kernel/linux.git/fs/Kconfig.binfmt, branch v6.18.21

binfmt_elf: preserve original ELF e_flags for core dumps

2025-09-04T03:49:32+00:00

Some architectures, such as RISC-V, use the ELF e_flags field to encode ABI-specific information (e.g., ISA extensions, fpu support). Debuggers like GDB rely on these flags in core dumps to correctly interpret optional register sets. If the flags are missing or incorrect, GDB may warn and ignore valid data, for example: warning: Unexpected size of section '.reg2/213' in core file. This can prevent access to fpu or other architecture-specific registers even when they were dumped. Save the e_flags field during ELF binary loading (in load_elf_binary()) into the mm_struct, and later retrieve it during core dump generation (in fill_note_info()). Kconfig option CONFIG_ARCH_HAS_ELF_CORE_EFLAGS is introduced for architectures that require this behaviour. Signed-off-by: Svetlana Parfenova Link: https://lore.kernel.org/r/20250901135350.619485-1-svetlana.parfenova@syntacore.com Signed-off-by: Kees Cook

exec: Add KUnit test for bprm_stack_limits()

2024-06-19T20:13:55+00:00

Since bprm_stack_limits() operates with very limited side-effects, add it as the first exec.c KUnit test. Add to Kconfig and adjust MAINTAINERS file to include it. Tested on 64-bit UML: $ tools/testing/kunit/kunit.py run exec Link: https://lore.kernel.org/lkml/20240520021615.741800-1-keescook@chromium.org/ Signed-off-by: Kees Cook

riscv: support the elf-fdpic binfmt loader

2023-08-23T21:17:43+00:00

Add support for enabling and using the binfmt_elf_fdpic program loader on RISC-V platforms. The most important change is to setup registers during program load to pass the mapping addresses to the new process. One of the interesting features of the elf-fdpic loader is that it also allows appropriately compiled ELF format binaries to be loaded on nommu systems. Appropriate being those compiled with -pie. Signed-off-by: Greg Ungerer Acked-by: Kees Cook Link: https://lore.kernel.org/r/20230711130754.481209-3-gerg@kernel.org Signed-off-by: Palmer Dabbelt

Merge tag 'xtensa-20221010' of https://github.com/jcmvbkbc/linux-xtensa

2022-10-10T21:21:11+00:00

Pull xtensa updates from Max Filippov: - add support for FDPIC and static PIE executable formats for noMMU * tag 'xtensa-20221010' of https://github.com/jcmvbkbc/linux-xtensa: xtensa: add FDPIC and static PIE support for noMMU xtensa: clean up ELF_PLAT_INIT macro

a.out: Remove the a.out implementation

2022-09-27T14:11:02+00:00

In commit 19e8b701e258 ("a.out: Stop building a.out/osf1 support on alpha and m68k") the last users of a.out were disabled. As nothing has turned up to cause this change to be reverted, let's remove the code implementing a.out support as well. There may be userspace users of the uapi bits left so the uapi headers have been left untouched. Signed-off-by: "Eric W. Biederman" Acked-by: Arnd Bergmann # arm defconfigs Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/871qrx3hq3.fsf@email.froward.int.ebiederm.org

xtensa: add FDPIC and static PIE support for noMMU

2022-09-14T01:28:00+00:00

Define ELFOSABI_XTENSA_FDPIC and use it as an OSABI tag in the ELF header to distinguish FDPIC ELF files from regular ELF files. Define ELF_FDPIC_PLAT_INIT and put executable map, interpreter map and executable dynamic section addresses into registers a4..a6. Update start_thread macro to preserve register values in the current register window. Add definitions for PTRACE_GETFDPIC, PTRACE_GETFDPIC_EXEC and PTRACE_GETFDPIC_INTERP. Signed-off-by: Max Filippov

