When the linker signs a Mach-O binary, it sets a flag in the signature’s code directory indicating that the signature was generated by a linker. Tools such as `strip` and `install_name_tool` read this flag and will
update ad hoc signatures after they perform their modifications.
The updated l64 supports signing binaries automatically. Both the updated cctools and LLVM will check for the linker-signed flag and resign binaries they modify automatically when it’s present. Given that, use of postLinkSignHook is unnecessary and potentially harmful.
In particular, if the hook is used and an unwrapped `strip` or `install_name_tool` is on the user’s path, they will not automatically update an ad hoc signature. Instead, they will issue a warning and create a binary with a broken signature.
It is more robust to let the tools handled this since the only time a signature would not be linker-signed is when the user is manually invoking `codesign` (or another tool such as `sigtool` or `rcodesign`), which by nature of the invocation updates the signature to a valid one.
Since `strip` no longer needs to be wrapped for code-signing, binutils-wrapper now uses the GNU strip wrapper on Darwin.
Fixes https://github.com/NixOS/nixpkgs/issues/208951.
This changes ld-wrapper to use a temporary file for the response file
passed to ld instead of using process substitution.
ld64 does not handle long command-lines when reading from the response
file, which defeats the point of using a response file to handle long
command-lines. cctools-port was patched to work around this, but nixpkgs
is now using Apple’s source release directly instead of the port.
Since it’s preferable not to patch Apple’s release heavily (to reduce
the difficulty of updating to new versions and to match upstream’s
behavior), use the approach that was adopted in cc-wrapper to work
around issues with response files in newer versions of clang.
Related PRs (cctools-port):
- https://github.com/NixOS/nixpkgs/pull/213831
- https://github.com/tpoechtrager/cctools-port/pull/132
Related PRs (cc-wrapper):
- https://github.com/NixOS/nixpkgs/pull/245282
- https://github.com/NixOS/nixpkgs/pull/258608
For a long time, we've had `crossLibcStdenv`, `*Cross` libc attributes,
and `*bsdCross` pre-libc package sets. This was always bad because
having "cross" things is "not declarative": the naming doesn't reflect
what packages *need* but rather how we *provide* something. This is
ugly, and creates needless friction between cross and native building.
Now, almost all of these `*Cross` attributes are gone: just these are
kept:
- Glibc's and Musl's are kept, because those packages are widely used
and I didn't want to risk changing the native builds of those at this
time.
- generic `libcCross`, `theadsCross`, and friends, because these relate
to the convolulted GCC bootstrap which still needs to be redone.
The BSD and obscure Linux or freestnanding libcs have conversely all
been made to use a new `stdenvNoLibc`, which is like the old
`crossLibcStdenv` except:
1. It usable for native and cross alike
2. It named according to what it *is* ("a standard environment without
libc but with a C compiler"), rather than some non-compositional
jargon ("the stdenv used for building libc when cross compiling",
yuck).
I should have done this change long ago, but I was stymied because of
"infinite recursions". The problem was that in too many cases we are
overriding `stdenv` to *remove* things we don't need, and this risks
cyles since those more minimal stdenvs are used to build things in the
more maximal stdenvs.
The solution is to pass `stage.nix` `stdenvNoCC`, so we can override to
*build up* rather than *tear down*. For now, the full `stdenv` is also
passed, so I don't need to change the native bootstraps, but I can see
this changing as we make things more uniform and clean those up.
Finally, the BSDs also had to be cleaned up, since they have a few
pre-libc dependencies, demanding a systematic approach. I realized what
rhelmot did in 61202561d9 (specify what
packages just need `stdenvNoLibc`) is definitely the right approach for
this, and adjusted NetBSD and OpenBSD to likewise use it.
The cc and bintools wrapper contained ad hoc bootstrapping logic for
expand-response-params (which was callPackage-ed in a let binding). This
lead to the strange situation that the bootstrapping logic related to
expand-response-params is split between the wrapper derivations (where
it is duplicated) and the actual stdenv bootstrapping.
To clean this up, the wrappers simply should take expand-response-params
as an ordinary input: They need an adjacent expand-response-params (i.e.
one that runs on their host platform), but don't care about the how.
Providing this is only problematic during stdenv bootstrapping where we
have to pull it from the previous stage at times.
We don't need to artificially make sure that we can execute the wrapper
scripts on the build platform by using stdenv's shell (which comes from
buildPackages) since our cross infrastructure will get us the wrapper
from buildPackages. The upside of this change is that cross-compiled
wrappers (e.g. pkgsCross.aarch64-multiplatform.gcc) will actually work
when executed!
