posix-timers: Preserve return value in clock_adjtime32()

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

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index bf540f5a4115a2bff84ee7c2eb9f1af21385e1cd..dd5697d7347b1daaa0e843dd1e23abc8c547ddfc 100644 (file)
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -1191,8 +1191,8 @@ SYSCALL_DEFINE2(clock_adjtime32, clockid_t, which_clock,
 
        err = do_clock_adjtime(which_clock, &ktx);
 
-       if (err >= 0)
-               err = put_old_timex32(utp, &ktx);
+       if (err >= 0 && put_old_timex32(utp, &ktx))
+               return -EFAULT;
 
        return err;
 }