diff options
| -rw-r--r-- | lib/Kconfig.debug | 13 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/test_firmware.c | 117 | ||||
| -rw-r--r-- | tools/testing/selftests/Makefile | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/firmware/Makefile | 27 | ||||
| -rw-r--r-- | tools/testing/selftests/firmware/fw_filesystem.sh | 62 | ||||
| -rw-r--r-- | tools/testing/selftests/firmware/fw_userhelper.sh | 89 |
7 files changed, 310 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 7a638aa..213cd9f 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1649,6 +1649,19 @@ config TEST_BPF If unsure, say N. +config TEST_FIRMWARE + tristate "Test firmware loading via userspace interface" + default n + depends on FW_LOADER + help + This builds the "test_firmware" module that creates a userspace + interface for testing firmware loading. This can be used to + control the triggering of firmware loading without needing an + actual firmware-using device. The contents can be rechecked by + userspace. + + If unsure, say N. + source "samples/Kconfig" source "lib/Kconfig.kgdb" diff --git a/lib/Makefile b/lib/Makefile index ba967a1..230b4b1 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o obj-$(CONFIG_TEST_MODULE) += test_module.o obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o obj-$(CONFIG_TEST_BPF) += test_bpf.o +obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o ifeq ($(CONFIG_DEBUG_KOBJECT),y) CFLAGS_kobject.o += -DDEBUG diff --git a/lib/test_firmware.c b/lib/test_firmware.c new file mode 100644 index 0000000..86374c1 --- /dev/null +++ b/lib/test_firmware.c @@ -0,0 +1,117 @@ +/* + * This module provides an interface to trigger and test firmware loading. + * + * It is designed to be used for basic evaluation of the firmware loading + * subsystem (for example when validating firmware verification). It lacks + * any extra dependencies, and will not normally be loaded by the system + * unless explicitly requested by name. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/printk.h> +#include <linux/firmware.h> +#include <linux/device.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/slab.h> +#include <linux/uaccess.h> + +static DEFINE_MUTEX(test_fw_mutex); +static const struct firmware *test_firmware; + +static ssize_t test_fw_misc_read(struct file *f, char __user *buf, + size_t size, loff_t *offset) +{ + ssize_t rc = 0; + + mutex_lock(&test_fw_mutex); + if (test_firmware) + rc = simple_read_from_buffer(buf, size, offset, + test_firmware->data, + test_firmware->size); + mutex_unlock(&test_fw_mutex); + return rc; +} + +static const struct file_operations test_fw_fops = { + .owner = THIS_MODULE, + .read = test_fw_misc_read, +}; + +static struct miscdevice test_fw_misc_device = { + .minor = MISC_DYNAMIC_MINOR, + .name = "test_firmware", + .fops = &test_fw_fops, +}; + +static ssize_t trigger_request_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int rc; + char *name; + + name = kzalloc(count + 1, GFP_KERNEL); + if (!name) + return -ENOSPC; + memcpy(name, buf, count); + + pr_info("loading '%s'\n", name); + + mutex_lock(&test_fw_mutex); + release_firmware(test_firmware); + test_firmware = NULL; + rc = request_firmware(&test_firmware, name, dev); + if (rc) + pr_info("load of '%s' failed: %d\n", name, rc); + pr_info("loaded: %zu\n", test_firmware ? test_firmware->size : 0); + mutex_unlock(&test_fw_mutex); + + kfree(name); + + return count; +} +static DEVICE_ATTR_WO(trigger_request); + +static int __init test_firmware_init(void) +{ + int rc; + + rc = misc_register(&test_fw_misc_device); + if (rc) { + pr_err("could not register misc device: %d\n", rc); + return rc; + } + rc = device_create_file(test_fw_misc_device.this_device, + &dev_attr_trigger_request); + if (rc) { + pr_err("could not create sysfs interface: %d\n", rc); + goto dereg; + } + + pr_warn("interface ready\n"); + + return 0; +dereg: + misc_deregister(&test_fw_misc_device); + return rc; +} + +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_request); + misc_deregister(&test_fw_misc_device); + pr_warn("removed interface\n"); +} + +module_exit(test_firmware_exit); + +MODULE_AUTHOR("Kees Cook <keescook@chromium.org>"); +MODULE_LICENSE("GPL"); diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index e66e710..5c2bf8e 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -11,6 +11,7 @@ TARGETS += vm TARGETS += powerpc TARGETS += user TARGETS += sysctl +TARGETS += firmware all: for TARGET in $(TARGETS); do \ diff --git a/tools/testing/selftests/firmware/Makefile b/tools/testing/selftests/firmware/Makefile new file mode 100644 index 0000000..e23cce0 --- /dev/null +++ b/tools/testing/selftests/firmware/Makefile @@ -0,0 +1,27 @@ +# Makefile for firmware loading selftests + +# No binaries, but make sure arg-less "make" doesn't trigger "run_tests" +all: + +fw_filesystem: + @if /bin/sh ./fw_filesystem.sh ; then \ + echo "fw_filesystem: ok"; \ + else \ + echo "fw_filesystem: [FAIL]"; \ + exit 1; \ + fi + +fw_userhelper: + @if /bin/sh ./fw_userhelper.sh ; then \ + echo "fw_userhelper: ok"; \ + else \ + echo "fw_userhelper: [FAIL]"; \ + exit 1; \ + fi + +run_tests: all fw_filesystem fw_userhelper + +# Nothing to clean up. +clean: + +.PHONY: all clean run_tests fw_filesystem fw_userhelper diff --git a/tools/testing/selftests/firmware/fw_filesystem.sh b/tools/testing/selftests/firmware/fw_filesystem.sh new file mode 100644 index 0000000..3fc6c10 --- /dev/null +++ b/tools/testing/selftests/firmware/fw_filesystem.sh @@ -0,0 +1,62 @@ +#!