kernel.git/arch/x86/include/asm/compat.h, branch linux-5.18.y

stat: fix inconsistency between struct stat and struct compat_stat

2022-04-12T23:35:08Z

struct stat (defined in arch/x86/include/uapi/asm/stat.h) has 32-bit st_dev and st_rdev; struct compat_stat (defined in arch/x86/include/asm/compat.h) has 16-bit st_dev and st_rdev followed by a 16-bit padding. This patch fixes struct compat_stat to match struct stat. [ Historical note: the old x86 'struct stat' did have that 16-bit field that the compat layer had kept around, but it was changes back in 2003 by "struct stat - support larger dev_t": https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=e95b2065677fe32512a597a79db94b77b90c968d and back in those days, the x86_64 port was still new, and separate from the i386 code, and had already picked up the old version with a 16-bit st_dev field ] Note that we can't change compat_dev_t because it is used by compat_loop_info. Also, if the st_dev and st_rdev values are 32-bit, we don't have to use old_valid_dev to test if the value fits into them. This fixes -EOVERFLOW on filesystems that are on NVMe because NVMe uses the major number 259. Signed-off-by: Mikulas Patocka Cc: Andreas Schwab Cc: Matthew Wilcox Cc: Christoph Hellwig Signed-off-by: Linus Torvalds

arch: remove compat_alloc_user_space

2021-09-08T22:32:35Z

All users of compat_alloc_user_space() and copy_in_user() have been removed from the kernel, only a few functions in sparc remain that can be changed to calling arch_copy_in_user() instead. Link: https://lkml.kernel.org/r/20210727144859.4150043-7-arnd@kernel.org Signed-off-by: Arnd Bergmann Reviewed-by: Christoph Hellwig Cc: Al Viro Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christian Borntraeger Cc: Christoph Hellwig Cc: "David S. Miller" Cc: Eric Biederman Cc: Feng Tang Cc: Heiko Carstens Cc: Helge Deller Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: "James E.J. Bottomley" Cc: Michael Ellerman Cc: Paul Mackerras Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

compat: make linux/compat.h available everywhere

2021-07-23T13:20:24Z

Parts of linux/compat.h are under an #ifdef, but we end up using more of those over time, moving things around bit by bit. To get it over with once and for all, make all of this file uncondititonal now so it can be accessed everywhere. There are only a few types left that are in asm/compat.h but not yet in the asm-generic version, so add those in the process. This requires providing a few more types in asm-generic/compat.h that were not already there. The only tricky one is compat_sigset_t, which needs a little help on 32-bit architectures and for x86. Signed-off-by: Arnd Bergmann Reviewed-by: Christoph Hellwig Signed-off-by: David S. Miller

[amd64] clean PRSTATUS_SIZE/SET_PR_FPVALID up properly

2021-01-06T13:40:56Z

To get rid of hardcoded size/offset in those macros we need to have a definition of i386 variant of struct elf_prstatus. However, we can't do that in asm/compat.h - the types needed for that are not there and adding an include of asm/user32.h into asm/compat.h would cause a lot of mess. That could be conveniently done in elfcore-compat.h, but currently there is nowhere to put arch-dependent parts of it - no asm/elfcore-compat.h. So we introduce a new file (asm/elfcore-compat.h, present on architectures that have CONFIG_ARCH_HAS_ELFCORE_COMPAT set, currently only on x86), have it pulled by linux/elfcore-compat.h and move the definitions there. As a side benefit, we don't need to worry about accidental inclusion of that file into binfmt_elf.c itself, so we don't need the dance with COMPAT_PRSTATUS_SIZE, etc. - only fs/compat_binfmt_elf.c will see that header. Signed-off-by: Al Viro

