Messages in this thread | | | Date | Sat, 8 Apr 2006 14:08:16 +0200 | From | Petr Baudis <> | Subject | Dumpable tasks and ownership of /proc/*/fd |
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Hello,
I would like to ask why is /proc/*/fd owned by root when the task is not dumpable - what security concern does it address? It would seem more reasonable to me if the /proc/*/fd owner would be simply always the real uid of the process.
The issue is that now all tasks calling setuid() from root to non-root during their lifetime will not be able to access their /proc/self/fd. This is troublesome because the fstatat() and other *at() routines are emulated by accessing /proc/self/fd/*/path and that will break with setuid()ing programs, leading to various weird consequences (e.g. with the latest glibc, nftw() does not work with setuid()ing programs and furthermore causes the LSB testsuite to fail because of this, etc.).
Thanks,
-- Petr "Pasky" Baudis Stuff: http://pasky.or.cz/ Right now I am having amnesia and deja-vu at the same time. I think I have forgotten this before. - 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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