kernel/linux.git/lib/ubsan.c, branch v5.10.257

panic: Consolidate open-coded panic_on_warn checks

2023-02-01T07:23:20+00:00

commit 79cc1ba7badf9e7a12af99695a557e9ce27ee967 upstream. Several run-time checkers (KASAN, UBSAN, KFENCE, KCSAN, sched) roll their own warnings, and each check "panic_on_warn". Consolidate this into a single function so that future instrumentation can be added in a single location. Cc: Marco Elver Cc: Dmitry Vyukov Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Juri Lelli Cc: Vincent Guittot Cc: Dietmar Eggemann Cc: Steven Rostedt Cc: Ben Segall Cc: Mel Gorman Cc: Daniel Bristot de Oliveira Cc: Valentin Schneider Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Vincenzo Frascino Cc: Andrew Morton Cc: David Gow Cc: tangmeng Cc: Jann Horn Cc: Shuah Khan Cc: Petr Mladek Cc: "Paul E. McKenney" Cc: Sebastian Andrzej Siewior Cc: "Guilherme G. Piccoli" Cc: Tiezhu Yang Cc: kasan-dev@googlegroups.com Cc: linux-mm@kvack.org Reviewed-by: Luis Chamberlain Signed-off-by: Kees Cook Reviewed-by: Marco Elver Reviewed-by: Andrey Konovalov Link: https://lore.kernel.org/r/20221117234328.594699-4-keescook@chromium.org Signed-off-by: Eric Biggers Signed-off-by: Sasha Levin

ubsan: no need to unset panic_on_warn in ubsan_epilogue()

2023-02-01T07:23:19+00:00

commit d83ce027a54068fabb70d2c252e1ce2da86784a4 upstream. panic_on_warn is unset inside panic(), so no need to unset it before calling panic() in ubsan_epilogue(). Link: https://lkml.kernel.org/r/1644324666-15947-5-git-send-email-yangtiezhu@loongson.cn Signed-off-by: Tiezhu Yang Reviewed-by: Marco Elver Cc: Andrey Ryabinin Cc: Baoquan He Cc: Jonathan Corbet Cc: Xuefeng Li Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Eric Biggers Signed-off-by: Sasha Levin

ubsan: implement __ubsan_handle_alignment_assumption

2021-02-17T10:02:24+00:00

[ Upstream commit 28abcc963149e06d956d95a18a85f4ba26af746f ] When building ARCH=mips 32r2el_defconfig with CONFIG_UBSAN_ALIGNMENT: ld.lld: error: undefined symbol: __ubsan_handle_alignment_assumption referenced by slab.h:557 (include/linux/slab.h:557) main.o:(do_initcalls) in archive init/built-in.a referenced by slab.h:448 (include/linux/slab.h:448) do_mounts_rd.o:(rd_load_image) in archive init/built-in.a referenced by slab.h:448 (include/linux/slab.h:448) do_mounts_rd.o:(identify_ramdisk_image) in archive init/built-in.a referenced 1579 more times Implement this for the kernel based on LLVM's handleAlignmentAssumptionImpl because the kernel is not linked against the compiler runtime. Link: https://github.com/ClangBuiltLinux/linux/issues/1245 Link: https://github.com/llvm/llvm-project/blob/llvmorg-11.0.1/compiler-rt/lib/ubsan/ubsan_handlers.cpp#L151-L190 Link: https://lkml.kernel.org/r/20210127224451.2587372-1-nathan@kernel.org Signed-off-by: Nathan Chancellor Acked-by: Kees Cook Reviewed-by: Nick Desaulniers Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

lib/ubsan.c: fix gcc-10 warnings

2020-06-05T02:06:28+00:00

The latest compiler expects slightly different function prototypes for the ubsan helpers: lib/ubsan.c:192:6: error: conflicting types for built-in function '__ubsan_handle_add_overflow'; expected 'void(void *, void *, void *)' [-Werror=builtin-declaration-mismatch] 192 | void __ubsan_handle_add_overflow(struct overflow_data *data, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/ubsan.c:200:6: error: conflicting types for built-in function '__ubsan_handle_sub_overflow'; expected 'void(void *, void *, void *)' [-Werror=builtin-declaration-mismatch] 200 | void __ubsan_handle_sub_overflow(struct overflow_data *data, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/ubsan.c:207:6: error: conflicting types for built-in function '__ubsan_handle_mul_overflow'; expected 'void(void *, void *, void *)' [-Werror=builtin-declaration-mismatch] 207 | void __ubsan_handle_mul_overflow(struct overflow_data *data, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/ubsan.c:214:6: error: conflicting types for built-in function '__ubsan_handle_negate_overflow'; expected 'void(void *, void *)' [-Werror=builtin-declaration-mismatch] 214 | void __ubsan_handle_negate_overflow(struct overflow_data *data, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/ubsan.c:234:6: error: conflicting types for built-in function '__ubsan_handle_divrem_overflow'; expected 'void(void *, void *, void *)' [-Werror=builtin-declaration-mismatch] 234 | void __ubsan_handle_divrem_overflow(struct overflow_data *data, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Change the Linux implementation to match these, using a local typed pointer. Signed-off-by: Arnd Bergmann Signed-off-by: Andrew Morton Reviewed-by: Kees Cook Cc: Andrey Ryabinin Cc: Herbert Xu Cc: Julien Grall Link: http://lkml.kernel.org/r/20200429185948.4189600-1-arnd@arndb.de Signed-off-by: Linus Torvalds

