[PATCH 00/20] Fix handling of compat_siginfo_t

[Amanieu d'Antras]

The current handling of compat_siginfo_t is a mess: each architecture has its
own implementation, all of which are incorrect in different ways. This patch
series replaces all of the arch-specific versions with a single generic one that
is guaranteed to produce the same results as a 32-bit kernel.

Most architectures are able to use the generic compat_siginfo_t, except x86 and
MIPS. MIPS uses a slightly different compat_siginfo_t structure for ABI reasons
but can still use the generic copy_siginfo_{to,from}_user32. x86 can't use the
generic versions because it needs special handling for __SI_CHLD for x32 tasks.

One issue that isn't resolved in this series is sending signals between a 32-bit
process and 64-bit process. Sending a si_int will work correctly, but a si_ptr
value will likely get corrupted due to the different layouts of the 32-bit and
64-bit siginfo_t structures.

signalfd_copyinfo was also modified to properly generate data for compat tasks.
In particular the ssi_ptr and ssi_data members need to be sign-extended to 64
bits rather than zero-extended, since that is the behavior in 32-bit kernels.

This series has been tested on x86_64 and arm64.

Amanieu d'Antras (20):
  compat: Add generic compat_siginfo_t
  compat: Add generic copy_siginfo_{to,from}_user32
  x86: Update compat_siginfo_t to be closer to the generic version
  x86: Rewrite copy_siginfo_{to,from}_user32
  mips: Clean up compat_siginfo_t
  mips: Use generic copy_siginfo_{to,from}_user32
  arm64: Use generic compat_siginfo_t
  arm64: Use generic copy_siginfo_{to,from}_user32
  parisc: Use generic compat_siginfo_t
  parsic: Use generic copy_siginfo_{to,from}_user32
  s390: Use generic compat_siginfo_t
  s390: Use generic copy_siginfo_{to,from}_user32
  powerpc: Use generic compat_siginfo_t
  powerpc: Use generic copy_siginfo_{to,from}_user32
  tile: Use generic compat_siginfo_t
  tile: Use generic copy_siginfo_{to,from}_user32
  sparc: Use generic compat_siginfo_t
  sparc: Use generic copy_siginfo_{to,from}_user32
  signalfd: Fix some issues in signalfd_copyinfo
  signal: Remove unnecessary zero-initialization of siginfo_t

 arch/arm64/include/asm/compat.h   |  59 ---------
 arch/arm64/kernel/signal32.c      |  85 ------------
 arch/mips/include/asm/compat.h    |  63 +++++----
 arch/mips/kernel/signal32.c       |  62 ---------
 arch/parisc/include/asm/compat.h  |  52 --------
 arch/parisc/kernel/signal32.c     | 102 ---------------
 arch/powerpc/include/asm/compat.h |  60 ---------
 arch/powerpc/kernel/signal_32.c   |  72 +---------
 arch/s390/include/asm/compat.h    |  51 --------
 arch/s390/kernel/compat_signal.c  | 102 ---------------
 arch/sparc/include/asm/compat.h   |  54 --------
 arch/sparc/kernel/signal32.c      |  69 ----------
 arch/tile/include/asm/compat.h    |  57 --------
 arch/tile/kernel/compat_signal.c  |  75 -----------
 arch/x86/include/asm/compat.h     |  39 ++++--
 arch/x86/kernel/signal_compat.c   | 269 +++++++++++++++++++++++++++-----------
 fs/signalfd.c                     |  58 +++++---
 include/linux/compat.h            |  66 +++++++++-
 kernel/compat.c                   | 204 +++++++++++++++++++++++++++++
 kernel/ptrace.c                   |   1 -
 kernel/signal.c                   |  16 ++-
 21 files changed, 574 insertions(+), 1042 deletions(-)

-- 
2.6.1

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