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author | fanquake <fanquake@gmail.com> | 2020-04-28 13:08:19 +0800 |
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committer | fanquake <fanquake@gmail.com> | 2020-04-28 13:32:45 +0800 |
commit | ac21090f209cb1b8ea6cd5074d5e9c6b82ce2a7f (patch) | |
tree | 007877ee7d31b0820137bcf68d34818fa06b5acb /contrib/gitian-descriptors | |
parent | 5352d14b3796d9e672a20ada8f7613a70fe448f4 (diff) | |
parent | 3e38023af724a76972d39cbccfb0bba4c54a0323 (diff) | |
download | bitcoin-ac21090f209cb1b8ea6cd5074d5e9c6b82ce2a7f.tar.xz |
Merge #18629: scripts: add PE .reloc section check to security-check.py
3e38023af724a76972d39cbccfb0bba4c54a0323 scripts: add PE .reloc section check to security-check.py (fanquake)
Pull request description:
The `ld` in binutils has historically had a few issues with PE binaries, there's a good summary in this [thread](https://sourceware.org/bugzilla/show_bug.cgi?id=19011).
One issue in particular was `ld` stripping the `.reloc` section out of PE binaries, even though it's required for functioning ASLR. This was [reported by a Tor developer in 2014](https://sourceware.org/bugzilla/show_bug.cgi?id=17321) and they have been patching their [own binutils](https://gitweb.torproject.org/builders/tor-browser-build.git/tree/projects/binutils) ever since. However their patch only made it into binutils at the [start of this year](https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=dc9bd8c92af67947db44b3cb428c050259b15cd0). It adds an `--enable-reloc-section` flag, which is turned on by default if you are using `--dynamic-base`. In the mean time this issue has also been worked around by other projects, such as FFmpeg, see [this commit](https://github.com/TheRyuu/FFmpeg/commit/91b668acd6decec0a6f8d20bf56e2644f96adcb9).
I have checked our recent supported Windows release binaries, and they do contain a `.reloc` section. From what I understand, we are using all the right compile/linker flags, including `-pie` & `-fPIE`, and have never run into the crashing/entrypoint issues that other projects might have seen.
One other thing worth noting here, it how Debian/Ubuntu patch the binutils that they distribute, because that's what we end up using in our gitian builds.
In the binutils-mingw-w64 in Bionic (18.04), which we currently use in gitian, PE hardening options/security flags are enabled by default. See the [changelog](https://changelogs.ubuntu.com/changelogs/pool/universe/b/binutils-mingw-w64/binutils-mingw-w64_8ubuntu1/changelog) and the [relevant commit](https://salsa.debian.org/mingw-w64-team/binutils-mingw-w64/-/commit/452b3013b8280cbe35eaeb166a43621b88d5f8b7).
However in Focal (20.04), this has now been reversed. PE hardening options are no-longer the default. See the [changelog](https://changelogs.ubuntu.com/changelogs/pool/universe/b/binutils-mingw-w64/binutils-mingw-w64_8.8/changelog) and [relevant commit](https://salsa.debian.org/mingw-w64-team/binutils-mingw-w64/-/commit/7bd8b2fbc242a8c2fc2217f29fd61f94d3babf6f), which cites same .reloc issue mentioned here.
Given that we explicitly specify/opt-in to everything that we want to use, the defaults aren't necessarily an issue for us. However I think it highlights the importance of continuing to be explicit about what we want, and not falling-back or relying on upstream.
This was also prompted by the possibility of us doing link time garbage collection, see #18579 & #18605. It seemed some sanity checks would be worthwhile in-case the linker goes haywire while garbage collecting.
I think Guix is going to bring great benefits when dealing with these kinds of issues. Carl you might have something to say in that regard.
ACKs for top commit:
dongcarl:
ACK 3e38023af724a76972d39cbccfb0bba4c54a0323
Tree-SHA512: af14d63bdb334bde548dd7de3e0946556b7e2598d817b56eb4e75b3f56c705c26aa85dd9783134c4b6a7aeb7cb4de567eed996e94d533d31511f57ed332287da
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