sock: fix sendmmsg for partial sendmsg

Do not send the next message in sendmmsg for partial sendmsg
invocations.

sendmmsg assumes that it can continue sending the next message
when the return value of the individual sendmsg invocations
is positive. It results in corrupting the data for TCP,
SCTP, and UNIX streams.

For example, sendmmsg([["abcd"], ["efgh"]]) can result in a stream
of "aefgh" if the first sendmsg invocation sends only the first
byte while the second sendmsg goes through.

Datagram sockets either send the entire datagram or fail, so
this patch affects only sockets of type SOCK_STREAM and
SOCK_SEQPACKET.

Fixes: 228e548e6020 ("net: Add sendmmsg socket system call")
Signed-off-by: Soheil Hassas Yeganeh <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: Willem de Bruijn <[email protected]>
Signed-off-by: Neal Cardwell <[email protected]>
Acked-by: Maciej Żenczykowski <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions