p71924506
/
linux_old1
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

bpf: Sockmap/tls, fix pop data with SK_DROP return code 

When user returns SK_DROP we need to reset the number of copied bytes
to indicate to the user the bytes were dropped and not sent. If we
don't reset the copied arg sendmsg will return as if those bytes were
copied giving the user a positive return value.

This works as expected today except in the case where the user also
pops bytes. In the pop case the sg.size is reduced but we don't correctly
account for this when copied bytes is reset. The popped bytes are not
accounted for and we return a small positive value potentially confusing
the user.

The reason this happens is due to a typo where we do the wrong comparison
when accounting for pop bytes. In this fix notice the if/else is not
needed and that we have a similar problem if we push data except its not
visible to the user because if delta is larger the sg.size we return a
negative value so it appears as an error regardless.

Fixes: 7246d8ed4d ("bpf: helper to pop data from messages")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/bpf/20200111061206.8028-9-john.fastabend@gmail.com
This commit is contained in:
John Fastabend 2020-01-11 06:12:06 +00:00 committed by Daniel Borkmann
parent 9aaaa56845
commit 7361d44896
2 changed files with 2 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
net/ipv4/tcp_bpf.c
View File

@ -315,10 +315,7 @@ static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
*/
delta = msg->sg.size;
psock->eval = sk_psock_msg_verdict(sk, psock, msg);
if (msg->sg.size < delta)
delta -= msg->sg.size;
else
delta = 0;
delta -= msg->sg.size;
}
if (msg->cork_bytes &&

5
net/tls/tls_sw.c
View File

@ -809,10 +809,7 @@ static int bpf_exec_tx_verdict(struct sk_msg *msg, struct sock *sk,
if (psock->eval == __SK_NONE) {
delta = msg->sg.size;
psock->eval = sk_psock_msg_verdict(sk, psock, msg);
if (delta < msg->sg.size)
delta -= msg->sg.size;
else
delta = 0;
delta -= msg->sg.size;
}
if (msg->cork_bytes && msg->cork_bytes > msg->sg.size &&
!enospc && !full_record) {