ubsan: include bug type in report header

2020-04-07T17:43:44+00:00

When syzbot tries to figure out how to deduplicate bug reports, it prefers seeing a hint about a specific bug type (we can do better than just "UBSAN"). This lifts the handler reason into the UBSAN report line that includes the file path that tripped a check. Unfortunately, UBSAN does not provide function names. Suggested-by: Dmitry Vyukov Signed-off-by: Kees Cook Signed-off-by: Andrew Morton Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Dan Carpenter Cc: Elena Petrova Cc: "Gustavo A. R. Silva" Link: http://lkml.kernel.org/r/20200227193516.32566-7-keescook@chromium.org Link: https://lore.kernel.org/lkml/CACT4Y+bsLJ-wFx_TaXqax3JByUOWB3uk787LsyMVcfW6JzzGvg@mail.gmail.com Signed-off-by: Linus Torvalds

ubsan: check panic_on_warn

2020-04-07T17:43:44+00:00

Syzkaller expects kernel warnings to panic when the panic_on_warn sysctl is set. More work is needed here to have UBSan reuse the WARN infrastructure, but for now, just check the flag manually. Signed-off-by: Kees Cook Signed-off-by: Andrew Morton Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Dan Carpenter Cc: Dmitry Vyukov Cc: Elena Petrova Cc: "Gustavo A. R. Silva" Link: https://lore.kernel.org/lkml/CACT4Y+bsLJ-wFx_TaXqax3JByUOWB3uk787LsyMVcfW6JzzGvg@mail.gmail.com Link: http://lkml.kernel.org/r/20200227193516.32566-5-keescook@chromium.org Signed-off-by: Linus Torvalds

lib/ubsan: don't serialize UBSAN report

2019-12-05T03:44:14+00:00

At the moment, UBSAN report will be serialized using a spin_lock(). On RT-systems, spinlocks are turned to rt_spin_lock and may sleep. This will result to the following splat if the undefined behavior is in a context that can sleep: BUG: sleeping function called from invalid context at /src/linux/kernel/locking/rtmutex.c:968 in_atomic(): 1, irqs_disabled(): 128, pid: 3447, name: make 1 lock held by make/3447: #0: 000000009a966332 (&mm->mmap_sem){++++}, at: do_page_fault+0x140/0x4f8 irq event stamp: 6284 hardirqs last enabled at (6283): [] _raw_spin_unlock_irqrestore+0x90/0xa0 hardirqs last disabled at (6284): [] _raw_spin_lock_irqsave+0x30/0x78 softirqs last enabled at (2430): [] fpsimd_restore_current_state+0x60/0xe8 softirqs last disabled at (2427): [] fpsimd_restore_current_state+0x28/0xe8 Preemption disabled at: [] rt_mutex_futex_unlock+0x4c/0xb0 CPU: 3 PID: 3447 Comm: make Tainted: G W 5.2.14-rt7-01890-ge6e057589653 #911 Call trace: dump_backtrace+0x0/0x148 show_stack+0x14/0x20 dump_stack+0xbc/0x104 ___might_sleep+0x154/0x210 rt_spin_lock+0x68/0xa0 ubsan_prologue+0x30/0x68 handle_overflow+0x64/0xe0 __ubsan_handle_add_overflow+0x10/0x18 __lock_acquire+0x1c28/0x2a28 lock_acquire+0xf0/0x370 _raw_spin_lock_irqsave+0x58/0x78 rt_mutex_futex_unlock+0x4c/0xb0 rt_spin_unlock+0x28/0x70 get_page_from_freelist+0x428/0x2b60 __alloc_pages_nodemask+0x174/0x1708 alloc_pages_vma+0x1ac/0x238 __handle_mm_fault+0x4ac/0x10b0 handle_mm_fault+0x1d8/0x3b0 do_page_fault+0x1c8/0x4f8 do_translation_fault+0xb8/0xe0 do_mem_abort+0x3c/0x98 el0_da+0x20/0x24 The spin_lock() will protect against multiple CPUs to output a report together, I guess to prevent them from being interleaved. However, they can still interleave with other messages (and even splat from __might_sleep). So the lock usefulness seems pretty limited. Rather than trying to accomodate RT-system by switching to a raw_spin_lock(), the lock is now completely dropped. Link: http://lkml.kernel.org/r/20190920100835.14999-1-julien.grall@arm.com Signed-off-by: Julien Grall Reported-by: Andre Przywara Acked-by: Andrey Ryabinin Cc: Thomas Gleixner Cc: Sebastian Andrzej Siewior Cc: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-11-26T18:42:40+00:00

