Merge pull request #7515 from MatthewCroughan/mc/check-trusted-user

Add Store::isTrustedClient()

14 files changed, 126 insertions, 3 deletions

diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index e22180670..58d6901d3 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -1415,6 +1415,9 @@ struct RestrictedStore : public virtual RestrictedStoreConfig, public virtual Lo
 
     virtual void addBuildLog(const StorePath & path, std::string_view log) override
     { unsupported("addBuildLog"); }
+
+    std::optional<TrustedFlag> isTrustedClient() override
+    { return NotTrusted; }
 };
 
 
@@ -1467,7 +1470,7 @@ void LocalDerivationGoal::startDaemon()
                 FdSink to(remote.get());
                 try {
                     daemon::processConnection(store, from, to,
-                        daemon::NotTrusted, daemon::Recursive);
+                        NotTrusted, daemon::Recursive);
                     debug("terminated daemon connection");
                 } catch (SysError &) {
                     ignoreException();
diff --git a/src/libstore/daemon.cc b/src/libstore/daemon.cc
index 656ad4587..63898f8dc 100644
--- a/src/libstore/daemon.cc
+++ b/src/libstore/daemon.cc
@@ -1032,6 +1032,15 @@ void processConnection(
     if (GET_PROTOCOL_MINOR(clientVersion) >= 33)
         to << nixVersion;
 
+    if (GET_PROTOCOL_MINOR(clientVersion) >= 35) {
+        // We and the underlying store both need to trust the client for
+        // it to be trusted.
+        auto temp = trusted
+            ? store->isTrustedClient()
+            : std::optional { NotTrusted };
+        worker_proto::write(*store, to, temp);
+    }
+
     /* Send startup error messages to the client. */
     tunnelLogger->startWork();
 
diff --git a/src/libstore/daemon.hh b/src/libstore/daemon.hh
index 67340a05b..1964c0d99 100644
--- a/src/libstore/daemon.hh
+++ b/src/libstore/daemon.hh
@@ -6,7 +6,6 @@
 
 namespace nix::daemon {
 
-enum TrustedFlag : bool { NotTrusted = false, Trusted = true };
 enum RecursiveFlag : bool { NotRecursive = false, Recursive = true };
 
 void processConnection(
diff --git a/src/libstore/dummy-store.cc b/src/libstore/dummy-store.cc
index 16e5fafd7..ae2777d0c 100644
--- a/src/libstore/dummy-store.cc
+++ b/src/libstore/dummy-store.cc
@@ -39,6 +39,14 @@ struct DummyStore : public virtual DummyStoreConfig, public virtual Store
         callback(nullptr);
     }
 
+    /**
+     * The dummy store is incapable of *not* trusting! :)
+     */
+    virtual std::optional<TrustedFlag> isTrustedClient() override
+    {
+        return Trusted;
+    }
+
     static std::set<std::string> uriSchemes() {
         return {"dummy"};
     }
diff --git a/src/libstore/http-binary-cache-store.cc b/src/libstore/http-binary-cache-store.cc
index 238fd1d98..85c5eed4c 100644
--- a/src/libstore/http-binary-cache-store.cc
+++ b/src/libstore/http-binary-cache-store.cc
@@ -194,6 +194,18 @@ protected:
             }});
     }
 
+    /**
+     * This isn't actually necessary read only. We support "upsert" now, so we
+     * have a notion of authentication via HTTP POST/PUT.
+     *
+     * For now, we conservatively say we don't know.
+     *
+     * \todo try to expose our HTTP authentication status.
+     */
+    std::optional<TrustedFlag> isTrustedClient() override
+    {
+        return std::nullopt;
+    }
 };
 
 static RegisterStoreImplementation<HttpBinaryCacheStore, HttpBinaryCacheStoreConfig> regHttpBinaryCacheStore;
diff --git a/src/libstore/legacy-ssh-store.cc b/src/libstore/legacy-ssh-store.cc
index 98322b045..eb471d8fc 100644
--- a/src/libstore/legacy-ssh-store.cc
+++ b/src/libstore/legacy-ssh-store.cc
@@ -389,6 +389,15 @@ public:
         return conn->remoteVersion;
     }
 
