eacedfb0230978748cbcfb13817fed7e7c756ba7 scripts: add additional type annotations to security-check.py (fanquake)
83d063e9541cc9ea41ea86919eb9435c73efb14e scripts: add run_command to security-check.py (fanquake)
13f606b4f940e5820ff21ea62fc27a5a91774b05 scripts: remove NONFATAL from security-check.py (fanquake)
061acf62a15ad3dbb9f055b7c2569b9832ed623a scripts: no-longer check for 32 bit windows in security-check.py (fanquake)
Pull request description:
* Remove 32-bit Windows checks.
* Remove NONFATAL checking. Added in #8249, however unused since #13764.
* Add `run_command` to de-duplicate all of the subprocess calls. Mentioned in #18713.
* Add additional type annotations.
* Print stderr when there is an issue running a command.
ACKs for top commit:
laanwj:
ACK eacedfb0230978748cbcfb13817fed7e7c756ba7
Tree-SHA512: 69a7ccfdf346ee202b3e8f940634c5daed1d2b5a5d15ac9800252866ba3284ec66e391a66a0b341f5a4e5e8482fe1b614d4671e8e766112ff059405081184a85
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](91b668acd6).
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](452b3013b8).
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](7bd8b2fbc2), 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
8334ee31f868f0f9baf0920d14d20174ed889dbe scripts: add MACHO LAZY_BINDINGS test to test-security-check.py (fanquake)
7b99c7454cdb74cd9cd7a5eedc2fb9d0a19df456 scripts: add MACHO Canary check to security-check.py (fanquake)
Pull request description:
7b99c7454cdb74cd9cd7a5eedc2fb9d0a19df456 uses `otool -Iv` to check for `___stack_chk_fail` in the macOS binaries. Similar to the [ELF check](https://github.com/bitcoin/bitcoin/blob/master/contrib/devtools/security-check.py#L105). Note that looking for a triple underscore prefixed function (as opposed to two for ELF) is correct for the macOS binaries. i.e:
```bash
otool -Iv bitcoind | grep chk
0x00000001006715b8 509 ___memcpy_chk
0x00000001006715be 510 ___snprintf_chk
0x00000001006715c4 511 ___sprintf_chk
0x00000001006715ca 512 ___stack_chk_fail
0x00000001006715d6 517 ___vsnprintf_chk
0x0000000100787898 513 ___stack_chk_guard
```
8334ee31f868f0f9baf0920d14d20174ed889dbe is a follow up to #18295 and adds test cases to `test-security-check.py` that for some reason I didn't add at the time. I'll sort out #18434 so that we can run these tests in the CI.
ACKs for top commit:
practicalswift:
ACK 8334ee31f868f0f9baf0920d14d20174ed889dbe: Mitigations are important. Important things are worth asserting :)
jonasschnelli:
utACK 8334ee31f868f0f9baf0920d14d20174ed889dbe.
Tree-SHA512: 1aa5ded34bbd187eddb112b27278deb328bfc21ac82316b20fab6ad894f223b239a76b53dab0ac1770d194c1760fcc40d4da91ec09959ba4fc8eadedb173936a
5ca90f8b598978437340bb8467f527b9edfb2bbf scripts: add MACHO lazy bindings check to security-check.py (fanquake)
Pull request description:
This is a slightly belated follow up to #17686 and some discussion with Cory. It's not entirely clear if we should make this change due to the way the macOS dynamic loader appears to work. However I'm opening this for some discussion. Also related to #17768.
#### Issue:
[`LD64`](https://opensource.apple.com/source/ld64/) doesn't set the [MH_BINDATLOAD](https://opensource.apple.com/source/xnu/xnu-6153.11.26/EXTERNAL_HEADERS/mach-o/loader.h.auto.html) bit in the header of MACHO executables, when building with `-bind_at_load`. This is in contradiction to the [documentation](https://opensource.apple.com/source/ld64/ld64-450.3/doc/man/man1/ld.1.auto.html):
```bash
-bind_at_load
Sets a bit in the mach header of the resulting binary which tells dyld to
bind all symbols when the binary is loaded, rather than lazily.
