fix: block memory allocation overflow #3639
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this fixes potential overflow bugs in pointer calculation by blocking memory allocation above a certain size. the size limit is set at `2**64`, which is the size of addressable memory on physical machines. practically, for EVM use cases, we could limit at a much smaller number (like `2**24`), but we want to allow for "exotic" targets which may allow much more addressable memory.
vyper/codegen/memory_allocator.py
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| if self.size_of_mem >= 2**64: | ||
| # this should not be caught | ||
| raise MemoryAllocationException( | ||
| "Tried to allocate {self.size_of_mem} bytes! (limit is 2**32 bytes)" |
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probably should make it a constant and use it here as an f-string (and in the if statement)
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good point, thanks
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oh, right, i wanted to do it that way in the error message because 2**32 is easier to read than 4294967296.
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oh, right, i wanted to do it that way in the error message because
2**32is easier to read than 4294967296.
do the constant as a string and then parse it to int lol
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i think eval() is a bit overkill here :P unless you are thinking there is a cleaner way of parsing the string?
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i don't know about that. that results in an error message like
vyper.exceptions.MemoryAllocationException: Tried to allocate 18446744073709551712 bytes! (limit is 2**64.0 bytes)and since floating point math is not very precise, we get the same error message for instance with _ALLOCATION_LIMIT = 2**64 - 1. so there is still the problem of drift between the error message and the value.
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In [5]: MEM_LIMIT = 2**64
In [6]: f"2**{math.log2(MEM_LIMIT):2.0f}"
Out[6]: '2**64'
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## master #3639 +/- ##
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- Coverage 89.13% 89.09% -0.05%
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Files 86 86
Lines 11463 11467 +4
Branches 2606 2607 +1
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- Misses 826 831 +5
- Partials 419 420 +1
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What I did
fix #3637
How I did it
this fixes potential overflow bugs in pointer calculation by blocking memory allocation above a certain size. the size limit is set at
2**64, which is the size of addressable memory on physical machines.practically, for EVM use cases, we could limit at a much smaller number (like
2**24), but we want to allow for "exotic" targets which may allow much more addressable memory.How to verify it
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