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Added signer module. #4

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452d6fd
Added signer module. Still its faster calling gpg2 directly
racerxdl Jan 18, 2018
a183a6a
Fix missing uninstd include and readme
racerxdl Jan 22, 2018
8eefdf3
Avoid buffer overflow in password callback
racerxdl Feb 9, 2018
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3 changes: 2 additions & 1 deletion .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -2,4 +2,5 @@ build/
node_modules/
npm-debug.log*
.DS_Store
*~
*~
yarn-error.log
2 changes: 2 additions & 0 deletions README.md
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Expand Up @@ -38,13 +38,15 @@ So far, you can only add a key (public or secret) and list those keys. Simple.

1. Adding a key

```js
var s = "-----BEGIN PGP PUBLIC KEY BLOCK ..."
var fingerprint = gpgme.importKey(s)
if (fingerprint === false) {
console.log("Couldn't import key.")
} else {
console.log("Key fingerprint :" + fingerprint);
}
```

2. Listing keys
```js
Expand Down
147 changes: 137 additions & 10 deletions src/context.cc
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Original file line number Diff line number Diff line change
@@ -1,10 +1,41 @@
#include <locale.h> /* locale support */
#include "context.h"
#include <iostream>
#include <unistd.h>
using namespace v8;

Nan::Persistent<Function> ContextWrapper::constructor;

static gpgme_error_t passphrase_cb (void *opaque, const char *uid_hint, const char *passphrase_info, int last_was_bad, int fd) {
int res;
char pass[255];
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@kiddouk kiddouk Feb 9, 2018

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I fear a nice buffer overflow here.

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@racerxdl racerxdl Feb 9, 2018

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Hmm makes sense, its copying from opaque but not checking the length. I will fix it.

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@racerxdl racerxdl Feb 9, 2018

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Fixed!


int inputLen = strlen((const char*) opaque);

if (inputLen >= 255) {
// Avoid Buffer Overflow
inputLen = 254;
}

memcpy(pass, (const char *)opaque, inputLen);
int passlen = strlen (pass);
pass[passlen] = '\n';
pass[passlen+1] = 0;
passlen += 1;
int off = 0;

do {
res = write (fd, &pass[off], passlen - off);
if (res > 0)
off += res;
}
while (res > 0 && off != passlen);

return off == passlen ? 0 : gpgme_error_from_errno (errno);

return 0;
}

ContextWrapper::ContextWrapper(Local<Object> conf) : _context(NULL) {

/* Fetch the configuration options or use defaults */
Expand Down Expand Up @@ -76,6 +107,7 @@ ContextWrapper::ContextWrapper(Local<Object> conf) : _context(NULL) {
return;
}
gpgme_set_armor(_context, armored);
gpgme_set_pinentry_mode(_context, GPGME_PINENTRY_MODE_LOOPBACK);
}

ContextWrapper::~ContextWrapper() {
Expand All @@ -93,7 +125,8 @@ NAN_MODULE_INIT(ContextWrapper::Init) {
SetPrototypeMethod(tpl, "toString", toString);
SetPrototypeMethod(tpl, "importKey", importKey);
SetPrototypeMethod(tpl, "listKeys", listKeys);
SetPrototypeMethod(tpl, "cipher", cipher);
SetPrototypeMethod(tpl, "cipher", cipher);
SetPrototypeMethod(tpl, "sign", sign);

constructor.Reset(tpl->GetFunction());
Nan::Set(target, Nan::New("GpgMeContext").ToLocalChecked(), tpl->GetFunction());
Expand All @@ -105,13 +138,13 @@ NAN_METHOD(ContextWrapper::New) {
Local<v8::Object> configuration;
// Invoked as constructor: `new MyObject(...)`
if (info.Length() >= 1 && info[0]->IsObject()) {
configuration = Nan::To<v8::Object>(info[0]).ToLocalChecked();
configuration = Nan::To<v8::Object>(info[0]).ToLocalChecked();
} else {
configuration = Nan::New<Object>();
}

ContextWrapper *contextWrapper = new ContextWrapper(configuration);

contextWrapper->Wrap(info.This());
info.GetReturnValue().Set(info.This());
} else {
Expand Down Expand Up @@ -174,6 +207,32 @@ NAN_METHOD(ContextWrapper::cipher) {
}


NAN_METHOD(ContextWrapper::sign) {
ContextWrapper* context = ObjectWrap::Unwrap<ContextWrapper>(info.This());
//arg0 should be the finger print of the key to use
//arg1 should be the payload to sign
//arg2 should be the password for the key

if (info.Length() != 3) Nan::ThrowError("Missing argument (fingerprint, message, password)");
if (!info[0]->IsString()) Nan::ThrowError("fingerprint should be a string");
if (!info[1]->IsString()) Nan::ThrowError("message should be a string");
if (!info[2]->IsString()) Nan::ThrowError("password should be a string");

Local<String> fingerprint = Nan::To<String>(info[0]).ToLocalChecked();
Local<String> message = Nan::To<String>(info[1]).ToLocalChecked();
Local<String> password = Nan::To<String>(info[2]).ToLocalChecked();

