From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,PDS_BTC_ID, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7FA4C432C0 for ; Tue, 3 Dec 2019 23:13:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 825252064B for ; Tue, 3 Dec 2019 23:13:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575414801; bh=XMIyt0Gn6jrtmYRjlka6sozVIKK78PjVdzAOQs2lAA8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=c8mitdKPBt4YE1La/7dV+L+hNr3F/adva9sm159zyFtKhT/xDq02bvjrMlTxz+8Sv 81kQS9fDcNdTSe77hqm3JYefdHennPjwKiY0h0Z6JPN1hWp58YLdwuI0BIFDov/1Ur iXeDE5Z0HXDx9G7dVCpHu0xrjI93D6ZsBv3MCYc8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728001AbfLCWi3 (ORCPT ); Tue, 3 Dec 2019 17:38:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:47438 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727543AbfLCWiZ (ORCPT ); Tue, 3 Dec 2019 17:38:25 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CE82B20803; Tue, 3 Dec 2019 22:38:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575412704; bh=XMIyt0Gn6jrtmYRjlka6sozVIKK78PjVdzAOQs2lAA8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jvVoVViEKgfpTtfH2SIFBigCKk/ar4JsnfcGyW+4GXnCqIGMhOUROYn5PVaALdWW6 nSrodItHRUVf/fAqwyEddfVTXRdw/AXxxtjjNL5+6mpL4BVXXb9j4PYmKWjUO+LAmx 2NYVEkgHiNtl4sln/lH5o+vekj+JaWxwBP549918= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jakub Kicinski , Simon Horman , "David S. Miller" Subject: [PATCH 5.4 31/46] net: skmsg: fix TLS 1.3 crash with full sk_msg Date: Tue, 3 Dec 2019 23:35:51 +0100 Message-Id: <20191203212748.151138279@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191203212705.175425505@linuxfoundation.org> References: <20191203212705.175425505@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jakub Kicinski [ Upstream commit 031097d9e079e40dce401031d1012e83d80eaf01 ] TLS 1.3 started using the entry at the end of the SG array for chaining-in the single byte content type entry. This mostly works: [ E E E E E E . . ] ^ ^ start end E < content type / [ E E E E E E C . ] ^ ^ start end (Where E denotes a populated SG entry; C denotes a chaining entry.) If the array is full, however, the end will point to the start: [ E E E E E E E E ] ^ start end And we end up overwriting the start: E < content type / [ C E E E E E E E ] ^ start end The sg array is supposed to be a circular buffer with start and end markers pointing anywhere. In case where start > end (i.e. the circular buffer has "wrapped") there is an extra entry reserved at the end to chain the two halves together. [ E E E E E E . . l ] (Where l is the reserved entry for "looping" back to front. As suggested by John, let's reserve another entry for chaining SG entries after the main circular buffer. Note that this entry has to be pointed to by the end entry so its position is not fixed. Examples of full messages: [ E E E E E E E E . l ] ^ ^ start end <---------------. [ E E . E E E E E E l ] ^ ^ end start Now the end will always point to an unused entry, so TLS 1.3 can always use it. Fixes: 130b392c6cd6 ("net: tls: Add tls 1.3 support") Signed-off-by: Jakub Kicinski Reviewed-by: Simon Horman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/skmsg.h | 26 +++++++++++++------------- net/core/filter.c | 8 ++++---- net/core/skmsg.c | 2 +- net/ipv4/tcp_bpf.c | 2 +- 4 files changed, 19 insertions(+), 19 deletions(-) --- a/include/linux/skmsg.h +++ b/include/linux/skmsg.h @@ -14,6 +14,7 @@ #include #define MAX_MSG_FRAGS MAX_SKB_FRAGS +#define NR_MSG_FRAG_IDS (MAX_MSG_FRAGS + 1) enum __sk_action { __SK_DROP = 0, @@ -29,11 +30,13 @@ struct sk_msg_sg { u32 size; u32 copybreak; bool copy[MAX_MSG_FRAGS]; - /* The extra element is used for