firmware: move firmware loader into its own directory

This will make it much easier to manage as we manage to
keep trimming componnents down into their own files to more
easily manage and maintain this codebase.

Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 661 insertions, 0 deletions

diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
new file mode 100644
index 000000000000..9b65837256d6
--- /dev/null
+++ b/drivers/base/firmware_loader/fallback.c
@@ -0,0 +1,661 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/types.h>
+#include <linux/kconfig.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include <linux/highmem.h>
+#include <linux/umh.h>
+
+#include "fallback.h"
+#include "firmware.h"
+
+/*
+ * firmware fallback mechanism
+ */
+
+extern struct firmware_fallback_config fw_fallback_config;
+
+/* These getters are vetted to use int properly */
+static inline int __firmware_loading_timeout(void)
+{
+        return fw_fallback_config.loading_timeout;
+}
+
+/* These setters are vetted to use int properly */
+static void __fw_fallback_set_timeout(int timeout)
+{
+        fw_fallback_config.loading_timeout = timeout;
+}
+
+/*
+ * use small loading timeout for caching devices' firmware because all these
+ * firmware images have been loaded successfully at lease once, also system is
+ * ready for completing firmware loading now. The maximum size of firmware in
+ * current distributions is about 2M bytes, so 10 secs should be enough.
+ */
+void fw_fallback_set_cache_timeout(void)
+{
+        fw_fallback_config.old_timeout = __firmware_loading_timeout();
+        __fw_fallback_set_timeout(10);
+}
+
+/* Restores the timeout to the value last configured during normal operation */
+void fw_fallback_set_default_timeout(void)
+{
+        __fw_fallback_set_timeout(fw_fallback_config.old_timeout);
+}
+
+static long firmware_loading_timeout(void)
+{
+        return __firmware_loading_timeout() > 0 ?
+                __firmware_loading_timeout() * HZ : MAX_JIFFY_OFFSET;
+}
+
+static inline bool fw_sysfs_done(struct fw_priv *fw_priv)
+{
+        return __fw_state_check(fw_priv, FW_STATUS_DONE);
+}
+
+static inline bool fw_sysfs_loading(struct fw_priv *fw_priv)
+{
+        return __fw_state_check(fw_priv, FW_STATUS_LOADING);
+}
+
+static inline int fw_sysfs_wait_timeout(struct fw_priv *fw_priv,  long timeout)
+{
+        return __fw_state_wait_common(fw_priv, timeout);
+}
+
+struct fw_sysfs {
+        bool nowait;
+        struct device dev;
+        struct fw_priv *fw_priv;
+        struct firmware *fw;
+};
+
+static struct fw_sysfs *to_fw_sysfs(struct device *dev)
+{
+        return container_of(dev, struct fw_sysfs, dev);
+}
+
+static void __fw_load_abort(struct fw_priv *fw_priv)
+{
+        /*
+         * There is a small window in which user can write to 'loading'
+         * between loading done and disappearance of 'loading'
+         */
+        if (fw_sysfs_done(fw_priv))
+                return;
+
+        list_del_init(&fw_priv->pending_list);
+        fw_state_aborted(fw_priv);
+}
+
+static void fw_load_abort(struct fw_sysfs *fw_sysfs)
+{
+        struct fw_priv *fw_priv = fw_sysfs->fw_priv;
+
+        __fw_load_abort(fw_priv);
+}
+
+static LIST_HEAD(pending_fw_head);
+
+void kill_pending_fw_fallback_reqs(bool only_kill_custom)
+{
+        struct fw_priv *fw_priv;
+        struct fw_priv *next;
+
+        mutex_lock(&fw_lock);
+        list_for_each_entry_safe(fw_priv, next, &pending_fw_head,
+                                 pending_list) {
+                if (!fw_priv->need_uevent || !only_kill_custom)
+                         __fw_load_abort(fw_priv);
+        }
+        mutex_unlock(&fw_lock);
+}
+
+static ssize_t timeout_show(struct class *class, struct class_attribute *attr,
+                            char *buf)
+{
+        return sprintf(buf, "%d\n", __firmware_loading_timeout());
+}
+
+/**
+ * firmware_timeout_store - set number of seconds to wait for firmware
+ * @class: device class pointer
+ * @attr: device attribute pointer
+ * @buf: buffer to scan for timeout value
+ * @count: number of bytes in @buf
+ *
+ *      Sets the number of seconds to wait for the firmware.  Once
+ *      this expires an error will be returned to the driver and no
+ *      firmware will be provided.
