Subject: [PATCH 14/23] net/tls: take into account that bpf_exec_tx_verdict() may free the record

From: Jakub Kicinski <[email-masked]>
Date: Wed, 27 Nov 2019 12:16:39 -0800

[ Upstream commit c329ef9684de9517d82af5b4758c9e1b64a8a11a ]

bpf_exec_tx_verdict() may free the record if tls_push_record()
fails, or if the entire record got consumed by BPF. Re-check
ctx->open_rec before touching the data.

Fixes: d3b18ad31f93 ("tls: add bpf support to sk_msg handling")
Signed-off-by: Jakub Kicinski <[email-masked]>
Reviewed-by: Simon Horman <[email-masked]>
Acked-by: John Fastabend <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/tls/tls_sw.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 41b2bdc05ba3..a337e22cfd30 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -979,7 +979,7 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 					num_async++;
 				else if (ret == -ENOMEM)
 					goto wait_for_memory;
-				else if (ret == -ENOSPC)
+				else if (ctx->open_rec && ret == -ENOSPC)
 					goto rollback_iter;
 				else if (ret != -EAGAIN)
 					goto send_end;
@@ -1048,11 +1048,12 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 		ret = sk_stream_wait_memory(sk, &timeo);
 		if (ret) {
 trim_sgl:
-			tls_trim_both_msgs(sk, orig_size);
+			if (ctx->open_rec)
+				tls_trim_both_msgs(sk, orig_size);
 			goto send_end;
 		}
 
-		if (msg_en->sg.size < required_size)
+		if (ctx->open_rec && msg_en->sg.size < required_size)
 			goto alloc_encrypted;
 	}
 
@@ -1185,11 +1186,13 @@ static int tls_sw_do_sendpage(struct sock *sk, struct page *page,
 wait_for_memory:
 		ret = sk_stream_wait_memory(sk, &timeo);
 		if (ret) {
-			tls_trim_both_msgs(sk, msg_pl->sg.size);
+			if (ctx->open_rec)
+				tls_trim_both_msgs(sk, msg_pl->sg.size);
 			goto sendpage_end;
 		}
 
-		goto alloc_payload;
+		if (ctx->open_rec)
+			goto alloc_payload;
 	}
 
 	if (num_async) {
-- 
2.20.1