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https://github.com/edk2-porting/linux-next.git
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b24413180f
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
325 lines
8.2 KiB
C
325 lines
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* This is for all the tests related to copy_to_user() and copy_from_user()
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* hardening.
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*/
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#include "lkdtm.h"
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/sched/task_stack.h>
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#include <linux/mman.h>
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#include <linux/uaccess.h>
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#include <asm/cacheflush.h>
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/*
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* Many of the tests here end up using const sizes, but those would
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* normally be ignored by hardened usercopy, so force the compiler
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* into choosing the non-const path to make sure we trigger the
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* hardened usercopy checks by added "unconst" to all the const copies,
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* and making sure "cache_size" isn't optimized into a const.
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*/
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static volatile size_t unconst = 0;
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static volatile size_t cache_size = 1024;
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static struct kmem_cache *bad_cache;
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static const unsigned char test_text[] = "This is a test.\n";
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/*
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* Instead of adding -Wno-return-local-addr, just pass the stack address
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* through a function to obfuscate it from the compiler.
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*/
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static noinline unsigned char *trick_compiler(unsigned char *stack)
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{
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return stack + 0;
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}
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static noinline unsigned char *do_usercopy_stack_callee(int value)
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{
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unsigned char buf[32];
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int i;
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/* Exercise stack to avoid everything living in registers. */
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for (i = 0; i < sizeof(buf); i++) {
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buf[i] = value & 0xff;
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}
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return trick_compiler(buf);
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}
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static noinline void do_usercopy_stack(bool to_user, bool bad_frame)
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{
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unsigned long user_addr;
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unsigned char good_stack[32];
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unsigned char *bad_stack;
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int i;
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/* Exercise stack to avoid everything living in registers. */
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for (i = 0; i < sizeof(good_stack); i++)
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good_stack[i] = test_text[i % sizeof(test_text)];
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/* This is a pointer to outside our current stack frame. */
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if (bad_frame) {
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bad_stack = do_usercopy_stack_callee((uintptr_t)&bad_stack);
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} else {
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/* Put start address just inside stack. */
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bad_stack = task_stack_page(current) + THREAD_SIZE;
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bad_stack -= sizeof(unsigned long);
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}
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user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_ANONYMOUS | MAP_PRIVATE, 0);
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if (user_addr >= TASK_SIZE) {
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pr_warn("Failed to allocate user memory\n");
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return;
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}
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if (to_user) {
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pr_info("attempting good copy_to_user of local stack\n");
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if (copy_to_user((void __user *)user_addr, good_stack,
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unconst + sizeof(good_stack))) {
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pr_warn("copy_to_user failed unexpectedly?!\n");
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goto free_user;
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}
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pr_info("attempting bad copy_to_user of distant stack\n");
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if (copy_to_user((void __user *)user_addr, bad_stack,
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unconst + sizeof(good_stack))) {
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pr_warn("copy_to_user failed, but lacked Oops\n");
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goto free_user;
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}
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} else {
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/*
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* There isn't a safe way to not be protected by usercopy
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* if we're going to write to another thread's stack.
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*/
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if (!bad_frame)
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goto free_user;
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pr_info("attempting good copy_from_user of local stack\n");
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if (copy_from_user(good_stack, (void __user *)user_addr,
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unconst + sizeof(good_stack))) {
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pr_warn("copy_from_user failed unexpectedly?!\n");
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goto free_user;
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}
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pr_info("attempting bad copy_from_user of distant stack\n");
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if (copy_from_user(bad_stack, (void __user *)user_addr,
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unconst + sizeof(good_stack))) {
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pr_warn("copy_from_user failed, but lacked Oops\n");
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goto free_user;
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}
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}
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free_user:
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vm_munmap(user_addr, PAGE_SIZE);
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}
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static void do_usercopy_heap_size(bool to_user)
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{
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unsigned long user_addr;
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unsigned char *one, *two;
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size_t size = unconst + 1024;
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one = kmalloc(size, GFP_KERNEL);
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two = kmalloc(size, GFP_KERNEL);
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if (!one || !two) {
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pr_warn("Failed to allocate kernel memory\n");
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goto free_kernel;
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}
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user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_ANONYMOUS | MAP_PRIVATE, 0);
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if (user_addr >= TASK_SIZE) {
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pr_warn("Failed to allocate user memory\n");
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goto free_kernel;
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}
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memset(one, 'A', size);
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memset(two, 'B', size);
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if (to_user) {
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pr_info("attempting good copy_to_user of correct size\n");
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if (copy_to_user((void __user *)user_addr, one, size)) {
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pr_warn("copy_to_user failed unexpectedly?!\n");
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goto free_user;
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}
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pr_info("attempting bad copy_to_user of too large size\n");
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if (copy_to_user((void __user *)user_addr, one, 2 * size)) {
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pr_warn("copy_to_user failed, but lacked Oops\n");
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goto free_user;
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}
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} else {
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pr_info("attempting good copy_from_user of correct size\n");
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if (copy_from_user(one, (void __user *)user_addr, size)) {
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pr_warn("copy_from_user failed unexpectedly?!\n");
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goto free_user;
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}
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pr_info("attempting bad copy_from_user of too large size\n");
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if (copy_from_user(one, (void __user *)user_addr, 2 * size)) {
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pr_warn("copy_from_user failed, but lacked Oops\n");
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goto free_user;
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}
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}
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free_user:
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vm_munmap(user_addr, PAGE_SIZE);
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free_kernel:
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kfree(one);
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kfree(two);
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}
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static void do_usercopy_heap_flag(bool to_user)
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{
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unsigned long user_addr;
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unsigned char *good_buf = NULL;
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unsigned char *bad_buf = NULL;
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/* Make sure cache was prepared. */
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if (!bad_cache) {
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pr_warn("Failed to allocate kernel cache\n");
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return;
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}
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/*
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* Allocate one buffer from each cache (kmalloc will have the
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* SLAB_USERCOPY flag already, but "bad_cache" won't).
