From patchwork Fri Jul 7 09:12:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 700150 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19B15EB64DA for ; Fri, 7 Jul 2023 09:13:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232370AbjGGJNd (ORCPT ); Fri, 7 Jul 2023 05:13:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229910AbjGGJNc (ORCPT ); Fri, 7 Jul 2023 05:13:32 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9D5F21FF3 for ; Fri, 7 Jul 2023 02:12:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1688721164; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=wU3D20g/JxtCROQUSiRgjpayIvu8cn+paX5zco5nOco=; b=bbWmP+qWBgfZp0Aut9eT3/nhgbpVfKdKfQ54k0lTAAF7CM7WjQXD0EUqV70qI9BIXZGBfF a/uujDeqw8y8mXfYOjc1/oEkw0ZaDpkPwFFWr4wbKK1zKWmcX96kNbil7xsoYqVzlJmKZq Fn1uYsVybGWdQmrDJS9akSkYvTvbaUA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-136-aTE9Asg2OD6HYPoA1q_yrQ-1; Fri, 07 Jul 2023 05:12:41 -0400 X-MC-Unique: aTE9Asg2OD6HYPoA1q_yrQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8C79483FC20; Fri, 7 Jul 2023 09:12:40 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.195]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3DAD64067A00; Fri, 7 Jul 2023 09:12:39 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells To: Herbert Xu cc: dhowells@redhat.com, syzbot , Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , linux-crypto@vger.kernel.org, netdev@vger.kernel.org, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] crypto: algif/hash: Fix race between MORE and non-MORE sends MIME-Version: 1.0 Content-ID: <2227987.1688721158.1@warthog.procyon.org.uk> Date: Fri, 07 Jul 2023 10:12:38 +0100 Message-ID: <2227988.1688721158@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org The 'MSG_MORE' state of the previous sendmsg() is fetched without the socket lock held, so two sendmsg calls can race. This can be seen with a large sendfile() as that now does a series of sendmsg() calls, and if a write() comes in on the same socket at an inopportune time, it can flip the state. Fix this by moving the fetch of ctx->more inside the socket lock. Fixes: c662b043cdca ("crypto: af_alg/hash: Support MSG_SPLICE_PAGES") Reported-by: syzbot+689ec3afb1ef07b766b2@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/000000000000554b8205ffdea64e@google.com/ Signed-off-by: David Howells Tested-by: syzbot+689ec3afb1ef07b766b2@syzkaller.appspotmail.com cc: Herbert Xu cc: Paolo Abeni cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: linux-crypto@vger.kernel.org cc: netdev@vger.kernel.org --- crypto/algif_hash.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c index 0ab43e149f0e..82c44d4899b9 100644 --- a/crypto/algif_hash.c +++ b/crypto/algif_hash.c @@ -68,13 +68,15 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg, struct hash_ctx *ctx = ask->private; ssize_t copied = 0; size_t len, max_pages, npages; - bool continuing = ctx->more, need_init = false; + bool continuing, need_init = false; int err; max_pages = min_t(size_t, ALG_MAX_PAGES, DIV_ROUND_UP(sk->sk_sndbuf, PAGE_SIZE)); lock_sock(sk); + continuing = ctx->more; + if (!continuing) { /* Discard a previous request that wasn't marked MSG_MORE. */ hash_free_result(sk, ctx);