firmware_class: make sure fw requests contain a name

commit 471b095dfe0d693a8d624cbc716d1ee4d74eb437 upstream.

An empty firmware request name will trigger warnings when building
device names. Make sure this is caught earlier and rejected.

The warning was visible via the test_firmware.ko module interface:

echo -ne "\x00" > /sys/devices/virtual/misc/test_firmware/trigger_request

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 3719c94..763b356 100644 (file)
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -521,6 +521,9 @@ static int _request_firmware(const struct firmware **firmware_p,
        if (!firmware_p)
                return -EINVAL;
 
+       if (!name || name[0] == '\0')
+               return -EINVAL;
+
        *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
        if (!firmware) {
                dev_err(device, "%s: kmalloc(struct firmware) failed\n",