lix/perl/lib/Nix/Manifest.pm
Eelco Dolstra 0fdf4da0e9 Support cryptographically signed binary caches
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.
2014-01-08 15:42:53 +01:00

468 lines
16 KiB
Perl
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package Nix::Manifest;
use strict;
use DBI;
use DBD::SQLite;
use Cwd;
use File::stat;
use File::Path;
use Fcntl ':flock';
use Nix::Config;
use Nix::Crypto;
our @ISA = qw(Exporter);
our @EXPORT = qw(readManifest writeManifest updateManifestDB addPatch deleteOldManifests parseNARInfo);
sub addNAR {
my ($narFiles, $storePath, $info) = @_;
$$narFiles{$storePath} = []
unless defined $$narFiles{$storePath};
my $narFileList = $$narFiles{$storePath};
my $found = 0;
foreach my $narFile (@{$narFileList}) {
$found = 1 if $narFile->{url} eq $info->{url};
}
push @{$narFileList}, $info if !$found;
}
sub addPatch {
my ($patches, $storePath, $patch) = @_;
$$patches{$storePath} = []
unless defined $$patches{$storePath};
my $patchList = $$patches{$storePath};
my $found = 0;
foreach my $patch2 (@{$patchList}) {
$found = 1 if
$patch2->{url} eq $patch->{url} &&
$patch2->{basePath} eq $patch->{basePath};
}
push @{$patchList}, $patch if !$found;
return !$found;
}
sub readManifest_ {
my ($manifest, $addNAR, $addPatch) = @_;
# Decompress the manifest if necessary.
if ($manifest =~ /\.bz2$/) {
open MANIFEST, "$Nix::Config::bzip2 -d < $manifest |"
or die "cannot decompress `$manifest': $!";
} else {
open MANIFEST, "<$manifest"
or die "cannot open `$manifest': $!";
}
my $inside = 0;
my $type;
my $manifestVersion = 2;
my ($storePath, $url, $hash, $size, $basePath, $baseHash, $patchType);
my ($narHash, $narSize, $references, $deriver, $copyFrom, $system, $compressionType);
while (<MANIFEST>) {
chomp;
s/\#.*$//g;
next if (/^$/);
if (!$inside) {
if (/^\s*(\w*)\s*\{$/) {
$type = $1;
$type = "narfile" if $type eq "";
$inside = 1;
undef $storePath;
undef $url;
undef $hash;
undef $size;
undef $narHash;
undef $narSize;
undef $basePath;
undef $baseHash;
undef $patchType;
undef $system;
$references = "";
$deriver = "";
$compressionType = "bzip2";
}
} else {
if (/^\}$/) {
$inside = 0;
if ($type eq "narfile") {
&$addNAR($storePath,
{ url => $url, hash => $hash, size => $size
, narHash => $narHash, narSize => $narSize
, references => $references
, deriver => $deriver
, system => $system
, compressionType => $compressionType
});
}
elsif ($type eq "patch") {
&$addPatch($storePath,
{ url => $url, hash => $hash, size => $size
, basePath => $basePath, baseHash => $baseHash
, narHash => $narHash, narSize => $narSize
, patchType => $patchType
});
}
}
elsif (/^\s*StorePath:\s*(\/\S+)\s*$/) { $storePath = $1; }
elsif (/^\s*CopyFrom:\s*(\/\S+)\s*$/) { $copyFrom = $1; }
elsif (/^\s*Hash:\s*(\S+)\s*$/) { $hash = $1; }
elsif (/^\s*URL:\s*(\S+)\s*$/) { $url = $1; }
