129 lines
3.6 KiB
C
Executable file
129 lines
3.6 KiB
C
Executable file
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2021 Google LLC
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*
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* This file can optionally be built into fips140.ko in order to support certain
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* types of testing that the FIPS lab has to do to evaluate the module. It
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* should not be included in production builds of the module.
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*/
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/*
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* We have to redefine inline to mean always_inline, so that _copy_to_user()
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* gets inlined. This is needed for it to be placed into the correct section.
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* See fips140_copy_to_user().
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*
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* We also need to undefine BUILD_FIPS140_KO to allow the use of the code
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* patching which copy_to_user() requires.
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*/
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#undef inline
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#define inline inline __attribute__((__always_inline__)) __gnu_inline \
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__inline_maybe_unused notrace
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#undef BUILD_FIPS140_KO
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#include <linux/cdev.h>
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include "fips140-module.h"
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#include "fips140-eval-testing-uapi.h"
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/*
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* This option allows deliberately failing the self-tests for a particular
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* algorithm.
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*/
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static char *fips140_fail_selftest;
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module_param_named(fail_selftest, fips140_fail_selftest, charp, 0);
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/* This option allows deliberately failing the integrity check. */
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static bool fips140_fail_integrity_check;
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module_param_named(fail_integrity_check, fips140_fail_integrity_check, bool, 0);
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static dev_t fips140_devnum;
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static struct cdev fips140_cdev;
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/* Inject a self-test failure (via corrupting the result) if requested. */
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void fips140_inject_selftest_failure(const char *impl, u8 *result)
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{
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if (fips140_fail_selftest && strcmp(impl, fips140_fail_selftest) == 0)
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result[0] ^= 0xff;
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}
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/* Inject an integrity check failure (via corrupting the text) if requested. */
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void fips140_inject_integrity_failure(u8 *textcopy)
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{
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if (fips140_fail_integrity_check)
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textcopy[0] ^= 0xff;
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}
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static long fips140_ioctl_is_approved_service(unsigned long arg)
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{
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const char *service_name = strndup_user((const char __user *)arg, 256);
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long ret;
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if (IS_ERR(service_name))
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return PTR_ERR(service_name);
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ret = fips140_is_approved_service(service_name);
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kfree(service_name);
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return ret;
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}
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/*
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* Code in fips140.ko is covered by an integrity check by default, and this
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* check breaks if copy_to_user() is called. This is because copy_to_user() is
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* an inline function that relies on code patching. However, since this is
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* "evaluation testing" code which isn't included in the production builds of
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* fips140.ko, it's acceptable to just exclude it from the integrity check.
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*/
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static noinline unsigned long __section("text.._fips140_unchecked")
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fips140_copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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return copy_to_user(to, from, n);
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}
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static long fips140_ioctl_module_version(unsigned long arg)
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{
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const char *version = fips140_module_version();
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size_t len = strlen(version) + 1;
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if (len > 256)
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return -EOVERFLOW;
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if (fips140_copy_to_user((void __user *)arg, version, len))
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return -EFAULT;
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return 0;
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}
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static long fips140_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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switch (cmd) {
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case FIPS140_IOCTL_IS_APPROVED_SERVICE:
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return fips140_ioctl_is_approved_service(arg);
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case FIPS140_IOCTL_MODULE_VERSION:
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return fips140_ioctl_module_version(arg);
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default:
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return -ENOTTY;
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}
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}
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static const struct file_operations fips140_fops = {
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.unlocked_ioctl = fips140_ioctl,
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};
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bool fips140_eval_testing_init(void)
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{
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if (alloc_chrdev_region(&fips140_devnum, 1, 1, "fips140") != 0) {
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pr_err("failed to allocate device number\n");
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return false;
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}
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cdev_init(&fips140_cdev, &fips140_fops);
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if (cdev_add(&fips140_cdev, fips140_devnum, 1) != 0) {
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pr_err("failed to add fips140 character device\n");
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return false;
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}
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return true;
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}
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