Re: [PATCH] gdb: fix possible use-after-free when executing commands

[Tom Tromey <tom@tromey.com>]

>>>>> "Jan" == Jan Vrany via Gdb-patches <gdb-patches@sourceware.org> writes:

Jan> This may lead into use-after-free error.  Imagine the command
Jan> being executed is a user-defined Python command that redefines
Jan> itself.  In that case, struct `cmd_list_element` pointed to by
Jan> `c` is deallocated during its execution so it is no longer valid
Jan> when post hook is executed.

Thanks for the patch.

Your analysis makes sense to me.  I wouldn't be surprised if there were
other issues along these lines.  Or if this were in bugzilla somewhere.

Jan> +      std::string c_name(c->name);

Space before the paren.  Also I think a comment here explaining why it's
needed would be good.

Jan>        /* If this command has been post-hooked, run the hook last.  */
Jan> -      execute_cmd_post_hook (c);
Jan> +      c = lookup_cmd_exact (c_name.c_str (), cmdlist);
Jan> +      if (c != nullptr)
Jan> +	execute_cmd_post_hook (c);
 
Perhaps a comment here as well explaining the need to redo the lookup.

This is ok with these minor changes.

thanks,
Tom