[Bug libc/19408] linux personality syscall wrapper may erroneously return an error on 32-bit architectures

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https://sourceware.org/bugzilla/show_bug.cgi?id=19408

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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=e0043e17dfc52fe1702746543127cb4a87232bcd

commit e0043e17dfc52fe1702746543127cb4a87232bcd
Author: Dmitry V. Levin <ldv@altlinux.org>
Date:   Sun Dec 27 16:30:02 2015 +0000

    Fix linux personality syscall wrapper

    The personality system call, starting with linux kernel commit
    v2.6.29-6609-g11d06b2a1e5658f448a308aa3beb97bacd64a940, always
    successfully changes the personality if requested.  The syscall
    wrapper, however, still can return an error in the following cases:
    - the value returned by the system call looks like an error
    due to architecture limitations of 32-bit kernels;
    - a personality greater than 0xffffffff is passed to the system call,
    and the 64-bit kernel does not have commit
    v2.6.35-rc1-372-g485d527686850d68a0e9006dd9904f19f122485e
    that would truncate this value to unsigned int;
    - on sparc64, the value returned by the system call looks like an error
    due to sparc64 kernel sign extension bug.

    The solution is three-fold:
    - move generic syscalls.list personality entry to generic 64-bit
    syscalls.list file;
    - for each 32-bit architecture that use negated errno semantics,
    add a NOERRNO personality entry to their syscalls.list file;
    - for sparc64 and 32-bit architectures that use dedicated registers
    to flag syscall errors, add a wrapper around personality syscall;
    if the system call return value is flagged as an error, this wrapper
    returns the negated "would be errno" value, otherwise it returns
    the system call return value; on sparc64, it also truncates the
    personality argument to unsigned int before passing it to the kernel.

    [BZ #19408]
    * sysdeps/unix/sysv/linux/personality.c: New file.
    * sysdeps/unix/sysv/linux/sparc/sparc64/personality.c: Likewise.
    * sysdeps/unix/sysv/linux/tst-personality.c: Likewise.
    * sysdeps/unix/sysv/linux/Makefile [$(subdir) == misc]
    (sysdep_routines): Add personality.
    (tests): Add tst-personality.
    * sysdeps/unix/sysv/linux/syscalls.list (personality): Move ...
    * sysdeps/unix/sysv/linux/wordsize-64/syscalls.list: ... here.
    * sysdeps/unix/sysv/linux/arm/syscalls.list (personality): New entry.
    * sysdeps/unix/sysv/linux/hppa/syscalls.list (personality): Likewise.
    * sysdeps/unix/sysv/linux/i386/syscalls.list (personality): Likewise.
    * sysdeps/unix/sysv/linux/m68k/syscalls.list (personality): Likewise.
    * sysdeps/unix/sysv/linux/microblaze/syscalls.list (personality):
    Likewise.
    * sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list (personality):
    Likewise.
    * sysdeps/unix/sysv/linux/s390/s390-32/syscalls.list (personality):
    Likewise.
    * sysdeps/unix/sysv/linux/sh/syscalls.list (personality): Likewise.
    * sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list (personality):
    Likewise.

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                                          |   25 ++++++++++
 sysdeps/unix/sysv/linux/Makefile                   |    5 +-
 sysdeps/unix/sysv/linux/arm/syscalls.list          |    2 +
 sysdeps/unix/sysv/linux/hppa/syscalls.list         |    1 +
 sysdeps/unix/sysv/linux/i386/syscalls.list         |    2 +
 sysdeps/unix/sysv/linux/m68k/syscalls.list         |    1 +
 sysdeps/unix/sysv/linux/microblaze/syscalls.list   |    1 +
 .../unix/sysv/linux/mips/mips64/n32/syscalls.list  |    2 +
 sysdeps/unix/sysv/linux/personality.c              |   49 ++++++++++++++++++++
 sysdeps/unix/sysv/linux/s390/s390-32/syscalls.list |    1 +
 sysdeps/unix/sysv/linux/sh/syscalls.list           |    2 +
 .../unix/sysv/linux/sparc/sparc64/personality.c    |    3 +
 sysdeps/unix/sysv/linux/syscalls.list              |    1 -
 sysdeps/unix/sysv/linux/tst-personality.c          |   45 ++++++++++++++++++
 sysdeps/unix/sysv/linux/wordsize-64/syscalls.list  |    1 +
 sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list   |    1 +
 16 files changed, 139 insertions(+), 3 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/personality.c
 create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/personality.c
 create mode 100644 sysdeps/unix/sysv/linux/tst-personality.c

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