From 71daae12271b4a668768aa7ff8ecfc529a0c0c0b Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 7 Dec 2017 09:34:11 +0400
Subject: [PATCH] Fix crash in RSA public key wrapper.

---
 Telegram/SourceFiles/base/openssl_help.h        |  3 +++
 Telegram/SourceFiles/mtproto/rsa_public_key.cpp | 14 ++++++++------
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/Telegram/SourceFiles/base/openssl_help.h b/Telegram/SourceFiles/base/openssl_help.h
index b5678d5c7..847021f2d 100644
--- a/Telegram/SourceFiles/base/openssl_help.h
+++ b/Telegram/SourceFiles/base/openssl_help.h
@@ -180,6 +180,9 @@ public:
 	const BIGNUM *raw() const {
 		return _data;
 	}
+	BIGNUM *takeRaw() {
+		return base::take(_data);
+	}
 
 	bool failed() const {
 		return _failed;
diff --git a/Telegram/SourceFiles/mtproto/rsa_public_key.cpp b/Telegram/SourceFiles/mtproto/rsa_public_key.cpp
index 5923b9405..d2d689ede 100644
--- a/Telegram/SourceFiles/mtproto/rsa_public_key.cpp
+++ b/Telegram/SourceFiles/mtproto/rsa_public_key.cpp
@@ -35,7 +35,7 @@ namespace {
 // This is a key setter for compatibility with OpenSSL 1.0
 int RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d) {
 	if ((r->n == nullptr && n == nullptr) || (r->e == nullptr && e == nullptr)) {
-		return false;
+		return 0;
 	}
 	if (n != nullptr) {
 		BN_free(r->n);
@@ -49,7 +49,7 @@ int RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d) {
 		BN_free(r->d);
 		r->d = d;
 	}
-	return true;
+	return 1;
 }
 
 // This is a key getter for compatibility with OpenSSL 1.0
@@ -79,10 +79,12 @@ public:
 	}
 	Private(base::const_byte_span nBytes, base::const_byte_span eBytes) : _rsa(RSA_new()) {
 		if (_rsa) {
-			BIGNUM *n = openssl::BigNum(nBytes).raw();
-			BIGNUM *e = openssl::BigNum(eBytes).raw();
-			RSA_set0_key(_rsa, n, e, nullptr);
-			if (!n || !e) {
+			auto n = openssl::BigNum(nBytes).takeRaw();
+			auto e = openssl::BigNum(eBytes).takeRaw();
+			auto valid = (n != nullptr) && (e != nullptr);
+			// We still pass both values to RSA_set0_key() so that even
+			// if only one of them is valid RSA would take ownership of it.
+			if (!RSA_set0_key(_rsa, n, e, nullptr) || !valid) {
 				RSA_free(base::take(_rsa));
 			} else {
 				computeFingerprint();