From patchwork Fri Jun 16 11:10:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 693310 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 8E506EB64DA for ; Fri, 16 Jun 2023 11:11:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229913AbjFPLL3 (ORCPT ); Fri, 16 Jun 2023 07:11:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343580AbjFPLL2 (ORCPT ); Fri, 16 Jun 2023 07:11:28 -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 EF323AC for ; Fri, 16 Jun 2023 04:10:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1686913843; 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=rZB7JzdcM+W3WnooI0jXz6/MmOAa3ZILp9sqWdRbOG0=; b=VMJ8m7LTorWuKErNzymRZQEd20xqTTSdptdlbHmd+W6OKcxIP073BPruPT1Nzy5Ki32z3r C9kGGE4B2h4s1dcqdqjyz7AtG44zsk76Gv0guFWtyCgm2IiXG3W4ipSPIdoQpW+olG/8S7 2u4mxGg+gAw0J7LREZu93JtKV5l3fQU= 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-675-uDkYus20Nqim4-FY4-BJ_Q-1; Fri, 16 Jun 2023 07:10:37 -0400 X-MC-Unique: uDkYus20Nqim4-FY4-BJ_Q-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4867B3804501; Fri, 16 Jun 2023 11:10:36 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.51]) by smtp.corp.redhat.com (Postfix) with ESMTP id A0E522166B25; Fri, 16 Jun 2023 11:10:33 +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: netdev@vger.kernel.org, Herbert Xu cc: dhowells@redhat.com, syzbot+13a08c0bf4d212766c3c@syzkaller.appspotmail.com, syzbot+14234ccf6d0ef629ec1a@syzkaller.appspotmail.com, syzbot+4e2e47f32607d0f72d43@syzkaller.appspotmail.com, syzbot+472626bb5e7c59fb768f@syzkaller.appspotmail.com, "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 v2] crypto: af_alg/hash: Fix recvmsg() after sendmsg(MSG_MORE) MIME-Version: 1.0 Content-ID: <427645.1686913832.1@warthog.procyon.org.uk> Date: Fri, 16 Jun 2023 12:10:32 +0100 Message-ID: <427646.1686913832@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 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 handling zero-length sends at the top of the hash_sendmsg() function. If we're not continuing the previous sendmsg(), then just ignore the send (hash_recvmsg() will invent something when called); if we are continuing, then we finalise the request at this point if MSG_MORE is not set to get any error here, otherwise the send is of no effect and can be ignored. 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 Reported-and-tested-by: syzbot+6efc50cc1f8d718d6cb7@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 | 38 +++++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 13 deletions(-) diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c index dfb048cefb60..0ab43e149f0e 100644 --- a/crypto/algif_hash.c +++ b/crypto/algif_hash.c @@ -76,13 +76,30 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg, lock_sock(sk); if (!continuing) { - if ((msg->msg_flags & MSG_MORE)) - hash_free_result(sk, ctx); + /* Discard a previous request that wasn't marked MSG_MORE. */ + hash_free_result(sk, ctx); + if (!msg_data_left(msg)) + goto done; /* Zero-length; don't start new req */ need_init = true; + } else if (!msg_data_left(msg)) { + /* + * No data - finalise the prev req if MSG_MORE so any error + * comes out here. + */ + if (!(msg->msg_flags & MSG_MORE)) { + err = hash_alloc_result(sk, ctx); + if (err) + goto unlock_free; + ahash_request_set_crypt(&ctx->req, NULL, + ctx->result, 0); + err = crypto_wait_req(crypto_ahash_final(&ctx->req), + &ctx->wait); + if (err) + goto unlock_free; + } + goto done_more; } - ctx->more = false; - while (msg_data_left(msg)) { ctx->sgl.sgt.sgl = ctx->sgl.sgl; ctx->sgl.sgt.nents = 0; @@ -93,15 +110,6 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg, 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); ctx->sgl.need_unpin = iov_iter_extract_will_pin(&msg->msg_iter); @@ -150,7 +158,9 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg, af_alg_free_sg(&ctx->sgl); } +done_more: ctx->more = msg->msg_flags & MSG_MORE; +done: err = 0; unlock: release_sock(sk); @@ -158,6 +168,8 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg, unlock_free: af_alg_free_sg(&ctx->sgl); + hash_free_result(sk, ctx); + ctx->more = false; goto unlock; }