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System executables that are not owned by root pose a security |
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risk. The owner of the executable is free to modify it at any time; |
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so, for example, he can change a daemon's behavior to make it |
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malicious before the next time the service is started (usually by |
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root). |
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|
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On a "normal" system, there is no good reason why the superuser should |
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not own every system executable. This commit adds a new install-time |
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check that reports any such binaries with a QA warning. To avoid false |
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positives, non-"normal" systems (like prefix) are skipped at the moment. |
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|
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Bug: https://bugs.gentoo.org/629398 |
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--- |
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bin/install-qa-check.d/90bad-bin-owner | 47 ++++++++++++++++++++++++++++++++++ |
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1 file changed, 47 insertions(+) |
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create mode 100644 bin/install-qa-check.d/90bad-bin-owner |
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|
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diff --git a/bin/install-qa-check.d/90bad-bin-owner b/bin/install-qa-check.d/90bad-bin-owner |
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new file mode 100644 |
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index 000000000..748e1dc99 |
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--- /dev/null |
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+++ b/bin/install-qa-check.d/90bad-bin-owner |
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@@ -0,0 +1,47 @@ |
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+# Copyright 1999-2018 Gentoo Foundation |
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+# Distributed under the terms of the GNU General Public License v2 |
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+ |
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+bad_bin_owner_check() { |
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+ # Warn about globally-installed executables (in /bin, /usr/bin, /sbin, |
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+ # /usr/sbin, or /opt/bin) that are owned by a nonzero UID. |
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+ |
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+ # This check doesn't work on non-root prefix installations at |
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+ # the moment, because every executable therein is owned by a |
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+ # nonzero UID. |
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+ [[ "${EUID}" -ne "0" || "${PORTAGE_INST_UID}" -ne "0" ]] && return |
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+ |
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+ local d f found=() |
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+ |
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+ for d in "${ED%/}/opt/bin" "${ED%/}/bin" "${ED%/}/usr/bin" \ |
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+ "${ED%/}/sbin" "${ED%/}/usr/sbin"; do |
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+ [[ -d "${d}" ]] || continue |
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+ |
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+ # Read the results of the "find" command into the "found" bash array. |
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+ # Use -L to catch symlinks whose targets are owned by a non-root user, |
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+ # even though it won't catch ABSOLUTE symlinks until the package |
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+ # is RE-installed (the first time around, the target won't exist). |
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+ # We do want to list non-superuser setuid executables, because |
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+ # they can be exploited. The owner can simply wipe the setuid |
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+ # bit, and then alter the contents of the file. The superuser |
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+ # will then have a time bomb in his $PATH. |
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+ while read -r -d '' f; do |
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+ found+=( "${f}" ) |
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+ done < <(find -L "${d}" \ |
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+ -maxdepth 1 \ |
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+ -type f \ |
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+ ! -uid 0 \ |
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+ -print0) |
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+ done |
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+ |
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+ if [[ ${found[@]} ]]; then |
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+ eqawarn "system executables owned by nonzero uid:" |
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+ for f in "${found[@]}"; do |
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+ # Strip off the leading destdir before outputting the path, |
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+ # but leave the prefix if there is one. |
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+ eqawarn " ${f#${D%/}/}" |
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+ done |
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+ fi |
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+} |
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+ |
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+bad_bin_owner_check |
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+: |
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-- |
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2.16.4 |