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*/
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good_buf = kmalloc(cache_size, GFP_KERNEL);
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bad_buf = kmem_cache_alloc(bad_cache, GFP_KERNEL);
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if (!good_buf || !bad_buf) {
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pr_warn("Failed to allocate buffers from caches\n");
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goto free_alloc;
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}
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/* Allocate user memory we'll poke at. */
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user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_ANONYMOUS | MAP_PRIVATE, 0);
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if (user_addr >= TASK_SIZE) {
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pr_warn("Failed to allocate user memory\n");
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goto free_alloc;
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}
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memset(good_buf, 'A', cache_size);
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memset(bad_buf, 'B', cache_size);
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if (to_user) {
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pr_info("attempting good copy_to_user with SLAB_USERCOPY\n");
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if (copy_to_user((void __user *)user_addr, good_buf,
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cache_size)) {
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pr_warn("copy_to_user failed unexpectedly?!\n");
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goto free_user;
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}
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pr_info("attempting bad copy_to_user w/o SLAB_USERCOPY\n");
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if (copy_to_user((void __user *)user_addr, bad_buf,
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cache_size)) {
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pr_warn("copy_to_user failed, but lacked Oops\n");
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goto free_user;
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}
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} else {
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pr_info("attempting good copy_from_user with SLAB_USERCOPY\n");
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if (copy_from_user(good_buf, (void __user *)user_addr,
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cache_size)) {
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pr_warn("copy_from_user failed unexpectedly?!\n");
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goto free_user;
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}
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pr_info("attempting bad copy_from_user w/o SLAB_USERCOPY\n");
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if (copy_from_user(bad_buf, (void __user *)user_addr,
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cache_size)) {
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pr_warn("copy_from_user failed, but lacked Oops\n");
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goto free_user;
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}
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}
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free_user:
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vm_munmap(user_addr, PAGE_SIZE);
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free_alloc:
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if (bad_buf)
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kmem_cache_free(bad_cache, bad_buf);
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kfree(good_buf);
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}
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/* Callable tests. */
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void lkdtm_USERCOPY_HEAP_SIZE_TO(void)
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{
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do_usercopy_heap_size(true);
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}
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void lkdtm_USERCOPY_HEAP_SIZE_FROM(void)
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{
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do_usercopy_heap_size(false);
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}
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void lkdtm_USERCOPY_HEAP_FLAG_TO(void)
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{
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do_usercopy_heap_flag(true);
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}
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void lkdtm_USERCOPY_HEAP_FLAG_FROM(void)
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{
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do_usercopy_heap_flag(false);
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}
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void lkdtm_USERCOPY_STACK_FRAME_TO(void)
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{
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do_usercopy_stack(true, true);
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}
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void lkdtm_USERCOPY_STACK_FRAME_FROM(void)
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{
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do_usercopy_stack(false, true);
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}
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void lkdtm_USERCOPY_STACK_BEYOND(void)
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{
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do_usercopy_stack(true, false);
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}
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void lkdtm_USERCOPY_KERNEL(void)
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{
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unsigned long user_addr;
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user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_ANONYMOUS | MAP_PRIVATE, 0);
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if (user_addr >= TASK_SIZE) {
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pr_warn("Failed to allocate user memory\n");
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return;
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}
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pr_info("attempting good copy_to_user from kernel rodata\n");
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if (copy_to_user((void __user *)user_addr, test_text,
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unconst + sizeof(test_text))) {
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pr_warn("copy_to_user failed unexpectedly?!\n");
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goto free_user;
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}
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pr_info("attempting bad copy_to_user from kernel text\n");
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if (copy_to_user((void __user *)user_addr, vm_mmap,
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unconst + PAGE_SIZE)) {
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pr_warn("copy_to_user failed, but lacked Oops\n");
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goto free_user;
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}
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free_user:
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vm_munmap(user_addr, PAGE_SIZE);
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}
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void __init lkdtm_usercopy_init(void)
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{
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/* Prepare cache that lacks SLAB_USERCOPY flag. */
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bad_cache = kmem_cache_create("lkdtm-no-usercopy", cache_size, 0,
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0, NULL);
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}
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void __exit lkdtm_usercopy_exit(void)
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{
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kmem_cache_destroy(bad_cache);
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}
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