For bootstrapping this is also not a problem, since we have a long
build->build platform chain so runtimeShell is just as good as
stdenvNoCC.shell. We do fall back to old ways, though, by explicitly
using the bootstrap-tools shell in stage2, so the adjacent bash is only
used from stage4 onwards. This is unnecessary in principle (I'll try
removing this hack in the future), but ensures this change causes zero
rebuilds.
In delicate code like this, it seems unwise to pass something of as
something it isn't for convenience's (?) sake. It causes a slight
possibility for confusion with `buildPackages.stdenv`. However, it
should be possible to eliminate the need for this in a separate change.
this makes it a lot easier to create a modified stdenv with a
different set of defaultHardeningFlags and as a bonus allows us
to inject the correct defaultHardeningFlags into toolchain wrapper
scripts, reducing repetition.
while most hardening flags are arguably more of a compiler thing,
it works better to put them in bintools-wrapper because cc-wrapper
can easily refer to bintools but not vice-versa.
mkDerivation can still easily refer to either when it is constructed.
this also switches fortran-hook.sh to use the same defaults for
NIX_HARDENING_ENABLE as for C. previously NIX_HARDENING_ENABLE
defaults were apparently used to avoid passing problematic flags
to a fortran compiler, but this falls apart as soon as mkDerivation
sets its own NIX_HARDENING_ENABLE - cc.hardeningUnsupportedFlags
is a more appropriate mechanism for this as it actively filters
out flags from being used by the wrapper, so switch to using that
instead.
this is still an imperfect mechanism because it doesn't handle a
compiler which has both langFortran *and* langC very well - applying
the superset of the two's hardeningUnsupportedFlags to either
compiler's invocation. however this is nothing new - cc-wrapper
already poorly handles a langFortran+langC compiler, applying two
setup hooks that have contradictory options.
Fixed conflict in pkgs/applications/graphics/krita/
krita: 5.1.5 -> 5.2.0
7a40fdc288
, and
treewide: use kde mirror everywhere, don't use pname in download urls
aa15f5066d
-B must be set to the root directory of avrlibc, otherwise gcc cannot
locate crt objects for some attiny devices. -L trains as set by
bintools-wrapper are not necessary with -B set correctly because gcc
takes care of that, and likewise we can drop the -B train from
cc-wrapper because the one spec is enough.
When a response file is in use, "$*" contains the response file and not
the parameters; both the linker and compiler wrappers are updated to use
the response-expanded params.
The compiler driver likes to pass parameters to the linker via a
response file, including -shared.
LLD rejects the combination of (-shared -pie), whereas other linkers
silently ignore the contradiction:
```
ld.lld: error: -shared and -pie may not be used together
```
This breaks certain configurations using LLD as a linker.
Changing `add-hardening.sh` results in a full rebuild. To avoid the
rebuild, here is a quick test case which shows the new hardening script
allows the link to succeed:
```
{ pkgs ? import <nixpkgs> {} }:
let
# gcc silently accepts -shared -pie together, lld does not.
linker = pkgs.wrapBintoolsWith { bintools = pkgs.llvmPackages.lld; };
patchWrapper = prev: prev.overrideAttrs (final: prev: let
prevScript = builtins.match (".*(/nix/store/[a-z0-9]+-add-hardening.sh).*") prev.postFixup;
in {
postFixup = (builtins.replaceStrings prevScript ["${./new-add-hardening.sh}"] prev.postFixup);
});
in
pkgs.stdenv.mkDerivation {
name = "nixpkgs-hardening-bug";
src = pkgs.writeText "src.c" "int main(int argc, char* argv[]) { return 0; }";
NIX_HARDENING_ENABLE = "pie";
unpackPhase = ":";
buildPhase = ''
$CC -c -o src.o $src
bash -x ${patchWrapper linker}/bin/ld.lld -o $out @${pkgs.writeText "responsefile" "-shared"} src.o
'';
}
```
Fixes: #178162
Signed-off-by: Peter Waller <p@pwaller.net>
LLD supports Windows-style linker arguments, but these previously
triggered purity check false positives, because it saw that they
started with a '/' and assumed they were paths.
This tweaks the path detection to allow through certain values that
could be paths, but are much more likely to be LINK.EXE-style flags.
