Re: [PATCH 1/2] af_bluetooth: Fix recvmsg return value

Hi Denis,

If recvmsg is called with a destination buffer that is too small to
receive the contents of skb in its entirety, the return value from
recvmsg was inconsistent with common SOCK_SEQPACKET or SOCK_DGRAM
semantics.

If destination buffer provided by userspace is too small (e.g. len <
copied), then MSG_TRUNC flag is set and copied is returned.  Instead, it
should return the length of the message, which is consistent with how
other datagram based sockets act.  Quoting 'man recv':

"All  three calls return the length of the message on successful comple‐
tion.  If a message is too long to fit in the supplied  buffer,  excess
bytes  may  be discarded depending on the type of socket the message is
received from."

and

"MSG_TRUNC (since Linux 2.2)

   For   raw   (AF_PACKET),   Internet   datagram   (since    Linux
   2.4.27/2.6.8),  netlink  (since Linux 2.6.22), and UNIX datagram
   (since Linux 3.4) sockets: return the real length of the packet
   or datagram, even when it was longer than the passed buffer."

Signed-off-by: Denis Kenzior <redacted>
---
net/bluetooth/af_bluetooth.c | 5 +++++
1 file changed, 5 insertions(+)

patch has been applied to bluetooth-next tree.

Regards

Marcel