[mono][aot] Avoid use of local buffer that could overflow

[BrzVlad]

Fixes https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2530461

[Copilot]

Pull Request Overview

This PR eliminates a potential buffer overflow vulnerability in the Mono AOT compiler by removing the use of a local buffer for symbol name handling. The change replaces sprintf operations that could exceed buffer bounds with direct usage of existing symbol strings.

Key Changes:

• Removes local symbol buffer that was vulnerable to overflow
• Eliminates unnecessary sprintf calls for symbol name copying
• Uses acfg->got_symbol directly instead of copying to local buffer

[BrzVlad]

@simonrozsival Looked over other uses of MAX_SYMBOL_SIZE throughout aot-compiler.c but couldn't find any other location that could potentially overflow. Thus decided against bumping the max symbol size.

[vitek-karas]

Looks good.

I don't understand why the code copied the strings before - makes no sense...

[BrzVlad]

Looks good.

I don't understand why the code copied the strings before - makes no sense...

Long time ago AOT code had a pattern of always using strdup_printf for creating symbol names. I believe this was so that all pointers to strings were free-able. Code was refactored around, optimization was added in order to use local buffers instead, and this redundancy was leftover.