linux-kernel - [PATCH v4 2/3] sched: Add helper for task stack page overrun checking

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:	Fri, 12 Sep 2014 14:16:18 +0100
From:	Aaron Tomlin <atomlin@...hat.com>
To:	peterz@...radead.org
Cc:	mingo@...hat.com, dzickus@...hat.com, bmr@...hat.com,
	jcastillo@...hat.com, atomlin@...hat.com, oleg@...hat.com,
	riel@...hat.com, prarit@...hat.com, jgh@...hat.com,
	linux-kernel@...r.kernel.org, tglx@...utronix.de, x86@...nel.org,
	rostedt@...dmis.org, hannes@...xchg.org,
	aneesh.kumar@...ux.vnet.ibm.com, akpm@...ux-foundation.org,
	akpm@...gle.com, linuxppc-dev@...ts.ozlabs.org, minchan@...nel.org,
	mpe@...erman.id.au
Subject: [PATCH v4 2/3] sched: Add helper for task stack page overrun checking

This facility is used in a few places so let's introduce
a helper function to improve code readability.

Signed-off-by: Aaron Tomlin <atomlin@...hat.com>
---
 arch/powerpc/mm/fault.c    | 4 +---
 arch/x86/mm/fault.c        | 4 +---
 include/linux/sched.h      | 2 ++
 kernel/trace/trace_stack.c | 2 +-
 4 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 35d0760c..99b2f27 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -507,7 +507,6 @@ bail:
 void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
 {
 	const struct exception_table_entry *entry;
-	unsigned long *stackend;
 
 	/* Are we prepared to handle this fault?  */
 	if ((entry = search_exception_tables(regs->nip)) != NULL) {
@@ -536,8 +535,7 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
 	printk(KERN_ALERT "Faulting instruction address: 0x%08lx\n",
 		regs->nip);
 
-	stackend = end_of_stack(current);
-	if (*stackend != STACK_END_MAGIC)
+	if (task_stack_end_corrupted(current))
 		printk(KERN_ALERT "Thread overran stack, or stack corrupted\n");
 
 	die("Kernel access of bad area", regs, sig);
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index bc23a70..6240bc7 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -648,7 +648,6 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 	   unsigned long address, int signal, int si_code)
 {
 	struct task_struct *tsk = current;
-	unsigned long *stackend;
 	unsigned long flags;
 	int sig;
 
@@ -708,8 +707,7 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 
 	show_fault_oops(regs, error_code, address);
 
-	stackend = end_of_stack(tsk);
-	if (*stackend != STACK_END_MAGIC)
+	if (task_stack_end_corrupted(tsk))
 		printk(KERN_EMERG "Thread overran stack, or stack corrupted\n");
 
 	tsk->thread.cr2		= address;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7ef34b7..a80e35d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2615,6 +2615,8 @@ static inline unsigned long *end_of_stack(struct task_struct *p)
 }
 
 #endif
+#define task_stack_end_corrupted(task) \
+		(*(end_of_stack(task)) != STACK_END_MAGIC)
 
 static inline int object_is_on_stack(void *obj)
 {
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 1636e41..16eddb3 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -170,7 +170,7 @@ check_stack(unsigned long ip, unsigned long *stack)
 			i++;
 	}
 
-	if (*end_of_stack(current) != STACK_END_MAGIC) {
+	if (task_stack_end_corrupted(current)) {
 		print_max_stack();
 		BUG();
 	}
-- 
1.9.3

--
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/