user/sven/linux.git/scripts/Makefile.ubsan, branch v5.10.46

Merge tag 'kbuild-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2020-10-22T20:13:57Z

Pull Kbuild updates from Masahiro Yamada: - Support 'make compile_commands.json' to generate the compilation database more easily, avoiding stale entries - Support 'make clang-analyzer' and 'make clang-tidy' for static checks using clang-tidy - Preprocess scripts/modules.lds.S to allow CONFIG options in the module linker script - Drop cc-option tests from compiler flags supported by our minimal GCC/Clang versions - Use always 12-digits commit hash for CONFIG_LOCALVERSION_AUTO=y - Use sha1 build id for both BFD linker and LLD - Improve deb-pkg for reproducible builds and rootless builds - Remove stale, useless scripts/namespace.pl - Turn -Wreturn-type warning into error - Fix build error of deb-pkg when CONFIG_MODULES=n - Replace 'hostname' command with more portable 'uname -n' - Various Makefile cleanups * tag 'kbuild-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits) kbuild: Use uname for LINUX_COMPILE_HOST detection kbuild: Only add -fno-var-tracking-assignments for old GCC versions kbuild: remove leftover comment for filechk utility treewide: remove DISABLE_LTO kbuild: deb-pkg: clean up package name variables kbuild: deb-pkg: do not build linux-headers package if CONFIG_MODULES=n kbuild: enforce -Werror=return-type scripts: remove namespace.pl builddeb: Add support for all required debian/rules targets builddeb: Enable rootless builds builddeb: Pass -n to gzip for reproducible packages kbuild: split the build log of kallsyms kbuild: explicitly specify the build id style scripts/setlocalversion: make git describe output more reliable kbuild: remove cc-option test of -Werror=date-time kbuild: remove cc-option test of -fno-stack-check kbuild: remove cc-option test of -fno-strict-overflow kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles kbuild: remove redundant CONFIG_KASAN check from scripts/Makefile.kasan kbuild: do not create built-in objects for external module builds ...

ubsan: introduce CONFIG_UBSAN_LOCAL_BOUNDS for Clang

2020-10-16T18:11:22Z

When the kernel is compiled with Clang, -fsanitize=bounds expands to -fsanitize=array-bounds and -fsanitize=local-bounds. Enabling -fsanitize=local-bounds with Clang has the unfortunate side-effect of inserting traps; this goes back to its original intent, which was as a hardening and not a debugging feature [1]. The same feature made its way into -fsanitize=bounds, but the traps remained. For that reason, -fsanitize=bounds was split into 'array-bounds' and 'local-bounds' [2]. Since 'local-bounds' doesn't behave like a normal sanitizer, enable it with Clang only if trapping behaviour was requested by CONFIG_UBSAN_TRAP=y. Add the UBSAN_BOUNDS_LOCAL config to Kconfig.ubsan to enable the 'local-bounds' option by default when UBSAN_TRAP is enabled. [1] http://lists.llvm.org/pipermail/llvm-dev/2012-May/049972.html [2] http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20131021/091536.html Suggested-by: Marco Elver Signed-off-by: George Popescu Signed-off-by: Andrew Morton Reviewed-by: David Brazdil Reviewed-by: Marco Elver Cc: Masahiro Yamada Cc: Michal Marek Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Kees Cook Cc: Dmitry Vyukov Cc: Arnd Bergmann Cc: Peter Zijlstra Link: https://lkml.kernel.org/r/20200922074330.2549523-1-georgepope@google.com Signed-off-by: Linus Torvalds

kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles

2020-09-24T15:36:50Z

Move CFLAGS_KASAN*, CFLAGS_UBSAN, CFLAGS_KCSAN to Makefile.kasan, Makefile.ubsan, Makefile.kcsan, respectively. This commit also avoids the same -fsanitize=* flags being added to CFLAGS_UBSAN multiple times. Prior to this commit, the ubsan flags were appended by the '+=' operator, without any initialization. Some build targets such as 'make bindeb-pkg' recurses to the top Makefile, and ended up with adding the same flags to CFLAGS_UBSAN twice. Clear CFLAGS_UBSAN with ':=' to make it a simply expanded variable. This is better than a recursively expanded variable, which evaluates $(call cc-option, ...) multiple times before Kbuild starts descending to subdirectories. Signed-off-by: Masahiro Yamada Acked-by: Marco Elver

kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled

2020-08-09T16:32:59Z

Currently, the top Makefile includes all of scripts/Makefile. even if the associated CONFIG option is disabled. Do not include unneeded Makefiles in order to slightly optimize the parse stage. Include $(include-y), and ignore $(include-). Signed-off-by: Masahiro Yamada