+    /**
+     * The legacy ssh protocol doesn't support checking for trusted-user.
+     * Try using ssh-ng:// instead if you want to know.
+     */
+    std::optional<TrustedFlag> isTrustedClient() override
+    {
+        return std::nullopt;
+    }
+
     void queryRealisationUncached(const DrvOutput &,
         Callback<std::shared_ptr<const Realisation>> callback) noexcept override
     // TODO: Implement
diff --git a/src/libstore/local-binary-cache-store.cc b/src/libstore/local-binary-cache-store.cc
index e5ee6fc15..5481dd762 100644
--- a/src/libstore/local-binary-cache-store.cc
+++ b/src/libstore/local-binary-cache-store.cc
@@ -95,6 +95,10 @@ protected:
         return paths;
     }
 
+    std::optional<TrustedFlag> isTrustedClient() override
+    {
+        return Trusted;
+    }
 };
 
 void LocalBinaryCacheStore::init()
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index f58d90895..e0ad50f6d 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -1685,6 +1685,11 @@ unsigned int LocalStore::getProtocol()
     return PROTOCOL_VERSION;
 }
 
+std::optional<TrustedFlag> LocalStore::isTrustedClient()
+{
+    return Trusted;
+}
+
 
 #if defined(FS_IOC_SETFLAGS) && defined(FS_IOC_GETFLAGS) && defined(FS_IMMUTABLE_FL)
 
diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh
index 1b668b6fd..6deaa051f 100644
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@@ -204,6 +204,8 @@ public:
 
     unsigned int getProtocol() override;
 
+    std::optional<TrustedFlag> isTrustedClient() override;
+
     void vacuumDB();
 
     void repairPath(const StorePath & path) override;
diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index d24d83117..e128c3a29 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -42,6 +42,40 @@ void write(const Store & store, Sink & out, const StorePath & storePath)
 }
 
 
+std::optional<TrustedFlag> read(const Store & store, Source & from, Phantom<std::optional<TrustedFlag>> _)
+{
+    auto temp = readNum<uint8_t>(from);
+    switch (temp) {
+        case 0:
+            return std::nullopt;
+        case 1:
+            return { Trusted };
+        case 2:
+            return { NotTrusted };
+        default:
+            throw Error("Invalid trusted status from remote");
+    }
+}
+
+void write(const Store & store, Sink & out, const std::optional<TrustedFlag> & optTrusted)
+{
+    if (!optTrusted)
+        out << (uint8_t)0;
+    else {
+        switch (*optTrusted) {
+        case Trusted:
+            out << (uint8_t)1;
+            break;
+        case NotTrusted:
+            out << (uint8_t)2;
+            break;
+        default:
+            assert(false);
+        };
+    }
+}
+
+
 ContentAddress read(const Store & store, Source & from, Phantom<ContentAddress> _)
 {
     return parseContentAddress(readString(from));
@@ -226,6 +260,13 @@ void RemoteStore::initConnection(Connection & conn)
             conn.daemonNixVersion = readString(conn.from);
         }
 
+        if (GET_PROTOCOL_MINOR(conn.daemonVersion) >= 35) {
+            conn.remoteTrustsUs = worker_proto::read(*this, conn.from, Phantom<std::optional<TrustedFlag>> {});
+        } else {
+            // We don't know the answer; protocol to old.
+            conn.remoteTrustsUs = std::nullopt;
+        }
+
         auto ex = conn.processStderr();
         if (ex) std::rethrow_exception(ex);
     }
@@ -1082,6 +1123,11 @@ unsigned int RemoteStore::getProtocol()
     return conn->daemonVersion;
 }
 
