Commit c3b3f524 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Al Viro
Browse files

signal: refactor copy_siginfo_to_user32 



Factor out a copy_siginfo_to_external32 helper from
copy_siginfo_to_user32 that fills out the compat_siginfo, but does so
on a kernel space data structure.  With that we can let architectures
override copy_siginfo_to_user32 with their own implementations using
copy_siginfo_to_external32.  That allows moving the x32 SIGCHLD purely
to x86 architecture code.

As a nice side effect copy_siginfo_to_external32 also comes in handy
for avoiding a set_fs() call in the coredump code later on.

Contains improvements from Eric W. Biederman <ebiederm@xmission.com>
and Arnd Bergmann <arnd@arndb.de>.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 5456ffde

arch/x86/ia32/ia32_signal.c

+1 −1
Original line number Diff line number Diff line
@@ -350,7 +350,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, 
	unsafe_put_user(*(__u64 *)set, (__u64 *)&frame->uc.uc_sigmask, Efault);

	user_access_end();



	if (__copy_siginfo_to_user32(&frame->info, &ksig->info, false))

	if (__copy_siginfo_to_user32(&frame->info, &ksig->info))

		return -EFAULT;



	/* Set up registers for signal handler */

arch/x86/include/asm/compat.h

+6 −2
Original line number Diff line number Diff line
@@ -214,7 +214,11 @@ static inline bool in_compat_syscall(void) 
#endif



struct compat_siginfo;

int __copy_siginfo_to_user32(struct compat_siginfo __user *to,

		const kernel_siginfo_t *from, bool x32_ABI);



#ifdef CONFIG_X86_X32_ABI

int copy_siginfo_to_user32(struct compat_siginfo __user *to,

		const kernel_siginfo_t *from);

#define copy_siginfo_to_user32 copy_siginfo_to_user32

#endif /* CONFIG_X86_X32_ABI */



#endif /* _ASM_X86_COMPAT_H */

arch/x86/kernel/signal.c

+27 −1
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <asm/vm86.h>



#ifdef CONFIG_X86_64

#include <linux/compat.h>

#include <asm/proto.h>

#include <asm/ia32_unistd.h>

#endif /* CONFIG_X86_64 */
@@ -511,6 +512,31 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, 
}

#endif /* CONFIG_X86_32 */



#ifdef CONFIG_X86_X32_ABI

static int x32_copy_siginfo_to_user(struct compat_siginfo __user *to,

		const struct kernel_siginfo *from)

{

	struct compat_siginfo new;



	copy_siginfo_to_external32(&new, from);

	if (from->si_signo == SIGCHLD) {

		new._sifields._sigchld_x32._utime = from->si_utime;

		new._sifields._sigchld_x32._stime = from->si_stime;

	}

	if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))

		return -EFAULT;

	return 0;

}



int copy_siginfo_to_user32(struct compat_siginfo __user *to,

			   const struct kernel_siginfo *from)

{

	if (in_x32_syscall())

		return x32_copy_siginfo_to_user(to, from);

	return __copy_siginfo_to_user32(to, from);

}

#endif /* CONFIG_X86_X32_ABI */



static int x32_setup_rt_frame(struct ksignal *ksig,

			      compat_sigset_t *set,

			      struct pt_regs *regs)
@@ -543,7 +569,7 @@ static int x32_setup_rt_frame(struct ksignal *ksig, 
	user_access_end();



	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {

		if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true))

		if (x32_copy_siginfo_to_user(&frame->info, &ksig->info))

			return -EFAULT;

	}

include/linux/compat.h

+9 −2
Original line number Diff line number Diff line
@@ -402,8 +402,15 @@ long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask, 
		       unsigned long bitmap_size);

long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,

		       unsigned long bitmap_size);

int copy_siginfo_from_user32(kernel_siginfo_t *to, const struct compat_siginfo __user *from);

int copy_siginfo_to_user32(struct compat_siginfo __user *to, const kernel_siginfo_t *from);

void copy_siginfo_to_external32(struct compat_siginfo *to,

		const struct kernel_siginfo *from);

int copy_siginfo_from_user32(kernel_siginfo_t *to,

		const struct compat_siginfo __user *from);

int __copy_siginfo_to_user32(struct compat_siginfo __user *to,

		const kernel_siginfo_t *from);

#ifndef copy_siginfo_to_user32

#define copy_siginfo_to_user32 __copy_siginfo_to_user32

#endif

int get_compat_sigevent(struct sigevent *event,

		const struct compat_sigevent __user *u_event);

kernel/signal.c

+53 −53
Original line number Diff line number Diff line
@@ -3235,94 +3235,94 @@ int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from) 
}



#ifdef CONFIG_COMPAT

int copy_siginfo_to_user32(struct compat_siginfo __user *to,

/**

 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo

 * @to: compat siginfo destination

 * @from: kernel siginfo source

 *

 * Note: This function does not work properly for the SIGCHLD on x32, but

 * fortunately it doesn't have to.  The only valid callers for this function are

 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.

