posix-timers: Preserve return value in clock_adjtime32()

commit 2d036dfa5f10df9782f5278fc591d79d283c1fad upstream.

The return value on success (>= 0) is overwritten by the return value of
put_old_timex32(). That works correct in the fault case, but is wrong for
the success case where put_old_timex32() returns 0.

Just check the return value of put_old_timex32() and return -EFAULT in case
it is not zero.

[ tglx: Massage changelog ]

Fixes: 3a4d44b61625 ("ntp: Move adjtimex related compat syscalls to native counterparts")
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Cochran <richardcochran@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210414030449.90692-1-chenjun102@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 5a01c4fdbfef40337a5a06b9944391820df8d5cd..48758108e055cd8d89d310c82dd0ca91bc36875f 100644 (file)
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -1166,8 +1166,8 @@ COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
 
        err = kc->clock_adj(which_clock, &ktx);
 
-       if (err >= 0)
-               err = compat_put_timex(utp, &ktx);
+       if (err >= 0 && compat_put_timex(utp, &ktx))
+               return -EFAULT;
 
        return err;
 }