diff --git a/ext/sodium/libsodium.c b/ext/sodium/libsodium.c
index 96e3f7489b9..b61c21dad2c 100644
--- a/ext/sodium/libsodium.c
+++ b/ext/sodium/libsodium.c
@@ -2989,9 +2989,6 @@ PHP_FUNCTION(sodium_crypto_kdf_derive_from_key)
 	if (key_len != crypto_kdf_KEYBYTES) {
 		zend_throw_exception(sodium_exception_ce, "key should be sodium_crypto_kdf_KEYBYTES bytes", 0);
 	}
-	if (key_len != crypto_kdf_KEYBYTES) {
-		zend_throw_exception(sodium_exception_ce, "context should be sodium_crypto_kdf_KEYBYTES bytes", 0);
-	}
 	memcpy(ctx_padded, ctx, crypto_kdf_CONTEXTBYTES);
 	memset(ctx_padded + crypto_kdf_CONTEXTBYTES, 0, sizeof ctx_padded - crypto_kdf_CONTEXTBYTES);
 	salt[0] = (unsigned char) (((uint64_t) subkey_id)	  );
diff --git a/ext/standard/dl.c b/ext/standard/dl.c
index 1739648ffa5..f7407927a97 100644
--- a/ext/standard/dl.c
+++ b/ext/standard/dl.c
@@ -135,8 +135,7 @@ PHPAPI int php_load_extension(char *filename, int type, int start_now)
 		}
 		libpath = estrdup(filename);
 	} else if (extension_dir && extension_dir[0]) {
-		int extension_dir_len = (int)strlen(extension_dir);
-		slash_suffix = IS_SLASH(extension_dir[extension_dir_len-1]);
+		slash_suffix = IS_SLASH(extension_dir[strlen(extension_dir)-1]);
 		/* Try as filename first */
 		if (slash_suffix) {
 			spprintf(&libpath, 0, "%s%s", extension_dir, filename); /* SAFE */
diff --git a/main/php_ini.c b/main/php_ini.c
index 4e013c8acab..7b0375027d8 100644
--- a/main/php_ini.c
+++ b/main/php_ini.c
@@ -353,7 +353,7 @@ static void php_load_php_extension_cb(void *arg)
 static void php_load_zend_extension_cb(void *arg)
 {
 	char *filename = *((char **) arg);
-	const int length = (int)strlen(filename);
+	const size_t length = strlen(filename);
 
 #ifndef PHP_WIN32
 	(void) length;
@@ -365,9 +365,13 @@ static void php_load_zend_extension_cb(void *arg)
 		DL_HANDLE handle;
 		char *libpath;
 		char *extension_dir = INI_STR("extension_dir");
-		int extension_dir_len = (int)strlen(extension_dir);
-		int slash_suffix = IS_SLASH(extension_dir[extension_dir_len-1]);
+		int slash_suffix = 0;
 		char *err1, *err2;
+
+		if (extension_dir && extension_dir[0]) {
+			slash_suffix = IS_SLASH(extension_dir[strlen(extension_dir)-1]);
+		}
+
 		/* Try as filename first */
 		if (slash_suffix) {
 			spprintf(&libpath, 0, "%s%s", extension_dir, filename); /* SAFE */