kernel.git/fs/binfmt_elf_fdpic.c, branch linux-6.7.y

Merge tag 'execve-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2023-10-31T05:28:19Z

Pull execve updates from Kees Cook: - Support non-BSS ELF segments with zero filesz Eric Biederman and I refactored ELF segment loading to handle the case where a segment has a smaller filesz than memsz. Traditionally linkers only did this for .bss and it was always the last segment. As a result, the kernel only handled this case when it was the last segment. We've had two recent cases where linkers were trying to use these kinds of segments for other reasons, and the were in the middle of the segment list. There was no good reason for the kernel not to support this, and the refactor actually ends up making things more readable too. - Enable namespaced binfmt_misc Christian Brauner has made it possible to use binfmt_misc with mount namespaces. This means some traditionally root-only interfaces (for adding/removing formats) are now more exposed (but believed to be safe). - Remove struct tag 'dynamic' from ELF UAPI Alejandro Colomar noticed that the ELF UAPI has been polluting the struct namespace with an unused and overly generic tag named "dynamic" for no discernible reason for many many years. After double-checking various distro source repositories, it has been removed. - Clean up binfmt_elf_fdpic debug output (Greg Ungerer) * tag 'execve-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: binfmt_misc: enable sandboxed mounts binfmt_misc: cleanup on filesystem umount binfmt_elf_fdpic: clean up debug warnings mm: Remove unused vm_brk() binfmt_elf: Only report padzero() errors when PROT_WRITE binfmt_elf: Use elf_load() for library binfmt_elf: Use elf_load() for interpreter binfmt_elf: elf_bss no longer used by load_elf_binary() binfmt_elf: Support segments with 0 filesz and misaligned starts elf, uapi: Remove struct tag 'dynamic'

binfmt_elf_fdpic: clean up debug warnings

2023-10-04T02:48:44Z

The binfmt_elf_fdpic loader has some debug trace that can be enabled at build time. The recent 64-bit additions cause some warnings if that debug is enabled, such as: fs/binfmt_elf_fdpic.c: In function ‘elf_fdpic_map_file’: fs/binfmt_elf_fdpic.c:46:33: warning: format ‘%x’ expects argument of type ‘unsigned int’, but argument 3 has type ‘Elf64_Addr’ {aka ‘long long unsigned int’} [-Wformat=] 46 | #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ ) | ^~~~~~~~ ./include/linux/printk.h:427:25: note: in definition of macro ‘printk_index_wrap’ 427 | _p_func(_fmt, ##__VA_ARGS__); \ | ^~~~ Cast values to the largest possible type (which is equivilent to unsigned long long in this case) and use appropriate format specifiers to match. Fixes: b922bf04d2c1 ("binfmt_elf_fdpic: support 64-bit systems") Signed-off-by: Greg Ungerer Link: https://lore.kernel.org/r/20230927132933.3290734-1-gerg@kernel.org Signed-off-by: Kees Cook

fs: binfmt_elf_efpic: fix personality for ELF-FDPIC

2023-09-30T00:20:45Z

The elf-fdpic loader hard sets the process personality to either PER_LINUX_FDPIC for true elf-fdpic binaries or to PER_LINUX for normal ELF binaries (in this case they would be constant displacement compiled with -pie for example). The problem with that is that it will lose any other bits that may be in the ELF header personality (such as the "bug emulation" bits). On the ARM architecture the ADDR_LIMIT_32BIT flag is used to signify a normal 32bit binary - as opposed to a legacy 26bit address binary. This matters since start_thread() will set the ARM CPSR register as required based on this flag. If the elf-fdpic loader loses this bit the process will be mis-configured and crash out pretty quickly. Modify elf-fdpic loader personality setting so that it preserves the upper three bytes by using the SET_PERSONALITY macro to set it. This macro in the generic case sets PER_LINUX and preserves the upper bytes. Architectures can override this for their specific use case, and ARM does exactly this. The problem shows up quite easily running under qemu using the ARM architecture, but not necessarily on all types of real ARM hardware. If the underlying ARM processor does not support the legacy 26-bit addressing mode then everything will work as expected. Link: https://lkml.kernel.org/r/20230907011808.2985083-1-gerg@kernel.org Fixes: 1bde925d23547 ("fs/binfmt_elf_fdpic.c: provide NOMMU loader for regular ELF binaries") Signed-off-by: Greg Ungerer Cc: Al Viro Cc: Christian Brauner Cc: Eric W. Biederman Cc: Greg Ungerer Cc: Kees Cook Cc: Signed-off-by: Andrew Morton

