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From: Atry <pop DOT atry AT gmail DOT com>
Date: Tue, 17 Jan 2012 19:06:55 +0800
Message-ID: <CA+nJC964zeB6WQBsh9+0+oc1=Se9y=SCfZ+kgfktxN97OKTABw@mail.gmail.com>
Subject: /etc/profile set $TMP to /tmp. It's insecure!
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Original $TMP and $TEMP is unset in /etc/defaults/etc/skel/.bashrc
version 3.9-3, which make %USERPROFILE% directory dirty. After some
disscuss at http://cygwin.com/ml/cygwin/2011-03/msg00211.html,
/etc/profile version 4.0-6 set $TMP and $TEMP to /tmp. Now any program
start from bash, create temporary files in /tmp, or C:\cygwin\tmp.

Cygwin program, which approves /tmp 's mode 1777, creates temporary
files with mode 400. That's OK.

Native Win32 program, which ignores /tmp 's mode 1777, creates
temporary files with mode 755. These files can be read from any user.
Win32 process may leak internal data, cause potential privilege
escalation attack.

I suggest that set $tmp (lowercase) to original $TMP, which is
meaningless for cygwin programs, and is recognized for Win32 programs.

Proposed settings in /etc/profile:

ORIGINAL_TMP=$TMP
ORIGINAL_TEMP=$TEMP
unset TMP TEMP
export tmp=`cygpath -w "$ORIGINAL_TMP"`
export temp=`cygpath -w "$ORIGINAL_TEMP"`

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