From 54786ab35ea25208aa864e01ac9edada73cb560a Mon Sep 17 00:00:00 2001 From: Ed Maste Date: Wed, 28 Sep 2016 21:22:51 +0000 Subject: [PATCH] portsnap: only move expected snapshot contents from snap/ to files/ Previously it was possible to smuggle in addional files that would be used by later portsnap runs. Now we only move those files expected to be in the snapshot into files/ and require that there are no unexpected files. This was used by portsnap attacks 2, 3, and 4 in the "non-cryptanalytic attacks against FreeBSD update components" anonymous gist. Reported by: anonymous gist Reviewed by: allanjude, delphij MFC after: ASAP Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D8052 --- usr.sbin/portsnap/portsnap/portsnap.sh | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/usr.sbin/portsnap/portsnap/portsnap.sh b/usr.sbin/portsnap/portsnap/portsnap.sh index 3dcf618ab53a..501c530acd60 100644 --- a/usr.sbin/portsnap/portsnap/portsnap.sh +++ b/usr.sbin/portsnap/portsnap/portsnap.sh @@ -691,6 +691,13 @@ fetch_snapshot() { fetch_index_sanity || return 1 # Verify the snapshot contents cut -f 2 -d '|' INDEX.new | fetch_snapshot_verify || return 1 + cut -f 2 -d '|' tINDEX.new INDEX.new | sort -u > files.expected + find snap -mindepth 1 | sed -E 's^snap/(.*)\.gz^\1^' | sort > files.snap + if ! cmp -s files.expected files.snap; then + echo "unexpected files in snapshot." + return 1 + fi + rm files.expected files.snap echo "done." # Move files into their proper locations