elsif (/^\s*Compression:\s*(\S+)\s*$/) { $compressionType = $1; }
elsif (/^\s*Size:\s*(\d+)\s*$/) { $size = $1; }
elsif (/^\s*BasePath:\s*(\/\S+)\s*$/) { $basePath = $1; }
elsif (/^\s*BaseHash:\s*(\S+)\s*$/) { $baseHash = $1; }
elsif (/^\s*Type:\s*(\S+)\s*$/) { $patchType = $1; }
elsif (/^\s*NarHash:\s*(\S+)\s*$/) { $narHash = $1; }
elsif (/^\s*NarSize:\s*(\d+)\s*$/) { $narSize = $1; }
elsif (/^\s*References:\s*(.*)\s*$/) { $references = $1; }
elsif (/^\s*Deriver:\s*(\S+)\s*$/) { $deriver = $1; }
elsif (/^\s*ManifestVersion:\s*(\d+)\s*$/) { $manifestVersion = $1; }
elsif (/^\s*System:\s*(\S+)\s*$/) { $system = $1; }
# Compatibility;
elsif (/^\s*NarURL:\s*(\S+)\s*$/) { $url = $1; }
elsif (/^\s*MD5:\s*(\S+)\s*$/) { $hash = "md5:$1"; }
}
}
close MANIFEST;
return $manifestVersion;
}
sub readManifest {
my ($manifest, $narFiles, $patches) = @_;
readManifest_($manifest,
sub { addNAR($narFiles, @_); },
sub { addPatch($patches, @_); } );
}
sub writeManifest {
my ($manifest, $narFiles, $patches, $noCompress) = @_;
open MANIFEST, ">$manifest.tmp"; # !!! check exclusive
print MANIFEST "version {\n";
print MANIFEST " ManifestVersion: 3\n";
print MANIFEST "}\n";
foreach my $storePath (sort (keys %{$narFiles})) {
my $narFileList = $$narFiles{$storePath};
foreach my $narFile (@{$narFileList}) {
print MANIFEST "{\n";
print MANIFEST " StorePath: $storePath\n";
print MANIFEST " NarURL: $narFile->{url}\n";
print MANIFEST " Compression: $narFile->{compressionType}\n";
print MANIFEST " Hash: $narFile->{hash}\n" if defined $narFile->{hash};
print MANIFEST " Size: $narFile->{size}\n" if defined $narFile->{size};
print MANIFEST " NarHash: $narFile->{narHash}\n";
print MANIFEST " NarSize: $narFile->{narSize}\n" if $narFile->{narSize};
print MANIFEST " References: $narFile->{references}\n"
if defined $narFile->{references} && $narFile->{references} ne "";
print MANIFEST " Deriver: $narFile->{deriver}\n"
if defined $narFile->{deriver} && $narFile->{deriver} ne "";
print MANIFEST " System: $narFile->{system}\n" if defined $narFile->{system};
print MANIFEST "}\n";
}
}
foreach my $storePath (sort (keys %{$patches})) {
my $patchList = $$patches{$storePath};
foreach my $patch (@{$patchList}) {
print MANIFEST "patch {\n";
print MANIFEST " StorePath: $storePath\n";
print MANIFEST " NarURL: $patch->{url}\n";
print MANIFEST " Hash: $patch->{hash}\n";
print MANIFEST " Size: $patch->{size}\n";
print MANIFEST " NarHash: $patch->{narHash}\n";
print MANIFEST " NarSize: $patch->{narSize}\n" if $patch->{narSize};
print MANIFEST " BasePath: $patch->{basePath}\n";
print MANIFEST " BaseHash: $patch->{baseHash}\n";
print MANIFEST " Type: $patch->{patchType}\n";
print MANIFEST "}\n";
}
}
close MANIFEST;
rename("$manifest.tmp", $manifest)
or die "cannot rename $manifest.tmp: $!";
