From 177a1713f4a5c03d3193785fb68690a5e4e6e241 Mon Sep 17 00:00:00 2001
From: Alexander Turenko <alexander.turenko@tarantool.org>
Date: Sun, 16 Jun 2019 23:27:00 +0300
Subject: [PATCH] lua: escape trigraphs in bundled lua sources
Built-in modules are bundled into tarantool in the following way. A lua
file from src/lua or src/box/lua is stored as a string literal in a C
file, then built and linked into tarantool. During startup tarantool
calls luaL_loadbuffer() on this string.
When a Lua source is converted to a C literal, proper escaping is
performed. However there is one case, which was not covered: trigraphs.
The patch adds escaping of question mark symbols to avoid matching ??X
sequences as trigraphs by C preprocessor.
The most simple way to check that it works is to apply the following
patch:
| diff --git a/src/lua/string.lua b/src/lua/string.lua
| index 6e12c59ae..2da2dbf4d 100644
| --- a/src/lua/string.lua
| +++ b/src/lua/string.lua
| @@ -425,3 +425,6 @@ string.fromhex = string_fromhex
| string.strip = string_strip
| string.lstrip = string_lstrip
| string.rstrip = string_rstrip
| +string.foo = function()
| + return '??('
| +end
And call the function like so:
| ./src/tarantool -e 'print(string.foo()) os.exit()'
If it printfs `??(`, then everything is okay. If it prints `[`, then
`??(` was preprocessed as the trigraph.
We hit this problem when tried to bundle luarocks-3: it contains
"^(.-)(%??)$" regexp, where `??)` was interpreted as `]`. Debug build or
a build with -DENABLE_WERROR reports an error in the case, but usual
RelWithDebInfo build passes (with -Wtrigraphs warnings) and can show
this unexpected behaviour.
Fixes #4291.
---
extra/txt2c.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/extra/txt2c.c b/extra/txt2c.c
index e1bad08254..3f701d6114 100644
--- a/extra/txt2c.c
+++ b/extra/txt2c.c
@@ -70,6 +70,8 @@ int main(int argc, char** argv) {
case '\r': fputs("\\r", out); break;
case '\\': fputs("\\\\", out); break;
case '\"': fputs("\\\"", out); break;
+ /* Don't interpret ??X as a trigraph. */
+ case '?': fputs("\\\?", out); break;
default: fputc(c, out); break;
}
}
--
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