lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 26 Jan 2022 12:13:16 -0800
From:   Kees Cook <>
To:     Matthew Wilcox <>
Cc:     Jann Horn <>,
        Ariadne Conill <>,
        Michael Kerrisk <>,
        Christian Brauner <>,
        Rich Felker <>,
        Eric Biederman <>,
        Alexander Viro <>,,,,
Subject: Re: [PATCH] fs/binfmt_elf: Add padding NULL when argc == 0

On Wed, Jan 26, 2022 at 08:08:14PM +0000, Matthew Wilcox wrote:
> On Wed, Jan 26, 2022 at 11:58:39AM -0800, Kees Cook wrote:
> > We can't mutate argc; it'll turn at least some userspace into an
> > infinite loop:
> >
> How does that become an infinite loop?  We obviously wouldn't mutate
> argc in the caller, just the callee.

Oh, sorry, I misread. It's using /bin/true, not argv[0] (another bit of
code I found was using argv[0]). Yeah, {"", NULL} could work.

> Also, there's a version of this where we only mutate argc if we're
> executing a setuid program, which would remove the privilege
> escalation part of things.

True; though I'd like to keep the logic as non-specialized as possible.
I don't like making stuff conditional on privilege boundaries if we can
make it always happen.

Kees Cook

Powered by blists - more mailing lists