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Re: [PATCH][BZ #15763][BZ #14752] Restrict shm_open and shm_unlink to SHMDIR.
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: OndÅej BÃlka <neleai at seznam dot cz>, <libc-alpha at sourceware dot org>
- Date: Wed, 23 Oct 2013 19:26:25 +0000
- Subject: Re: [PATCH][BZ #15763][BZ #14752] Restrict shm_open and shm_unlink to SHMDIR.
- Authentication-results: sourceware.org; auth=none
- References: <20131015073738 dot GA32465 at domone dot podge> <5264FB77 dot 7090400 at redhat dot com> <20131023124140 dot GA5434 at domone dot podge> <526812E1 dot 5010700 at redhat dot com>
On Wed, 23 Oct 2013, Florian Weimer wrote:
> Sorry, I missed the NAME_MAX reference. I don't think it's guarantueed to be
> available. I see that it's desirable to have some upper bound to avoid alloca
> issues. Not sure if it's okay to put in some arbitrary constant (1024 would
> be fine in my book).
I believe such limits are fine in files in sysdeps/unix/sysv/linux, as
long as they use the appropriate macro and it describes an actual limit in
the kernel (NAME_MAX comes from linux/limits.h and I think does describe
an actual kernel limit), just not in generic files that may be used on
other systems without such limits.
(Quite a lot of the fallback code for !__ASSUME_ATFCTS really should be
using a PATH_MAX check so an appropriate error, rather than oversized
alloca, occurs for very long arguments.)
Joseph S. Myers