From a02f3d9f824ac4d2fc333c5c0cf83ff4317c60f6 Mon Sep 17 00:00:00 2001
From: Denis Kasak <dkasak@termina.org.uk>
Date: Tue, 14 Dec 2021 21:57:34 +0100
Subject: [PATCH] fix: Properly check error conditions for int-returning
 functions.

OpenSSL functions returning an int like `EVP_PKEY_derive_init` return
non-positive (0 or negative) integers on an error condition, so we need
to check for both.

See e.g. https://www.openssl.org/docs/man1.1.1/man3/EVP_PKEY_derive.html
---
 src/crypto.cpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/crypto.cpp b/src/crypto.cpp
index 99f47e9..cb7ac6b 100644
--- a/src/crypto.cpp
+++ b/src/crypto.cpp
@@ -34,13 +34,21 @@ static const std::size_t SHA256_BLOCK_LENGTH = 64;
 static const std::uint8_t HKDF_DEFAULT_SALT[32] = {};
 
 template <typename T>
-static T checked(T val) {
+inline T checked(T val) {
     if (!val) {
         abort();
     }
     return val;
 }
 
+template <>
+inline int checked(int val) {
+    if (val <= 0) {
+        abort();
+    }
+    return val;
+}
+
 } // namespace
 
 void _olm_crypto_curve25519_generate_key(