+ *
+ *      Note: zero means 'wait forever'.
+ **/
+static ssize_t timeout_store(struct class *class, struct class_attribute *attr,
+                             const char *buf, size_t count)
+{
+        int tmp_loading_timeout = simple_strtol(buf, NULL, 10);
+
+        if (tmp_loading_timeout < 0)
+                tmp_loading_timeout = 0;
+
+        __fw_fallback_set_timeout(tmp_loading_timeout);
+
+        return count;
+}
+static CLASS_ATTR_RW(timeout);
+
+static struct attribute *firmware_class_attrs[] = {
+        &class_attr_timeout.attr,
+        NULL,
+};
+ATTRIBUTE_GROUPS(firmware_class);
+
+static void fw_dev_release(struct device *dev)
+{
+        struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+
+        kfree(fw_sysfs);
+}
+
+static int do_firmware_uevent(struct fw_sysfs *fw_sysfs, struct kobj_uevent_env *env)
+{
+        if (add_uevent_var(env, "FIRMWARE=%s", fw_sysfs->fw_priv->fw_name))
+                return -ENOMEM;
+        if (add_uevent_var(env, "TIMEOUT=%i", __firmware_loading_timeout()))
+                return -ENOMEM;
+        if (add_uevent_var(env, "ASYNC=%d", fw_sysfs->nowait))
+                return -ENOMEM;
+
+        return 0;
+}
+
+static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+        struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+        int err = 0;
+
+        mutex_lock(&fw_lock);
+        if (fw_sysfs->fw_priv)
+                err = do_firmware_uevent(fw_sysfs, env);
+        mutex_unlock(&fw_lock);
+        return err;
+}
+
+static struct class firmware_class = {
+        .name           = "firmware",
+        .class_groups   = firmware_class_groups,
+        .dev_uevent     = firmware_uevent,
+        .dev_release    = fw_dev_release,
+};
+
+int register_sysfs_loader(void)
+{
+        return class_register(&firmware_class);
+}
+
+void unregister_sysfs_loader(void)
+{
+        class_unregister(&firmware_class);
+}
+
+static ssize_t firmware_loading_show(struct device *dev,
+                                     struct device_attribute *attr, char *buf)
+{
+        struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+        int loading = 0;
+
+        mutex_lock(&fw_lock);
+        if (fw_sysfs->fw_priv)
+                loading = fw_sysfs_loading(fw_sysfs->fw_priv);
+        mutex_unlock(&fw_lock);
+
+        return sprintf(buf, "%d\n", loading);
+}
+
+/* Some architectures don't have PAGE_KERNEL_RO */
+#ifndef PAGE_KERNEL_RO
+#define PAGE_KERNEL_RO PAGE_KERNEL
+#endif
+
+/* one pages buffer should be mapped/unmapped only once */
+static int map_fw_priv_pages(struct fw_priv *fw_priv)
+{
+        if (!fw_priv->is_paged_buf)
+                return 0;
+
+        vunmap(fw_priv->data);
+        fw_priv->data = vmap(fw_priv->pages, fw_priv->nr_pages, 0,
+                             PAGE_KERNEL_RO);
+        if (!fw_priv->data)
+                return -ENOMEM;
+        return 0;
+}
+
+/**
+ * firmware_loading_store - set value in the 'loading' control file
+ * @dev: device pointer
+ * @attr: device attribute pointer
+ * @buf: buffer to scan for loading control value
+ * @count: number of bytes in @buf
+ *
+ *      The relevant values are:
+ *
+ *       1: Start a load, discarding any previous partial load.
+ *       0: Conclude the load and hand the data to the driver code.
+ *      -1: Conclude the load with an error and discard any written data.
