE_DFA=0 grep '^\s*foo' file.txt
foo <= space
foo <= tab
The program now matches the other two lines, but not the one that
should match.
This is a serious issue since disabling DFA is the default for
multi-byte encodings such as UTF-8.
You can get the same (wrong) results by setting LANG:
$ LANG=C grep '^\s*foo' file.txt
sfoo
$ LANG=en_US.UTF-8 grep '^\s*foo' file.txt
foo <= space
foo <= tab
-- System Information:
Debian Release: 5.0.1
APT prefers stable
APT policy: (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 2.6.26-2-amd64 (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Versions of packages grep depends on:
ii libc6 2.7-18 GNU C Library: Shared
libraries
grep recommends no packages.
grep suggests no packages.
-- no debconf information
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