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

[Xiaoming Ni <nixiaoming@huawei.com>]

On 2022/11/4 19:00, Szabolcs Nagy wrote:
> 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.
_dl_make_tlsdesc_dynamic() is called by "void elf_machine_rela()"
Whether to add _dl_error_printf() to elf_machine_rela() when 
_dl_make_tlsdesc_dynamic() returns NULL ?
Or change "void elf_machine_rela()"  to non-void ?

> 
> 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.
> 
I don't have permission to submit, thank you for your review and help.

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

Thanks
Xiaoming Ni


> 
>> ---
>>   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
>>
> .
>