From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doron Roberts-Kedes Subject: [PATCH net] strparser: Fix incorrect strp->need_bytes value. Date: Wed, 11 Apr 2018 15:05:16 -0700 Message-ID: <20180411220516.3062277-1-doronrk@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , Doron Roberts-Kedes To: Return-path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:56720 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751960AbeDKWFj (ORCPT ); Wed, 11 Apr 2018 18:05:39 -0400 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w3BM5Tlf001862 for ; Wed, 11 Apr 2018 15:05:39 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2h9su5r8gm-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Wed, 11 Apr 2018 15:05:39 -0700 Sender: netdev-owner@vger.kernel.org List-ID: strp_data_ready resets strp->need_bytes to 0 if strp_peek_len indicates that the remainder of the message has been received. However, do_strp_work does not reset strp->need_bytes to 0. If do_strp_work completes a partial message, the value of strp->need_bytes will continue to reflect the needed bytes of the previous message, causing future invocations of strp_data_ready to return early if strp->need_bytes is less than strp_peek_len. Resetting strp->need_bytes to 0 in __strp_recv on handing a full message to the upper layer solves this problem. __strp_recv also calculates strp->need_bytes using stm->accum_len before stm->accum_len has been incremented by cand_len. This can cause strp->need_bytes to be equal to the full length of the message instead of the full length minus the accumulated length. This, in turn, causes strp_data_ready to return early, even when there is sufficient data to complete the partial message. Incrementing stm->accum_len before using it to calculate strp->need_bytes solves this problem. Found while testing net/tls_sw recv path. Fixes: 43a0c6751a322847 ("strparser: Stream parser for messages") Signed-off-by: Doron Roberts-Kedes --- net/strparser/strparser.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c index b9283ce..805b139 100644 --- a/net/strparser/strparser.c +++ b/net/strparser/strparser.c @@ -296,9 +296,9 @@ static int __strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb, strp_start_timer(strp, timeo); } + stm->accum_len += cand_len; strp->need_bytes = stm->strp.full_len - stm->accum_len; - stm->accum_len += cand_len; stm->early_eaten = cand_len; STRP_STATS_ADD(strp->stats.bytes, cand_len); desc->count = 0; /* Stop reading socket */ @@ -321,6 +321,7 @@ static int __strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb, /* Hurray, we have a new message! */ cancel_delayed_work(&strp->msg_timer_work); strp->skb_head = NULL; + strp->need_bytes = 0; STRP_STATS_INCR(strp->stats.msgs); /* Give skb to upper layer */ @@ -410,9 +411,7 @@ void strp_data_ready(struct strparser *strp) return; if (strp->need_bytes) { - if (strp_peek_len(strp) >= strp->need_bytes) - strp->need_bytes = 0; - else + if (strp_peek_len(strp) < strp->need_bytes) return; } -- 2.9.5