waitid(): switch copyout of siginfo to unsafe_put_user()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 25 insertions, 15 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 97db9ee03f90..f3b8c3a87bc1 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1625,15 +1625,18 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
         if (!infop)
                 return err;
 
-        if (put_user(err ? 0 : SIGCHLD, &infop->si_signo) ||
-            put_user(0, &infop->si_errno) ||
-            put_user((short)info.cause, &infop->si_code) ||
-            put_user(info.pid, &infop->si_pid) ||
-            put_user(info.uid, &infop->si_uid) ||
-            put_user(info.status, &infop->si_status))
-                err = -EFAULT;
-
+        user_access_begin();
+        unsafe_put_user(err ? 0 : SIGCHLD, &infop->si_signo, Efault);
+        unsafe_put_user(0, &infop->si_errno, Efault);
+        unsafe_put_user((short)info.cause, &infop->si_code, Efault);
+        unsafe_put_user(info.pid, &infop->si_pid, Efault);
+        unsafe_put_user(info.uid, &infop->si_uid, Efault);
+        unsafe_put_user(info.status, &infop->si_status, Efault);
+        user_access_end();
         return err;
+Efault:
+        user_access_end();
+        return -EFAULT;
 }
 
 static long kernel_wait4(pid_t upid, int __user *stat_addr,
@@ -1736,13 +1739,20 @@ COMPAT_SYSCALL_DEFINE5(waitid,
                         return -EFAULT;
         }
 
-        if (put_user(err ? 0 : SIGCHLD, &infop->si_signo) ||
-            put_user(0, &infop->si_errno) ||
-            put_user((short)info.cause, &infop->si_code) ||
-            put_user(info.pid, &infop->si_pid) ||
-            put_user(info.uid, &infop->si_uid) ||
-            put_user(info.status, &infop->si_status))
-                err = -EFAULT;
+        if (!infop)
+                return err;
+
+        user_access_begin();
+        unsafe_put_user(err ? 0 : SIGCHLD, &infop->si_signo, Efault);
+        unsafe_put_user(0, &infop->si_errno, Efault);
+        unsafe_put_user((short)info.cause, &infop->si_code, Efault);
+        unsafe_put_user(info.pid, &infop->si_pid, Efault);
+        unsafe_put_user(info.uid, &infop->si_uid, Efault);
+        unsafe_put_user(info.status, &infop->si_status, Efault);
+        user_access_end();
         return err;
+Efault:
+        user_access_end();
+        return -EFAULT;
 }
 #endif