From patchwork Wed Jun 14 23:27:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 692707 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 D0D0FEB64D8 for ; Wed, 14 Jun 2023 23:28:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234331AbjFNX2n (ORCPT ); Wed, 14 Jun 2023 19:28:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229516AbjFNX2n (ORCPT ); Wed, 14 Jun 2023 19:28:43 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB0551BD2 for ; Wed, 14 Jun 2023 16:28:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1686785280; 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=aH8zwLa8Ht2nXaE8fo3wqv7zLHm1tw4+70R/cDKjh3s=; b=Pib7553m97gLDb/s0E3V+7jCoW58jZS1t2ygyRC3W7QMAac1p0Sq5dX/2Dl2zYWSUouRHl y6nssujR7lIzBoi4HSx69+yp+7uUIAEugKCZzc1pZlqRo0ix07AtEinXcrul7CHlH7RP4N LsA5s3QmdWxiYniv6S3TZ9b4qMWeA1s= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-85-n6p0z6GaO3ei54QFL73rZQ-1; Wed, 14 Jun 2023 19:27:56 -0400 X-MC-Unique: n6p0z6GaO3ei54QFL73rZQ-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 1504A296A603; Wed, 14 Jun 2023 23:27:56 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.67]) by smtp.corp.redhat.com (Postfix) with ESMTP id 559E240C6F5E; Wed, 14 Jun 2023 23:27:54 +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 To: netdev@vger.kernel.org cc: dhowells@redhat.com, syzbot+13a08c0bf4d212766c3c@syzkaller.appspotmail.com, syzbot+14234ccf6d0ef629ec1a@syzkaller.appspotmail.com, syzbot+4e2e47f32607d0f72d43@syzkaller.appspotmail.com, syzbot+472626bb5e7c59fb768f@syzkaller.appspotmail.com, Herbert Xu , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jens Axboe , Matthew Wilcox , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next] crypto: af_alg/hash: Fix recvmsg() after sendmsg(MSG_MORE) MIME-Version: 1.0 Content-ID: <1679811.1686785244.1@warthog.procyon.org.uk> From: David Howells Date: Thu, 15 Jun 2023 00:27:53 +0100 Message-ID: <1679829.1686785273@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 If an AF_ALG socket bound to a hashing algorithm is sent a zero-length message with MSG_MORE set and then recvmsg() is called without first sending another message without MSG_MORE set to end the operation, an oops will occur because the crypto context and result doesn't now get set up in advance because hash_sendmsg() now defers that as long as possible in the hope that it can use crypto_ahash_digest() - and then because the message is zero-length, it the data wrangling loop is skipped. Fix this by always making a pass of the loop, even in the case that no data is provided to the sendmsg(). Fix also extract_iter_to_sg() to handle a zero-length iterator by returning 0 immediately. Whilst we're at it, remove the code to create a kvmalloc'd scatterlist if we get more than ALG_MAX_PAGES - this shouldn't happen. Fixes: c662b043cdca ("crypto: af_alg/hash: Support MSG_SPLICE_PAGES") Reported-by: syzbot+13a08c0bf4d212766c3c@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/000000000000b928f705fdeb873a@google.com/ Reported-by: syzbot+14234ccf6d0ef629ec1a@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/000000000000c047db05fdeb8790@google.com/ Reported-by: syzbot+4e2e47f32607d0f72d43@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/000000000000bcca3205fdeb87fb@google.com/ Reported-by: syzbot+472626bb5e7c59fb768f@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/000000000000b55d8805fdeb8385@google.com/ Signed-off-by: David Howells Tested-by: syzbot+13a08c0bf4d212766c3c@syzkaller.appspotmail.com Tested-by: syzbot+14234ccf6d0ef629ec1a@syzkaller.appspotmail.com Tested-by: syzbot+4e2e47f32607d0f72d43@syzkaller.appspotmail.com Tested-by: syzbot+472626bb5e7c59fb768f@syzkaller.appspotmail.com cc: Herbert Xu cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: linux-crypto@vger.kernel.org cc: netdev@vger.kernel.org Acked-by: Herbert Xu --- crypto/algif_hash.c | 21 +++++---------------- lib/scatterlist.c | 2 +- 2 files changed, 6 insertions(+), 17 deletions(-) diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c index dfb048cefb60..1176533a55c9 100644 --- a/crypto/algif_hash.c +++ b/crypto/algif_hash.c @@ -83,26 +83,14 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg, ctx->more = false; - while (msg_data_left(msg)) { + do { ctx->sgl.sgt.sgl = ctx->sgl.sgl; ctx->sgl.sgt.nents = 0; ctx->sgl.sgt.orig_nents = 0; err = -EIO; npages = iov_iter_npages(&msg->msg_iter, max_pages); - if (npages == 0) - goto unlock_free; - - if (npages > ARRAY_SIZE(ctx->sgl.sgl)) { - err = -ENOMEM; - ctx->sgl.sgt.sgl = - kvmalloc(array_size(npages, - sizeof(*ctx->sgl.sgt.sgl)), - GFP_KERNEL); - if (!ctx->sgl.sgt.sgl) - goto unlock_free; - } - sg_init_table(ctx->sgl.sgl, npages); + sg_init_table(ctx->sgl.sgl, max_t(size_t, npages, 1)); ctx->sgl.need_unpin = iov_iter_extract_will_pin(&msg->msg_iter); @@ -111,7 +99,8 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg, if (err < 0) goto unlock_free; len = err; - sg_mark_end(ctx->sgl.sgt.sgl + ctx->sgl.sgt.nents - 1); + if (len > 0) + sg_mark_end(ctx->sgl.sgt.sgl + ctx->sgl.sgt.nents - 1); if (!msg_data_left(msg)) { err = hash_alloc_result(sk, ctx); @@ -148,7 +137,7 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg, copied += len; af_alg_free_sg(&ctx->sgl); - } + } while (msg_data_left(msg)); ctx->more = msg->msg_flags & MSG_MORE; err = 0; diff --git a/lib/scatterlist.c b/lib/scatterlist.c index e97d7060329e..77a7b18ee751 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -1340,7 +1340,7 @@ ssize_t extract_iter_to_sg(struct iov_iter *iter, size_t maxsize, struct sg_table *sgtable, unsigned int sg_max, iov_iter_extraction_t extraction_flags) { - if (maxsize == 0) + if (!maxsize || !iter->count) return 0; switch (iov_iter_type(iter)) {