Re: [PATCH] elf/tlsdeschtab.h: Add the Malloc return value check in _dl_make_tlsdesc_dynamic()

[Szabolcs Nagy <szabolcs.nagy@arm.com>]

The 11/04/2022 17:30, Xiaoming Ni wrote:
> Check the return value of malloc based on the function header comment of
>  _dl_make_tlsdesc_dynamic(). If the return value fails, NULL is returned.
> 
> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>

note that allocation failure is not recoverable here:
the caller cannot really deal with NULL so tls access
will crash.

i think the patch is good, but it will only help if
the failure is propagated to _dl_relocate_object and
handled in dlopen by returning an error.

let me know if you don't have commit access, then i
can commit it for you.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>

> ---
>  elf/tlsdeschtab.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/elf/tlsdeschtab.h b/elf/tlsdeschtab.h
> index 8c02e45a49..82733159e3 100644
> --- a/elf/tlsdeschtab.h
> +++ b/elf/tlsdeschtab.h
> @@ -110,6 +110,8 @@ _dl_make_tlsdesc_dynamic (struct link_map *map, size_t ti_offset)
>      }
>  
>    *entry = td = malloc (sizeof (struct tlsdesc_dynamic_arg));
> +  if (! td)
> +    return 0;
>    /* This may be higher than the map's generation, but it doesn't
>       matter much.  Worst case, we'll have one extra DTV update per
>       thread.  */
> -- 
> 2.27.0
>