[gentoo-portage-dev] [PATCH 1/2] bin/install-qa-check.d: add new 90bad-bin-owner QA check.

[Michael Orlitzky]

System executables that are not owned by root pose a security
risk. The owner of the executable is free to modify it at any time;
so, for example, he can change a daemon's behavior to make it
malicious before the next time the service is started (usually by
root).

On a "normal" system, there is no good reason why the superuser should
not own every system executable. This commit adds a new install-time
check that reports any such binaries with a QA warning. To avoid false
positives, non-"normal" systems (like prefix) are skipped at the moment.

Bug: https://bugs.gentoo.org/629398
---
 bin/install-qa-check.d/90bad-bin-owner | 38 ++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 bin/install-qa-check.d/90bad-bin-owner

diff --git a/bin/install-qa-check.d/90bad-bin-owner b/bin/install-qa-check.d/90bad-bin-owner
new file mode 100644
index 000000000..188d67a51
--- /dev/null
+++ b/bin/install-qa-check.d/90bad-bin-owner
@@ -0,0 +1,38 @@
+# Copyright 1999-2018 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+bad_bin_owner_check() {
+	# Warn about globally-installed executables (in /bin, /usr/bin, /sbin,
+	# or /usr/sbin) that are owned by a nonzero UID.
+
+	# This check doesn't work on non-root prefix installations at
+	# the moment, because every executable therein is owned by a
+	# nonzero UID.
+	[[ "${EUID}" -ne "0" || "${PORTAGE_INST_UID}" -ne "0" ]] && return
+
+	local d f found=()
+
+	for d in "${ED%/}/bin" "${ED%/}/usr/bin" "${ED%/}/sbin" "${ED%/}/usr/sbin"; do
+		[[ -d "${d}" ]] || continue
+
+		# Read the results of the "find" command into the "found" bash array.
+		# Use -L to catch symlinks whose targets are owned by a non-root user,
+		# even though it won't catch ABSOLUTE symlinks until the package
+		# is RE-installed (the first time around, the target won't exist).
+		while read -r -d '' f; do
+			found+=( "${f}" )
+		done < <(find -L "${d}" -maxdepth 1 -type f ! -uid 0 -print0)
+
+		if [[ ${found[@]} ]]; then
+			eqawarn "system executables owned by nonzero uid:"
+			for f in "${found[@]}"; do
+				# Strip off the leading destdir before outputting the path,
+				# but leave the prefix if there is one.
+				eqawarn "  ${f#${D%/}/}"
+			done
+		fi
+	done
+}
+
+bad_bin_owner_check
+:
-- 
2.16.4