```
The [`ld` in Apples cctools](https://opensource.apple.com/source/cctools/cctools-927.0.2/ld/layout.c.auto.html) does set the bit, however the [cctools-port](https://github.com/tpoechtrager/cctools-port/) that we use for release builds, bundles `LD64`.
However; even if the linker hasn't set that bit, the dynamic loader ([`dyld`](https://opensource.apple.com/source/dyld/)) doesn't seem to ever check for it, and from what I understand, it looks at a different part of the header when determining whether to lazily load symbols.
Note that our release binaries are currently working as expected, and no lazy loading occurs.
#### Example:
Using a small program, we can observe the behaviour of the dynamic loader.
Conducted using:
```bash
clang++ --version
Apple clang version 11.0.0 (clang-1100.0.33.17)
Target: x86_64-apple-darwin18.7.0
ld -v
@(#)PROGRAM:ld PROJECT:ld64-530
BUILD 18:57:17 Dec 13 2019
LTO support using: LLVM version 11.0.0, (clang-1100.0.33.17) (static support for 23, runtime is 23)
TAPI support using: Apple TAPI version 11.0.0 (tapi-1100.0.11)
```
```cpp
#include <iostream>
int main() {
std::cout << "Hello World!\n";
return 0;
}
```
Compile and check the MACHO header:
```bash
clang++ test.cpp -o test
otool -vh test
...
Mach header
magic cputype cpusubtype caps filetype ncmds sizeofcmds flags
MH_MAGIC_64 X86_64 ALL LIB64 EXECUTE 16 1424 NOUNDEFS DYLDLINK TWOLEVEL WEAK_DEFINES BINDS_TO_WEAK PIE
# Run and dump dynamic loader bindings:
DYLD_PRINT_BINDINGS=1 DYLD_PRINT_TO_FILE=no_bind.txt ./test
Hello World!
```
Recompile with `-bind_at_load`. Note still no `BINDATLOAD` flag:
```bash
clang++ test.cpp -o test -Wl,-bind_at_load
otool -vh test
Mach header
magic cputype cpusubtype caps filetype ncmds sizeofcmds flags
MH_MAGIC_64 X86_64 ALL LIB64 EXECUTE 16 1424 NOUNDEFS DYLDLINK TWOLEVEL WEAK_DEFINES BINDS_TO_WEAK PIE
...
DYLD_PRINT_BINDINGS=1 DYLD_PRINT_TO_FILE=bind.txt ./test
Hello World!
```
If we diff the outputs, you can see that `dyld` doesn't perform any lazy bindings when the binary is compiled with `-bind_at_load`, even if the `BINDATLOAD` flag is not set:
```diff
@@ -1,11 +1,27 @@
+dyld: bind: test:0x103EDF030 = libc++.1.dylib:__ZNKSt3__16locale9use_facetERNS0_2idE, *0x103EDF030 = 0x7FFF70C9FA58
+dyld: bind: test:0x103EDF038 = libc++.1.dylib:__ZNKSt3__18ios_base6getlocEv, *0x103EDF038 = 0x7FFF70CA12C2
+dyld: bind: test:0x103EDF068 = libc++.1.dylib:__ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEE6sentryC1ERS3_, *0x103EDF068 = 0x7FFF70CA12B6
+dyld: bind: test:0x103EDF070 = libc++.1.dylib:__ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEE6sentryD1Ev, *0x103EDF070 = 0x7FFF70CA1528
+dyld: bind: test:0x103EDF080 = libc++.1.dylib:__ZNSt3__16localeD1Ev, *0x103EDF080 = 0x7FFF70C9FAE6
<trim>
-dyld: lazy bind: test:0x10D4AC0C8 = libsystem_platform.dylib:_strlen, *0x10D4AC0C8 = 0x7FFF73C5C6E0