char *data = context->signPayload(fingerprint, message, password);
if (data == NULL) {
info.GetReturnValue().Set(false);
return;
}

info.GetReturnValue().Set(Nan::New<v8::String>(data).ToLocalChecked());
gpgme_free(data);
}



NAN_METHOD(ContextWrapper::listKeys) {
ContextWrapper* context = ObjectWrap::Unwrap<ContextWrapper>(info.This());
Expand All @@ -185,7 +244,7 @@ NAN_METHOD(ContextWrapper::listKeys) {
Nan::ThrowError("Internal error when retrieving the keys");
return;
}

Local<Array> v8Keys= Nan::New<Array>();
std::list<gpgme_key_t>::const_iterator iterator;
int i;
Expand Down Expand Up @@ -216,11 +275,11 @@ NAN_METHOD(ContextWrapper::listKeys) {
v8Keys->Set(i, v8Key);

v8Key->Set(Nan::New("secret").ToLocalChecked(), (*iterator)->secret ? Nan::True() : Nan::False());

v8Keys->Set(i, v8Key);
gpgme_key_unref((*iterator));
}

info.GetReturnValue().Set(v8Keys);
}

Expand All @@ -235,7 +294,7 @@ char* ContextWrapper::getVersion() {
}


bool ContextWrapper::addKey(char *key, int length, std::string& fingerprint) {
bool ContextWrapper::addKey(char *key, int length, std::string& fingerprint) {
gpgme_data_t gpgme_key_data;
gpgme_error_t err;

Expand Down Expand Up @@ -267,7 +326,7 @@ bool ContextWrapper::getKeys(std::list<gpgme_key_t> *keys) {
do {
err = gpgme_op_keylist_next(_context, &key);
if (err) break;
keys->insert(keys->end(), key);
keys->insert(keys->end(), key);
} while (err == GPG_ERR_NO_ERROR);
if (gpg_err_code (err) != GPG_ERR_EOF) {
std::cout << "FAIL\n";
Expand All @@ -277,6 +336,73 @@ bool ContextWrapper::getKeys(std::list<gpgme_key_t> *keys) {
return true;
}

char *ContextWrapper::signPayload(v8::Local<v8::String> fpr, v8::Local<v8::String> msg, v8::Local<v8::String> passphrase) {
gpgme_error_t err;
gpgme_key_t recp = NULL;
char *fingerprint = StringToCharPointer(fpr);
char *message = StringToCharPointer(msg);
char *pass = StringToCharPointer(passphrase);

gpgme_set_passphrase_cb (_context, passphrase_cb, pass);

err = gpgme_get_key(_context, fingerprint, &recp, 1);
if(err != GPG_ERR_NO_ERROR) {
free(fingerprint);
free(message);
free(pass);
Nan::ThrowError("Error loading private key.");
return NULL;
}

gpgme_signers_clear(_context);
err = gpgme_signers_add (_context, recp);
gpgme_key_unref (recp);
if(err != GPG_ERR_NO_ERROR) {
Nan::ThrowError("Error adding key to signer list");
free(fingerprint);
free(message);
free(pass);
return NULL;
}

gpgme_data_t message_data;
err = gpgme_data_new_from_mem(&message_data, message, msg->Length(), 0);
if(err != GPG_ERR_NO_ERROR) {
Nan::ThrowError("Error allocating buffer for message");
free(fingerprint);
free(message);
free(pass);
return NULL;
}

gpgme_data_t signer;
gpgme_data_new(&signer);
err = gpgme_op_sign(_context, message_data, signer, GPGME_SIG_MODE_NORMAL);
free(fingerprint);
free(message);
free(pass);

if (err != GPG_ERR_NO_ERROR) {
Nan::ThrowError("Error signing message. If GPG2 check if allow-pinentry-loopback is enabled in agent or use gpg-preset-passphrase");
gpgme_data_release(signer);
return NULL;
}

gpgme_sign_result_t res = gpgme_op_sign_result(_context);
if (!res->signatures) {
gpgme_data_release(signer);
return NULL;
};

size_t nread;
char *data = gpgme_data_release_and_get_mem(signer, &nread);
char *encrypted_message = (char *) malloc((nread + 1) * sizeof(char));
memset(encrypted_message, 0, nread);
memcpy(encrypted_message, data, nread);
gpgme_free(data);
return encrypted_message;
}

char *ContextWrapper::cipherPayload(Local<String> fpr, Local<String> msg) {

gpgme_error_t err;
Expand All @@ -296,15 +422,16 @@ char *ContextWrapper::cipherPayload(Local<String> fpr, Local<String> msg) {
if(err != GPG_ERR_NO_ERROR) {
free(fingerprint);
free(message);
return NULL;
return NULL;
}

gpgme_data_t cipher;
gpgme_data_new(&cipher);
err = gpgme_op_encrypt(_context, recp, GPGME_ENCRYPT_ALWAYS_TRUST, message_data, cipher);
gpgme_key_unref (recp[0]);
free(fingerprint);
free(message);

if (err != GPG_ERR_NO_ERROR) {
gpgme_data_release(cipher);
return NULL;
Expand Down
6 changes: 4 additions & 2 deletions src/context.h
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Expand Up @@ -23,14 +23,16 @@ class ContextWrapper : public ObjectWrap {
bool addKey(char *key, int length, std::string& fingerprint);
bool getKeys(std::list<gpgme_key_t> *keys);
char *cipherPayload(v8::Local<v8::String> fpr, v8::Local<v8::String> msg);
char *signPayload(v8::Local<v8::String> fpr, v8::Local<v8::String> msg, v8::Local<v8::String> passphrase);
char *StringToCharPointer(v8::Local<v8::String> str);

static NAN_METHOD(New);
static NAN_METHOD(toString);
static NAN_METHOD(toString);
static NAN_METHOD(importKey);
static NAN_METHOD(listKeys);
static NAN_METHOD(cipher);

static NAN_METHOD(sign);

public:
static Persistent<v8::Function> constructor;

Expand Down
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