This has been rumored for about a year; close cooperation between Israeli intelligence and the Saudi government on granting Israel a corridor through which Israeli jets would have overflight permission:
Saudi Arabia has conducted tests to stand down its air defences to enable Israeli jets to make a bombing raid on Iran's nuclear facilities, The Times can reveal.
In the week that the UN Security Council imposed a new round of sanctions on Tehran, defence sources in the Gulf say that Riyadh has agreed to allow Israel to use a narrow corridor of its airspace in the north of the country to shorten the distance for a bombing run on Iran.
To ensure the Israeli bombers pass unmolested, Riyadh has carried out tests to make certain its own jets are not scrambled and missile defence systems not activated. Once the Israelis are through, the kingdom's air defences will return to full alert. "The Saudis have given their permission for the Israelis to pass over and they will look the other way," said a US defence source in the area. "They have already done tests to make sure their own jets aren't scrambled and no one gets shot down. This has all been done with the agreement of the [US] State Department."
Sources in Saudi Arabia say it is common knowledge within defence circles in the kingdom that an arrangement is in place if Israel decides to launch the raid. Despite the tension between the two governments, they share a mutual loathing of the regime in Tehran and a common fear of Iran's nuclear ambitions. "We all know this. We will let them [the Israelis] through and see nothing," said one.
This doesn't make an Israeli raid any more or less likely. There's still the opposition of the Obama administration to consider - important because Israeli jets will almost certainly have to overfly Iraq to reach Iran.
Would the Israelis carry out the raid even if that permission is not forthcoming? If the Jewish state feels itself threatened, I have no doubt that there is nothing that would stop them from hitting the Iranian nuclear infrastructure. All consequences would pale in comparison to the existential threat of an Iranian bomb, and it is likely that Israel would hit Iran first, and pick up the diplomatic pieces afterward.
The new UN sanctions have probably bought Iran another 4-6 months. That's how much time the world has to convince Iran to give up its enrichment program and dismantle its centrifuges.