-dyld: lazy bind: test:0x10D4AC068 = libc++.1.dylib:__ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEE6sentryC1ERS3_, *0x10D4AC068 = 0x7FFF70CA12B6
-dyld: lazy bind: test:0x10D4AC038 = libc++.1.dylib:__ZNKSt3__18ios_base6getlocEv, *0x10D4AC038 = 0x7FFF70CA12C2
-dyld: lazy bind: test:0x10D4AC030 = libc++.1.dylib:__ZNKSt3__16locale9use_facetERNS0_2idE, *0x10D4AC030 = 0x7FFF70C9FA58
-dyld: lazy bind: test:0x10D4AC080 = libc++.1.dylib:__ZNSt3__16localeD1Ev, *0x10D4AC080 = 0x7FFF70C9FAE6
-dyld: lazy bind: test:0x10D4AC070 = libc++.1.dylib:__ZNSt3__113basic_ostreamIcNS_11char_traitsIcEEE6sentryD1Ev, *0x10D4AC070 = 0x7FFF70CA1528
```
Note: `dyld` also has a `DYLD_BIND_AT_LAUNCH=1` environment variable, that when set, will force any lazy bindings to be non-lazy:
```bash
dyld: forced lazy bind: test:0x10BEC8068 = libc++.1.dylib:__ZNSt3__113basic_ostream
```
#### Thoughts:
After looking at the dyld source, I can't find any checks for `MH_BINDATLOAD`. You can see the flags it does check for, such as MH_PIE or MH_BIND_TO_WEAK [here](https://opensource.apple.com/source/dyld/dyld-732.8/src/ImageLoaderMachO.cpp.auto.html).
It seems that the lazy binding of any symbols depends on whether or not [lazy_bind_size](https://opensource.apple.com/source/xnu/xnu-6153.11.26/EXTERNAL_HEADERS/mach-o/loader.h.auto.html) from the `LC_DYLD_INFO_ONLY` load command is > 0. Which was mentioned in [#17686](https://github.com/bitcoin/bitcoin/pull/17686#issue-350216254).
#### Changes:
This PR is one of [Corys commits](7b6ba26178), that I've rebased and modified to make build. I've also included an addition to the `security-check.py` script to check for the flag.
However, given the above, I'm not entirely sure this patch is the correct approach. If the linker no-longer inserts it, and the dynamic loader doesn't look for it, there might be little benefit to setting it. Or, maybe this is an oversight from Apple and needs some upstream discussion. Looking for some thoughts / Concept ACK/NACK.
One alternate approach we could take is to drop the patch and modify security-check.py to look for `lazy_bind_size` == 0 in the `LC_DYLD_INFO_ONLY` load command, using `otool -l`.
ACKs for top commit:
theuni:
ACK 5ca90f8b598978437340bb8467f527b9edfb2bbf
Tree-SHA512: 444022ea9d19ed74dd06dc2ab3857a9c23fbc2f6475364e8552d761b712d684b3a7114d144f20de42328d1a99403b48667ba96885121392affb2e05b834b6e1c
7142d50ac33e0ad7d24e49e04c1fc7e3e769ed46 scripts: rename test_64bit_PE to test_PE (fanquake)
edaca2dd123cef958699c07ab248cf0ffc71af07 scripts: add MACHO NX check to security-check.py (fanquake)
1a4e9f32efcc5f6a74290446dc58784fd85c7b31 scripts: add MACHO tests to test-security-check.py (fanquake)
Pull request description:
Adds tests for the MACHO checks in security-check.py:
ac579ada7e/contrib/devtools/security-check.py (L212-L214)
I'm planning on following up with more checks in security-check.py, and corresponding tests in test-security-check.py.
