Time Travel: 2014

In short, Lin Hui felt that the Yuan Universe was very unreliable in the ten years after his rebirth.

Although the Metaverse is unreliable.

But it seems like a good idea to deceive people by using something that seems a bit far away, yet within reach, and a bit beautiful to imagine. [Bad laugh]

However, these are all things for later.

Speaking of which, Lin Hui does not plan to get deeply involved in the IP field in the short term except for long-term development.

There is another very important reason:

——Lin Hui is short of money.

The reason why Lin Hui is short of money is simple:

——There are too many things I want to do.

Moreover, basically anything Lin Hui wants to do is extremely expensive.

It goes without saying how expensive technology products such as hardware are.

Many software projects are also gold-swallowing behemoths.

For a seemingly ordinary AI model, the specific training/training process often requires countless real money.

As for more complex facial recognition technology, the advent of Fuchisia OS and the like requires even more gold and silver.

It’s impossible to play without money.

Maybe some people don't understand Lin Hui's "ambition".

In fact, Lin Hui also knows that rebirth does not necessarily have to be spectacular.

You can also fish and firewood in the rivers and cranes.

But Lin Hui felt that he couldn't do this.

At least it will be difficult for Lin Hui to do so in the past six months.

There are too many things that Lin Hui needs to do personally.

Although no one forced Lin Hui to take any route.

However, under the subtle influence of family background, educational experience, and life encounters, the route a person should take is actually determined.

In addition to reasons other than family factors, educational experience and life encounters.

It also has a lot to do with Lin Hui's personal thoughts.

Lin Hui feels that a person's destiny can only be closely integrated with the destiny of the country and the nation.

Only then can we go higher and further.

With lofty ideals, Lin Hui will naturally not be hampered by the small difficulties in front of him.

Although Lin Hui was short of money, it was not a big problem.

Making money is easy!

In this era, money is everywhere for Lin Hui.

Software can be exchanged for money, algorithms can be exchanged for money, business models can be exchanged for money...

But Lin Hui is not in the mood to tinker with these things for the time being.

For the time being, it is better to find some easy ways to make money.

Speaking of making money easily, Lin Hui first thought of the news he saw a few days ago:

——Apple has fully opened its bug bounty program.

Under the program, bugs can be submitted in exchange for payment.

After security personnel submit a vulnerability to a "bug bounty program".

Apple said it will measure the complexity and severity of these vulnerabilities based on the development chain.

Bounties of up to $1 million are available for each security vulnerability.

And if the vulnerability can be found in the Beta version (test version) software.

The maximum bounty can be awarded at one time is US$1.5 million.

The reason why Lin Hui did not submit the vulnerability immediately some time ago was mainly because he had a wait-and-see attitude.

If a vulnerability is submitted, it would be tragic if Apple refuses to acknowledge it.

It’s not like Apple has never done this before.

Not only Apple has done this, but companies like Google and Microsoft have also done this.

However, Lin Hui learned from some public news.

Several security teams have submitted security vulnerabilities through this security website and received nearly a million dollars in exchange.

Of course, this does not mean that Apple follows the rules.

Lin Hui thinks this is mainly because the bug bounty program has just been launched.

Apple is not ready to slap itself in the face so soon.

If this is the reason, then the recent period.

Lin Hui didn't seem to have to worry too much. He just needed to follow the same pattern and submit some loopholes.

When it comes to vulnerabilities in Apple’s iOS, the first thing Lin Hui thinks of is the “time regression vulnerability.”

The time regression vulnerability can be said to be one of the most classic vulnerabilities in the iOS system.

The so-called time regression vulnerability refers to the fact that for a period of time, Apple's mobile phone will become bricked when adjusting the time.

Will my phone become bricked if I adjust the time?

It may sound funny, but this vulnerability is real.

On earlier versions of iOS 64-bit devices.

As long as you set the time on your iPhone to January 1, 1970, and then restart it, your iPhone will become a brick.

The reason why such a vulnerability exists has a lot to do with the bottom layer of the iOS system - the Unix system.

The Unix operating system is a powerful multi-user, multi-tasking operating system.

The system supports multiple processor architectures.

According to the classification of operating systems, they belong to time-sharing operating systems.

The system was first developed at AT\u0026T's Bell Laboratories in 1969 by Ken Thompson, Dennis Ritchie, and Douglas McIlroy.

There are many derivatives of Unix systems.

Darwin, which iOS is based on, is one of the branches of Unix.

iOS as a system inherits the characteristics of Unix to a certain extent.

Since it is a system, timing issues will inevitably be involved.

It is different from the counting format of "year + month + day" that humans generally use.

Unix uses a completely different way of timing:

In the Unix system, the timing method is to first set (UTC time zone) January 1, 1970 00:00 to 0 o'clock.

The number of seconds elapsed so far is then calculated.

Give me a chestnut.

June 22, 2014 18:30:25.

Expressed as 1403433025 seconds.

Convert to the corresponding binary to represent time under Unix system.

This method of timing is called timestamps.

The iOS system also follows the Unix timing method.

It is for this reason that the time setting in iOS can only go back to January 1, 1970 00:00 in the UTC time zone for this reason.

There will be no problem if you just set it to this time.

But when it comes to some special local key functions that have rules for querying past information

Setting the time to UTC time zone January 1, 1970 00:00 can easily lead to problems.

Although most of the time this vulnerability can be avoided through human factors.

But when the Apple mobile phone is turned on, there is a mechanism to force query past information, which is almost inevitable.

There is no way to cancel this mechanism, because after shutting down and restarting, the phone must read part of the previous log data.

In this case, if the timestamp is a normal time, there will be no problem reading the previous log data.

But when the UTC time zone is 00:00 on January 1, 1970, the timestamp time at this time is 0.

When the local time is earlier than the timestamp 0 o'clock.

How should we express a time earlier than the timestamp 0 o'clock?

There seems to be no good solution.

Although there is no other good way, the system is a machine.

It is not an intelligent creature, it still needs to find an earlier time through the query mechanism.

At this time, the -1 operation will be performed based on the timestamp 0.

(This is to subtract the number of seconds from the time expressed by the system timestamp to query the previous content)

But -1 on the basis of 0 is quite sad.

The result obtained is not -1.

0-1≠-1?

It sounds weird, but in fact, this phenomenon is commonly seen in programs.