[tip: timers/core] posix-timers: Preserve return value in clock_adjtime32()

[tip-bot2 for Chen Jun]

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     2d036dfa5f10df9782f5278fc591d79d283c1fad
Gitweb:        https://git.kernel.org/tip/2d036dfa5f10df9782f5278fc591d79d283c1fad
Author:        Chen Jun <chenjun102@xxxxxxxxxx>
AuthorDate:    Wed, 14 Apr 2021 03:04:49 
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Sat, 17 Apr 2021 14:55:06 +02:00

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@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Richard Cochran <richardcochran@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20210414030449.90692-1-chenjun102@xxxxxxxxxx
---
 kernel/time/posix-timers.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index bf540f5..dd5697d 100644
--- 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;
 }