Note that you'll probably have to be on macOS to run them. You can run just this suite with `python3 test-security-check.py TestSecurityChecks.test_MACHO`.
ACKs for top commit:
laanwj:
ACK 7142d50ac33e0ad7d24e49e04c1fc7e3e769ed46
Tree-SHA512: ace3ca9f6df5d4fedd5988938fb7dc7563ec7dc587aa275f780b5f51e9b8d7d6f7768e0a1e05ce438510a07b8640aba92c76847b30c2990f46c66b78a0acf960
7c9e821c4e6cb186208ead9c8df616d1f393a49a scripts: add MACHO NOUNDEFS check to security-check.py (fanquake)
4ca92dc6d3f3e487d63286d8871d1829b3d279ff scripts: add MACHO PIE check to security-check.py (fanquake)
Pull request description:
This uses `otool -vh` to print the mach header and look for the `PIE` flag:
```bash
otool -vh src/bitcoind
Mach header
magic cputype cpusubtype caps filetype ncmds sizeofcmds flags
MH_MAGIC_64 X86_64 ALL LIB64 EXECUTE 24 2544 NOUNDEFS DYLDLINK TWOLEVEL WEAK_DEFINES BINDS_TO_WEAK PIE
```
From [`mach-o/loader.h`](https://opensource.apple.com/source/cctools/cctools-927.0.2/include/mach-o/loader.h.auto.html):
```c
#define MH_PIE 0x200000 /* When this bit is set, the OS will
load the main executable at a
random address. Only used in
MH_EXECUTE filetypes. */
```
ACKs for top commit:
laanwj:
code review ACK 7c9e821c4e6cb186208ead9c8df616d1f393a49a
Tree-SHA512: 5ba2f60440d0e31c70371a355c91ca4f723d80f7287d04e2098bf5b11892cc74216ff8f1454603c4db9675d4f7983614843b992b8dcfca0309aadf2aa7ab2e4b
af1ed206f Fix broken Gmane URLs (Craig Younkins)
Pull request description:
This is an automated pull request to fix broken Gmane URLs.
Here's what I did:
First I searched for Gmane URLs in your repo. For each Gmane URL, I checked if the content was available at the URL. For URLs where the content was not available, I first checked the `article` subdomain of Gmane, which has some content not available on the `thread` and `comments` subdomains.
If the content wasn't anywhere on Gmane's web interface, I resolved the URL to a [Message-ID](https://en.wikipedia.org/wiki/Message-ID) via the Gmane NNTP interface and tried to find the Message-ID on other mailing list archivers. I checked `mail-archive.com`, then `marc.info`, then `lists.debian.org` and so on.
If a new URL was found, I replaced it in this pull request. If the content wasn't found, I left the link alone.
Tree-SHA512: b46258de485a411fc4fbd6b8fb044c30fa062fd3a7ef78c6b8b405802c91283bc5c9f7f8b8c83385f3a12fe39578ea0695efd19ce19f3bb4606fbbd1be894d0e
1e60713a68296a0ff221befb48b2958fbf019ebf contrib: Fix test-security-check fail in Ubuntu 18.04 (Chun Kuan Lee)
Pull request description:
- Fix test-security-check fail in Ubuntu 18.04. Those flags are enabled by default, so we must specify `-no` to make the executable does 'not' have those attributes.
- Drop HIGH_ENTROPY_VA. After update our gitian system to Bionic, the compiler should support HIGH_ENTROPY_VA
Tree-SHA512: 78c1f2aae1253ddd52faa1af569b7151a503a217c7ccbe21b8004d8910c45d8a27ff04695eacbdadd7192d2c91c0d59941ca20c651dd2d5052b9999163a11ae4
37d363dd4acf7d41196d44b295593019add241c3 Tools: fix BIND_NOW check in security-check.py (Conrado Gouvea)
Pull request description:
Previously, the BIND_NOW check would work only if it was the first value in FLAGS.
