linux-kernel - [PATCH] resource: Add NULL check in next

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

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

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

Date:	Sun, 21 Sep 2014 08:51:44 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Mikael Starvik <starvik@...s.com>,
	Jesper Nilsson <jesper.nilsson@...s.com>,
	linux-kernel@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>,
	Vivek Goyal <vgoyal@...hat.com>
Subject: [PATCH] resource: Add NULL check in next_resource

Commit 8c86e70acead ("resource: provide new functions to walk through
resources") adds a suble new requirement that iomem_resource.child must
not be NULL when walk_system_ram_range is called. This can cause a crash
if it turns out that there are no children. The crash ('Unable to handle
kernel NULL pointer dereference') is seen when trying to test a crisv32
image on kernels with this commit applied.

Fix by adding a NULL check into next_resource().

Fixes: 8c86e70acead ("resource: provide new functions to walk through resources")
Cc: Vivek Goyal <vgoyal@...hat.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
The NULL check could be added elsewhere instead. I am open to suggestions.

 kernel/resource.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/resource.c b/kernel/resource.c
index 60c5a38..00c57ad 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -61,6 +61,9 @@ static DEFINE_SPINLOCK(bootmem_resource_lock);
 
 static struct resource *next_resource(struct resource *p, bool sibling_only)
 {
+	if (p == NULL)
+		return NULL;
+
 	/* Caller wants to traverse through siblings only */
 	if (sibling_only)
 		return p->sibling;
-- 
1.9.1

--
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/