# Create a bzipped manifest.
unless (defined $noCompress) {
system("$Nix::Config::bzip2 < $manifest > $manifest.bz2.tmp") == 0
or die "cannot compress manifest";
rename("$manifest.bz2.tmp", "$manifest.bz2")
or die "cannot rename $manifest.bz2.tmp: $!";
}
}
sub updateManifestDB {
my $manifestDir = $Nix::Config::manifestDir;
my @manifests = glob "$manifestDir/*.nixmanifest";
return undef if scalar @manifests == 0;
mkpath($manifestDir);
unlink "$manifestDir/cache.sqlite"; # remove obsolete cache
my $dbPath = "$manifestDir/cache-v2.sqlite";
# Open/create the database.
our $dbh = DBI->connect("dbi:SQLite:dbname=$dbPath", "", "")
or die "cannot open database `$dbPath'";
$dbh->{RaiseError} = 1;
$dbh->{PrintError} = 0;
$dbh->do("pragma foreign_keys = on");
$dbh->do("pragma synchronous = off"); # we can always reproduce the cache
$dbh->do("pragma journal_mode = truncate");
# Initialise the database schema, if necessary.
$dbh->do(<<EOF);
create table if not exists Manifests (
id integer primary key autoincrement not null,
path text unique not null,
timestamp integer not null
);
EOF
$dbh->do(<<EOF);
create table if not exists NARs (
id integer primary key autoincrement not null,
manifest integer not null,
storePath text not null,
url text not null,
compressionType text not null,
hash text,
size integer,
narHash text,
narSize integer,
refs text,
deriver text,
system text,
foreign key (manifest) references Manifests(id) on delete cascade
);
EOF
$dbh->do("create index if not exists NARs_storePath on NARs(storePath)");
$dbh->do(<<EOF);
create table if not exists Patches (
id integer primary key autoincrement not null,
manifest integer not null,
storePath text not null,
basePath text not null,
baseHash text not null,
url text not null,
hash text,
size integer,
narHash text,
narSize integer,
patchType text not null,
foreign key (manifest) references Manifests(id) on delete cascade
);
EOF
$dbh->do("create index if not exists Patches_storePath on Patches(storePath)");
# Acquire an exclusive lock to ensure that only one process
# updates the DB at the same time. This isn't really necessary,
# but it prevents work duplication and lock contention in SQLite.
my $lockFile = "$manifestDir/cache.lock";
open MAINLOCK, ">>$lockFile" or die "unable to acquire lock $lockFile: $!\n";
flock(MAINLOCK, LOCK_EX) or die;
our $insertNAR = $dbh->prepare(
"insert into NARs(manifest, storePath, url, compressionType, hash, size, narHash, " .
"narSize, refs, deriver, system) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)") or die;
our $insertPatch = $dbh->prepare(
"insert into Patches(manifest, storePath, basePath, baseHash, url, hash, " .
"size, narHash, narSize, patchType) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)");
$dbh->begin_work;
# Read each manifest in $manifestDir and add it to the database,
# unless we've already done so on a previous run.
my %seen;
for my $manifestLink (@manifests) {
my $manifest = Cwd::abs_path($manifestLink);
next unless -f $manifest;
my $timestamp = lstat($manifest)->mtime;
$seen{$manifest} = 1;
next if scalar @{$dbh->selectcol_arrayref(
"select 1 from Manifests where path = ? and timestamp = ?",
{}, $manifest, $timestamp)} == 1;
print STDERR "caching $manifest...\n";
$dbh->do("delete from Manifests where path = ?", {}, $manifest);
$dbh->do("insert into Manifests(path, timestamp) values (?, ?)",
{}, $manifest, $timestamp);
our $id = $dbh->last_insert_id("", "", "", "");
sub addNARToDB {
my ($storePath, $narFile) = @_;
$insertNAR->execute(
$id, $storePath, $narFile->{url}, $narFile->{compressionType}, $narFile->{hash},
$narFile->{size}, $narFile->{narHash}, $narFile->{narSize}, $narFile->{references},
$narFile->{deriver}, $narFile->{system});
};
sub addPatchToDB {
my ($storePath, $patch) = @_;
$insertPatch->execute(
$id, $storePath, $patch->{basePath}, $patch->{baseHash}, $patch->{url},
$patch->{hash}, $patch->{size}, $patch->{narHash}, $patch->{narSize},
$patch->{patchType});
};
my $version = readManifest_($manifest, \&addNARToDB, \&addPatchToDB);
if ($version < 3) {
die "you have an old-style or corrupt manifest `$manifestLink'; please delete it\n";
}
if ($version >= 10) {
die "manifest `$manifestLink' is too new; please delete it or upgrade Nix\n";
