Re: [GIT PULL] siginfo cleanups for 4.16-rc1

[Eric W. Biederman]

ebiederm@xxxxxxxxxxxx (Eric W. Biederman) writes:

> Linus,
>
> Please pull the siginfo-linus branch from the git tree:
>
>    git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git siginfo-linus
>
>    HEAD: c0f45555b82450a56c0da11866163b764aeb1a21 signal/memory-failure: Use force_sig_mceerr and send_sig_mceerr
>
> Long ago when 2.4 was just a testing release copy_siginfo_to_user was
> made to copy individual fields to userspace, possibly for efficiency and
> to ensure initialized values were not copied to userspace.
> Unfortunately the design was complex, it's assumptions unstated, and
> humans are failible and so while work much of the time that design
> failed to ensure unitialized memory is not copied to userspace.
>
> This set of changes is part of a new design to clean up siginfo
> and simplify things, and hopefully make the siginfo handling robust
> enough that a simple inspection of the code can be made to ensure we
> don't copy any unitializied fields to userspace.
>
> The design is to unifiy struct siginfo and struct compat_siginfo
> into a single definition that is shared between all architectures so
> that anyone adding to the set of information shared with struct siginfo
> can see the whole picture.  Hopefully ensuring all future si_code
> assignments are arch independent.
>
> The design is to unify copy_siginfo_to_user32 and
> copy_siginfo_from_user32 so that those function are complete and cope
> with all of the different cases documented in signinfo_layout.  I don't
> think there was a single implementation of either of those functions
> that was complete and correct before my changes unified them.
>
> The design is to introduce a series of helpers including
> force_siginfo_fault that take the values that are needed in struct
> siginfo and build the siginfo structure for their callers.  Ensuring
> struct siginfo is built correctly.
>
> The remaining work for 4.17 (unless someone thinks it is post -rc1
> material) is to push usage of those helpers down into the architectures
> so that architecture specific code will not need to deal with the fiddly
> work of intializing struct siginfo, and then when struct siginfo is
> guaranteed to be fully initialized change copy siginfo_to_user into
> a simple wrapper around copy_to_user.
>
> Further there is work in progress on the issues that have been
> documented requires arch specific knowledge to sort out.
>
> The changes below fix or at least document all of the issues that have
> been found with siginfo generation.  Then proceed to unify struct
> siginfo the 32 bit helpers that copy siginfo to and from userspace,
> and generally clean up anything that is not arch specific with
> regards to siginfo generation.
>
> It is a lot but with the unification you can of siginfo you can
> already see the code reduction in the kernel.

I should add there is a trivial conflict with powerpc.  The powerpc
branch in linux-next adds a new use of the memory_failure function,
while this code removes the unused trapno argument from the
memory_failure function.   Conflict resolution just remove
the middle argument to memory_failure from the powerpc branch.

