gh-88116: Avoid undefined behavior when decoding varints in code objects #94375
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…e objects
It seems like we'll fail to correctly decode a varint between INT_MAX
and UINT_MAX or if a signed varint is > INT_MAX / 2 or < INT_MIN / 2 as
this is written today. In fact, it might left shift a 1 into the sign
bit, which would be UB.
Indeed, this test program shows the issue:
```
int main()
{
int val = 2147483647;
unsigned int shift = 1;
std::cout << (val << shift) << std::endl;
}
```
As this prints -2.
markshannon
approved these changes
Jun 28, 2022
|
Thanks @pablogsal for the PR 🌮🎉.. I'm working now to backport this PR to: 3.11. |
miss-islington
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…e objects (pythonGH-94375) (cherry picked from commit c485ec0) Co-authored-by: Pablo Galindo Salgado <[email protected]>
|
GH-94387 is a backport of this pull request to the 3.11 branch. |
miss-islington
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Jun 28, 2022
…cts (GH-94375) (cherry picked from commit c485ec0) Co-authored-by: Pablo Galindo Salgado <[email protected]>
gvanrossum
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Jun 30, 2022
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It seems like we'll fail to correctly decode a varint between INT_MAX
and UINT_MAX or if a signed varint is > INT_MAX / 2 or < INT_MIN / 2 as
this is written today. In fact, it might left shift a 1 into the sign
bit, which would be UB.
Indeed, this test program shows the issue:
As this prints -2.