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time: Validate user input in compat_settimeofday()

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The user value is validated after converting the timeval to a timespec, but
for a wide range of negative tv_usec values the multiplication overflow turns
them in positive numbers. So the 'validated later' is not catching the
invalid input.

Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1562460701-113301-1-git-send-email-zhengbin13@huawei.com
This commit is contained in:
zhengbin 2019-07-07 08:51:41 +08:00 committed by Thomas Gleixner
parent 28ef2db886
commit 9176ab1b84
1 changed files with 4 additions and 0 deletions
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kernel/time/time.c
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@ -251,6 +251,10 @@ COMPAT_SYSCALL_DEFINE2(settimeofday, struct old_timeval32 __user *, tv,
if (tv) {
if (compat_get_timeval(&user_tv, tv))
return -EFAULT;
if (!timeval_valid(&user_tv))
return -EINVAL;
new_ts.tv_sec = user_tv.tv_sec;
new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
}