On Mon, 13 Feb 2023 16:57:17 GMT, Severin Gehwolf <sgehw...@openjdk.org> wrote:
> The `jimage` location attributes are terminated with `ATTRIBUTE_END`-kinds. > However, > the byte containing `ATTRIBUTE_END` (most significant 5 bits, represent > `kind`), might > be non-zero in the lower 3 bits (values up to `0x07` represent > `ATTRIBUTE_END`). The JDK code > handles this case correctly in > [`ImageLocation.decompress()`](https://github.com/openjdk/jdk/blob/master/src/java.base/share/classes/jdk/internal/jimage/ImageLocation.java#L69..L71). > However, the `libjimage` > code in `java.base` doesn't. That can lead to segfaults reading random bytes > and offsets. > > I propose to break the loop if `ATTRIBUTE_END` is being encountered so that > reading stops. > > Testing: > - [x] `test/jdk/tools/jimage` and `test/jdk/jdk/internal/jimage` tests. > - [x] Manual testing with a patched JDK to write non-zero bytes containing > `ATTRIBUTE_END` into the jimage. Segfaults before, runs fine after. > - [ ] GHA. In progress. > > Thoughts? Marked as reviewed by alanb (Reviewer). The change looks good, I'm just curious whether you observed a crash or whether this was noticed by inspection. ------------- PR: https://git.openjdk.org/jdk/pull/12539
