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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig 2020-05-05 12:12:53 +02:00 committed by Al Viro
parent 5456ffdee6
commit c3b3f52476
5 changed files with 96 additions and 59 deletions

View file

@ -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);