The risk of false negatives here is low — the only things we'd now
fail to catch would be attempts to link with libraries in the root
directory, which doesn't happen in practice.
We also teach the wrapper how to apply its purity checks to library
paths specified with the /LIBPATH: option.
Tested that paths we expect to be rejected (like /lib/libfoo.so) still
are.
NixOS/nixpkgs#146275 has more discussion on this; the abridged version
is that `lld` defaults to using `--build-id=fast` while GNU `ld` defaults
to `--build-id=sha1`. These differ in length and so
`separate-debug-info.sh`, as of this writing, errors on `lld`'s shorter
`--build-id=fast`-generated hashes.
`lld` offers the following `build-id` styles:
- UUID (random; fast but bad for reproducibility)
- fast (xxhash; fast but shorter hashes)
- user provided hexstring
- SHA1
- MD5
GNU `ld` supports the latter three options, `mold` supports all of these
plus SHA256.
UUID is out because it's not reproducible, fast isn't supported by GNU
`ld`
Using a nix provided (sourced from the output base hash) hash as the
`build-id` seems tempting but would require a little extra work
(we have to include some characteristic of the binary being hashed
so that binaries within a derivation still have unique hashes; it
seems easy to get this wrong; i.e. a path based approach would make
two otherwise identical binaries that reside at different paths have
different `build-id` hashes)
That leaves SHA1 and MD5 and GNU `ld` already defaults to the former.
This commit adds `$NIX_BUILD_ID_STYLE` as an escape hatch, in case any
packages have strong opinions about which hash to use.
----
Note that if/when NixOS/nixpkgs#146275 goes through, this change can be
reverted if linker speed is a priority.
The motivation behind this is to alleviate the problem
described in https://github.com/NixOS/nixpkgs/issues/41340.
I'm not sure if this completely fixes the problem, but it
eliminates one more area where we can exceed command line
length limits.
This is essentially the same change as in #112449,
except for `ld-wrapper.sh` instead of `cc-wrapper.sh`.
However, that change alone was not enough; on macOS the
`ld` provided by `darwin.cctools` fails if you use process
substitution to generate the response file, so I put up a
PR to fix that:
https://github.com/tpoechtrager/cctools-port/pull/131
… and I included a patch referencing that fix so that the
new `ld-wrapper` still works on macOS.
not all linkers have a ld binary in bin
also note the '${ld:-}' which allows users to set the ld path with a env
var
> '${foo:-val}' $foo, or val if unset (or null)
For reasons explained in the commit contents, in order to build the
native gnat package for x86_64-darwin, the native gnatboot package for
x86_64-darwin must have access to both the Clang integrated assembler
and the cctools GNU assembler for that platform. This commit creates a
package with both of those assemblers that x86_64-darwin gnatboot can
then be wrapped with.
Co-authored-by: Robin Gloster <mail@glob.in>
stdenv: print message if structuredAttrs is enabled
stdenv: add _append
reduces the chance of a user doing it wrong
fix nix develop issue
output hooks don't work yet in nix develop though
making $outputs be the same on non-structuredAttrs and structuredAttrs
is too much trouble.
lets instead make a function that gets the output names
reading environment file '/nix/store/2x7m69a2sm2kh0r6v0q5s9z1dh41m4xf-xz-5.2.5-env-bin'
nix: src/nix/develop.cc:299: std::string Common::makeRcScript(nix::ref<nix::Store>, const BuildEnvironment&, const Path&): Assertion `outputs != buildEnvironment.vars.end()' failed.
use a function to get all output names instead of using $outputs
copy env functionality from https://github.com/NixOS/nixpkgs/pull/76732/commits
`exit -1` is equivalent to `exit 255`, since Bash does modulo 256 on the
number.
As per ShellCheck:
> SC2242 (error): Can only exit with status 0-255. Other data should be
> written to stdout/stderr.
POSIX sh (and `bash`) impose a restriction on environment variable name
format and disallow hypheps in the names. Normally it's not a problem
as nothing usually tries to refer nyphenated names.
One exception is `nix develop` (https://github.com/NixOS/nix/issues/6848):
$ nix develop -f. gcc -L
gcc-wrapper> ...-get-env.sh: line 70: expand-response-params: bad substitution
Note that bash usually uses explicitly created `expandResponseParams`
variant of the same variable.
To work the problem around let's avoid environment variable export and move
it to `passthru` for `cc` (used ina few places) and remove it completely for
`binutils` (does not seem to be used at all).
