Re: [PATCH net] udp: fix the len check in udp_lib_getsockopt

On Sun, May 30, 2021 at 9:31 PM David Ahern [off-list ref] wrote:

On 5/29/21 10:47 AM, Xin Long wrote:

quoted

On Fri, May 28, 2021 at 9:57 PM David Ahern [off-list ref] wrote:

quoted

On 5/28/21 7:47 PM, Xin Long wrote:

quoted

The partial byte(or even 0) of the value returned due to passing a wrong
optlen should be considered as an error. "On error, -1 is returned, and
errno is set appropriately.". Success returned in that case only confuses
the user.

It is feasible that some app could use bool or u8 for options that have
0 or 1 values and that code has so far worked. This change would break that.

Got it.
Not sure if it's possible or necessary to also return -EINVAL if optlen == 0

do_tcp_getsockopt for example does not fail on optlen 0; no reason to
make this one fail.

I was about to say do_tcp_getsockopt has the same issue. :-)