Merge tag 'driver-core-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is a small set of patches for the driver core code for 6.12-rc1.

  This set is the one that caused the most delay on my side, due to lots
  of last-minute reports of problems in the async shutdown feature that
  was added. In the end, I've reverted all of the patches in that series
  so we are back to "normal" and the patch set is being reworked for the
  next merge window.

  Other than the async shutdown patches that were reverted, included in
  here are:

   - minor driver core cleanups

   - minor driver core bus and class api cleanups and simplifications
     for some callbacks

   - some const markings of structures

   - other even more minor cleanups

  All of these, including the last minute reverts, have been in
  linux-next, but all of the reports of problems in linux-next were
  before the reverts happened. After the reverts, all is good"

* tag 'driver-core-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits)
  Revert "driver core: don't always lock parent in shutdown"
  Revert "driver core: separate function to shutdown one device"
  Revert "driver core: shut down devices asynchronously"
  Revert "nvme-pci: Make driver prefer asynchronous shutdown"
  Revert "driver core: fix async device shutdown hang"
  driver core: fix async device shutdown hang
  driver core: attribute_container: Remove unused functions
  driver core: Trivially simplify ((struct device_private *)curr)->device->p to @curr
  devres: Correclty strip percpu address space of devm_free_percpu() argument
  driver core: Make parameter check consistent for API cluster device_(for_each|find)_child()
  bus: fsl-mc: make fsl_mc_bus_type const
  nvme-pci: Make driver prefer asynchronous shutdown
  driver core: shut down devices asynchronously
  driver core: separate function to shutdown one device
  driver core: don't always lock parent in shutdown
  platform: Make platform_bus_type constant
  driver core: class: Check namespace relevant parameters in class_register()
  driver:base:core: Adding a "Return:" line in comment for device_link_add()
  drivers/base: Introduce device_match_t for device finding APIs
  firmware_loader: Block path traversal
  ...

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index a03ee4b11134..324a9a3c087a 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -849,6 +849,26 @@ static void fw_log_firmware_info(const struct firmware *fw, const char *name,
 {}
 #endif
 
+/*
+ * Reject firmware file names with ".." path components.
+ * There are drivers that construct firmware file names from device-supplied
+ * strings, and we don't want some device to be able to tell us "I would like to
+ * be sent my firmware from ../../../etc/shadow, please".
+ *
+ * Search for ".." surrounded by either '/' or start/end of string.
+ *
+ * This intentionally only looks at the firmware name, not at the firmware base
+ * directory or at symlink contents.
+ */
+static bool name_contains_dotdot(const char *name)
+{
+	size_t name_len = strlen(name);
+
+	return strcmp(name, "..") == 0 || strncmp(name, "../", 3) == 0 ||
+	       strstr(name, "/../") != NULL ||
+	       (name_len >= 3 && strcmp(name+name_len-3, "/..") == 0);
+}
+
 /* called from request_firmware() and request_firmware_work_func() */
 static int
 _request_firmware(const struct firmware **firmware_p, const char *name,
@@ -869,6 +889,14 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 		goto out;
 	}
 
+	if (name_contains_dotdot(name)) {
+		dev_warn(device,
+			 "Firmware load for '%s' refused, path contains '..' component\n",
+			 name);
+		ret = -EINVAL;
+		goto out;
+	}
+
 	ret = _request_firmware_prepare(&fw, name, device, buf, size,
 					offset, opt_flags);
 	if (ret <= 0) /* error or already assigned */
@@ -946,6 +974,8 @@ out:
  *      @name will be used as $FIRMWARE in the uevent environment and
  *      should be distinctive enough not to be confused with any other
  *      firmware image for this or any other device.
+ *	It must not contain any ".." path components - "foo/bar..bin" is
+ *	allowed, but "foo/../bar.bin" is not.
  *
  *	Caller must hold the reference count of @device.
  *