Fix GH-10634: Lexing memory corruption #10866
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Perfect, thank you! Feel free to merge. Maybe you could also add a short comment on why the |
We're not relying on re2c's bounds checking mechanism because re2c:yyfill:check = 0; is set. We just return 0 if we read over the end of the input in YYFILL. Note that we used to use the "any character" wildcard in the comment regexes. But that means if we go over the end in the comment regexes, we don't know that and it's just like the 0 bytes are part of the token. Since a 0 byte already is considered as an end-of-file, we can just block those in the regex. For the regexes with newlines, I had to not only include \x00 in the denylist, but also \n and \r because otherwise it would greedily match those and let the single-line comment run over multiple lines.
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Fixes GH-10634
We're not relying on re2c's bounds checking mechanism because re2c:yyfill:check = 0; is set. We just return 0 if we read over the end of the input in YYFILL. Note that we used to use the "any character" wildcard in the comment regexes.
But that means if we go over the end in the comment regexes, we don't know that and it's just like the 0 bytes are part of the token. Since a 0 byte already is considered as an end-of-file, we can just block those in the regex.
For the regexes with newlines, I had to not only include \x00 in the denylist, but also \n and \r because otherwise it would greedily match those and let the single-line comment run over multiple lines.