lix/src/nix/verify.cc
Eelco Dolstra 0abb3ad537 Allow content-addressable paths to have references
This adds a command 'nix make-content-addressable' that rewrites the
specified store paths into content-addressable paths. The advantage of
such paths is that 1) they can be imported without signatures; 2) they
can enable deduplication in cases where derivation changes do not
cause output changes (apart from store path hashes).

For example,

  $ nix make-content-addressable -r nixpkgs.cowsay
  rewrote '/nix/store/g1g31ah55xdia1jdqabv1imf6mcw0nb1-glibc-2.25-49' to '/nix/store/48jfj7bg78a8n4f2nhg269rgw1936vj4-glibc-2.25-49'
  ...
  rewrote '/nix/store/qbi6rzpk0bxjw8lw6azn2mc7ynnn455q-cowsay-3.03+dfsg1-16' to '/nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16'

We can then copy the resulting closure to another store without
signatures:

  $ nix copy --trusted-public-keys '' ---to ~/my-nix /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16

In order to support self-references in content-addressable paths,
these paths are hashed "modulo" self-references, meaning that
self-references are zeroed out during hashing. Somewhat annoyingly,
this means that the NAR hash stored in the Nix database is no longer
necessarily equal to the output of "nix hash-path"; for
content-addressable paths, you need to pass the --modulo flag:

  $ nix path-info --json /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16  | jq -r .[].narHash
  sha256:0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw

  $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16
  1ggznh07khq0hz6id09pqws3a8q9pn03ya3c03nwck1kwq8rclzs

  $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 --modulo iq6g2x4q62xp7y7493bibx0qn5w7xz67
  0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw
2019-10-21 17:47:24 +02:00

184 lines
5.8 KiB
C++

#include "command.hh"
#include "shared.hh"
#include "store-api.hh"
#include "sync.hh"
#include "thread-pool.hh"
#include "references.hh"
#include <atomic>
using namespace nix;
struct CmdVerify : StorePathsCommand
{
bool noContents = false;
bool noTrust = false;
Strings substituterUris;
size_t sigsNeeded = 0;
CmdVerify()
{
mkFlag(0, "no-contents", "do not verify the contents of each store path", &noContents);
mkFlag(0, "no-trust", "do not verify whether each store path is trusted", &noTrust);
mkFlag()
.longName("substituter")
.shortName('s')
.labels({"store-uri"})
.description("use signatures from specified store")
.arity(1)
.handler([&](std::vector<std::string> ss) { substituterUris.push_back(ss[0]); });
mkIntFlag('n', "sigs-needed", "require that each path has at least N valid signatures", &sigsNeeded);
}
std::string name() override
{
return "verify";
}
std::string description() override
{
return "verify the integrity of store paths";
}
Examples examples() override
{
return {
Example{
"To verify the entire Nix store:",
"nix verify --all"
},
Example{
"To check whether each path in the closure of Firefox has at least 2 signatures:",
"nix verify -r -n2 --no-contents $(type -p firefox)"
},
};
}
void run(ref<Store> store, Paths storePaths) override
{
std::vector<ref<Store>> substituters;
for (auto & s : substituterUris)
substituters.push_back(openStore(s));
auto publicKeys = getDefaultPublicKeys();
Activity act(*logger, actVerifyPaths);
std::atomic<size_t> done{0};
std::atomic<size_t> untrusted{0};
std::atomic<size_t> corrupted{0};
std::atomic<size_t> failed{0};
std::atomic<size_t> active{0};
auto update = [&]() {
act.progress(done, storePaths.size(), active, failed);
};
ThreadPool pool;
auto doPath = [&](const Path & storePath) {
try {
checkInterrupt();
Activity act2(*logger, lvlInfo, actUnknown, fmt("checking '%s'", storePath));
MaintainCount<std::atomic<size_t>> mcActive(active);
update();
auto info = store->queryPathInfo(storePath);
if (!noContents) {
std::unique_ptr<AbstractHashSink> hashSink;
if (info->ca == "")
hashSink = std::make_unique<HashSink>(info->narHash.type);
else
hashSink = std::make_unique<HashModuloSink>(info->narHash.type, storePathToHash(info->path));
store->narFromPath(info->path, *hashSink);
auto hash = hashSink->finish();
if (hash.first != info->narHash) {
corrupted++;
act2.result(resCorruptedPath, info->path);
printError(
format("path '%s' was modified! expected hash '%s', got '%s'")
% info->path % info->narHash.to_string() % hash.first.to_string());
}
}
if (!noTrust) {
bool good = false;
if (info->ultimate && !sigsNeeded)
good = true;
else {
StringSet sigsSeen;
size_t actualSigsNeeded = std::max(sigsNeeded, (size_t) 1);
size_t validSigs = 0;
auto doSigs = [&](StringSet sigs) {
for (auto sig : sigs) {
if (!sigsSeen.insert(sig).second) continue;
if (validSigs < ValidPathInfo::maxSigs && info->checkSignature(publicKeys, sig))
validSigs++;
}
};
if (info->isContentAddressed(*store)) validSigs = ValidPathInfo::maxSigs;
doSigs(info->sigs);
for (auto & store2 : substituters) {
if (validSigs >= actualSigsNeeded) break;
try {
auto info2 = store2->queryPathInfo(info->path);
if (info2->isContentAddressed(*store)) validSigs = ValidPathInfo::maxSigs;
doSigs(info2->sigs);
} catch (InvalidPath &) {
} catch (Error & e) {
printError(format(ANSI_RED "error:" ANSI_NORMAL " %s") % e.what());
}
}
if (validSigs >= actualSigsNeeded)
good = true;
}
if (!good) {
untrusted++;
act2.result(resUntrustedPath, info->path);
printError(format("path '%s' is untrusted") % info->path);
}
}
done++;
} catch (Error & e) {
printError(format(ANSI_RED "error:" ANSI_NORMAL " %s") % e.what());
failed++;
}
update();
};
for (auto & storePath : storePaths)
pool.enqueue(std::bind(doPath, storePath));
pool.process();
throw Exit(
(corrupted ? 1 : 0) |
(untrusted ? 2 : 0) |
(failed ? 4 : 0));
}
};
static RegisterCommand r1(make_ref<CmdVerify>());