Pull x86 asm updates from Ingo Molnar: "The main changes in this cycle were: - Cross-arch changes to move the linker sections for NOTES and EXCEPTION_TABLE into the RO_DATA area, where they belong on most architectures. (Kees Cook) - Switch the x86 linker fill byte from x90 (NOP) to 0xcc (INT3), to trap jumps into the middle of those padding areas instead of sliding execution. (Kees Cook) - A thorough cleanup of symbol definitions within x86 assembler code. The rather randomly named macros got streamlined around a (hopefully) straightforward naming scheme: SYM_START(name, linkage, align...) SYM_END(name, sym_type) SYM_FUNC_START(name) SYM_FUNC_END(name) SYM_CODE_START(name) SYM_CODE_END(name) SYM_DATA_START(name) SYM_DATA_END(name) etc - with about three times of these basic primitives with some label, local symbol or attribute variant, expressed via postfixes. No change in functionality intended. (Jiri Slaby) - Misc other changes, cleanups and smaller fixes" * 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits) x86/entry/64: Remove pointless jump in paranoid_exit x86/entry/32: Remove unused resume_userspace label x86/build/vdso: Remove meaningless CFLAGS_REMOVE_*.o m68k: Convert missed RODATA to RO_DATA x86/vmlinux: Use INT3 instead of NOP for linker fill bytes x86/mm: Report actual image regions in /proc/iomem x86/mm: Report which part of kernel image is freed x86/mm: Remove redundant address-of operators on addresses xtensa: Move EXCEPTION_TABLE to RO_DATA segment powerpc: Move EXCEPTION_TABLE to RO_DATA segment parisc: Move EXCEPTION_TABLE to RO_DATA segment microblaze: Move EXCEPTION_TABLE to RO_DATA segment ia64: Move EXCEPTION_TABLE to RO_DATA segment h8300: Move EXCEPTION_TABLE to RO_DATA segment c6x: Move EXCEPTION_TABLE to RO_DATA segment arm64: Move EXCEPTION_TABLE to RO_DATA segment alpha: Move EXCEPTION_TABLE to RO_DATA segment x86/vmlinux: Move EXCEPTION_TABLE to RO_DATA segment x86/vmlinux: Actually use _etext for the end of the text segment vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA ...

int128: move __uint128_t compiler test to Kconfig

2019-11-17T01:02:42+00:00

In order to use 128-bit integer arithmetic in C code, the architecture needs to have declared support for it by setting ARCH_SUPPORTS_INT128, and it requires a version of the toolchain that supports this at build time. This is why all existing tests for ARCH_SUPPORTS_INT128 also test whether __SIZEOF_INT128__ is defined, since this is only the case for compilers that can support 128-bit integers. Let's fold this additional test into the Kconfig declaration of ARCH_SUPPORTS_INT128 so that we can also use the symbol in Makefiles, e.g., to decide whether a certain object needs to be included in the first place. Cc: Masahiro Yamada Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu

ubsan, x86: Annotate and allow __ubsan_handle_shift_out_of_bounds() in uaccess regions

2019-10-28T09:43:00+00:00

The new check_zeroed_user() function uses variable shifts inside of a user_access_begin()/user_access_end() section and that results in GCC emitting __ubsan_handle_shift_out_of_bounds() calls, even though through value range analysis it would be able to see that the UB in question is impossible. Annotate and whitelist this UBSAN function; continued use of user_access_begin()/user_access_end() will undoubtedly result in further uses of function. Reported-by: Randy Dunlap Tested-by: Randy Dunlap Signed-off-by: Peter Zijlstra (Intel) Acked-by: Randy Dunlap Acked-by: Christian Brauner Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephen Rothwell Cc: Thomas Gleixner Cc: cyphar@cyphar.com Cc: keescook@chromium.org Cc: linux@rasmusvillemoes.dk Fixes: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper") Link: https://lkml.kernel.org/r/20191021131149.GA19358@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar