NAR info files in binary caches can now have a cryptographic signature
that Nix will verify before using the corresponding NAR file.
To create a private/public key pair for signing and verifying a binary
cache, do:
$ openssl genrsa -out ./cache-key.sec 2048
$ openssl rsa -in ./cache-key.sec -pubout > ./cache-key.pub
You should also come up with a symbolic name for the key, such as
"cache.example.org-1". This will be used by clients to look up the
public key. (It's a good idea to number keys, in case you ever need
to revoke/replace one.)
To create a binary cache signed with the private key:
$ nix-push --dest /path/to/binary-cache --key ./cache-key.sec --key-name cache.example.org-1
The public key (cache-key.pub) should be distributed to the clients.
They should have a nix.conf should contain something like:
signed-binary-caches = *
binary-cache-public-key-cache.example.org-1 = /path/to/cache-key.pub
If all works well, then if Nix fetches something from the signed
binary cache, you will see a message like:
*** Downloading ‘http://cache.example.org/nar/7dppcj5sc1nda7l54rjc0g5l1hamj09j-subversion-1.7.11’ (signed by ‘cache.example.org-1’) to ‘/nix/store/7dppcj5sc1nda7l54rjc0g5l1hamj09j-subversion-1.7.11’...
On the other hand, if the signature is wrong, you get a message like
NAR info file `http://cache.example.org/7dppcj5sc1nda7l54rjc0g5l1hamj09j.narinfo' has an invalid signature; ignoring
Signatures are implemented as a single line appended to the NAR info
file, which looks like this:
Signature: 1;cache.example.org-1;HQ9Xzyanq9iV...muQ==
Thus the signature has 3 fields: a version (currently "1"), the ID of
key, and the base64-encoded signature of the SHA-256 hash of the
contents of the NAR info file up to but not including the Signature
line.
Issue #75.
This reverts commit 194e3374b8.
Checking the command line for GC roots means that
$ nix-store --delete $path
will fail because $path is now a root because it's mentioned on the
command line.
Ever since SQLite in Nixpkgs was updated to 3.8.0.2, Nix has randomly
segfaulted on Darwin:
http://hydra.nixos.org/build/6175515http://hydra.nixos.org/build/6611038
It turns out that this is because the binary cache substituter somehow
ends up loading two versions of SQLite: the one in Nixpkgs and the
other from /usr/lib/libsqlite3.dylib. It's not exactly clear why the
latter is loaded, but it appears to be because WWW::Curl indirectly loads
/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation,
which in turn seems to load /usr/lib/libsqlite3.dylib. This leads to
a segfault when Perl exits:
#0 0x00000001010375f4 in sqlite3_finalize ()
#1 0x000000010125806e in sqlite_st_destroy ()
#2 0x000000010124bc30 in XS_DBD__SQLite__st_DESTROY ()
#3 0x00000001001c8155 in XS_DBI_dispatch ()
...
#14 0x0000000100023224 in perl_destruct ()
#15 0x0000000100000d6a in main ()
...
The workaround is to explicitly load DBD::SQLite before WWW::Curl.
nix-shell with the --command flag might be used non-interactively, but
if bash starts non-interactively (i.e. with stdin or stderr not a
terminal), it won't source the script given in --rcfile. However, in
that case it *will* source the script found in $BASH_ENV, so we can use
that instead.
Also, don't source ~/.bashrc in a non-interactive shell (detectable by
checking the PS1 env var)
Signed-off-by: Shea Levy <shea@shealevy.com>
Nixpkgs's stdenv setup script sets the "nullglob" option, but doing so
breaks Bash completion on NixOS (when ‘programs.bash.enableCompletion’
is set) and on Ubuntu. So clear that flag afterwards. Of course,
this may break stdenv functions in subtle ways...
Nixpkgs' stdenv disables dependency tracking by default. That makes
sense for one-time builds, but in an interactive environment we expect
repeated "make" invocations to do the right thing.
This reverts commit 69b8f9980f.
The timeout should be enforced remotely. Otherwise, if the garbage
collector is running either locally or remotely, if will block the
build or closure copying for some time. If the garbage collector
takes too long, the build may time out, which is not what we want.
Also, on heavily loaded systems, copying large paths to and from the
remote machine can take a long time, also potentially resulting in a
timeout.
For instance, it's pointless to keep copy-from-other-stores running if
there are no other stores, or download-using-manifests if there are no
manifests. This also speeds things up because we don't send queries
to those substituters.
Previously, if a binary cache is hanging/unreachable/slow,
download-from-binary-cache.pl would also hang without any indication
to the user. Now, if fetching a URL takes more than 5 seconds, it
will print a message to that effect.
Amazon S3 returns HTTP status code 403 if a file doesn't exist and the
user has no permission to list the contents of the bucket. So treat
it as 404 (meaning it's cached in the NARExistence table).
The "$UID != 0" makes no sense: if the local side has write access to
the Nix store (which is always the case) then it doesn't matter if
we're root - we can import unsigned paths either way.
Otherwise it will set the parent's stdin to non-blocking mode, causing
the subsequent read of the set of inputs/outputs to fail randomly.
That's insane.
Before selecting a machine, build-remote.pl will try to run the
command "nix-builds-inhibited" on the machine. If this command exists
and returns a 0 exit code, then the machine won't be used. It's up to
the user to provide this command, but it would typically be a script
that checks whether there is enough disk space and whether the load is
not too high.
