Re: [PATCH] gitk: use mktemp -d to avoid predictable temporary directories

[Pat Thoyts <patthoyts@users.sourceforge.net>]

David Aguilar <davvid@gmail.com> writes:

>gitk uses a predictable ".gitk-tmp.$PID" pattern when generating
>a temporary directory.
>
>Use "mktemp -d .gitk-tmp.XXXXXX" to harden gitk against someone
>seeding /tmp with files matching the pid pattern.
>
>Signed-off-by: David Aguilar <davvid@gmail.com>
>---
>This issue was brought up during the first review of the previous patch
>back in 2009.
>
>http://thread.gmane.org/gmane.comp.version-control.git/132609/focus=132748
>
>This is really [PATCH 2/2] and should be applied on top of my previous
>gitk patch.
>
> gitk | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/gitk b/gitk
>index 82293dd..dd2ff63 100755
>--- a/gitk
>+++ b/gitk
>@@ -3502,7 +3502,8 @@ proc gitknewtmpdir {} {
> 	} else {
> 	    set tmpdir $gitdir
> 	}
>-	set gitktmpdir [file join $tmpdir [format ".gitk-tmp.%s" [pid]]]
>+	set gitktmpformat [file join $tmpdir ".gitk-tmp.XXXXXX"]
>+	set gitktmpdir [exec mktemp -d $gitktmpformat]
> 	if {[catch {file mkdir $gitktmpdir} err]} {
> 	    error_popup "[mc "Error creating temporary directory %s:" $gitktmpdir] $err"
> 	    unset gitktmpdir

This is a problem on Windows where we will not have mktemp. In Tcl 8.6
the file command acquired a "file tempfile" command to help with this
kind of issue (https://www.tcl.tk/man/tcl8.6/TclCmd/file.htm#M39) but
for older versions we should probably stick with the existing pattern at
least on Windows.

-- 
Pat Thoyts                            http://www.patthoyts.tk/
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