linux-kernel - Re: [PATCH v5] Fix INT1 Recursion with unregistered breakpoints

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] [day] [month] [year] [list]

Date:	Sat, 19 Dec 2015 20:15:52 -0700
From:	Jeff Merkey <linux.mdb@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	x86@...nel.org, peterz@...radead.org, luto@...nel.org
Subject: Re: [PATCH v5] Fix INT1 Recursion with unregistered breakpoints

>  		/*
> +		 * Check if we got an execute breakpoint, if so
> +		 * set the resume flag to avoid int1 recursion.
> +		 */
> +		if ((dr7 & (DR_RW_MASK << ((i * DR_CONTROL_SIZE) +
> +			DR_CONTROL_SHIFT))) == DR_RW_EXECUTE)
> +			args->regs->flags |= X86_EFLAGS_RF;
> +
> +		/*

This patch is functionaly correct but I still need to make it perfect.
I more try and test run.
I tested this and it works, but I need to shift it the other way
(right) rather than (left) since DR_RW_EXECUTE is always 0 this will
always work but to be perfect I need to do:

if (((dr7 >> ((i * DR_CONTROL_SIZE) + DR_CONTROL_SHIFT)) & DR_RW_MASK)
== DR_RW_EXECUTE)

and that is perfect syntax.

Jeff
--
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/