PARISC: fix user-triggerable panic on parisc

commit 441a179d upstream.

int sys32_rt_sigprocmask(int how, compat_sigset_t __user *set, compat_sigset_t __user *oset,
                                    unsigned int sigsetsize)
{
        sigset_t old_set, new_set;
        int ret;

        if (set && get_sigset32(set, &new_set, sigsetsize))

...
static int
get_sigset32(compat_sigset_t __user *up, sigset_t *set, size_t sz)
{
        compat_sigset_t s;
        int r;

        if (sz != sizeof *set) panic("put_sigset32()");

In other words, rt_sigprocmask(69, (void *)69, 69) done by 32bit process
will promptly panic the box.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

arch/parisc/kernel/signal32.c

@@ -68,7 +68,8 @@ put_sigset32(compat_sigset_t __user *up, sigset_t *set, size_t sz)
 {
 	compat_sigset_t s;
 
-	if (sz != sizeof *set) panic("put_sigset32()");
+	if (sz != sizeof *set)
+		return -EINVAL;
 	sigset_64to32(&s, set);
 
 	return copy_to_user(up, &s, sizeof s);
@@ -80,7 +81,8 @@ get_sigset32(compat_sigset_t __user *up, sigset_t *set, size_t sz)
 	compat_sigset_t s;
 	int r;
 
-	if (sz != sizeof *set) panic("put_sigset32()");
+	if (sz != sizeof *set)
+		return -EINVAL;
 
 	if ((r = copy_from_user(&s, up, sz)) == 0) {
 		sigset_32to64(set, &s);