On 12/16/20 6:49 PM, Oliver Hartkopp wrote: > Multiple filters (struct can_filter) can be set with the setsockopt() > function, which was originally intended as a write-only operation. > > As getsockopt() also provides a CAN_RAW_FILTER option to read back the > given filters, the caller has to provide an appropriate user space buffer. > In the case this buffer is too small the getsockopt() silently truncates > the filter information and gives no information about the needed space. > This is safe but not convenient for the programmer. > > In net/core/sock.c the SO_PEERGROUPS sockopt had a similar requirement > and solved it by returning -ERANGE in the case that the provided data > does not fit into the given user space buffer and fills the required size > into optlen, so that the caller can retry with a matching buffer length. > > This patch adopts this approach for CAN_RAW_FILTER getsockopt(). > > Reported-by: Phillip Schichtel <phillip@xxxxxxxxxx> > Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Added to linux-can-next/testing. Do we need an update to the in kernel Documentation? Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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