Workaround Patterns (Part 5)

We resume our workaround patterns for common reusable solutions to common software execution problems. In the past we proposed a general pattern of Axed Code for removing problem software behavior. The Shadow File blog post about fixing free() crashes by introducing heap metadata header with a data length set to zero led me to generalize and introduce a complementary Axed Data pattern. Such a pattern suggests cutting the data size specified in metadata memory plane (which may be separate from the data plane). In some cases, it may avoid buffer overwrites including Local and Shared in addition to Dynamic Memory Corruption (process heap and kernel pool). The following picture illustrates this general pattern approach.

Sometimes, it may even be possible to provide a workaround by cutting real file data, for example, by changing its file or database record size. But this is also done conceptually by changing file or database system metadata.

- Dmitry Vostokov @ + -

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