binfmt_elf_fdpic: support 64-bit systems

2023-08-23T21:17:42Z

The binfmt_flat_fdpic code has a number of 32-bit specific data structures associated with it. Extend it to be able to support and be used on 64-bit systems as well. The new code defines a number of key 64-bit variants of the core elf-fdpic data structures - along side the existing 32-bit sized ones. A common set of generic named structures are defined to be either the 32-bit or 64-bit ones as required at compile time. This is a similar technique to that used in the ELF binfmt loader. For example: elf_fdpic_loadseg is either elf32_fdpic_loadseg or elf64_fdpic_loadseg elf_fdpic_loadmap is either elf32_fdpic_loadmap or elf64_fdpic_loadmap the choice based on ELFCLASS32 or ELFCLASS64. Signed-off-by: Greg Ungerer Acked-by: Kees Cook Link: https://lore.kernel.org/r/20230711130754.481209-2-gerg@kernel.org Signed-off-by: Palmer Dabbelt

binfmt: Slightly simplify elf_fdpic_map_file()

2023-05-30T22:49:46Z

There is no point in initializing 'load_addr' and 'seg' here, they are both re-written just before being used below. Doing so, 'load_addr' can be moved in the #ifdef CONFIG_MMU section. Signed-off-by: Christophe JAILLET Acked-by: "Eric W. Biederman" Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/4f5e4096ad7f17716e924b5bd080e5709fc0b84b.1685290790.git.christophe.jaillet@wanadoo.fr

binfmt: Use struct_size()

2023-05-30T22:49:46Z

Use struct_size() instead of hand-writing it. It is less verbose, more robust and more informative. Signed-off-by: Christophe JAILLET Acked-by: "Eric W. Biederman" Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/53150beae5dc04dac513dba391a2e4ae8696a7f3.1685290790.git.christophe.jaillet@wanadoo.fr

coredump, vmcore: Set p_align to 4 for PT_NOTE

2023-05-16T21:32:00Z

Tools like readelf/llvm-readelf use p_align to parse a PT_NOTE program header as an array of 4-byte entries or 8-byte entries. Currently, there are workarounds[1] in place for Linux to treat p_align==0 as 4. However, it would be more appropriate to set the correct alignment so that tools do not have to rely on guesswork. FreeBSD coredumps set p_align to 4 as well. [1]: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=82ed9683ec099d8205dc499ac84febc975235af6 [2]: https://reviews.llvm.org/D150022 Signed-off-by: Fangrui Song Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20230512022528.3430327-1-maskray@google.com

ELF: fix all "Elf" typos

2023-04-08T20:45:37Z

ELF is acronym and therefore should be spelled in all caps. I left one exception at Documentation/arm/nwfpe/nwfpe.rst which looks like being written in the first person. Link: https://lkml.kernel.org/r/Y/3wGWQviIOkyLJW@p183 Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton

elfcore: Add a cprm parameter to elf_core_extra_{phdrs,data_size}

2023-01-05T15:12:12Z

A subsequent fix for arm64 will use this parameter to parse the vma information from the snapshot created by dump_vma_snapshot() rather than traversing the vma list without the mmap_lock. Fixes: 6dd8b1a0b6cb ("arm64: mte: Dump the MTE tags in the core file") Cc: # 5.18.x Signed-off-by: Catalin Marinas Reported-by: Seth Jenkins Suggested-by: Seth Jenkins Cc: Will Deacon Cc: Eric Biederman Cc: Kees Cook Link: https://lore.kernel.org/r/20221222181251.1345752-3-catalin.marinas@arm.com Signed-off-by: Will Deacon

binfmt: Fix error return code in load_elf_fdpic_binary()

2022-12-02T03:15:52Z

Fix to return a negative error code from create_elf_fdpic_tables() instead of 0. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Wang Yufen Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/1669945261-30271-1-git-send-email-wangyufen@huawei.com