 * The latter does not care because SIGCHLD will never cause a coredump.

 */

void copy_siginfo_to_external32(struct compat_siginfo *to,

		const struct kernel_siginfo *from)

#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)

{

	return __copy_siginfo_to_user32(to, from, in_x32_syscall());

}

int __copy_siginfo_to_user32(struct compat_siginfo __user *to,

			     const struct kernel_siginfo *from, bool x32_ABI)

#endif

{

	struct compat_siginfo new;

	memset(&new, 0, sizeof(new));

	memset(to, 0, sizeof(*to));



	new.si_signo = from->si_signo;

	new.si_errno = from->si_errno;

	new.si_code  = from->si_code;

	to->si_signo = from->si_signo;

	to->si_errno = from->si_errno;

	to->si_code  = from->si_code;

	switch(siginfo_layout(from->si_signo, from->si_code)) {

	case SIL_KILL:

		new.si_pid = from->si_pid;

		new.si_uid = from->si_uid;

		to->si_pid = from->si_pid;

		to->si_uid = from->si_uid;

		break;

	case SIL_TIMER:

		new.si_tid     = from->si_tid;

		new.si_overrun = from->si_overrun;

		new.si_int     = from->si_int;

		to->si_tid     = from->si_tid;

		to->si_overrun = from->si_overrun;

		to->si_int     = from->si_int;

		break;

	case SIL_POLL:

		new.si_band = from->si_band;

		new.si_fd   = from->si_fd;

		to->si_band = from->si_band;

		to->si_fd   = from->si_fd;

		break;

	case SIL_FAULT:

		new.si_addr = ptr_to_compat(from->si_addr);

		to->si_addr = ptr_to_compat(from->si_addr);

#ifdef __ARCH_SI_TRAPNO

		new.si_trapno = from->si_trapno;

		to->si_trapno = from->si_trapno;

#endif

		break;

	case SIL_FAULT_MCEERR:

		new.si_addr = ptr_to_compat(from->si_addr);

		to->si_addr = ptr_to_compat(from->si_addr);

#ifdef __ARCH_SI_TRAPNO

		new.si_trapno = from->si_trapno;

		to->si_trapno = from->si_trapno;

#endif

		new.si_addr_lsb = from->si_addr_lsb;

		to->si_addr_lsb = from->si_addr_lsb;

		break;

	case SIL_FAULT_BNDERR:

		new.si_addr = ptr_to_compat(from->si_addr);

		to->si_addr = ptr_to_compat(from->si_addr);

#ifdef __ARCH_SI_TRAPNO

		new.si_trapno = from->si_trapno;

		to->si_trapno = from->si_trapno;

#endif

		new.si_lower = ptr_to_compat(from->si_lower);

		new.si_upper = ptr_to_compat(from->si_upper);

		to->si_lower = ptr_to_compat(from->si_lower);

		to->si_upper = ptr_to_compat(from->si_upper);

		break;

	case SIL_FAULT_PKUERR:

		new.si_addr = ptr_to_compat(from->si_addr);

		to->si_addr = ptr_to_compat(from->si_addr);

#ifdef __ARCH_SI_TRAPNO

		new.si_trapno = from->si_trapno;

		to->si_trapno = from->si_trapno;

#endif

		new.si_pkey = from->si_pkey;

		to->si_pkey = from->si_pkey;

		break;

	case SIL_CHLD:

		new.si_pid    = from->si_pid;

		new.si_uid    = from->si_uid;

		new.si_status = from->si_status;

#ifdef CONFIG_X86_X32_ABI

		if (x32_ABI) {

			new._sifields._sigchld_x32._utime = from->si_utime;

			new._sifields._sigchld_x32._stime = from->si_stime;

		} else

#endif

		{

			new.si_utime = from->si_utime;

			new.si_stime = from->si_stime;

		}

		to->si_pid = from->si_pid;

		to->si_uid = from->si_uid;

		to->si_status = from->si_status;

		to->si_utime = from->si_utime;

		to->si_stime = from->si_stime;

		break;

	case SIL_RT:

		new.si_pid = from->si_pid;

		new.si_uid = from->si_uid;

		new.si_int = from->si_int;

		to->si_pid = from->si_pid;

		to->si_uid = from->si_uid;

		to->si_int = from->si_int;

		break;

	case SIL_SYS:

		new.si_call_addr = ptr_to_compat(from->si_call_addr);

		new.si_syscall   = from->si_syscall;

		new.si_arch      = from->si_arch;

		to->si_call_addr = ptr_to_compat(from->si_call_addr);

		to->si_syscall   = from->si_syscall;

		to->si_arch      = from->si_arch;

		break;

	}

}



int __copy_siginfo_to_user32(struct compat_siginfo __user *to,

			   const struct kernel_siginfo *from)

{

	struct compat_siginfo new;



	copy_siginfo_to_external32(&new, from);

	if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))

		return -EFAULT;



	return 0;

}