}
}
# Removed cached information for removed manifests from the DB.
foreach my $manifest (@{$dbh->selectcol_arrayref("select path from Manifests")}) {
next if defined $seen{$manifest};
$dbh->do("delete from Manifests where path = ?", {}, $manifest);
}
$dbh->commit;
close MAINLOCK;
return $dbh;
}
# Delete all old manifests downloaded from a given URL.
sub deleteOldManifests {
my ($url, $curUrlFile) = @_;
for my $urlFile (glob "$Nix::Config::manifestDir/*.url") {
next if defined $curUrlFile && $urlFile eq $curUrlFile;
open URL, "<$urlFile" or die;
my $url2 = <URL>;
chomp $url2;
close URL;
next unless $url eq $url2;
my $base = $urlFile; $base =~ s/.url$//;
unlink "${base}.url";
unlink "${base}.nixmanifest";
}
}
# Parse a NAR info file.
sub parseNARInfo {
my ($storePath, $content, $requireValidSig, $location) = @_;
my ($storePath2, $url, $fileHash, $fileSize, $narHash, $narSize, $deriver, $system, $sig);
my $signedData = "";
my $compression = "bzip2";
my @refs;
foreach my $line (split "\n", $content) {
return undef unless $line =~ /^(.*): (.*)$/;
if ($1 eq "StorePath") { $storePath2 = $2; }
elsif ($1 eq "URL") { $url = $2; }
elsif ($1 eq "Compression") { $compression = $2; }
elsif ($1 eq "FileHash") { $fileHash = $2; }
elsif ($1 eq "FileSize") { $fileSize = int($2); }
elsif ($1 eq "NarHash") { $narHash = $2; }
elsif ($1 eq "NarSize") { $narSize = int($2); }
elsif ($1 eq "References") { @refs = split / /, $2; }
elsif ($1 eq "Deriver") { $deriver = $2; }
elsif ($1 eq "System") { $system = $2; }
elsif ($1 eq "Signature") { $sig = $2; last; }
$signedData .= "$line\n";
}
return undef if $storePath ne $storePath2 || !defined $url || !defined $narHash;
my $res =
{ url => $url
, compression => $compression
, fileHash => $fileHash
, fileSize => $fileSize
, narHash => $narHash
, narSize => $narSize
, refs => [ @refs ]
, deriver => $deriver
, system => $system
};
if ($requireValidSig) {
if (!defined $sig) {
warn "NAR info file `$location' lacks a signature; ignoring\n";
return undef;
}
my ($sigVersion, $keyName, $sig64) = split ";", $sig;
$sigVersion //= 0;
if ($sigVersion != 1) {
warn "NAR info file `$location' has unsupported version $sigVersion; ignoring\n";
return undef;
}
return undef unless defined $keyName && defined $sig64;
my $publicKeyFile = $Nix::Config::config{"binary-cache-public-key-$keyName"};
if (!defined $publicKeyFile) {
warn "NAR info file `$location' is signed by unknown key `$keyName'; ignoring\n";
return undef;
}
if (! -f $publicKeyFile) {
die "binary cache public key file `$publicKeyFile' does not exist\n";
return undef;
}
if (!isValidSignature($publicKeyFile, $sig64, $signedData)) {
warn "NAR info file `$location' has an invalid signature; ignoring\n";
return undef;
}
$res->{signedBy} = $keyName;
}
return $res;
}
return 1;