Comment on Copy Fail 2: Electric BoogalooComments−Mindless21124moHow much pain must there be until people realize we actually do need memory safety?−delamon4moHow would've memory safety helped here?−Mindless21124moIn CHERI, for example, pointers have permissions. The pointer to the COW memory would not have the "write" permission.I could be misunderstanding the bug, of course.−delamon4moIf you "forget" to mark COW memory pointer as no-write, the net effect would be same, would it not? If I'm reading the diff correctly, the problem was that code missed to mark some pages as shared (aka no-write).−Mindless21124moA fair point...I thought the bug was a missing check for the COW flag, but looking at it again it seems it was missing both setting and checking the flag.−delamon4moApparently it is both...−tatersolid4moBecause “Page-cache write into any readable file” is a memory safety bug? All of these recent Linux LPEs are memory safety issues.
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How much pain must there be until people realize we actually do need memory safety?
How would've memory safety helped here?
In CHERI, for example, pointers have permissions. The pointer to the COW memory would not have the "write" permission.
I could be misunderstanding the bug, of course.
If you "forget" to mark COW memory pointer as no-write, the net effect would be same, would it not? If I'm reading the diff correctly, the problem was that code missed to mark some pages as shared (aka no-write).
A fair point...
I thought the bug was a missing check for the COW flag, but looking at it again it seems it was missing both setting and checking the flag.
Apparently it is both...
Because “Page-cache write into any readable file” is a memory safety bug? All of these recent Linux LPEs are memory safety issues.