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 PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Tue, 20 Oct 2009 08:14:15 +0200 From: Ingo Molnar <mingo@...e.hu> To: Jan Beulich <JBeulich@...ell.com> Cc: tglx@...utronix.de, hpa@...or.com, stable@...nel.org, linux-kernel@...r.kernel.org Subject: Re: Withdraw: [PATCH] x86-64: fix another kernel data leak to 32-bit processes * Jan Beulich <JBeulich@...ell.com> wrote: > >Unfortunately I didn't realize that the other instances of branches > >to int_ret_from_sys_call also need fixing when preparing the previous > >similar patch. The issue fixed here was in fact introduced by an > >earlier patch of mine (295286a89107c353b9677bc604361c537fd6a1c0, i.e. > >in 2.6.28, but through stable now also present in 2.6.27), making > >kernel stack contents potentially visible through R8...R11 when an > >this or earlier syscall got interrupted prior to the handler being > >able to decrement the stack pointer (such that the space normally > >used by those registers within pt_regs would get overwritten by the > >interrupt handler stub). > > That analysis wasn't right after all - there's a CLEAR_RREGS in each > of the modified paths already, so the change is unnecessary (and > adding redundant code). Please don't apply it. > > >While touching the code, I also swapped the branch pairs so that the > >static branch prediction logic would consider the syscall-number-in- > >range case the taken path. > > If this would seem a worthwhile change, I can re-send it as a > separate, lower priority patch... Please do - thanks! Ingo -- 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/
Powered by blists - more mailing lists