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fix: block memory allocation overflow #3639

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merged 3 commits into from
Oct 5, 2023
Merged

fix: block memory allocation overflow #3639

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9c71339
fix: block memory allocation overflow
charles-cooper Oct 4, 2023
b5d9263
factor out allocation limit
charles-cooper Oct 4, 2023
9296ff4
update error message
charles-cooper Oct 4, 2023
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9 changes: 8 additions & 1 deletion vyper/codegen/memory_allocator.py
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
from typing import List

from vyper.exceptions import CompilerPanic
from vyper.exceptions import CompilerPanic, MemoryAllocationException
from vyper.utils import MemoryPositions


Expand Down Expand Up @@ -110,6 +110,13 @@ def _expand_memory(self, size: int) -> int:
before_value = self.next_mem
self.next_mem += size
self.size_of_mem = max(self.size_of_mem, self.next_mem)

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**32 is 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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or do log2

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@charles-cooper charles-cooper Oct 4, 2023 •
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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'

)

return before_value

def deallocate_memory(self, pos: int, size: int) -> None:
Expand Down
4 changes: 4 additions & 0 deletions vyper/exceptions.py
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Expand Up @@ -269,6 +269,10 @@ class StorageLayoutException(VyperException):
"""Invalid slot for the storage layout overrides"""


class MemoryAllocationException(VyperException):
"""Tried to allocate too much memory"""


class JSONError(Exception):

"""Invalid compiler input JSON."""
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