Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 495 insertions, 0 deletions

diff --git a/fs/ecryptfs/miscdev.c b/fs/ecryptfs/miscdev.c
new file mode 100644
index 000000000..4e62c3cef
--- /dev/null
+++ b/fs/ecryptfs/miscdev.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2008 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/hash.h>
+#include <linux/random.h>
+#include <linux/miscdevice.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include "ecryptfs_kernel.h"
+
+static atomic_t ecryptfs_num_miscdev_opens;
+
+/**
+ * ecryptfs_miscdev_poll
+ * @file: dev file
+ * @pt: dev poll table (ignored)
+ *
+ * Returns the poll mask
+ */
+static __poll_t
+ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
+{
+	struct ecryptfs_daemon *daemon = file->private_data;
+	__poll_t mask = 0;
+
+	mutex_lock(&daemon->mux);
+	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+		printk(KERN_WARNING "%s: Attempt to poll on zombified "
+		       "daemon\n", __func__);
+		goto out_unlock_daemon;
+	}
+	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
+		goto out_unlock_daemon;
+	if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
+		goto out_unlock_daemon;
+	daemon->flags |= ECRYPTFS_DAEMON_IN_POLL;
+	mutex_unlock(&daemon->mux);
+	poll_wait(file, &daemon->wait, pt);
+	mutex_lock(&daemon->mux);
+	if (!list_empty(&daemon->msg_ctx_out_queue))
+		mask |= EPOLLIN | EPOLLRDNORM;
+out_unlock_daemon:
+	daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
+	mutex_unlock(&daemon->mux);
+	return mask;
+}
+
+/**
+ * ecryptfs_miscdev_open
+ * @inode: inode of miscdev handle (ignored)
+ * @file: file for miscdev handle
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_miscdev_open(struct inode *inode, struct file *file)
+{
+	struct ecryptfs_daemon *daemon = NULL;
+	int rc;
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	rc = ecryptfs_find_daemon_by_euid(&daemon);
+	if (!rc) {
+		rc = -EINVAL;
+		goto out_unlock_daemon_list;
+	}
+	rc = ecryptfs_spawn_daemon(&daemon, file);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to spawn daemon; "
+		       "rc = [%d]\n", __func__, rc);
+		goto out_unlock_daemon_list;
+	}
+	mutex_lock(&daemon->mux);
+	if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
+		rc = -EBUSY;
+		goto out_unlock_daemon;
+	}
+	daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
+	file->private_data = daemon;
+	atomic_inc(&ecryptfs_num_miscdev_opens);
+out_unlock_daemon:
+	mutex_unlock(&daemon->mux);
+out_unlock_daemon_list:
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	return rc;
+}
+
+/**
+ * ecryptfs_miscdev_release
+ * @inode: inode of fs/ecryptfs/euid handle (ignored)
+ * @file: file for fs/ecryptfs/euid handle
+ *
+ * This keeps the daemon registered until the daemon sends another
+ * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_miscdev_release(struct inode *inode, struct file *file)
+{
+	struct ecryptfs_daemon *daemon = file->private_data;
+	int rc;
+
+	mutex_lock(&daemon->mux);
+	BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
+	daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
+	atomic_dec(&ecryptfs_num_miscdev_opens);
+	mutex_unlock(&daemon->mux);
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	rc = ecryptfs_exorcise_daemon(daemon);
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	if (rc) {
+		printk(KERN_CRIT "%s: Fatal error whilst attempting to "
+		       "shut down daemon; rc = [%d]. Please report this "
+		       "bug.\n", __func__, rc);
+		BUG();
+	}
+	return rc;
+}
+
+/**
+ * ecryptfs_send_miscdev
+ * @data: Data to send to daemon; may be NULL
+ * @data_size: Amount of data to send to daemon
+ * @msg_ctx: Message context, which is used to handle the reply. If
+ *           this is NULL, then we do not expect a reply.
