From 9538cbaab6e8b8046039b4b2eb6c9d614dc782bd Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Fri, 10 May 2013 21:48:21 +0000
Subject: b43: stop format string leaking into error msgs

The module parameter "fwpostfix" is userspace controllable, unfiltered,
and is used to define the firmware filename. b43_do_request_fw() populates
ctx->errors[] on error, containing the firmware filename. b43err()
parses its arguments as a format string. For systems with b43 hardware,
this could lead to a uid-0 to ring-0 escalation.

CVE-2013-2852

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>
---
diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 6dd07e2..a95b77a 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -2458,7 +2458,7 @@ static void b43_request_firmware(struct work_struct *work)
 	for (i = 0; i < B43_NR_FWTYPES; i++) {
 		errmsg = ctx->errors[i];
 		if (strlen(errmsg))
-			b43err(dev->wl, errmsg);
+			b43err(dev->wl, "%s", errmsg);
 	}
 	b43_print_fw_helptext(dev->wl, 1);
 	goto out;
--
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