File 0576-Fix-memory-leak-in-dyn_erl.c-realpath-code-path.patch of Package erlang

From 72308bcd93fd86ba9443464d865529861a127b7e Mon Sep 17 00:00:00 2001
From: matt <matt@steponnopets.net>
Date: Sat, 6 Dec 2025 23:14:28 +0000
Subject: [PATCH] Fix memory leak in dyn_erl.c --realpath code path

The find_prog() function returns a strdup()'d string that must be freed
by the caller. In the --realpath code path (line 365-373), the function
returns early without freeing this allocated memory, causing ASAN to
report a 57-byte leak during Erlang builds with AddressSanitizer enabled.

This leak prevents building Erlang/OTP with ASAN leak detection enabled,
which is valuable for fuzzing and security research of Erlang applications
with native C code.

In the normal execution path, this memory is correctly freed at line 403
with efree(abspath). This fix adds the same cleanup to the --realpath
early return path.

Tested by building OTP 26.2.5.12 with CFLAGS="-fsanitize=address" and
ASAN_OPTIONS="detect_leaks=1", which previously failed at this leak and
now completes successfully.
---
 erts/etc/unix/dyn_erl.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/erts/etc/unix/dyn_erl.c b/erts/etc/unix/dyn_erl.c
index 28f56d645d..09b063ebdc 100644
--- a/erts/etc/unix/dyn_erl.c
+++ b/erts/etc/unix/dyn_erl.c
@@ -369,6 +369,7 @@ main(int argc, char **argv)
             ;
         *p = '\0';
         printf("%s", abspath);
+        efree(abspath);
         return 0;
     }
     /* Determine progname */
-- 
2.51.0