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Fix small typo in heap allocation post (#628)

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Donald Pinckney
2019-06-27 00:55:21 -07:00
committed by Philipp Oppermann
parent 9c9ad4a172
commit a40b65a77d
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blog/content/second-edition/posts/10-heap-allocation/index.md
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@@ -104,7 +104,7 @@ We see that the `z[1]` slot is free again and can be reused for the next `alloca
Apart from memory leaks, which are unfortunate but don't make the program vulnerable to attackers, there are two common types of bugs with more severe consequences:
- When we accidentally continue to use a variable after calling `deallocate` on it, we have a so-called **use-after-free** vulnerability. Such a bug causes undefined behavior and can often exploited by attackers to execute arbitrary code.
- When we accidentally free a variable twice, we have a **double-free** vulnerability. This is problematic because it might free a different a different allocation that was allocated in the same spot after the first `deallocate` call. Thus, it can lead to an use-after-free vulnerability again.
- When we accidentally free a variable twice, we have a **double-free** vulnerability. This is problematic because it might free a different allocation that was allocated in the same spot after the first `deallocate` call. Thus, it can lead to an use-after-free vulnerability again.
These types of vulnerabilities are commonly known, so one might expect that people learned how to avoid them by now. But no, such vulnerabilities are still regularly found, for example this recent [use-after-free vulnerability in Linux][linux vulnerability] that allowed arbitrary code execution. This shows that even the best programmers are not always able to correctly handle dynamic memory in complex projects.