Re: [PATCH] set*uid() must not fail-and-return on OOM/rlimits

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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

---

• References:
  • [PATCH] set*uid() must not fail-and-return on OOM/rlimits
    • From: Solar Designer <[email protected]>
  • Re: [PATCH] set*uid() must not fail-and-return on OOM/rlimits
    • From: [email protected] (Alex Riesen)
  • Re: [PATCH] set*uid() must not fail-and-return on OOM/rlimits
    • From: Solar Designer <[email protected]>
  • Re: [PATCH] set*uid() must not fail-and-return on OOM/rlimits
    • From: Arjan van de Ven <[email protected]>

• Prev by Date: [PATCH] PCI: add ICH7/8 ACPI/GPIO io resource quirks
• Next by Date: Re: [PATCH] 2.6.17.9 Incorrect string length checking in param_set_copystring()
• Previous by thread: Re: [PATCH] set*uid() must not fail-and-return on OOM/rlimits
• Next by thread: Re: [PATCH] set*uid() must not fail-and-return on OOM/rlimits
• Index(es):
  • Date
  • Thread

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]