+ **/
+static ssize_t firmware_loading_store(struct device *dev,
+                                      struct device_attribute *attr,
+                                      const char *buf, size_t count)
+{
+        struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+        struct fw_priv *fw_priv;
+        ssize_t written = count;
+        int loading = simple_strtol(buf, NULL, 10);
+        int i;
+
+        mutex_lock(&fw_lock);
+        fw_priv = fw_sysfs->fw_priv;
+        if (fw_state_is_aborted(fw_priv))
+                goto out;
+
+        switch (loading) {
+        case 1:
+                /* discarding any previous partial load */
+                if (!fw_sysfs_done(fw_priv)) {
+                        for (i = 0; i < fw_priv->nr_pages; i++)
+                                __free_page(fw_priv->pages[i]);
+                        vfree(fw_priv->pages);
+                        fw_priv->pages = NULL;
+                        fw_priv->page_array_size = 0;
+                        fw_priv->nr_pages = 0;
+                        fw_state_start(fw_priv);
+                }
+                break;
+        case 0:
+                if (fw_sysfs_loading(fw_priv)) {
+                        int rc;
+
+                        /*
+                         * Several loading requests may be pending on
+                         * one same firmware buf, so let all requests
+                         * see the mapped 'buf->data' once the loading
+                         * is completed.
+                         * */
+                        rc = map_fw_priv_pages(fw_priv);
+                        if (rc)
+                                dev_err(dev, "%s: map pages failed\n",
+                                        __func__);
+                        else
+                                rc = security_kernel_post_read_file(NULL,
+                                                fw_priv->data, fw_priv->size,
+                                                READING_FIRMWARE);
+
+                        /*
+                         * Same logic as fw_load_abort, only the DONE bit
+                         * is ignored and we set ABORT only on failure.
+                         */
+                        list_del_init(&fw_priv->pending_list);
+                        if (rc) {
+                                fw_state_aborted(fw_priv);
+                                written = rc;
+                        } else {
+                                fw_state_done(fw_priv);
+                        }
+                        break;
+                }
+                /* fallthrough */
+        default:
+                dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
+                /* fallthrough */
+        case -1:
+                fw_load_abort(fw_sysfs);
+                break;
+        }
+out:
+        mutex_unlock(&fw_lock);
+        return written;
+}
+
+static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
+
+static void firmware_rw_data(struct fw_priv *fw_priv, char *buffer,
+                           loff_t offset, size_t count, bool read)
+{
+        if (read)
+                memcpy(buffer, fw_priv->data + offset, count);
+        else
+                memcpy(fw_priv->data + offset, buffer, count);
+}
+
+static void firmware_rw(struct fw_priv *fw_priv, char *buffer,
+                        loff_t offset, size_t count, bool read)
+{
+        while (count) {
+                void *page_data;
+                int page_nr = offset >> PAGE_SHIFT;
+                int page_ofs = offset & (PAGE_SIZE-1);
+                int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
+
+                page_data = kmap(fw_priv->pages[page_nr]);
+
+                if (read)
+                        memcpy(buffer, page_data + page_ofs, page_cnt);
+                else
+                        memcpy(page_data + page_ofs, buffer, page_cnt);
+
+                kunmap(fw_priv->pages[page_nr]);
+                buffer += page_cnt;
+                offset += page_cnt;
+                count -= page_cnt;
+        }
+}
+
+static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
+                                  struct bin_attribute *bin_attr,
+                                  char *buffer, loff_t offset, size_t count)
+{
+        struct device *dev = kobj_to_dev(kobj);
+        struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+        struct fw_priv *fw_priv;
+        ssize_t ret_count;
+
+        mutex_lock(&fw_lock);
+        fw_priv = fw_sysfs->fw_priv;
+        if (!fw_priv || fw_sysfs_done(fw_priv)) {
+                ret_count = -ENODEV;
