[PATCH net v2 2/4] llc: Improve setsockopt() handling of malformed user input

[Michal Luczaj]

On 11/16/24 01:59, David Wei wrote:
> On 2024-11-15 05:21, Michal Luczaj wrote:
>> copy_from_sockptr()'s non-zero result represents the number of bytes that
>> could not be copied. Turn that into EFAULT.
>>
>> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
>> Signed-off-by: Michal Luczaj <mhal at rbox.co>
>> ---
>>  net/llc/af_llc.c | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
>> index 4eb52add7103b0f83d6fe7318abf1d1af533d254..711c8a7a423f1cf1b03e684a6e23c8eefbab830f 100644
>> --- a/net/llc/af_llc.c
>> +++ b/net/llc/af_llc.c
>> @@ -1096,12 +1096,12 @@ static int llc_ui_setsockopt(struct socket *sock, int level, int optname,
>>  	int rc = -EINVAL;
>>  
>>  	lock_sock(sk);
>> -	if (unlikely(level != SOL_LLC || optlen != sizeof(int)))
>> +	if (unlikely(level != SOL_LLC || optlen != sizeof(opt)))
>>  		goto out;
>> -	rc = copy_from_sockptr(&opt, optval, sizeof(opt));
>> -	if (rc)
>> +	if (copy_from_sockptr(&opt, optval, sizeof(opt))) {
>> +		rc = -EFAULT;
>>  		goto out;
>> -	rc = -EINVAL;
>> +	}
>>  	switch (optname) {
>>  	case LLC_OPT_RETRY:
>>  		if (opt > LLC_OPT_MAX_RETRY)
>>
> 
> Can copy_from_sockptr() be deprecated here in favour of
> copy_safe_from_sockptr()?

Yeah, good point. I'll wait a bit and send v3.

Thanks!