chaining the front and sections when - * the list becomes partitioned (e.g. end < start). The crypto APIs - * require the chaining. + /* The extra two elements: + * 1) used for chaining the front and sections when the list becomes + * partitioned (e.g. end < start). The crypto APIs require the + * chaining; + * 2) to chain tailer SG entries after the message. */ - struct scatterlist data[MAX_MSG_FRAGS + 1]; + struct scatterlist data[MAX_MSG_FRAGS + 2]; }; /* UAPI in filter.c depends on struct sk_msg_sg being first element. */ @@ -141,13 +144,13 @@ static inline void sk_msg_apply_bytes(st static inline u32 sk_msg_iter_dist(u32 start, u32 end) { - return end >= start ? end - start : end + (MAX_MSG_FRAGS - start); + return end >= start ? end - start : end + (NR_MSG_FRAG_IDS - start); } #define sk_msg_iter_var_prev(var) \ do { \ if (var == 0) \ - var = MAX_MSG_FRAGS - 1; \ + var = NR_MSG_FRAG_IDS - 1; \ else \ var--; \ } while (0) @@ -155,7 +158,7 @@ static inline u32 sk_msg_iter_dist(u32 s #define sk_msg_iter_var_next(var) \ do { \ var++; \ - if (var == MAX_MSG_FRAGS) \ + if (var == NR_MSG_FRAG_IDS) \ var = 0; \ } while (0) @@ -172,9 +175,9 @@ static inline void sk_msg_clear_meta(str static inline void sk_msg_init(struct sk_msg *msg) { - BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != MAX_MSG_FRAGS); + BUILD_BUG_ON(ARRAY_SIZE(msg->sg.data) - 1 != NR_MSG_FRAG_IDS); memset(msg, 0, sizeof(*msg)); - sg_init_marker(msg->sg.data, MAX_MSG_FRAGS); + sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS); } static inline void sk_msg_xfer(struct sk_msg *dst, struct sk_msg *src, @@ -195,14 +198,11 @@ static inline void sk_msg_xfer_full(stru static inline bool sk_msg_full(const struct sk_msg *msg) { - return (msg->sg.end == msg->sg.start) && msg->sg.size; + return sk_msg_iter_dist(msg->sg.start, msg->sg.end) == MAX_MSG_FRAGS; } static inline u32 sk_msg_elem_used(const struct sk_msg *msg) { - if (sk_msg_full(msg)) - return MAX_MSG_FRAGS; - return sk_msg_iter_dist(msg->sg.start, msg->sg.end); } --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2299,7 +2299,7 @@ BPF_CALL_4(bpf_msg_pull_data, struct sk_ WARN_ON_ONCE(last_sge == first_sge); shift = last_sge > first_sge ? last_sge - first_sge - 1 : - MAX_SKB_FRAGS - first_sge + last_sge - 1; + NR_MSG_FRAG_IDS - first_sge + last_sge - 1; if (!shift) goto out; @@ -2308,8 +2308,8 @@ BPF_CALL_4(bpf_msg_pull_data, struct sk_ do { u32 move_from; - if (i + shift >= MAX_MSG_FRAGS) - move_from = i + shift - MAX_MSG_FRAGS; + if (i + shift >= NR_MSG_FRAG_IDS) + move_from = i + shift - NR_MSG_FRAG_IDS; else move_from = i + shift; if (move_from == msg->sg.end) @@ -2323,7 +2323,7 @@ BPF_CALL_4(bpf_msg_pull_data, struct sk_ } while (1); msg->sg.end = msg->sg.end - shift > msg->sg.end ? - msg->sg.end - shift + MAX_MSG_FRAGS : + msg->sg.end - shift + NR_MSG_FRAG_IDS : msg->sg.end - shift; out: msg->data = sg_virt(&msg->sg.data[first_sge]) + start - offset; --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -421,7 +421,7 @@ static int sk_psock_skb_ingress(struct s copied = skb->len; msg->sg.start = 0; msg->sg.size = copied; - msg->sg.end = num_sge == MAX_MSG_FRAGS ? 0 : num_sge; + msg->sg.end = num_sge; msg->skb = skb; sk_psock_queue_msg(psock, msg); --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -301,7 +301,7 @@ EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir) static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock, struct sk_msg *msg, int *copied, int flags) { - bool cork = false, enospc = msg->sg.start == msg->sg.end; + bool cork = false, enospc = sk_msg_full(msg); struct sock *sk_redir; u32 tosend, delta = 0; int ret;