Add plugin signature verification policies

1 files changed, 93 insertions, 0 deletions

diff --git a/lib/pluginloader/pluginloader.cpp b/lib/pluginloader/pluginloader.cpp
new file mode 100644
index 0000000..f47c39e
--- /dev/null
+++ b/lib/pluginloader/pluginloader.cpp
@@ -0,0 +1,93 @@
+/*
+ * This file is part of smolbote. It's copyrighted by the contributors recorded
+ * in the version control history of the file, available from its original
+ * location: https://neueland.iserlohn-fortress.net/gitea/aqua/smolbote
+ *
+ * SPDX-License-Identifier: GPL-3.0
+ */
+
+#include "pluginloader.h"
+#include <QFile>
+#include <openssl/evp.h>
+#include <openssl/pem.h>
+#include "publicKey.h"
+
+PluginLoader::PluginLoader(const QString &fileName, const VerifyState sigLevel, QObject *parent)
+    : QPluginLoader(fileName, parent)
+    , requiredSignatureLevel(sigLevel)
+{
+}
+
+PluginLoader::VerifyState PluginLoader::verify(const char *hashName) const
+{
+    const QString sigName = this->fileName() + ".sig";
+    if(!QFile::exists(sigName)) {
+        return SignatureMissing;
+    }
+
+    auto *bio = BIO_new_mem_buf(publicKey_pem, publicKey_pem_len);
+    Q_CHECK_PTR(bio);
+
+    auto *key = PEM_read_bio_PUBKEY(bio, NULL, NULL, NULL);
+    Q_CHECK_PTR(key);
+
+    auto *ctx = EVP_MD_CTX_new();
+    Q_CHECK_PTR(ctx);
+
+    const auto *md = EVP_get_digestbyname(hashName);
+    Q_CHECK_PTR(md);
+
+    int rc = EVP_DigestVerifyInit(ctx, NULL, md, NULL, key);
+    if(rc != 1) {
+        return SignatureMismatched;
+    }
+
+    // read plugin into DigestVerifyUpdate
+    QFile plugin(this->fileName());
+    plugin.open(QIODevice::ReadOnly);
+    int len = plugin.size();
+    int read = 0;
+    auto *buf = new unsigned char[1024];
+    while(len > 0) {
+        read = plugin.read((char*) buf, 1024);
+        len -= read;
+
+        rc = EVP_DigestVerifyUpdate(ctx, buf, read);
+        if(rc != 1)
+            return SignatureComputeFailed;
+    }
+    delete buf;
+    plugin.close();
+
+    // read signature into DigestVerifyFinal
+    QFile sigFile(sigName);
+    sigFile.open(QIODevice::ReadOnly);
+    const int sig_len = sigFile.size();
+    const auto* sig = [&sigFile, sig_len]() {
+        auto* buf = new unsigned char[sig_len];
+        sigFile.read((char*) buf, sig_len);
+        return buf;
+    }();
+    sigFile.close();
+
+    rc = EVP_DigestVerifyFinal(ctx, sig, sig_len);
+    delete sig;
+
+    if(rc == 1)
+        return SignatureMatched;
+    else {
+        return SignatureMismatched;
+    }
+}
+/*
+bool PluginLoader::load()
+{
+    if(signature == SignatureUnverified)
+        signature = this->verify();
+
+    if(signature > requiredSignatureLevel)
+        return QPluginLoader::load();
+    else
+        return false;
+}
+*/