use client-side storage to defend against rollback attack #955

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zooko · 2010-02-15T05:40:59Z

zooko commented

2010-02-15 05:40:59 +00:00

As mentioned in (@@http://www.mail-archive.com/cryptography@metzdowd.com/msg10865.html@@) , clients which have previously viewed a mutable file or directory could remember the version number that they had already seen and refuse to accept an earlier version number after that. This would prevent rollback attack whenever that client-side storage was carried from the first read to the next.

The client-side storage of the version numbers could be integrated with the backupdb, which already likes to remember a few facts about files and directories in order to optimize backups. (And eventually perhaps restores and "mirrorings" and reads and writes as well.)

As mentioned in (@@http://www.mail-archive.com/cryptography@metzdowd.com/msg10865.html@@) , clients which have previously viewed a mutable file or directory could remember the version number that they had already seen and refuse to accept an earlier version number after that. This would prevent rollback attack whenever that client-side storage was carried from the first read to the next. The client-side storage of the version numbers could be integrated with the backupdb, which already likes to remember a few facts about files and directories in order to optimize backups. (And eventually perhaps restores and "mirrorings" and reads and writes as well.)

zooko added the

labels 2010-02-15 05:40:59 +00:00

zooko added this to the undecided milestone 2010-02-15 05:40:59 +00:00

zooko commented

2010-02-15 06:15:46 +00:00

#956 (embed security metadata in parent directory) and #957 (embed security metadata in URL) are about other places that this information (and other kinds of "security-related metadata") could be usefully stored.