[PATCH 8/8] waitid(): switch copyout of siginfo to unsafe_put_user()

[Al Viro]

From: Al Viro <v...@zeniv.linux.org.uk>

Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
---
 kernel/exit.c | 40 +++++++++++++++++++++++++---------------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index e93876b06b28..a13dd4d0dc34 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.why, &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.why, &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, &uinfo->si_signo) ||
-           put_user(0, &uinfo->si_errno) ||
-           put_user((short)info.why, &uinfo->si_code) ||
-           put_user(info.pid, &uinfo->si_pid) ||
-           put_user(info.uid, &uinfo->si_uid) ||
-           put_user(info.status, &uinfo->si_status))
-               err = -EFAULT;
+       if (!uinfo)
+               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.why, &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
-- 
2.11.0