[PATCH] Fix 32bit siginfo problems on x86-64

From: Andi Kleen <ak@muc.de>

32bit siginfo would sometimes get passed incorrectly on x86-64. This
change fixes the conversion function to be a bit dumber, but more
correct.

arch/x86_64/ia32/ia32_signal.c

@@ -46,25 +46,25 @@ void signal_fault(struct pt_regs *regs, void *frame, char *where);
 
 static int ia32_copy_siginfo_to_user(siginfo_t32 *to, siginfo_t *from)
 {
+	int err;
 	if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
 		return -EFAULT;
-	if (from->si_code < 0) { 
-		/* the only field that's different is the alignment
-		   of the pointer in sigval_t. Move that 4 bytes down including
-		   padding. */
-		memmove(&((siginfo_t32 *)&from)->si_int,
-			&from->si_int, 
-			sizeof(siginfo_t) - offsetof(siginfo_t, si_int));
-		/* last 4 bytes stay the same */
-		return __copy_to_user(to, from, sizeof(siginfo_t32));
-	} else {
-		int err;
 
-		/* If you change siginfo_t structure, please be sure
+	/* If you change siginfo_t structure, please make sure that
 		   this code is fixed accordingly.
 		   It should never copy any pad contained in the structure
 		   to avoid security leaks, but must copy the generic
 		   3 ints plus the relevant union member.  */
+
+	if (from->si_code < 0) {
+		err = __put_user(from->si_signo, &to->si_signo);
+		err |= __put_user(from->si_errno, &to->si_errno);
+		err |= __put_user(from->si_code, &to->si_code);
+		err |= __put_user(from->_sifields._rt._pid, &to->_sifields._rt._pid);
+		err |= __put_user(from->_sifields._rt._uid, &to->_sifields._rt._uid);
+		err |= __put_user((u32)(u64)from->_sifields._rt._sigval.sival_ptr,
+				  &to->_sifields._rt._sigval.sival_ptr);
+	} else {
 		err = __put_user(from->si_signo, &to->si_signo);
 		err |= __put_user(from->si_errno, &to->si_errno);
 		err |= __put_user(from->si_code, &to->si_code);
@@ -86,8 +86,8 @@ static int ia32_copy_siginfo_to_user(siginfo_t32 *to, siginfo_t *from)
 			break;
 		/* case __SI_RT: This is not generated by the kernel as of now.  */
 		}
-		return err;
 	}
+	return err;
 }
 
 asmlinkage long