Subject: CVS commit: src/sys/kern
To: None <source-changes@NetBSD.org>
From: Elad Efrat <elad@netbsd.org>
List: source-changes
Date: 11/23/2006 13:11:29
Module Name: src
Committed By: elad
Date: Thu Nov 23 13:11:29 UTC 2006
Modified Files:
src/sys/kern: kern_verifiedexec.c
Log Message:
Document flaw in veriexec_rawchk(). This is what I added to the comment:
* XXX: This is bogus. There's an obvious race condition between the time
* XXX: the disk is open for writing, in which an attacker can access a
* XXX: monitored file to get its signature cached again, and when the raw
* XXX: file is overwritten on disk.
* XXX:
* XXX: To solve this, we need something like the following:
* XXX: open raw disk:
* XXX: - raise refcount,
* XXX: - invalidate fingerprints,
* XXX: - mark all entries with "no cache" flag
* XXX:
* XXX: veriexec_verify:
* XXX: - if "no cache", don't cache evaluation result
* XXX:
* XXX: close raw disk:
* XXX: - lower refcount,
* XXX: - if refcount == 0, remove "no cache" flag from all entries
To generate a diff of this commit:
cvs rdiff -r1.69 -r1.70 src/sys/kern/kern_verifiedexec.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.