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Message-ID: <20120215123223.GA14094@albatros>
Date: Wed, 15 Feb 2012 16:32:23 +0400
From: Vasiliy Kulikov <segoon@...nwall.com>
To: netdev@...r.kernel.org, security@...nel.org, shemminger@...l.org,
kuznet@....inr.ac.ru
Cc: Solar Designer <solar@...nwall.com>
Subject: [patch] iproute: fix dangerous /tmp/ handling
Using "/tmp/file" without checking file owner is dangerous.
It could be a symlink pointing to user's file. If one creates
such symlink and makes victim do "./configure", gcc executed with
UID=victim would compile attacker's source file into arbitrary
location (e.g. into ~victim/bin/).
Instead use a directory created with mktemp and handle all temporary
files in this directory only.
The same with dhcp-client-script sample script.
Signed-off-by: Vasiliy Kulikov <segoon@...nwall.com>
--
configure | 34 +++++++++++++++++++---------------
examples/dhcp-client-script | 2 +-
2 files changed, 20 insertions(+), 16 deletions(-)
--
diff -uNp -r iproute2-3.2.0.old/configure iproute2-3.2.0/configure
--- iproute2-3.2.0.old/configure 2012-01-05 16:34:31 +0000
+++ iproute2-3.2.0/configure 2012-02-15 12:29:16 +0000
@@ -3,9 +3,13 @@
#
INCLUDE=${1:-"$PWD/include"}
+TMPDIR="`mktemp -dt iproute.XXXXXXXXXX`" || exit
+trap 'rm -rf -- "$TMPDIR"' EXIT
+trap 'trap - EXIT; rm -rf -- "$TMPDIR"; exit 1' HUP INT QUIT TERM
+
check_atm()
{
-cat >/tmp/atmtest.c <<EOF
+cat >$TMPDIR/atmtest.c <<EOF
#include <atm.h>
int main(int argc, char **argv) {
struct atm_qos qos;
@@ -13,7 +17,7 @@ int main(int argc, char **argv) {
return 0;
}
EOF
-gcc -I$INCLUDE -o /tmp/atmtest /tmp/atmtest.c -latm >/dev/null 2>&1
+gcc -I$INCLUDE -o $TMPDIR/atmtest $TMPDIR/atmtest.c -latm >/dev/null 2>&1
if [ $? -eq 0 ]
then
echo "TC_CONFIG_ATM:=y" >>Config
@@ -21,13 +25,13 @@ then
else
echo no
fi
-rm -f /tmp/atmtest.c /tmp/atmtest
+rm -f $TMPDIR/atmtest.c $TMPDIR/atmtest
}
check_xt()
{
#check if we have xtables from iptables >= 1.4.5.
-cat >/tmp/ipttest.c <<EOF
+cat >$TMPDIR/ipttest.c <<EOF
#include <xtables.h>
#include <linux/netfilter.h>
static struct xtables_globals test_globals = {
@@ -47,12 +51,12 @@ int main(int argc, char **argv)
EOF
-if gcc -I$INCLUDE $IPTC -o /tmp/ipttest /tmp/ipttest.c $IPTL $(pkg-config xtables --cflags --libs) -ldl >/dev/null 2>&1
+if gcc -I$INCLUDE $IPTC -o $TMPDIR/ipttest $TMPDIR/ipttest.c $IPTL $(pkg-config xtables --cflags --libs) -ldl >/dev/null 2>&1
then
echo "TC_CONFIG_XT:=y" >>Config
echo "using xtables"
fi
-rm -f /tmp/ipttest.c /tmp/ipttest
+rm -f $TMPDIR/ipttest.c $TMPDIR/ipttest
}
check_xt_old()
@@ -64,7 +68,7 @@ then
fi
#check if we dont need our internal header ..
-cat >/tmp/ipttest.c <<EOF
+cat >$TMPDIR/ipttest.c <<EOF
#include <xtables.h>
char *lib_dir;
unsigned int global_option_offset = 0;
@@ -84,14 +88,14 @@ int main(int argc, char **argv) {
}
EOF
-gcc -I$INCLUDE $IPTC -o /tmp/ipttest /tmp/ipttest.c $IPTL -ldl >/dev/null 2>&1
+gcc -I$INCLUDE $IPTC -o $TMPDIR/ipttest $TMPDIR/ipttest.c $IPTL -ldl >/dev/null 2>&1
if [ $? -eq 0 ]
then
echo "TC_CONFIG_XT_OLD:=y" >>Config
echo "using old xtables (no need for xt-internal.h)"
fi
-rm -f /tmp/ipttest.c /tmp/ipttest
+rm -f $TMPDIR/ipttest.c $TMPDIR/ipttest
}
check_xt_old_internal_h()
@@ -103,7 +107,7 @@ then
fi
#check if we need our own internal.h
-cat >/tmp/ipttest.c <<EOF
+cat >$TMPDIR/ipttest.c <<EOF
#include <xtables.h>
#include "xt-internal.h"
char *lib_dir;
@@ -124,14 +128,14 @@ int main(int argc, char **argv) {
}
EOF
-gcc -I$INCLUDE $IPTC -o /tmp/ipttest /tmp/ipttest.c $IPTL -ldl >/dev/null 2>&1
+gcc -I$INCLUDE $IPTC -o $TMPDIR/ipttest $TMPDIR/ipttest.c $IPTL -ldl >/dev/null 2>&1
if [ $? -eq 0 ]
then
echo "using old xtables with xt-internal.h"
echo "TC_CONFIG_XT_OLD_H:=y" >>Config
fi
-rm -f /tmp/ipttest.c /tmp/ipttest
+rm -f $TMPDIR/ipttest.c $TMPDIR/ipttest
}
check_ipt()
@@ -160,7 +164,7 @@ check_ipt_lib_dir()
check_setns()
{
-cat >/tmp/setnstest.c <<EOF
+cat >$TMPDIR/setnstest.c <<EOF
#include <sched.h>
int main(int argc, char **argv)
{
@@ -168,7 +172,7 @@ int main(int argc, char **argv)
return 0;
}
EOF
-gcc -I$INCLUDE -o /tmp/setnstest /tmp/setnstest.c >/dev/null 2>&1
+gcc -I$INCLUDE -o $TMPDIR/setnstest $TMPDIR/setnstest.c >/dev/null 2>&1
if [ $? -eq 0 ]
then
echo "IP_CONFIG_SETNS:=y" >>Config
@@ -176,7 +180,7 @@ then
else
echo "no"
fi
-rm -f /tmp/setnstest.c /tmp/setnstest
+rm -f $TMPDIR/setnstest.c $TMPDIR/setnstest
}
echo "# Generated config based on" $INCLUDE >Config
diff -uNp -r iproute2-3.2.0.old/examples/dhcp-client-script iproute2-3.2.0/examples/dhcp-client-script
--- iproute2-3.2.0.old/examples/dhcp-client-script 2012-01-05 16:34:31 +0000
+++ iproute2-3.2.0/examples/dhcp-client-script 2012-02-15 12:29:37 +0000
@@ -14,7 +14,7 @@
# we should install and preserve.
#
-exec >> /tmp/DHS.log 2>&1
+exec >> /var/log/DHS.log 2>&1
echo dhc-script $* reason=$reason
set | grep "^\(old_\|new_\|check_\)"
--
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments
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