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

[David Aguilar <davvid@gmail.com>]

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
-- 
2.0.0.257.g75cc6c6