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buffer.cpp incorrectly free's the current entry before removing it from the list. #281

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mkilgore opened this issue Jan 8, 2023 · 0 comments · Fixed by #284
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buffer.cpp incorrectly free's the current entry before removing it from the list. #281

mkilgore opened this issue Jan 8, 2023 · 0 comments · Fixed by #284
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mkilgore commented Jan 8, 2023

Fairly straight forward, in buffer.cpp we free the finished entry and then unlink it from the list, which is a bug as the order is wrong. When we access buffer->head->next to unlink the current entry, we're accessing the entry we just free'd. It is easily fixed by switching the order of those operations.
@mkilgore mkilgore added the bug Something isn't working label Jan 8, 2023
@mkilgore mkilgore self-assigned this Jan 8, 2023
mkilgore added a commit to mkilgore/QB64pe that referenced this issue Jan 8, 2023
@mkilgore
Fix use-after-free bug in buffer.cpp
e0a69e0 
Fairly simple, the finished entry is free'd and then removed from the
list, but that order results in us accessing the entry's next member
after it has been free'd. Swapping the order of the operations fixes the
issue.

Fixes: QB64-Phoenix-Edition#281
mkilgore added a commit to mkilgore/QB64pe that referenced this issue Jan 9, 2023
@mkilgore
Fix use-after-free bug in buffer.cpp
f889609 
Fairly simple, the finished entry is free'd and then removed from the
list, but that order results in us accessing the entry's next member
after it has been free'd. Swapping the order of the operations fixes the
issue.

Fixes: QB64-Phoenix-Edition#281
@mkilgore mkilgore mentioned this issue Jan 9, 2023
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Fix startup time delay in QB64-PE programs mkilgore/QB64pe
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