Merge tag 'm68knommu-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu

2022-05-30T17:56:18+00:00

Pull m68knommu updates from Greg Ungerer: "A collection of changes to add elf-fdpic loader support for m68k. Also a collection of various fixes. They include typo corrections, undefined symbol compilation fixes, removal of the ISA_DMA_API support and removal of unused code. Summary: - correctly set up ZERO_PAGE pointer - drop ISA_DMA_API support - fix comment typos - fixes for undefined symbols - remove unused code and variables - elf-fdpic loader support for m68k" * tag 'm68knommu-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu: m68knommu: fix 68000 CPU link with no platform selected m68k: removed unused "mach_get_ss" m68knommu: fix undefined reference to `mach_get_rtc_pll' m68knommu: fix undefined reference to `_init_sp' m68knommu: allow elf_fdpic loader to be selected m68knommu: add definitions to support elf_fdpic program loader m68knommu: implement minimal regset support m68knommu: use asm-generic/mmu.h for nommu setups m68k: fix typos in comments m68k: coldfire: drop ISA_DMA_API support m68knommu: set ZERO_PAGE() to the allocated zeroed page

m68knommu: allow elf_fdpic loader to be selected

2022-05-16T03:18:30+00:00

The m68k architecture code is capable of supporting the binfmt_elf_fdpic loader, so allow it to be configured. It is restricted to nommu configurations at this time due to the MMU context structures/code not supporting everything elf_fdpic needs when MMU is enabled. Signed-off-by: Greg Ungerer

binfmt_flat: Remove shared library support

2022-04-22T17:57:18+00:00

In a recent discussion[1] it was reported that the binfmt_flat library support was only ever used on m68k and even on m68k has not been used in a very long time. The structure of binfmt_flat is different from all of the other binfmt implementations because of this shared library support and it made life and code review more effort when I refactored the code in fs/exec.c. Since in practice the code is dead remove the binfmt_flat shared library support and make maintenance of the code easier. [1] https://lkml.kernel.org/r/81788b56-5b15-7308-38c7-c7f2502c4e15@linux-m68k.org Signed-off-by: "Eric W. Biederman" Reviewed-by: Damien Le Moal Acked-by: Vladimir Murzin # ARM Tested-by: Patrice Chotard Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/87levzzts4.fsf_-_@email.froward.int.ebiederm.org

Merge tag 'execve-v5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2022-03-22T02:16:02+00:00

Pull execve updates from Kees Cook: "Execve and binfmt updates. Eric and I have stepped up to be the active maintainers of this area, so here's our first collection. The bulk of the work was in coredump handling fixes; additional details are noted below: - Handle unusual AT_PHDR offsets (Akira Kawata) - Fix initial mapping size when PT_LOADs are not ordered (Alexey Dobriyan) - Move more code under CONFIG_COREDUMP (Alexey Dobriyan) - Fix missing mmap_lock in file_files_note (Eric W. Biederman) - Remove a.out support for alpha and m68k (Eric W. Biederman) - Include first pages of non-exec ELF libraries in coredump (Jann Horn) - Don't write past end of notes for regset gap in coredump (Rick Edgecombe) - Comment clean-ups (Tom Rix) - Force single empty string when argv is empty (Kees Cook) - Add NULL argv selftest (Kees Cook) - Properly redefine PT_GNU_* in terms of PT_LOOS (Kees Cook) - MAINTAINERS: Update execve entry with tree (Kees Cook) - Introduce initial KUnit testing for binfmt_elf (Kees Cook)" * tag 'execve-v5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: binfmt_elf: Don't write past end of notes for regset gap a.out: Stop building a.out/osf1 support on alpha and m68k coredump: Don't compile flat_core_dump when coredumps are disabled coredump: Use the vma snapshot in fill_files_note coredump/elf: Pass coredump_params into fill_note_info coredump: Remove the WARN_ON in dump_vma_snapshot coredump: Snapshot the vmas in do_coredump coredump: Move definition of struct coredump_params into coredump.h binfmt_elf: Introduce KUnit test ELF: Properly redefine PT_GNU_* in terms of PT_LOOS MAINTAINERS: Update execve entry with more details exec: cleanup comments fs/binfmt_elf: Refactor load_elf_binary function fs/binfmt_elf: Fix AT_PHDR for unusual ELF files binfmt: move more stuff undef CONFIG_COREDUMP selftests/exec: Test for empty string on NULL argv exec: Force single empty string when argv is empty coredump: Also dump first pages of non-executable ELF libraries ELF: fix overflow in total mapping size calculation