Messages in this thread | | | Subject | Re: [PATCH] private mounts | From | Bryan Henderson <> | Date | Thu, 28 Apr 2005 10:58:18 -0700 |
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>This is why you have identity squashing and/or strong security: to stop >the CLIENT administrator impersonating whoever he wants and working >around your security measures.
That's more of a confirmation than a refutation of the statement that NFS root squashing is broken. Root squashing itself simply does not squash a typical system administrator's ability to get at other people's files. "broken" isn't the right word, because as long as you recognize root squashing for what it is, it's working as designed. It just isn't what it appears to be.
But, in the context of the current thread, I think the perception of NFS root squashing as something broken and not to be built upon with private mounts has to do with the fact that it messes up Linux's basic file permission scheme: a process with CAP_DAC_OVERRIDE can get EACCES. EACCESS means discretionary access controls (DAC) prevent access. So this behavior is unexpected and unnatural. Worse, an operation can succeed _without_ CAP_DAC_OVERRIDE, but not _with_ it. I've seen this behavior cause trouble a number of times -- mostly because it's entirely unanticipated.
-- Bryan Henderson IBM Almaden Research Center San Jose CA Filesystems - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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