ebuild-helpers: avoid exec loops or fork bombs in wrappers (bug 547086)

Since commit 130c01b9e561dd6ff7733a4905b21a0a921e9a22, extra portage
paths in PATH could trigger exec loops or fork bombs in wrappers.

Fixes: 130c01b9e561 ("_doebuild_path: add fallback for temp PORTAGE_BIN_PATH (bug 547086)")
X-Gentoo-Bug: 547086
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=547086
Acked-by: Brian Dolbec <dolsen@gentoo.org>

4 files changed, 22 insertions, 4 deletions

diff --git a/bin/ebuild-helpers/bsd/sed b/bin/ebuild-helpers/bsd/sed
index 01b88471d..9a7f2d4bb 100755
--- a/bin/ebuild-helpers/bsd/sed
+++ b/bin/ebuild-helpers/bsd/sed
@@ -1,5 +1,5 @@
 #!/bin/bash
-# Copyright 2007-2012 Gentoo Foundation
+# Copyright 2007-2015 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 scriptpath=${BASH_SOURCE[0]}
@@ -15,6 +15,8 @@ else
 
 	for path in $PATH; do
 		if [[ -x ${path}/${scriptname} ]]; then
+			[[ ${path} == ${PORTAGE_OVERRIDE_EPREFIX}/usr/lib*/portage/* ]] && continue
+			[[ ${path} == */._portage_reinstall_.* ]] && continue
 			[[ ${path}/${scriptname} -ef ${scriptpath} ]] && continue
 			exec "${path}/${scriptname}" "$@"
 			exit 0
diff --git a/bin/ebuild-helpers/portageq b/bin/ebuild-helpers/portageq
index 4151bac70..ba889ebcc 100755
--- a/bin/ebuild-helpers/portageq
+++ b/bin/ebuild-helpers/portageq
@@ -1,5 +1,5 @@
 #!/bin/bash
-# Copyright 2009-2013 Gentoo Foundation
+# Copyright 2009-2015 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 scriptpath=${BASH_SOURCE[0]}
@@ -15,6 +15,8 @@ set -f # in case ${PATH} contains any shell glob characters
 
 for path in ${PATH}; do
 	[[ -x ${path}/${scriptname} ]] || continue
+	[[ ${path} == ${PORTAGE_OVERRIDE_EPREFIX}/usr/lib*/portage/* ]] && continue
+	[[ ${path} == */._portage_reinstall_.* ]] && continue
 	[[ ${path}/${scriptname} -ef ${scriptpath} ]] && continue
 	PYTHONPATH=${PORTAGE_PYTHONPATH:-${PORTAGE_PYM_PATH}} \
 		exec "${PORTAGE_PYTHON:-/usr/bin/python}" \
diff --git a/bin/ebuild-helpers/unprivileged/chown b/bin/ebuild-helpers/unprivileged/chown
index 08fa650c5..2f1f1617d 100755
--- a/bin/ebuild-helpers/unprivileged/chown
+++ b/bin/ebuild-helpers/unprivileged/chown
@@ -1,5 +1,5 @@
 #!/bin/bash
-# Copyright 2012-2013 Gentoo Foundation
+# Copyright 2012-2015 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 scriptpath=${BASH_SOURCE[0]}
@@ -9,6 +9,8 @@ IFS=':'
 
 for path in ${PATH}; do
 	[[ -x ${path}/${scriptname} ]] || continue
+	[[ ${path} == ${PORTAGE_OVERRIDE_EPREFIX}/usr/lib*/portage/* ]] && continue
+	[[ ${path} == */._portage_reinstall_.* ]] && continue
 	[[ ${path}/${scriptname} -ef ${scriptpath} ]] && continue
 	IFS=$' \t\n'
 	output=$("${path}/${scriptname}" "$@" 2>&1)
diff --git a/bin/ebuild-helpers/xattr/install b/bin/ebuild-helpers/xattr/install
index d572fe6ef..2d2a693a9 100755
--- a/bin/ebuild-helpers/xattr/install
+++ b/bin/ebuild-helpers/xattr/install
@@ -1,5 +1,5 @@
 #!/bin/bash
-# Copyright 2013 Gentoo Foundation
+# Copyright 2013-2015 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 PORTAGE_BIN_PATH=${PORTAGE_BIN_PATH:-/usr/lib/portage/bin}
@@ -24,6 +24,18 @@ else
 	fi
 fi
 
+# Filter internal portage paths from PATH, in order to avoid
+# a possible exec loop or fork bomb (see bug 547086).
+IFS=':'
+set -f
+path=
+for x in ${PATH}; do
+	[[ ${x} == ${PORTAGE_OVERRIDE_EPREFIX}/usr/lib*/portage/* ]] && continue
+	[[ ${x} == */._portage_reinstall_.* ]] && continue
+	path+=":${x}"
+done
+PATH=${path#:}
+
 if [[ "${implementation}" == "c" ]]; then
 	exec "${INSTALL_XATTR}" "$@"
 elif [[ "${implementation}" == "python" ]]; then