From nobody Fri Nov 29 09:22:54 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9FF4C1A00ED for ; Mon, 23 Sep 2024 15:09:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727104145; cv=none; b=tp9bd0T3pBBiNFxO7A8DVvh2xumzWESNCQ8HOvsyyju6PlHhGvXUSdCQNyc6Lvpyr76sFH8H7iTcn42VPZYqBcvSyeSXHL8uhbWr5ZdIHQd2tR8OmDYvS0hvEGH1pT+l6ruxS4T7nuMpdTNyYYb3ucqGmUURzpSjnEyljT7F4Mw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727104145; c=relaxed/simple; bh=rtYlhOMdVR41jeKY9q/c0ZlVGDD4ajFvswOXM9o792g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=We6dJnx8LSE5fxHqSwonL65eSURn6nMK6PTA9CIpHAUXIc3oSInkkbTk/MVt6FChgttNqx0iVXAtk8k5rysHiGfB8OxAbR0mvR3BBXUMpe1lUsUZjhH1ia+mSESt0wEdUfV3QzrgvwdZ+WdMXKwyZXbZiSqRbToJQ7SrLhQ5fGk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=VGdb2Fgc; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="VGdb2Fgc" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1727104142; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=en0FbhjuTrTUZN9cCFkNjaE5g8iEA8EQ8DfNicZc0lg=; b=VGdb2FgcCv4ChPj9IzSqZeuuqJUvwbzsSZWVOl2L9/KAI6ckFNhVDWOn2gubfieqc8Ugii iNa6+0XPj4Rl5L2f4GyOKlVOaCGFvYQW4lsGZHFrlS1hD8xxzPjxaQyUzvtJxfQOMTDnZa ZJhMgGaKo070PTeZv7eky8qTu2NiIUs= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-118-hNdBfCa9Nk6QzasA8zlp7Q-1; Mon, 23 Sep 2024 11:08:57 -0400 X-MC-Unique: hNdBfCa9Nk6QzasA8zlp7Q-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (unknown [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 102351895D51; Mon, 23 Sep 2024 15:08:50 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.145]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C5CF4197700E; Mon, 23 Sep 2024 15:08:42 +0000 (UTC) From: David Howells To: Christian Brauner , Steve French , Marc Dionne Cc: David Howells , Paulo Alcantara , Jeff Layton , Matthew Wilcox , netfs@lists.linux.dev, linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs@lists.linux.dev, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shyam Prasad N , Rohith Surabattula Subject: [PATCH 7/8] cifs: Fix reversion of the iter in cifs_readv_receive(). Date: Mon, 23 Sep 2024 16:07:51 +0100 Message-ID: <20240923150756.902363-8-dhowells@redhat.com> In-Reply-To: <20240923150756.902363-1-dhowells@redhat.com> References: <20240923150756.902363-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Content-Type: text/plain; charset="utf-8" cifs_read_iter_from_socket() copies the iterator that's passed in for the socket to modify as and if it will, and then advances the original iterator by the amount sent. However, both callers revert the advancement (although receive_encrypted_read() zeros beyond the iterator first). The problem is, though, that cifs_readv_receive() reverts by the original length, not the amount transmitted which can cause an oops in iov_iter_revert(). Fix this by: (1) Remove the iov_iter_advance() from cifs_read_iter_from_socket(). (2) Remove the iov_iter_revert() from both callers. This fixes the bug in cifs_readv_receive(). (3) In receive_encrypted_read(), if we didn't get back as much data as the buffer will hold, copy the iterator, advance the copy and use the copy to drive iov_iter_zero(). As a bonus, this gets rid of some unnecessary work. This was triggered by generic/074 with the "-o sign" mount option. Fixes: 3ee1a1fc3981 ("cifs: Cut over to using netfslib") Signed-off-by: David Howells cc: Steve French cc: Paulo Alcantara cc: Shyam Prasad N cc: Rohith Surabattula cc: Jeff Layton cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org --- fs/smb/client/connect.c | 6 +----- fs/smb/client/smb2ops.c | 9 ++++++--- fs/smb/client/transport.c | 3 --- 3 files changed, 7 insertions(+), 11 deletions(-) diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index 08a41c7aaf72..be6e632388f8 100644 --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -811,13 +811,9 @@ cifs_read_iter_from_socket(struct TCP_Server_Info *ser= ver, struct iov_iter *iter unsigned int to_read) { struct msghdr smb_msg =3D { .msg_iter =3D *iter }; - int ret; =20 iov_iter_truncate(&smb_msg.msg_iter, to_read); - ret =3D cifs_readv_from_socket(server, &smb_msg); - if (ret > 0) - iov_iter_advance(iter, ret); - return ret; + return cifs_readv_from_socket(server, &smb_msg); } =20 static bool diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index 7381ec333c6d..1ee2dd4a1cae 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -4869,9 +4869,12 @@ receive_encrypted_read(struct TCP_Server_Info *serve= r, struct mid_q_entry **mid, goto discard_data; =20 server->total_read +=3D rc; - if (rc < len) - iov_iter_zero(len - rc, &iter); - iov_iter_revert(&iter, len); + if (rc < len) { + struct iov_iter tmp =3D iter; + + iov_iter_advance(&tmp, rc); + iov_iter_zero(len - rc, &tmp); + } iov_iter_truncate(&iter, dw->len); =20 rc =3D cifs_discard_remaining_data(server); diff --git a/fs/smb/client/transport.c b/fs/smb/client/transport.c index fd5a85d43759..91812150186c 100644 --- a/fs/smb/client/transport.c +++ b/fs/smb/client/transport.c @@ -1817,11 +1817,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, s= truct mid_q_entry *mid) length =3D data_len; /* An RDMA read is already done. */ else #endif - { length =3D cifs_read_iter_from_socket(server, &rdata->subreq.io_iter, data_len); - iov_iter_revert(&rdata->subreq.io_iter, data_len); - } if (length > 0) rdata->got_bytes +=3D length; server->total_read +=3D length;