+                goto out;
+        }
+        if (offset > fw_priv->size) {
+                ret_count = 0;
+                goto out;
+        }
+        if (count > fw_priv->size - offset)
+                count = fw_priv->size - offset;
+
+        ret_count = count;
+
+        if (fw_priv->data)
+                firmware_rw_data(fw_priv, buffer, offset, count, true);
+        else
+                firmware_rw(fw_priv, buffer, offset, count, true);
+
+out:
+        mutex_unlock(&fw_lock);
+        return ret_count;
+}
+
+static int fw_realloc_pages(struct fw_sysfs *fw_sysfs, int min_size)
+{
+        struct fw_priv *fw_priv= fw_sysfs->fw_priv;
+        int pages_needed = PAGE_ALIGN(min_size) >> PAGE_SHIFT;
+
+        /* If the array of pages is too small, grow it... */
+        if (fw_priv->page_array_size < pages_needed) {
+                int new_array_size = max(pages_needed,
+                                         fw_priv->page_array_size * 2);
+                struct page **new_pages;
+
+                new_pages = vmalloc(new_array_size * sizeof(void *));
+                if (!new_pages) {
+                        fw_load_abort(fw_sysfs);
+                        return -ENOMEM;
+                }
+                memcpy(new_pages, fw_priv->pages,
+                       fw_priv->page_array_size * sizeof(void *));
+                memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
+                       (new_array_size - fw_priv->page_array_size));
+                vfree(fw_priv->pages);
+                fw_priv->pages = new_pages;
+                fw_priv->page_array_size = new_array_size;
+        }
+
+        while (fw_priv->nr_pages < pages_needed) {
+                fw_priv->pages[fw_priv->nr_pages] =
+                        alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
+
+                if (!fw_priv->pages[fw_priv->nr_pages]) {
+                        fw_load_abort(fw_sysfs);
+                        return -ENOMEM;
+                }
+                fw_priv->nr_pages++;
+        }
+        return 0;
+}
+
+/**
+ * firmware_data_write - write method for firmware
+ * @filp: open sysfs file
+ * @kobj: kobject for the device
+ * @bin_attr: bin_attr structure
+ * @buffer: buffer being written
+ * @offset: buffer offset for write in total data store area
+ * @count: buffer size
+ *
+ *      Data written to the 'data' attribute will be later handed to
+ *      the driver as a firmware image.
+ **/
+static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
+                                   struct bin_attribute *bin_attr,
+                                   char *buffer, loff_t offset, size_t count)
+{
+        struct device *dev = kobj_to_dev(kobj);
+        struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+        struct fw_priv *fw_priv;
+        ssize_t retval;
+
+        if (!capable(CAP_SYS_RAWIO))
+                return -EPERM;
+
+        mutex_lock(&fw_lock);
+        fw_priv = fw_sysfs->fw_priv;
+        if (!fw_priv || fw_sysfs_done(fw_priv)) {
+                retval = -ENODEV;
+                goto out;
+        }
+
+        if (fw_priv->data) {
+                if (offset + count > fw_priv->allocated_size) {
+                        retval = -ENOMEM;
+                        goto out;
+                }
+                firmware_rw_data(fw_priv, buffer, offset, count, false);
+                retval = count;
+        } else {
+                retval = fw_realloc_pages(fw_sysfs, offset + count);
+                if (retval)
+                        goto out;
+
+                retval = count;
+                firmware_rw(fw_priv, buffer, offset, count, false);
+        }
+
+        fw_priv->size = max_t(size_t, offset + count, fw_priv->size);
+out:
+        mutex_unlock(&fw_lock);
+        return retval;
+}
+
+static struct bin_attribute firmware_attr_data = {
+        .attr = { .name = "data", .mode = 0644 },
+        .size = 0,
+        .read = firmware_data_read,
+        .write = firmware_data_write,
+};
+
+static struct attribute *fw_dev_attrs[] = {
+        &dev_attr_loading.attr,
+        NULL
+};
+
+static struct bin_attribute *fw_dev_bin_attrs[] = {
+        &firmware_attr_data,
+        NULL
+};
+
+static const struct attribute_group fw_dev_attr_group = {
+        .attrs = fw_dev_attrs,
+        .bin_attrs = fw_dev_bin_attrs,
+};
+
+static const struct attribute_group *fw_dev_attr_groups[] = {
+        &fw_dev_attr_group,
+        NULL
+};
+
+static struct fw_sysfs *
+fw_create_instance(struct firmware *firmware, const char *fw_name,
+                   struct device *device, unsigned int opt_flags)
+{
