linux-kernel - [PATCH v2 08/44] x86/dumpstack: fix irq stack bounds calculation in show_stack_log

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]

Message-Id: <84a87d66b0672f9535a80a7bf0a739da3538c489.1470345772.git.jpoimboe@redhat.com>
Date:	Thu,  4 Aug 2016 17:22:04 -0500
From:	Josh Poimboeuf <jpoimboe@...hat.com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>,
	"H . Peter Anvin" <hpa@...or.com>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org,
	Andy Lutomirski <luto@...capital.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Brian Gerst <brgerst@...il.com>,
	Kees Cook <keescook@...omium.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Byungchul Park <byungchul.park@....com>
Subject: [PATCH v2 08/44] x86/dumpstack: fix irq stack bounds calculation in show_stack_log_lvl()

The percpu irq_stack_ptr variable has a 64-byte gap from the end of the
allocated irq stack area, so subtracting IRQ_STACK_SIZE from it actually
results in a value 64 bytes before the beginning of the stack.  Use
IRQ_USABLE_STACK_SIZE instead.

Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 arch/x86/kernel/dumpstack_64.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 7ea6ed0..0fdd371 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -253,8 +253,8 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	preempt_disable();
 	cpu = smp_processor_id();
 
-	irq_stack_end	= (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
-	irq_stack	= (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
+	irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
+	irq_stack     = irq_stack_end - (IRQ_USABLE_STACK_SIZE / sizeof(long));
 
 	/*
 	 * Debugging aid: "show_stack(NULL, NULL);" prints the
-- 
2.7.4