/bin/sh +# This validates that the kernel will load firmware out of its list of +# firmware locations on disk. Since the user helper does similar work, +# we reset the custom load directory to a location the user helper doesn't +# know so we can be sure we're not accidentally testing the user helper. +set -e + +modprobe test_firmware + +DIR=/sys/devices/virtual/misc/test_firmware + +OLD_TIMEOUT=$(cat /sys/class/firmware/timeout) +OLD_FWPATH=$(cat /sys/module/firmware_class/parameters/path) + +FWPATH=$(mktemp -d) +FW="$FWPATH/test-firmware.bin" + +test_finish() +{ + echo "$OLD_TIMEOUT" >/sys/class/firmware/timeout + echo -n "$OLD_PATH" >/sys/module/firmware_class/parameters/path + rm -f "$FW" + rmdir "$FWPATH" +} + +trap "test_finish" EXIT + +# Turn down the timeout so failures don't take so long. +echo 1 >/sys/class/firmware/timeout +# Set the kernel search path. +echo -n "$FWPATH" >/sys/module/firmware_class/parameters/path + +# This is an unlikely real-world firmware content. :) +echo "ABCD0123" >"$FW" + +NAME=$(basename "$FW") + +# Request a firmware that doesn't exist, it should fail. +echo -n "nope-$NAME" >"$DIR"/trigger_request +if diff -q "$FW" /dev/test_firmware >/dev/null ; then + echo "$0: firmware was not expected to match" >&2 + exit 1 +else + echo "$0: timeout works" +fi + +# This should succeed via kernel load or will fail after 1 second after +# being handed over to the user helper, which won't find the fw either. +if ! echo -n "$NAME" >"$DIR"/trigger_request ; then + echo "$0: could not trigger request" >&2 + exit 1 +fi + +# Verify the contents are what we expect. +if ! diff -q "$FW" /dev/test_firmware >/dev/null ; then + echo "$0: firmware was not loaded" >&2 + exit 1 +else + echo "$0: filesystem loading works" +fi + +exit 0 diff --git a/tools/testing/selftests/firmware/fw_userhelper.sh b/tools/testing/selftests/firmware/fw_userhelper.sh new file mode 100644 index 0000000..6efbade --- /dev/null +++ b/tools/testing/selftests/firmware/fw_userhelper.sh @@ -0,0 +1,89 @@ +#!/bin/sh +# This validates that the kernel will fall back to using the user helper +# to load firmware it can't find on disk itself. We must request a firmware +# that the kernel won't find, and any installed helper (e.g. udev) also +# won't find so that we can do the load ourself manually. +set -e + +modprobe test_firmware + +DIR=/sys/devices/virtual/misc/test_firmware + +OLD_TIMEOUT=$(cat /sys/class/firmware/timeout) + +FWPATH=$(mktemp -d) +FW="$FWPATH/test-firmware.bin" + +test_finish() +{ + echo "$OLD_TIMEOUT" >/sys/class/firmware/timeout + rm -f "$FW" + rmdir "$FWPATH" +} + +load_fw() +{ + local name="$1" + local file="$2" + + # This will block until our load (below) has finished. + echo -n "$name" >"$DIR"/trigger_request & + + # Give kernel a chance to react. + local timeout=10 + while [ ! -e "$DIR"/"$name"/loading ]; do + sleep 0.1 + timeout=$(( $timeout - 1 )) + if [ "$timeout" -eq 0 ]; then + echo "$0: firmware interface never appeared" >&2 + exit 1 + fi + done + + echo 1 >"$DIR"/"$name"/loading + cat "$file" >"$DIR"/"$name"/data + echo 0 >"$DIR"/"$name"/loading + + # Wait for request to finish. + wait +} + +trap "test_finish" EXIT + +# This is an unlikely real-world firmware content. :) +echo "ABCD0123" >"$FW" +NAME=$(basename "$FW") + +# Test failure when doing nothing (timeout works). +echo 1 >/sys/class/firmware/timeout +echo -n "$NAME" >"$DIR"/trigger_request +if diff -q "$FW" /dev/test_firmware >/dev/null ; then + echo "$0: firmware was not expected to match" >&2 + exit 1 +else + echo "$0: timeout works" +fi + +# Put timeout high enough for us to do work but not so long that failures +# slow down this test too much. +echo 4 >/sys/class/firmware/timeout + +# Load this script instead of the desired firmware. +load_fw "$NAME" "$0" +if diff -q "$FW" /dev/test_firmware >/dev/null ; then + echo "$0: firmware was not expected to match" >&2 + exit 1 +else + echo "$0: firmware comparison works" +fi + +# Do a proper load, which should work correctly. +load_fw "$NAME" "$FW" +if ! diff -q "$FW" /dev/test_firmware >/dev/null ; then + echo "$0: firmware was not loaded" >&2 + exit 1 +else + echo "$0: user helper firmware loading works" +fi + +exit 0 |
