Squashed commit of the following:
commit 04fff3a637d455cbb1d75937a235950e43008db9
Author: Eelco Dolstra <edolstra@gmail.com>
Date: Thu Jun 12 12:30:32 2025 +0200
Chown structured attr files safely
commit 5417ad445e414c649d0cfc71a05661c7bf8f3ef5
Author: Eelco Dolstra <edolstra@gmail.com>
Date: Thu Jun 12 12:14:04 2025 +0200
Replace 'bool sync' with an enum for clarity
And drop writeFileAndSync().
commit 7ae0141f328d8e8e1094be24665789c05f974ba6
Author: Eelco Dolstra <edolstra@gmail.com>
Date: Thu Jun 12 11:35:28 2025 +0200
Drop guessOrInventPathFromFD()
No need to do hacky stuff like that when we already know the original path.
commit 45b05098bd019da7c57cd4227a89bfd0fa65bb08
Author: Eelco Dolstra <edolstra@gmail.com>
Date: Thu Jun 12 11:15:58 2025 +0200
Tweak comment
commit 0af15b31209d1b7ec8addfae9a1a6b60d8f35848
Author: Raito Bezarius <raito@lix.systems>
Date: Thu Mar 27 12:22:26 2025 +0100
libstore: ensure that temporary directory is always 0o000 before deletion
In the case the deletion fails, we should ensure that the temporary
directory cannot be used for nefarious purposes.
Change-Id: I498a2dd0999a74195d13642f44a5de1e69d46120
Signed-off-by: Raito Bezarius <raito@lix.systems>
commit 2c20fa37b15cfa03ac6a1a6a47cdb2ed66c0827e
Author: Raito Bezarius <raito@lix.systems>
Date: Wed Mar 26 12:42:55 2025 +0100
libutil: ensure that `_deletePath` does NOT use absolute paths with dirfds
When calling `_deletePath` with a parent file descriptor, `openat` is
made effective by using relative paths to the directory file descriptor.
To avoid the problem, the signature is changed to resist misuse with an
assert in the prologue of the function.
Change-Id: I6b3fc766bad2afe54dc27d47d1df3873e188de96
Signed-off-by: Raito Bezarius <raito@lix.systems>
commit d3c370bbcae48bb825ce19fd0f73bb4eefd2c9ea
Author: Raito Bezarius <raito@lix.systems>
Date: Wed Mar 26 01:07:47 2025 +0100
libstore: ensure that `passAsFile` is created in the original temp dir
This ensures that `passAsFile` data is created inside the expected
temporary build directory by `openat()` from the parent directory file
descriptor.
This avoids a TOCTOU which is part of the attack chain of CVE-????.
Change-Id: Ie5273446c4a19403088d0389ae8e3f473af8879a
Signed-off-by: Raito Bezarius <raito@lix.systems>
commit 45d3598724f932d024ef6bc2ffb00c1bb90e6018
Author: Raito Bezarius <raito@lix.systems>
Date: Wed Mar 26 01:06:03 2025 +0100
libutil: writeFile variant for file descriptors
`writeFile` lose its `sync` boolean flag to make things simpler.
A new `writeFileAndSync` function is created and all call sites are
converted to it.
Change-Id: Ib871a5283a9c047db1e4fe48a241506e4aab9192
Signed-off-by: Raito Bezarius <raito@lix.systems>
commit 732bd9b98cabf4aaf95a01fd318923de303f9996
Author: Raito Bezarius <raito@lix.systems>
Date: Wed Mar 26 01:05:34 2025 +0100
libstore: chown to builder variant for file descriptors
We use it immediately for the build temporary directory.
Change-Id: I180193c63a2b98721f5fb8e542c4e39c099bb947
Signed-off-by: Raito Bezarius <raito@lix.systems>
commit 962c65f8dcd5570dd92c72370a862c7b38942e0d
Author: Raito Bezarius <raito@lix.systems>
Date: Wed Mar 26 01:04:59 2025 +0100
libstore: open build directory as a dirfd as well
We now keep around a proper AutoCloseFD around the temporary directory
which we plan to use for openat operations and avoiding the build
directory being swapped out while we are doing something else.
Change-Id: I18d387b0f123ebf2d20c6405cd47ebadc5505f2a
Signed-off-by: Raito Bezarius <raito@lix.systems>
commit c9b42462b75b5a37ee6564c2b53cff186c8323da
Author: Raito Bezarius <raito@lix.systems>
Date: Wed Mar 26 01:04:12 2025 +0100
libutil: guess or invent a path from file descriptors
This is useful for certain error recovery paths (no pun intended) that
does not thread through the original path name.
Change-Id: I2d800740cb4f9912e64c923120d3f977c58ccb7e
Signed-off-by: Raito Bezarius <raito@lix.systems>
OpenBSD doesn't support `lutimes`, but does support `utimensat` which
subsumes it. In fact, all the BSDs, Linux, and newer macOS all support
it. So lets make this our first choice for the implementation.
