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authorJohn Fastabend <john.fastabend@gmail.com>2020-01-11 06:12:06 +0000
committerDaniel Borkmann <daniel@iogearbox.net>2020-01-15 23:26:13 +0100
commit7361d44896ff20d48bdd502d1a0cd66308055d45 (patch)
treebf73100781a6b1416cb714f3d72321f247bf44ea /net
parent9aaaa56845a06aeabdd597cbe19492dc01f281ec (diff)
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: 7246d8ed4dcce ("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
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_bpf.c5
-rw-r--r--net/tls/tls_sw.c5
2 files changed, 2 insertions, 8 deletions
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index e6b08b5a0895..8a01428f80c1 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -315,10 +315,7 @@ more_data:
*/
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 &&
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 21c7725d17ca..159d49dab403 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -809,10 +809,7 @@ more_data:
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) {

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