test: firmware_class: add asynchronous request trigger
We might want to test for bugs like that found in commit f9692b2699bd
("firmware: fix possible use after free on name on asynchronous
request"), where the asynchronous request API had race conditions.
Let's add a simple file that will launch the async request, then wait
until it's complete and report the status. It's not a true async test
(we're using a mutex + wait_for_completion(), so we can't get more than
one going at the same time), but it does help make sure the basic API is
sane, and it can catch some class of bugs.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
diff --git a/lib/test_firmware.c b/lib/test_firmware.c
index 690b9c3..a3e8ec3 100644
--- a/lib/test_firmware.c
+++ b/lib/test_firmware.c
@@ -12,6 +12,7 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/printk.h>
+#include <linux/completion.h>
#include <linux/firmware.h>
#include <linux/device.h>
#include <linux/fs.h>
@@ -80,6 +81,57 @@
}
static DEVICE_ATTR_WO(trigger_request);
+static DECLARE_COMPLETION(async_fw_done);
+
+static void trigger_async_request_cb(const struct firmware *fw, void *context)
+{
+ test_firmware = fw;
+ complete(&async_fw_done);
+}
+
+static ssize_t trigger_async_request_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int rc;
+ char *name;
+
+ name = kstrndup(buf, count, GFP_KERNEL);
+ if (!name)
+ return -ENOSPC;
+
+ pr_info("loading '%s'\n", name);
+
+ mutex_lock(&test_fw_mutex);
+ release_firmware(test_firmware);
+ test_firmware = NULL;
+ rc = request_firmware_nowait(THIS_MODULE, 1, name, dev, GFP_KERNEL,
+ NULL, trigger_async_request_cb);
+ if (rc) {
+ pr_info("async load of '%s' failed: %d\n", name, rc);
+ kfree(name);
+ goto out;
+ }
+ /* Free 'name' ASAP, to test for race conditions */
+ kfree(name);
+
+ wait_for_completion(&async_fw_done);
+
+ if (test_firmware) {
+ pr_info("loaded: %zu\n", test_firmware->size);
+ rc = count;
+ } else {
+ pr_err("failed to async load firmware\n");
+ rc = -ENODEV;
+ }
+
+out:
+ mutex_unlock(&test_fw_mutex);
+
+ return rc;
+}
+static DEVICE_ATTR_WO(trigger_async_request);
+
static int __init test_firmware_init(void)
{
int rc;
@@ -96,9 +148,20 @@
goto dereg;
}
+ rc = device_create_file(test_fw_misc_device.this_device,
+ &dev_attr_trigger_async_request);
+ if (rc) {
+ pr_err("could not create async sysfs interface: %d\n", rc);
+ goto remove_file;
+ }
+
pr_warn("interface ready\n");
return 0;
+
+remove_file:
+ device_remove_file(test_fw_misc_device.this_device,
+ &dev_attr_trigger_async_request);
dereg:
misc_deregister(&test_fw_misc_device);
return rc;
@@ -110,6 +173,8 @@
{
release_firmware(test_firmware);
device_remove_file(test_fw_misc_device.this_device,
+ &dev_attr_trigger_async_request);
+ device_remove_file(test_fw_misc_device.this_device,
&dev_attr_trigger_request);
misc_deregister(&test_fw_misc_device);
pr_warn("removed interface\n");