Re: [PATCH, binutils/ARM] Fix leak of local internal symbols in elf32_arm_size_stubs

[Nick Clifton <nickc at redhat dot com>]

Hi Thomas,

> In elf32_arm_size_stubs, when encountering a relocation against a local symbol for the first time in a given input section, bfd_elf_get_elf_syms is called if symtab_hdr->contents is NULL. However, the allocation performed by this function is never freed, hence a potential leak if such a situation occurs. This patch adds a free before exiting the scope in which local_syms is valid.

Hmm, something seems slightly wrong here...

>   		      if (elf_section_data (section)->relocs == NULL)
>   			free (internal_relocs);
> +		      if (!symtab_hdr->contents)
> +			free (local_syms);
>   		      goto error_ret_free_local;

Why doesn't the code at the error_ret_free_local label actually free the 
local symbols as the name implies ?  [Answer: because the label is 
outside of the scope of local_syms.  But why ?  If the label were inside 
the scope it could free the memory and then return, making the patch 
above unnecessary].

Also - why do you need to check symtab_hdr->contents ?  Wouldn't it make 
more sense to check "local_syms != NULL" ?


> +	  if (!symtab_hdr->contents)
> +	    {
> +	      free (local_syms);
> +	      local_syms = NULL;
> +	    }

Again it would appear to make more sense to check local_syms than 
symtab_hdr->contents.

Cheers
  Nick