linux/arch/mips/kernel/signal32.c
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

79 lines
2.1 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 1994 - 2000, 2006 Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2016, Imagination Technologies Ltd.
*/
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <asm/compat.h>
#include <asm/compat-signal.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include "signal-common.h"
/* 32-bit compatibility types */
typedef unsigned int __sighandler32_t;
typedef void (*vfptr_t)(void);
/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
asmlinkage int sys32_sigsuspend(compat_sigset_t __user *uset)
{
return compat_sys_rt_sigsuspend(uset, sizeof(compat_sigset_t));
}
SYSCALL_DEFINE3(32_sigaction, long, sig, const struct compat_sigaction __user *, act,
struct compat_sigaction __user *, oact)
{
struct k_sigaction new_ka, old_ka;
int ret;
int err = 0;
if (act) {
old_sigset_t mask;
s32 handler;
if (!access_ok(VERIFY_READ, act, sizeof(*act)))
return -EFAULT;
err |= __get_user(handler, &act->sa_handler);
new_ka.sa.sa_handler = (void __user *)(s64)handler;
err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
err |= __get_user(mask, &act->sa_mask.sig[0]);
if (err)
return -EFAULT;
siginitset(&new_ka.sa.sa_mask, mask);
}
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
return -EFAULT;
err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
err |= __put_user((u32)(u64)old_ka.sa.sa_handler,
&oact->sa_handler);
err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
err |= __put_user(0, &oact->sa_mask.sig[1]);
err |= __put_user(0, &oact->sa_mask.sig[2]);
err |= __put_user(0, &oact->sa_mask.sig[3]);
if (err)
return -EFAULT;
}
return ret;
}