ubsan: split "bounds" checker from other options

2020-04-07T17:43:44Z

In order to do kernel builds with the bounds checker individually available, introduce CONFIG_UBSAN_BOUNDS, with the remaining options under CONFIG_UBSAN_MISC. For example, using this, we can start to expand the coverage syzkaller is providing. Right now, all of UBSan is disabled for syzbot builds because taken as a whole, it is too noisy. This will let us focus on one feature at a time. For the bounds checker specifically, this provides a mechanism to eliminate an entire class of array overflows with close to zero performance overhead (I cannot measure a difference). In my (mostly) defconfig, enabling bounds checking adds ~4200 checks to the kernel. Performance changes are in the noise, likely due to the branch predictors optimizing for the non-fail path. Some notes on the bounds checker: - it does not instrument {mem,str}*()-family functions, it only instruments direct indexed accesses (e.g. "foo[i]"). Dealing with the {mem,str}*()-family functions is a work-in-progress around CONFIG_FORTIFY_SOURCE[1]. - it ignores flexible array members, including the very old single byte (e.g. "int foo[1];") declarations. (Note that GCC's implementation appears to ignore _all_ trailing arrays, but Clang only ignores empty, 0, and 1 byte arrays[2].) [1] https://github.com/KSPP/linux/issues/6 [2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92589 Suggested-by: Elena Petrova Signed-off-by: Kees Cook Signed-off-by: Andrew Morton Reviewed-by: Andrey Ryabinin Acked-by: Dmitry Vyukov Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Dan Carpenter Cc: "Gustavo A. R. Silva" Link: http://lkml.kernel.org/r/20200227193516.32566-3-keescook@chromium.org Signed-off-by: Linus Torvalds

ubsan: add trap instrumentation option

2020-04-07T17:43:44Z

Patch series "ubsan: Split out bounds checker", v5. This splits out the bounds checker so it can be individually used. This is enabled in Android and hopefully for syzbot. Includes LKDTM tests for behavioral corner-cases (beyond just the bounds checker), and adjusts ubsan and kasan slightly for correct panic handling. This patch (of 6): The Undefined Behavior Sanitizer can operate in two modes: warning reporting mode via lib/ubsan.c handler calls, or trap mode, which uses __builtin_trap() as the handler. Using lib/ubsan.c means the kernel image is about 5% larger (due to all the debugging text and reporting structures to capture details about the warning conditions). Using the trap mode, the image size changes are much smaller, though at the loss of the "warning only" mode. In order to give greater flexibility to system builders that want minimal changes to image size and are prepared to deal with kernel code being aborted and potentially destabilizing the system, this introduces CONFIG_UBSAN_TRAP. The resulting image sizes comparison: text data bss dec hex filename 19533663 6183037 18554956 44271656 2a38828 vmlinux.stock 19991849 7618513 18874448 46484810 2c54d4a vmlinux.ubsan 19712181 6284181 18366540 44362902 2a4ec96 vmlinux.ubsan-trap CONFIG_UBSAN=y: image +4.8% (text +2.3%, data +18.9%) CONFIG_UBSAN_TRAP=y: image +0.2% (text +0.9%, data +1.6%) Additionally adjusts the CONFIG_UBSAN Kconfig help for clarity and removes the mention of non-existing boot param "ubsan_handle". Suggested-by: Elena Petrova Signed-off-by: Kees Cook Signed-off-by: Andrew Morton Acked-by: Dmitry Vyukov Cc: Andrey Ryabinin Cc: Andrey Konovalov Cc: Alexander Potapenko Cc: Dan Carpenter Cc: "Gustavo A. R. Silva" Cc: Arnd Bergmann Cc: Ard Biesheuvel Link: http://lkml.kernel.org/r/20200227193516.32566-2-keescook@chromium.org Signed-off-by: Linus Torvalds

ubsan: Remove vla bound checks.

2019-05-06T18:12:09Z

The kernel the kernel is built with -Wvla for some time, so is not supposed to have any variable length arrays. Remove vla bounds checking from ubsan since it's useless now. Signed-off-by: Andrey Ryabinin Signed-off-by: Linus Torvalds

lib/ubsan: remove null-pointer checks

2018-08-11T03:19:58Z

With gcc-8 fsanitize=null become very noisy. GCC started to complain about things like &a->b, where 'a' is NULL pointer. There is no NULL dereference, we just calculate address to struct member. It's technically undefined behavior so UBSAN is correct to report it. But as long as there is no real NULL-dereference, I think, we should be fine. -fno-delete-null-pointer-checks compiler flag should protect us from any consequences. So let's just no use -fsanitize=null as it's not useful for us. If there is a real NULL-deref we will see crash. Even if userspace mapped something at NULL (root can do this), with things like SMAP should catch the issue. Link: http://lkml.kernel.org/r/20180802153209.813-1-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/ubsan: remove returns-nonnull-attribute checks

2018-02-07T02:32:46Z

Similarly to type mismatch checks, new GCC 8.x and Clang also changed for ABI for returns_nonnull checks. While we can update our code to conform the new ABI it's more reasonable to just remove it. Because it's just dead code, we don't have any single user of returns_nonnull attribute in the whole kernel. And AFAIU the advantage that this attribute could bring would be mitigated by -fno-delete-null-pointer-checks cflag that we use to build the kernel. So it's unlikely we will have a lot of returns_nonnull attribute in future. So let's just remove the code, it has no use. [aryabinin@virtuozzo.com: fix warning] Link: http://lkml.kernel.org/r/20180122165711.11510-1-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/20180119152853.16806-2-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin Cc: Sodagudi Prasad Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55Z

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 Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman