lua: add base64 lib

Export our base64 decoding and encoding functions to Lua.

Ticket: #7074

src/Makefile.am

@@ -510,6 +510,7 @@ noinst_HEADERS = \
 	util-landlock.h \
 	util-logopenfile.h \
 	util-log-redis.h \
+	util-lua-base64lib.h \
 	util-lua-builtins.h \
 	util-lua-common.h \
 	util-lua-dataset.h \
@@ -1066,6 +1067,7 @@ libsuricata_c_a_SOURCES = \
 	util-logopenfile.c \
 	util-log-redis.c \
 	util-lua.c \
+	util-lua-base64lib.c \
 	util-lua-builtins.c \
 	util-lua-common.c \
 	util-lua-dataset.c \

src/util-lua-base64lib.c

@@ -0,0 +1,118 @@
+/* Copyright (C) 2025 Open Information Security Foundation
+ *
+ * You can copy, redistribute or modify this Program under the terms of
+ * the GNU General Public License version 2 as published by the Free
+ * Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include "suricata-common.h"
+#include "util-lua-base64lib.h"
+#include "util-validate.h"
+#include "lauxlib.h"
+#include "rust.h"
+
+static int LuaBase64Encode(lua_State *L, SCBase64Mode mode)
+{
+    size_t input_len;
+    const char *input = luaL_checklstring(L, 1, &input_len);
+    size_t out_len = SCBase64EncodeBufferSize(input_len);
+    char *output = SCCalloc(out_len + 1, sizeof(char));
+    if (output == NULL) {
+        return luaL_error(L, "malloc");
+    }
+    if (SCBase64EncodeWithMode((uint8_t *)input, (unsigned long)input_len, (u_char *)output,
+                (unsigned long *)&out_len, mode) != 0) {
+        SCFree(output);
+        return luaL_error(L, "base64 encoding failed");
+    }
+    lua_pushstring(L, (const char *)output);
+    SCFree(output);
+
+    return 1;
+}
+
+static int LuaBase64EncodeStandard(lua_State *L)
+{
+    return LuaBase64Encode(L, SCBase64ModeStrict);
+}
+
+static int LuaBase64EncodeStandardNoPad(lua_State *L)
+{
+    return LuaBase64Encode(L, SCBase64ModeNoPad);
+}
+
+static int LuaBase64Decode(lua_State *L, SCBase64Mode mode)
+{
+    size_t input_len;
+    const char *input = luaL_checklstring(L, 1, &input_len);
+    char *output = SCCalloc(input_len, sizeof(char));
+    if (output == NULL) {
+        return luaL_error(L, "malloc");
+    }
+    uint32_t n = SCBase64Decode((uint8_t *)input, (uintptr_t)input_len, mode, (uint8_t *)output);
+    if (n == 0) {
+        SCFree(output);
+        return luaL_error(L, "base64 decoding failed");
+    }
+    DEBUG_VALIDATE_BUG_ON(n > input_len);
+    output[n] = '\0';
+    lua_pushstring(L, (const char *)output);
+    SCFree(output);
+
+    return 1;
+}
+
+static int LuaBase64DecodeStandard(lua_State *L)
+{
+    return LuaBase64Decode(L, SCBase64ModeStrict);
+}
+
+static int LuaBase64DecodeStandardNoPad(lua_State *L)
+{
+    return LuaBase64Decode(L, SCBase64ModeNoPad);
+}
+
+static int LuaBase64DecodeStandardPadOpt(lua_State *L)
+{
+    return LuaBase64Decode(L, SCBase64ModePadOpt);
+}
+
+static int LuaBase64DecodeRFC2045(lua_State *L)
+{
+    return LuaBase64Decode(L, SCBase64ModeRFC2045);
+}
+
+static int LuaBase64DecodeRFC4648(lua_State *L)
+{
+    return LuaBase64Decode(L, SCBase64ModeRFC4648);
+}
+
+static const struct luaL_Reg base64lib[] = {
+    // clang-format off
+    { "encode", LuaBase64EncodeStandard },
+    { "encode_nopad", LuaBase64EncodeStandardNoPad },
+    { "decode", LuaBase64DecodeStandard },
+    { "decode_nopad", LuaBase64DecodeStandardNoPad },
+    { "decode_padopt", LuaBase64DecodeStandardPadOpt },
+    { "decode_rfc2045", LuaBase64DecodeRFC2045 },
+    { "decode_rfc4648", LuaBase64DecodeRFC4648 },
+    { NULL, NULL },
+    // clang-format on
+};
+
+int SCLuaLoadBase64Lib(lua_State *L)
+{
+    luaL_newlib(L, base64lib);
+
+    return 1;
+}

src/util-lua-base64lib.h

@@ -0,0 +1,25 @@
+/* Copyright (C) 2025 Open Information Security Foundation
+ *
+ * You can copy, redistribute or modify this Program under the terms of
+ * the GNU General Public License version 2 as published by the Free
+ * Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef SURICATA_LUA_UTIL_BASE64LIB_H
+#define SURICATA_LUA_UTIL_BASE64LIB_H
+
+#include "lua.h"
+
+int SCLuaLoadBase64Lib(lua_State *L);
+
+#endif /* SURICATA_LUA_UTIL_BASE64LIB_H */

src/util-lua-builtins.c

@@ -17,15 +17,17 @@
 
 #include "suricata-common.h"
 #include "util-lua-builtins.h"
-#include "util-lua-hashlib.h"
+#include "util-lua-base64lib.h"
 #include "util-lua-dataset.h"
+#include "util-lua-hashlib.h"
 #include "util-lua-packetlib.h"
 
 #include "lauxlib.h"
 
 static const luaL_Reg builtins[] = {
-    { "suricata.hashlib", SCLuaLoadHashlib },
+    { "suricata.base64", SCLuaLoadBase64Lib },
     { "suricata.dataset", LuaLoadDatasetLib },
+    { "suricata.hashlib", SCLuaLoadHashlib },
     { "suricata.packet", LuaLoadPacketLib },
     { NULL, NULL },
 };