> Al Viro (3):
>       signal/mips: switch mips to generic siginfo
>       signal: kill __ARCH_SI_UID_T
>       signal: unify compat_siginfo_t
>
> Eric W. Biederman (42):
>       signal: Simplify and fix kdb_send_sig
>       signal/sh: Ensure si_signo is initialized in do_divide_error
>       signal/openrisc: Fix do_unaligned_access to send the proper signal
>       signal/parisc: Document a conflict with SI_USER with SIGFPE
>       signal/metag: Document a conflict with SI_USER with SIGFPE
>       signal/powerpc: Document conflicts with SI_USER and SIGFPE and SIGTRAP
>       signal/arm64: Document conflicts with SI_USER and SIGFPE,SIGTRAP,SIGBUS
>       signal/arm: Document conflicts with SI_USER and SIGFPE
>       signal: Reduce copy_siginfo to just a memcpy
>       signal: Introduce clear_siginfo
>       signal: Ensure generic siginfos the kernel sends have all bits initialized
>       mn10300/misalignment: Use SIGSEGV SEGV_MAPERR to report a failed user copy
>       x86/mm/pkeys: Fix fill_sig_info_pkey
>       signal: Document all of the signals that use the _sigfault union member
>       signal: Document the strange si_codes used by ptrace event stops
>       signal: Document glibc's si_code of SI_ASYNCNL
>       signal: Ensure no siginfo union member increases the size of struct siginfo
>       signal: Clear si_sys_private before copying siginfo to userspace
>       signal: Remove _sys_private and _overrun_incr from struct compat_siginfo
>       ia64/signal: switch to generic struct siginfo
>       signal/ia64: switch the last arch-specific copy_siginfo_to_user() to generic version
>       signal: Remove unnecessary ifdefs now that there is only one struct siginfo
>       signal: Move addr_lsb into the _sigfault union for clarity
>       signal/powerpc: Remove redefinition of NSIGTRAP on powerpc
>       signal/ia64: Move the ia64 specific si_codes to asm-generic/siginfo.h
>       signal/frv: Move the frv specific si_codes to asm-generic/siginfo.h
>       signal/tile: Move the tile specific si_codes to asm-generic/siginfo.h
>       signal/blackfin: Move the blackfin specific si_codes to asm-generic/siginfo.h
>       signal/blackfin: Remove pointless UID16_SIGINFO_COMPAT_NEEDED
>       signal: Unify and correct copy_siginfo_from_user32
>       signal: Remove the code to clear siginfo before calling copy_siginfo_from_user32
>       signal: Unify and correct copy_siginfo_to_user32
>       ptrace: Use copy_siginfo in setsiginfo and getsiginfo
>       signal/arm64: Better isolate the COMPAT_TASK portion of ptrace_hbptriggered
>       signal: Don't use structure initializers for struct siginfo
>       signal: Replace memset(info,...) with clear_siginfo for clarity
>       signal: Add send_sig_fault and force_sig_fault
>       signal: Helpers for faults with specialized siginfo layouts
>       signal/powerpc: Remove unnecessary signal_code parameter of do_send_trap
>       signal/ptrace: Add force_sig_ptrace_errno_trap and use it where needed
>       mm/memory_failure: Remove unused trapno from memory_failure
>       signal/memory-failure: Use force_sig_mceerr and send_sig_mceerr
>
>  arch/arc/kernel/traps.c                            |  14 +-
>  arch/arm/include/uapi/asm/siginfo.h                |  13 +
>  arch/arm/kernel/ptrace.c                           |   8 +-
>  arch/arm/vfp/vfpmodule.c                           |   2 +-
>  arch/arm64/include/asm/compat.h                    |  64 ----
>  arch/arm64/include/uapi/asm/siginfo.h              |  21 ++
>  arch/arm64/kernel/debug-monitors.c                 |  13 +-
>  arch/arm64/kernel/fpsimd.c                         |   2 +-
>  arch/arm64/kernel/ptrace.c                         |  42 +--
>  arch/arm64/kernel/signal32.c                       |  80 -----
>  arch/arm64/mm/fault.c                              | 114 +++----
>  arch/blackfin/include/uapi/asm/siginfo.h           |  34 --
>  arch/frv/include/uapi/asm/Kbuild                   |   1 +
>  arch/frv/include/uapi/asm/siginfo.h                |  13 -
>  arch/ia64/include/uapi/asm/siginfo.h               |  96 ------
>  arch/ia64/kernel/signal.c                          |  52 ---
>  arch/m68k/mm/fault.c                               |   3 +-
>  arch/metag/include/uapi/asm/siginfo.h              |   7 +
>  arch/metag/kernel/traps.c                          |   2 +-
>  arch/mips/include/asm/compat.h                     |  73 -----
>  arch/mips/include/uapi/asm/siginfo.h               |  86 +----
>  arch/mips/kernel/signal32.c                        |  67 ----
>  arch/mips/kernel/traps.c                           |  29 +-
>  arch/mn10300/mm/misalignment.c                     |   2 +-
>  arch/openrisc/kernel/traps.c                       |  10 +-
>  arch/parisc/include/asm/compat.h                   |  64 ----
>  arch/parisc/include/uapi/asm/siginfo.h             |   7 +
>  arch/parisc/kernel/pdt.c                           |   2 +-
>  arch/parisc/kernel/signal32.c                      | 106 -------
>  arch/parisc/kernel/signal32.h                      |   3 -
>  arch/parisc/kernel/traps.c                         |   2 +-
>  arch/powerpc/include/asm/compat.h                  |  65 ----
>  arch/powerpc/include/asm/debug.h                   |   2 +-
>  arch/powerpc/include/uapi/asm/siginfo.h            |  16 +-
>  arch/powerpc/kernel/process.c                      |  13 +-
>  arch/powerpc/kernel/signal_32.c                    |  66 ----
>  arch/powerpc/kernel/traps.c                        |  22 +-
>  .../powerpc/platforms/powernv/opal-memory-errors.c |   2 +-
>  arch/s390/include/asm/compat.h                     |  73 -----
>  arch/s390/kernel/compat_signal.c                   | 100 ------
>  arch/sh/kernel/traps_32.c                          |   3 +-
>  arch/sparc/include/asm/compat.h                    |  59 ----
>  arch/sparc/kernel/signal32.c                       |  69 ----
>  arch/tile/include/asm/compat.h                     |  62 ----
>  arch/tile/include/uapi/asm/siginfo.h               |   8 -
>  arch/tile/kernel/compat_signal.c                   |  73 -----
>  arch/tile/kernel/single_step.c                     |  24 +-
>  arch/tile/kernel/traps.c                           |   4 +-
>  arch/tile/kernel/unaligned.c                       |  46 +--
>  arch/um/kernel/trap.c                              |   2 +-
>  arch/x86/include/asm/compat.h                      |  86 +----
>  arch/x86/include/asm/fpu/signal.h                  |   6 -
>  arch/x86/kernel/cpu/mcheck/mce.c                   |   6 +-
>  arch/x86/kernel/signal_compat.c                    | 123 +-------
>  arch/x86/mm/fault.c                                |   7 +-
>  arch/xtensa/kernel/ptrace.c                        |   8 +-
>  drivers/acpi/apei/ghes.c                           |   2 +-
>  drivers/base/memory.c                              |   2 +-
>  drivers/ras/cec.c                                  |   2 +-
>  drivers/usb/core/devio.c                           |   4 +-
>  fs/fcntl.c                                         |   1 +
>  include/linux/compat.h                             | 100 +++++-
>  include/linux/mm.h                                 |   4 +-
>  include/linux/sched/signal.h                       |  28 ++
>  include/linux/signal.h                             |  15 +-
>  include/uapi/asm-generic/siginfo.h                 | 109 +++++--
>  ipc/mqueue.c                                       |   1 +
>  kernel/debug/kdb/kdb_main.c                        |  10 +-
>  kernel/debug/kdb/kdb_private.h                     |   2 +-
>  kernel/ptrace.c                                    |   5 +-
>  kernel/seccomp.c                                   |   2 +-
>  kernel/signal.c                                    | 350 +++++++++++++++++++--
>  kernel/time/posix-timers.c                         |   2 +-
>  mm/hwpoison-inject.c                               |   2 +-
>  mm/madvise.c                                       |   2 +-
>  mm/memory-failure.c                                |  48 ++-
>  76 files changed, 858 insertions(+), 1810 deletions(-)