linux-kernel - Re: [PATCH] x86: prevent binaries from making system calls using the wrong syscall interface

lists.openwall.net		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 linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 7 Aug 2008 11:15:39 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	md@...gle.com (Michael Davidson)
Cc:	mingo@...hat.com, tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: prevent binaries from making system calls using
 the wrong syscall interface

> Currently there is nothing to prevent 64 bit binaries from
> attempting to make system calls using the 32 bit system call
> interfaces and vice versa.

What about applications that choose to do this
- Test tools
- Tools where certain interfaces are only available 32bit ?

> Since the 32 bit and 64 bit system call numbers are different
> this means that a binary could attempt to obfuscate which system
> calls it was actually making by using the "wrong" system call
> interface. In particular, the call to audit_syscall_entry()
> relies on checking the TIF_IA32 flag to determine whether it is
> dealing with a 32 or 64 bit system call without regard to the
> actual type of system call that was made.While this specific issue
> could be addressed by checking the TS_COMPAT flag in threadinfo_status
> it seems preferable to simply disallow this situation altogether.

That is a significant change of kernel ABI considering it exists just to
wallpaper over crappy audit tools.

I'm definitely against that approach.

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