+        struct fw_sysfs *fw_sysfs;
+        struct device *f_dev;
+
+        fw_sysfs = kzalloc(sizeof(*fw_sysfs), GFP_KERNEL);
+        if (!fw_sysfs) {
+                fw_sysfs = ERR_PTR(-ENOMEM);
+                goto exit;
+        }
+
+        fw_sysfs->nowait = !!(opt_flags & FW_OPT_NOWAIT);
+        fw_sysfs->fw = firmware;
+        f_dev = &fw_sysfs->dev;
+
+        device_initialize(f_dev);
+        dev_set_name(f_dev, "%s", fw_name);
+        f_dev->parent = device;
+        f_dev->class = &firmware_class;
+        f_dev->groups = fw_dev_attr_groups;
+exit:
+        return fw_sysfs;
+}
+
+/* load a firmware via user helper */
+static int _request_firmware_load(struct fw_sysfs *fw_sysfs,
+                                  unsigned int opt_flags, long timeout)
+{
+        int retval = 0;
+        struct device *f_dev = &fw_sysfs->dev;
+        struct fw_priv *fw_priv = fw_sysfs->fw_priv;
+
+        /* fall back on userspace loading */
+        if (!fw_priv->data)
+                fw_priv->is_paged_buf = true;
+
+        dev_set_uevent_suppress(f_dev, true);
+
+        retval = device_add(f_dev);
+        if (retval) {
+                dev_err(f_dev, "%s: device_register failed\n", __func__);
+                goto err_put_dev;
+        }
+
+        mutex_lock(&fw_lock);
+        list_add(&fw_priv->pending_list, &pending_fw_head);
+        mutex_unlock(&fw_lock);
+
+        if (opt_flags & FW_OPT_UEVENT) {
+                fw_priv->need_uevent = true;
+                dev_set_uevent_suppress(f_dev, false);
+                dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_name);
+                kobject_uevent(&fw_sysfs->dev.kobj, KOBJ_ADD);
+        } else {
+                timeout = MAX_JIFFY_OFFSET;
+        }
+
+        retval = fw_sysfs_wait_timeout(fw_priv, timeout);
+        if (retval < 0) {
+                mutex_lock(&fw_lock);
+                fw_load_abort(fw_sysfs);
+                mutex_unlock(&fw_lock);
+        }
+
+        if (fw_state_is_aborted(fw_priv)) {
+                if (retval == -ERESTARTSYS)
+                        retval = -EINTR;
+                else
+                        retval = -EAGAIN;
+        } else if (fw_priv->is_paged_buf && !fw_priv->data)
+                retval = -ENOMEM;
+
+        device_del(f_dev);
+err_put_dev:
+        put_device(f_dev);
+        return retval;
+}
+
+static int fw_load_from_user_helper(struct firmware *firmware,
+                                    const char *name, struct device *device,
+                                    unsigned int opt_flags)
+{
+        struct fw_sysfs *fw_sysfs;
+        long timeout;
+        int ret;
+
+        timeout = firmware_loading_timeout();
+        if (opt_flags & FW_OPT_NOWAIT) {
+                timeout = usermodehelper_read_lock_wait(timeout);
+                if (!timeout) {
+                        dev_dbg(device, "firmware: %s loading timed out\n",
+                                name);
+                        return -EBUSY;
+                }
+        } else {
+                ret = usermodehelper_read_trylock();
+                if (WARN_ON(ret)) {
+                        dev_err(device, "firmware: %s will not be loaded\n",
+                                name);
+                        return ret;
+                }
+        }
+
+        fw_sysfs = fw_create_instance(firmware, name, device, opt_flags);
+        if (IS_ERR(fw_sysfs)) {
+                ret = PTR_ERR(fw_sysfs);
+                goto out_unlock;
+        }
+
+        fw_sysfs->fw_priv = firmware->priv;
+        ret = _request_firmware_load(fw_sysfs, opt_flags, timeout);
+
+        if (!ret)
+                ret = assign_fw(firmware, device, opt_flags);
+
+out_unlock:
+        usermodehelper_read_unlock();
+
+        return ret;
+}
+
+static bool fw_force_sysfs_fallback(unsigned int opt_flags)
+{
+        if (fw_fallback_config.force_sysfs_fallback)
+                return true;
+        if (!(opt_flags & FW_OPT_USERHELPER))
+                return false;
+        return true;
+}
+
+static bool fw_run_sysfs_fallback(unsigned int opt_flags)
+{
+        if ((opt_flags & FW_OPT_NOFALLBACK))
+                return false;
+
+        return fw_force_sysfs_fallback(opt_flags);
+}
+
+int fw_sysfs_fallback(struct firmware *fw, const char *name,
+                      struct device *device,
+                      unsigned int opt_flags,
+                      int ret)
+{
+        if (!fw_run_sysfs_fallback(opt_flags))
+                return ret;
+
+        dev_warn(device, "Falling back to user helper\n");
+        return fw_load_from_user_helper(fw, name, device, opt_flags);
+}