+std::optional<TrustedFlag> RemoteStore::isTrustedClient()
+{
+    auto conn(getConnection());
+    return conn->remoteTrustsUs;
+}
 
 void RemoteStore::flushBadConnections()
 {
diff --git a/src/libstore/remote-store.hh b/src/libstore/remote-store.hh
index f5f45f853..f220dbc20 100644
--- a/src/libstore/remote-store.hh
+++ b/src/libstore/remote-store.hh
@@ -144,6 +144,8 @@ public:
 
     unsigned int getProtocol() override;
 
+    std::optional<TrustedFlag> isTrustedClient() override;
+
     void flushBadConnections();
 
     struct Connection
@@ -151,6 +153,7 @@ public:
         FdSink to;
         FdSource from;
         unsigned int daemonVersion;
+        std::optional<TrustedFlag> remoteTrustsUs;
         std::optional<std::string> daemonNixVersion;
         std::chrono::time_point<std::chrono::steady_clock> startTime;
 
diff --git a/src/libstore/s3-binary-cache-store.cc b/src/libstore/s3-binary-cache-store.cc
index ac82147ee..d2fc6abaf 100644
--- a/src/libstore/s3-binary-cache-store.cc
+++ b/src/libstore/s3-binary-cache-store.cc
@@ -509,6 +509,16 @@ struct S3BinaryCacheStoreImpl : virtual S3BinaryCacheStoreConfig, public virtual
         return paths;
     }
 
+    /**
+     * For now, we conservatively say we don't know.
+     *
+     * \todo try to expose our S3 authentication status.
+     */
+    std::optional<TrustedFlag> isTrustedClient() override
+    {
+        return std::nullopt;
+    }
+
     static std::set<std::string> uriSchemes() { return {"s3"}; }
 
 };
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 4d1047380..9c6e80486 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -89,6 +89,7 @@ const uint32_t exportMagic = 0x4558494e;
 
 
 enum BuildMode { bmNormal, bmRepair, bmCheck };
+enum TrustedFlag : bool { NotTrusted = false, Trusted = true };
 
 struct BuildResult;
 
@@ -815,6 +816,17 @@ public:
         return 0;
     };
 
+    /**
+     * @return/ whether store trusts *us*.
+     *
+     * `std::nullopt` means we do not know.
+     *
+     * @note This is the opposite of the StoreConfig::isTrusted
+     * store setting. That is about whether *we* trust the store.
+     */
+    virtual std::optional<TrustedFlag> isTrustedClient() = 0;
+
+
     virtual Path toRealPath(const Path & storePath)
     {
         return storePath;
diff --git a/src/libstore/worker-protocol.hh b/src/libstore/worker-protocol.hh
index 697dd2b8c..c7a6f8688 100644
--- a/src/libstore/worker-protocol.hh
+++ b/src/libstore/worker-protocol.hh
@@ -10,7 +10,7 @@ namespace nix {
 #define WORKER_MAGIC_1 0x6e697863
 #define WORKER_MAGIC_2 0x6478696f
 
-#define PROTOCOL_VERSION (1 << 8 | 34)
+#define PROTOCOL_VERSION (1 << 8 | 35)
 #define GET_PROTOCOL_MAJOR(x) ((x) & 0xff00)
 #define GET_PROTOCOL_MINOR(x) ((x) & 0x00ff)
 
@@ -103,6 +103,7 @@ MAKE_WORKER_PROTO(, DerivedPath);
 MAKE_WORKER_PROTO(, Realisation);
 MAKE_WORKER_PROTO(, DrvOutput);
 MAKE_WORKER_PROTO(, BuildResult);
+MAKE_WORKER_PROTO(, std::optional<TrustedFlag>);
 
 MAKE_WORKER_PROTO(template<typename T>, std::vector<T>);
 MAKE_WORKER_PROTO(template<typename T>, std::set<T>);