linux-stable/arch/parisc/kernel/signal32.h
Eric W. Biederman ea64d5acc8 signal: Unify and correct copy_siginfo_to_user32
Among the existing architecture specific versions of
copy_siginfo_to_user32 there are several different implementation
problems.  Some architectures fail to handle all of the cases in in
the siginfo union.  Some architectures perform a blind copy of the
siginfo union when the si_code is negative.  A blind copy suggests the
data is expected to be in 32bit siginfo format, which means that
receiving such a signal via signalfd won't work, or that the data is
in 64bit siginfo and the code is copying nonsense to userspace.

Create a single instance of copy_siginfo_to_user32 that all of the
architectures can share, and teach it to handle all of the cases in
the siginfo union correctly, with the assumption that siginfo is
stored internally to the kernel is 64bit siginfo format.

A special case is made for x86 x32 format.  This is needed as presence
of both x32 and ia32 on x86_64 results in two different 32bit signal
formats.  By allowing this small special case there winds up being
exactly one code base that needs to be maintained between all of the
architectures.  Vastly increasing the testing base and the chances of
finding bugs.

As the x86 copy of copy_siginfo_to_user32 the call of the x86
signal_compat_build_tests were moved into sigaction_compat_abi, so
that they will keep running.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-01-15 19:56:20 -06:00

86 lines
3.5 KiB
C

/*
* Copyright (C) 2001 Matthew Wilcox <willy at parisc-linux.org>
* Copyright (C) 2003 Carlos O'Donell <carlos at parisc-linux.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _PARISC64_KERNEL_SIGNAL32_H
#define _PARISC64_KERNEL_SIGNAL32_H
#include <linux/compat.h>
/* 32-bit ucontext as seen from an 64-bit kernel */
struct compat_ucontext {
compat_uint_t uc_flags;
compat_uptr_t uc_link;
compat_stack_t uc_stack; /* struct compat_sigaltstack (12 bytes)*/
/* FIXME: Pad out to get uc_mcontext to start at an 8-byte aligned boundary */
compat_uint_t pad[1];
struct compat_sigcontext uc_mcontext;
compat_sigset_t uc_sigmask; /* mask last for extensibility */
};
/* ELF32 signal handling */
/* In a deft move of uber-hackery, we decide to carry the top half of all
* 64-bit registers in a non-portable, non-ABI, hidden structure.
* Userspace can read the hidden structure if it *wants* but is never
* guaranteed to be in the same place. In fact the uc_sigmask from the
* ucontext_t structure may push the hidden register file downards
*/
struct compat_regfile {
/* Upper half of all the 64-bit registers that were truncated
on a copy to a 32-bit userspace */
compat_int_t rf_gr[32];
compat_int_t rf_iasq[2];
compat_int_t rf_iaoq[2];
compat_int_t rf_sar;
};
#define COMPAT_SIGRETURN_TRAMP 4
#define COMPAT_SIGRESTARTBLOCK_TRAMP 5
#define COMPAT_TRAMP_SIZE (COMPAT_SIGRETURN_TRAMP + \
COMPAT_SIGRESTARTBLOCK_TRAMP)
struct compat_rt_sigframe {
/* XXX: Must match trampoline size in arch/parisc/kernel/signal.c
Secondary to that it must protect the ERESTART_RESTARTBLOCK
trampoline we left on the stack (we were bad and didn't
change sp so we could run really fast.) */
compat_uint_t tramp[COMPAT_TRAMP_SIZE];
compat_siginfo_t info;
struct compat_ucontext uc;
/* Hidden location of truncated registers, *must* be last. */
struct compat_regfile regs;
};
/*
* The 32-bit ABI wants at least 48 bytes for a function call frame:
* 16 bytes for arg0-arg3, and 32 bytes for magic (the only part of
* which Linux/parisc uses is sp-20 for the saved return pointer...)
* Then, the stack pointer must be rounded to a cache line (64 bytes).
*/
#define SIGFRAME32 64
#define FUNCTIONCALLFRAME32 48
#define PARISC_RT_SIGFRAME_SIZE32 (((sizeof(struct compat_rt_sigframe) + FUNCTIONCALLFRAME32) + SIGFRAME32) & -SIGFRAME32)
long restore_sigcontext32(struct compat_sigcontext __user *sc,
struct compat_regfile __user *rf,
struct pt_regs *regs);
long setup_sigcontext32(struct compat_sigcontext __user *sc,
struct compat_regfile __user *rf,
struct pt_regs *regs, int in_syscall);
#endif