Why Raspberry Pi Isn't Vulnerable to Spectre or Meltdown

Re:Why Raspberry Pi Isn't Vulnerable to Spectre or Meltdown by JdeBP on Friday January 05, 2018 @02:15PM (#16080830)

Yes, that is the this is left as an exercise for the reader part of the explanation. (-:

The remaining part is to iterate the process over all of the bits in the word, using different bitmasks. The resultant set of 0 or 1 results for each bit yields the complete word.

Then one iterates that whole process over all (useful) words in (mapped) kernel memory.

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Re:Why Raspberry Pi Isn't Vulnerable to Spectre or Meltdown by rofex on Friday January 05, 2018 @03:09PM (#16081231)

Thanks, this was the missing piece in my understanding. I was wondering how only knowing only 1 bit would be useful. Suppose the attacker wants to read this entire address (0xabde3167) using this method. Is it guaranteed that over multiple runs, this address would be the same each time at that point in execution?

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Re:Why Raspberry Pi Isn't Vulnerable to Spectre or Meltdown by ufo on Friday January 05, 2018 @03:33PM (#16081421)

It is certainly possible that the memory the exploit is trying to read might be changing under its nose. An actual implementation of the exploit would need to account for that.

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Re:Why Raspberry Pi Isn't Vulnerable to Spectre or Meltdown by pqh on Saturday January 06, 2018 @09:02AM (#16085272)

How might one know which address to attack like this? I thought memory was fairly randomly laid out.

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