Messages in this thread | | | Date | Fri, 14 Sep 2007 20:25:45 +1000 | From | Greg Banks <> | Subject | Re: [NFS] [PATCH 2/7] NFS: if ATTR_KILL_S*ID bits are set, then skip mode change |
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On Tue, Sep 04, 2007 at 10:37:04AM -0400, Jeff Layton wrote: > If the ATTR_KILL_S*ID bits are set then any mode change is only for > clearing the setuid/setgid bits. For NFS skip the mode change and > let the server handle it.
You're assuming the server will remove setuid and setgid bits on WRITE? I don't see that behaviour specified in the RFC, at least for v3. The RFC specifies a behaviour for the mtime attribute as a side effect of WRITE, but says nothing about mode. This means server implementations are free to clobber setuid or not. A quick experiment shows that at least the Irix server will *NOT* clobber those bits. So with an Irix server you've now lost this Linux-specific "security feature".
I'm curious about the reasons behind this change. You mention credential issues; how exactly is it that you have the correct creds to perform a WRITE rpc but not a SETATTR rpc?
Greg. -- Greg Banks, R&D Software Engineer, SGI Australian Software Group. Apparently, I'm Bedevere. Which MPHG character are you? I don't speak for SGI. - 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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