gcc/jit/jit-recording.cc: recording::global::write_to_dump: Avoid crashes when writing psuedo-C for globals with string initializers.
Commit Message
If a char * global was initialized with a rvalue from
`gcc_jit_context_new_string_literal` containing a format string,
dumping the context causes libgccjit to SIGSEGV due to an improperly
constructed call to vasprintf. The following code snippet can reproduce
the crash:
int main(int argc, char **argv)
{
gcc_jit_context *ctxt = gcc_jit_context_acquire ();
gcc_jit_lvalue *var = gcc_jit_context_new_global(
ctxt, NULL, GCC_JIT_GLOBAL_EXPORTED,
gcc_jit_context_get_type(ctxt, GCC_JIT_TYPE_CONST_CHAR_PTR),
"var");
gcc_jit_global_set_initializer_rvalue(
var, gcc_jit_context_new_string_literal(ctxt, "%s"));
gcc_jit_context_dump_to_file (ctxt, "output", 0);
return 0;
}
The offending line is jit-recording.cc:4922, where a call to d.write
passes the initializer rvalue's debug string to `write` without a
format specifier. The attached patch fixes this issue.
Thanks,
Vibhav
Comments
On Fri, 2022-11-25 at 02:13 +0530, Vibhav Pant via Jit wrote:
> If a char * global was initialized with a rvalue from
> `gcc_jit_context_new_string_literal` containing a format string,
> dumping the context causes libgccjit to SIGSEGV due to an improperly
> constructed call to vasprintf. The following code snippet can
> reproduce
> the crash:
>
> int main(int argc, char **argv)
> {
> gcc_jit_context *ctxt = gcc_jit_context_acquire ();
> gcc_jit_lvalue *var = gcc_jit_context_new_global(
> ctxt, NULL, GCC_JIT_GLOBAL_EXPORTED,
> gcc_jit_context_get_type(ctxt, GCC_JIT_TYPE_CONST_CHAR_PTR),
> "var");
> gcc_jit_global_set_initializer_rvalue(
> var, gcc_jit_context_new_string_literal(ctxt, "%s"));
> gcc_jit_context_dump_to_file (ctxt, "output", 0);
> return 0;
> }
>
> The offending line is jit-recording.cc:4922, where a call to d.write
> passes the initializer rvalue's debug string to `write` without a
> format specifier. The attached patch fixes this issue.
Thanks for spotting this, and sorry about missing your patch.
I've gone ahead and pushed this to trunk (as r14-4923-gac66744d94226a),
and will backport it.
Dave
From e598a4076b2bff72b4a3cc29d1d70db8c53baf45 Mon Sep 17 00:00:00 2001
From: Vibhav Pant <vibhavp@gmail.com>
Date: Fri, 25 Nov 2022 02:02:09 +0530
Subject: [PATCH] jit-recording.cc: Dump string literal initializers correctly
---
gcc/jit/jit-recording.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
@@ -4919,7 +4919,7 @@ recording::global::write_to_dump (dump &d)
else if (m_rvalue_init)
{
d.write (" = ");
- d.write (m_rvalue_init->get_debug_string ());
+ d.write ("%s", m_rvalue_init->get_debug_string ());
d.write (";\n");
}
--
2.38.1