[Lucid][CVE-2013-2852] b43: stop format string leaking into error msgs

[Luis Henriques]

From: Kees Cook <keescook at chromium.org>

BugLink: https://bugs.launchpad.net/bugs/1189833

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 at chromium.org>
Cc: stable at vger.kernel.org
Signed-off-by: John W. Linville <linville at tuxdriver.com>
(cherry picked from commit e0e29b683d6784ef59bbc914eac85a04b650e63c)

Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/wireless/b43/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 9bd5366..c14acea 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -2287,7 +2287,7 @@ static int b43_request_firmware(struct b43_wldev *dev)
 	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);
 	err = -ENOENT;
-- 
1.8.1.2