From eb910947c82f93cee6ee00a59a4ed86f12cf6e7f Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Wed, 9 Dec 2015 14:50:27 -0800 Subject: 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 Cc: Luis R. Rodriguez Acked-by: Kees Cook Signed-off-by: Shuah Khan --- lib/test_firmware.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) (limited to 'lib') diff --git a/lib/test_firmware.c b/lib/test_firmware.c index 690b9c35a274..a3e8ec3fb1c5 100644 --- a/lib/test_firmware.c +++ b/lib/test_firmware.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -80,6 +81,57 @@ out: } 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 @@ static int __init test_firmware_init(void) 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; @@ -109,6 +172,8 @@ module_init(test_firmware_init); static void __exit test_firmware_exit(void) { 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); -- cgit v1.2.3-59-g8ed1b