binfmt_elf: partially sanitize PRSTATUS_SIZE and SET_PR_FPVALID

2021-01-04T23:27:37Z

On 64bit architectures that support 32bit processes there are two possible layouts for NT_PRSTATUS note in ELF coredumps. For one thing, several fields are 64bit for native processes and 32bit for compat ones (pr_sigpend, etc.). For another, the register dump is obviously different - the size and number of registers are not going to be the same for 32bit and 64bit variants of processor. Usually that's handled by having two structures - elf_prstatus for native layout and compat_elf_prstatus for 32bit one. 32bit processes are handled by fs/compat_binfmt_elf.c, which defines a macro called 'elf_prstatus' that expands to compat_elf_prstatus. Then it includes fs/binfmt_elf.c, which makes all references to struct elf_prstatus to be textually replaced with struct compat_elf_prstatus. Ugly and somewhat brittle, but it works. However, amd64 is worse - there are _three_ possible layouts. One for native 64bit processes, another for i386 (32bit) processes and yet another for x32 (32bit address space with full 64bit registers). Both i386 and x32 processes are handled by fs/compat_binfmt_elf.c, with usual compat_binfmt_elf.c trickery. However, the layouts for i386 and x32 are not identical - they have the common beginning, but the register dump part (pr_reg) is bigger on x32. Worse, pr_reg is not the last field - it's followed by int pr_fpvalid, so that field ends up at different offsets for i386 and x32 layouts. Fortunately, there's not much code that cares about any of that - it's all encapsulated in fill_thread_core_info(). Since x32 variant is bigger, we define compat_elf_prstatus to match that layout. That way i386 processes have enough space to fit their layout into. Moreover, since these layouts are identical prior to pr_reg, we don't need to distinguish x32 and i386 cases when we are setting the fields prior to pr_reg. Filling pr_reg itself is done by calling ->get() method of appropriate regset, and that method knows what layout (and size) to use. We do need to distinguish x32 and i386 cases only for two things: setting ->pr_fpvalid (offset differs for x32 and i386) and choosing the right size for our note. The way it's done is Not Nice, for the lack of more accurate printable description. There are two macros (PRSTATUS_SIZE and SET_PR_FPVALID), that default essentially to sizeof(struct elf_prstatus) and (S)->pr_fpvalid = 1. On x86 asm/compat.h provides its own variants. Unfortunately, quite a few things go wrong there: * PRSTATUS_SIZE doesn't use the normal test for process being an x32 one; it compares the size reported by regset with the size of pr_reg. * it hardcodes the sizes of x32 and i386 variants (296 and 144 resp.), so if some change in includes leads to asm/compat.h pulled in by fs/binfmt_elf.c we are in trouble - it will end up using the size of x32 variant for 64bit processes. * it's in the wrong place; asm/compat.h couldn't define the structure for i386 layout, since it lacks quite a few types needed for it. Hardcoded sizes are largely due to that. The proper fix would be to have an explicitly defined i386 variant of structure and have PRSTATUS_SIZE/SET_PR_FPVALID check for TIF_X32 to choose the variant that should be used. Unfortunately, that requires some manipulations of headers; we'll do that later in the series, but for now let's go with the minimal variant - rename PRSTATUS_SIZE in asm/compat.h to COMPAT_PRSTATUS_SIZE, have fs/compat_binfmt_elf.c define PRSTATUS_SIZE to COMPAT_PRSTATUS_SIZE and use the normal TIF_X32 check in that macro. The size of i386 variant is kept hardcoded for now. Similar story for SET_PR_FPVALID. Signed-off-by: Al Viro

x86/compat: Simplify compat syscall userspace allocation

2020-10-26T12:46:46Z

When allocating user memory space for a compat system call, don't consider whether the originating code is IA32 or X32, just allocate from a safe region for both, beyond the redzone. This should be safe for IA32, and has the benefit of avoiding TIF_IA32, which is about to be removed. Suggested-by: Andy Lutomirski Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20201004032536.1229030-3-krisman@collabora.com

compat: add a compat_need_64bit_alignment_fixup() helper

2020-09-17T17:00:46Z

Add a helper to check if the calling syscall needs a fixup for non-natural 64-bit type alignment in the compat ABI. This will only return true for i386 syscalls on x86_64. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

compat: lift compat_s64 and compat_u64 to

2020-09-17T17:00:46Z

lift the compat_s64 and compat_u64 definitions into common code using the COMPAT_FOR_U64_ALIGNMENT symbol for the x86 special case. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

signal: refactor copy_siginfo_to_user32

2020-05-05T20:46:09Z

Factor out a copy_siginfo_to_external32 helper from copy_siginfo_to_user32 that fills out the compat_siginfo, but does so on a kernel space data structure. With that we can let architectures override copy_siginfo_to_user32 with their own implementations using copy_siginfo_to_external32. That allows moving the x32 SIGCHLD purely to x86 architecture code. As a nice side effect copy_siginfo_to_external32 also comes in handy for avoiding a set_fs() call in the coredump code later on. Contains improvements from Eric W. Biederman and Arnd Bergmann . Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

compat: provide compat_ptr() on all architectures

2020-01-03T08:32:51Z

In order to avoid needless #ifdef CONFIG_COMPAT checks, move the compat_ptr() definition to linux/compat.h where it can be seen by any file regardless of the architecture. Only s390 needs a special definition, this can use the self-#define trick we have elsewhere. Reviewed-by: Ben Hutchings Signed-off-by: Arnd Bergmann