Messages in this thread | | | Date | Sun, 20 Aug 2006 18:17:39 +0200 | From | Willy Tarreau <> | Subject | Re: [PATCH] set*uid() must not fail-and-return on OOM/rlimits |
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On Sun, Aug 20, 2006 at 05:53:22PM +0200, Arjan van de Ven wrote: > On Sun, 2006-08-20 at 19:30 +0400, Solar Designer wrote: > > On Sun, Aug 20, 2006 at 12:07:06PM +0200, Alex Riesen wrote: > > > Solar Designer, Sun, Aug 20, 2006 02:38:40 +0200: > > > > Attached is a trivial patch (extracted from 2.4.33-ow1) that makes > > > > set*uid() kill the current process rather than proceed with -EAGAIN when > > > > the kernel is running out of memory. Apparently, alloc_uid() can't fail > > > > and return anyway due to properties of the allocator, in which case the > > > > patch does not change a thing. But better safe than sorry. > > > > > > Why not ENOMEM? > > > > ENOMEM would not be any better than EAGAIN from the security standpoint. > > > > The problem is that there are lots of privileged userspace programs that > > do not bother to check the return value from set*uid() calls (or > > otherwise check that the calls succeeded) before proceeding with work > > that is only safe to do with the *uid switched as intended. > > sounds like a good argument to get the setuid functions marked > __must_check in glibc...
Agreed, as I'm sure that I've not always checked it in some of my own programs. A warning would have helped.
Willy
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