In addition, let's get rid of the `lutimes` `ENOSYS` special case. The
Linux manpage says
> ENOSYS
>
> The kernel does not support this call; Linux 2.6.22 or later is
> required.
which I think is the origin of this check, but that's a very old version
of Linux at this point. The code can be simplified a lot of we drop
support for it here (as we've done elsewhere, anyways).
Co-Authored-By: John Ericson <John.Ericson@Obsidian.Systems>
(cherry picked from commit d023202811)
* Only build perl subproject on Linux
* Fix various Windows regressions
* Don't put the emulator hook in test builds
We run the tests in a separate derivation. Only need it for the dev shell.
* Fix native dev shells
* Fix cross dev shells we don't know how to emulate
Co-authored-by: PoweredByPie <poweredbypie@users.noreply.github.com>
Co-authored-by: Joachim Schiele <js@lastlog.de>
Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems>
... at call sites that are may be in the hot path.
I do not know how clever the compiler gets at these sites.
My primary concern is to not regress performance and I am confident
that this achieves it the easy way.
Instead of running the builds under
`$TMPDIR/{unique-build-directory-owned-by-the-build-user}`, run them
under `$TMPDIR/{unique-build-directory-owned-by-the-daemon}/{subdir-owned-by-the-build-user}`
where the build directory is only readable and traversable by the daemon user.
This achieves two things:
1. It prevents builders from making their build directory world-readable
(or even writeable), which would allow the outside world to interact
with them.
2. It prevents external processes running as the build user (either
because that somehow leaked, maybe as a consequence of 1., or because
`build-users` isn't in use) from gaining access to the build
directory.
the `std::filesystem::create_directories` can fail due to insufficient
permissions. We convert this error into a `SysError` and catch it
wherever required.
The implementation of `nix::createDirs` allows it to be a simple wrapper
around `std::filesystem::create_directories` as its return value is not
used anywhere.
the old `copyFile` was just a wrapper that was calling the `copy`
function. This wrapper function is removed and the `copy` function is
renamed to `copyFile`.
This makes for shorter and more portable code.
The only tricky part is catching exceptions: I just searched for near by
`catch (Error &)` or `catch (SysError &)` and adjusted them to `catch
(std::filesystem::filesystem_error &)` according to my human judgement.
Good for windows portability; will help @siddhantk232 with his GSOC
project.
At this point many features are stripped out, but this works:
- Can run libnix{util,store,expr} unit tests
- Can run some Nix commands
Co-Authored-By volth <volth@volth.com>
Co-Authored-By Brian McKenna <brian@brianmckenna.org>
This function is nice for more than `PosixSourceAccessor`. We can make a
few things simpler with it.
Note that the error logic slightly changes in some of the call sites, in
that we also count `ENOTDIR` and not just `ENOENT` as not having the
file, but that should be fine.
Fixes an instance of
nix: src/libutil/util.cc:139: nix::Path nix::canonPath(PathView, bool): Assertion `path != ""' failed.
... which I've been getting in one of my shells for some reason.
I have yet to find out why TMPDIR was empty, but it's no reason for
Nix to break.
It is possible to exfiltrate a file descriptor out of the build sandbox
of FODs, and use it to modify the store path after it has been
registered.
To avoid that issue, don't register the output of the build, but a copy
of it (that will be free of any leaked file descriptor).
`canonPath` and `absPath` work on native paths, and so should switch
between supporting Unix paths and Windows paths accordingly.
The templating is because `CanonPath`, which shares the implementation,
should always be Unix style. It is the pure "nix-native" path type for
virtual file operations --- it is part of Nix's "business logic", and
should not vary with the host OS accordingly.
The core `CanonPath` constructors were using `absPath`, but `absPath` in
some situations does IO which is not appropriate. It turns out that
these constructors avoided those situations, and thus were pure, but it
was far from obvious this was the case.
To remedy the situation, abstract the core algorithm from `canonPath` to
use separately in `CanonPath` without any IO. No we know by-construction
that those constructors are pure.
That leaves `CanonPath::fromCWD` as the only operation which uses IO /
is impure. Add docs on it, and `CanonPath` as a whole, explaining the
situation.
This is also necessary to support Windows paths on windows without
messing up `CanonPath`. But, I think it is good even without that.
Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
It is entirely possible for the path to be an empty string and many
unit tests actually pass it as an empty string (e.g. both_roundrip or
turnsEmptyPathIntoCWD). In this case, without this patch, absPath will
perform a one-byte out-of-bounds access.
This was discovered while enabling the nix test suite on Alpine where
we compile all software with `-D_GLIBCXX_ASSERTIONS=1`, thus resulting
in a test failure on Alpine.
more buffers that can be uninitialized and on the stack. small
difference, but still worth doing.
before:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 6.963 s ± 0.011 s [User: 5.330 s, System: 1.421 s]
Range (min … max): 6.943 s … 6.974 s 10 runs
after:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 6.952 s ± 0.015 s [User: 5.294 s, System: 1.452 s]
Range (min … max): 6.926 s … 6.974 s 10 runs
All OS and IO operations should be moved out, leaving only some misc
portable pure functions.
This is useful to avoid copious CPP when doing things like Windows and
Emscripten ports.
Newly exposed functions to break cycles:
- `restoreSignals`
- `updateWindowSize`