Tree-SHA512: 39cd83f673a6b521803be5585ada516f2db4eede718f0c5aea3377825ed1adcefed5bbb41dd9a5f24a26f7d27116cfc81bde7e26283232593b72768c5ae3d321
78214588d Use for-loop instead of list comprehension (practicalswift)
823979436 Use the variable name _ for unused return values (practicalswift)
2e6080bbf Remove unused variables and/or function calls (practicalswift)
9b94054b7 Avoid reference to undefined name: stderr does not exist, sys.stderr does (practicalswift)
51cb6b822 Use print(...) instead of undefined printf(...) (practicalswift)
25cd520fc Use sys.exit(...) instead of exit(...): exit(...) should not be used in programs (practicalswift)
Pull request description:
Python cleanups:
* Avoid reference to undefined name: `stderr` does not exist, `sys.stderr` does
* Use `print(...)` instead of undefined `printf(...)`
* Avoid redefinition of variable (`tx`) in list comprehension
* Remove unused variables and/or function calls
* Use `sys.exit(...)` instead of `exit(...)`: [`exit(...)` should not be used in programs](https://github.com/bitcoin/bitcoin/pull/10753#discussion_r125935027)
Tree-SHA512: 1238dfbc1d20f7edadea5e5406a589f293065638f6234809f0d5b6ba746dffe3d276bc5884c7af388a6c798c61a8759faaccf57f381225644754c0f61914eb4b
* Merge #11881: Remove Python2 support
1874058 Make base58 python contrib code work with python3 (Evan Klitzke)
bc6fdf2 Change all python files to use Python3 (John Newbery)
Pull request description:
Following discussion here: https://github.com/bitcoin/bitcoin/pull/11843#issuecomment-351033742
It's easier for maintainers if all python tools/scripts support only a single version of Python. There are only a few scripts that aren't explicitly python3 at this point, so this PR changes those remaining scripts to explicitly require python3.
Tree-SHA512: 5d38eef6e0fc7d8515e23a1f4c75e8b4160fd0fe23cba52a1f41689b114e54a9e503e0724829e8b41982ef98f2d113df80d9e238213b74f09ceaed0344a19e24
* Merge #12829: Python3 fixup
f50975b [contrib] fixup symbol-check.py Python3 support (John Newbery)
5de2b18 [contrib] fixup security-check.py Python3 support (John Newbery)
Pull request description:
security-check.py and symbol-check.py were broken by #11881. Fix them.
Tree-SHA512: 86de3d6dc3292b1ae4cc04c2d7d7dbbf39c9270551d7b224b8d8b19e3184c30c897dbf823200403706d06bb405c0decad5cfd690cb2c0312992a235a4ffcf6bf
62c2915 build: supply `-Wl,--high-entropy-va` (Wladimir J. van der Laan)
9a75d29 devtools: Check for high-entropy ASLR in 64-bit PE executables (Wladimir J. van der Laan)
- fix parsing of BIND_NOW with older readelf
- add _IO_stdin_used to ignored exports
For details see: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=634261#109
- add check-symbols and check-security make targets
These are not added to the default checks because some of them depend on
release-build configs.
- always link librt for glibc back-compat builds
glibc absorbed clock_gettime in 2.17. librt (its previous location) is safe to
link in anyway for back-compat.
Fixes#7420
- add security/symbol checks to gitian
Github-Pull: #7424
Rebased-From: cd27bf51e0475813ba5bf3d3eaf78ea8ce872118a81c87fafc
Perform the following ELF security checks:
- PIE: Check for position independent executable (PIE), allowing for address space randomization
- NX: Check that no sections are writable and executable (including the stack)
- RELRO: Check for read-only relocations, binding at startup
- Canary: Check for use of stack canary
Also add a check to symbol-check.py that checks that only the subset of
allowed libraries is imported (to avoid incompatibilities).