+ * @msg_type: Type of message
+ * @msg_flags: Flags for message
+ * @daemon: eCryptfs daemon object
+ *
+ * Add msg_ctx to queue and then, if it exists, notify the blocked
+ * miscdevess about the data being available. Must be called with
+ * ecryptfs_daemon_hash_mux held.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_send_miscdev(char *data, size_t data_size,
+			  struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
+			  u16 msg_flags, struct ecryptfs_daemon *daemon)
+{
+	struct ecryptfs_message *msg;
+
+	msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	mutex_lock(&msg_ctx->mux);
+	msg_ctx->msg = msg;
+	msg_ctx->msg->index = msg_ctx->index;
+	msg_ctx->msg->data_len = data_size;
+	msg_ctx->type = msg_type;
+	memcpy(msg_ctx->msg->data, data, data_size);
+	msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
+	list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
+	mutex_unlock(&msg_ctx->mux);
+
+	mutex_lock(&daemon->mux);
+	daemon->num_queued_msg_ctx++;
+	wake_up_interruptible(&daemon->wait);
+	mutex_unlock(&daemon->mux);
+
+	return 0;
+}
+
+/*
+ * miscdevfs packet format:
+ *  Octet 0: Type
+ *  Octets 1-4: network byte order msg_ctx->counter
+ *  Octets 5-N0: Size of struct ecryptfs_message to follow
+ *  Octets N0-N1: struct ecryptfs_message (including data)
+ *
+ *  Octets 5-N1 not written if the packet type does not include a message
+ */
+#define PKT_TYPE_SIZE		1
+#define PKT_CTR_SIZE		4
+#define MIN_NON_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE)
+#define MIN_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE \
+				 + ECRYPTFS_MIN_PKT_LEN_SIZE)
+/* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
+#define MAX_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE \
+				 + ECRYPTFS_MAX_PKT_LEN_SIZE \
+				 + sizeof(struct ecryptfs_message) \
+				 + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
+#define PKT_TYPE_OFFSET		0
+#define PKT_CTR_OFFSET		PKT_TYPE_SIZE
+#define PKT_LEN_OFFSET		(PKT_TYPE_SIZE + PKT_CTR_SIZE)
+
+/**
+ * ecryptfs_miscdev_read - format and send message from queue
+ * @file: miscdevfs handle
+ * @buf: User buffer into which to copy the next message on the daemon queue
+ * @count: Amount of space available in @buf
+ * @ppos: Offset in file (ignored)
+ *
+ * Pulls the most recent message from the daemon queue, formats it for
+ * being sent via a miscdevfs handle, and copies it into @buf
+ *
+ * Returns the number of bytes copied into the user buffer
+ */
+static ssize_t
+ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
+		      loff_t *ppos)
+{
+	struct ecryptfs_daemon *daemon = file->private_data;
+	struct ecryptfs_msg_ctx *msg_ctx;
+	size_t packet_length_size;
+	char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
+	size_t i;
+	size_t total_length;
+	int rc;
+
+	mutex_lock(&daemon->mux);
+	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+		rc = 0;
+		printk(KERN_WARNING "%s: Attempt to read from zombified "
+		       "daemon\n", __func__);
+		goto out_unlock_daemon;
+	}
+	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
+		rc = 0;
+		goto out_unlock_daemon;
+	}
+	/* This daemon will not go away so long as this flag is set */
+	daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
+check_list:
+	if (list_empty(&daemon->msg_ctx_out_queue)) {
+		mutex_unlock(&daemon->mux);
+		rc = wait_event_interruptible(
+			daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
+		mutex_lock(&daemon->mux);
+		if (rc < 0) {
+			rc = 0;
+			goto out_unlock_daemon;
+		}
+	}
+	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+		rc = 0;
+		goto out_unlock_daemon;
+	}
+	if (list_empty(&daemon->msg_ctx_out_queue)) {
+		/* Something else jumped in since the
+		 * wait_event_interruptable() and removed the
+		 * message from the queue; try again */
+		goto check_list;
+	}
+	msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
+				   struct ecryptfs_msg_ctx, daemon_out_list);
+	BUG_ON(!msg_ctx);
+	mutex_lock(&msg_ctx->mux);
+	if (msg_ctx->msg) {
+		rc = ecryptfs_write_packet_length(packet_length,
+						  msg_ctx->msg_size,
+						  &packet_length_size);
+		if (rc) {
+			rc = 0;
+			printk(KERN_WARNING "%s: Error writing packet length; "
+			       "rc = [%d]\n", __func__, rc);
+			goto out_unlock_msg_ctx;
+		}
+	} else {
+		packet_length_size = 0;
+		msg_ctx->msg_size = 0;
+	}
+	total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
+			+ msg_ctx->msg_size);
+	if (count < total_length) {
+		rc = 0;
+		printk(KERN_WARNING "%s: Only given user buffer of "
+		       "size [%zd], but we need [%zd] to read the "
+		       "pending message\n", __func__, count, total_length);
+		goto out_unlock_msg_ctx;
+	}
+	rc = -EFAULT;
+	if (put_user(msg_ctx->type, buf))
+		goto out_unlock_msg_ctx;
+	if (put_user(cpu_to_be32(msg_ctx->counter),
+		     (__be32 __user *)(&buf[PKT_CTR_OFFSET])))
+		goto out_unlock_msg_ctx;
+	i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
+	if (msg_ctx->msg) {
+		if (copy_to_user(&buf[i], packet_length, packet_length_size))
+			goto out_unlock_msg_ctx;
+		i += packet_length_size;
+		if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
+			goto out_unlock_msg_ctx;
+		i += msg_ctx->msg_size;
+	}
+	rc = i;
+	list_del(&msg_ctx->daemon_out_list);
+	kfree(msg_ctx->msg);
+	msg_ctx->msg = NULL;
+	/* We do not expect a reply from the userspace daemon for any
+	 * message type other than ECRYPTFS_MSG_REQUEST */
+	if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
+		ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
+out_unlock_msg_ctx:
+	mutex_unlock(&msg_ctx->mux);
+out_unlock_daemon:
+	daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
+	mutex_unlock(&daemon->mux);
+	return rc;
+}
+
+/**
+ * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
+ * @daemon: eCryptfs daemon object
+ * @data: Bytes comprising struct ecryptfs_message
+ * @data_size: sizeof(struct ecryptfs_message) + data len
+ * @seq: Sequence number for miscdev response packet
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_miscdev_response(struct ecryptfs_daemon *daemon, char *data,
+				     size_t data_size, u32 seq)
+{
+	struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
+	int rc;
+
+	if ((sizeof(*msg) + msg->data_len) != data_size) {
+		printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
+		       "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
+		       (sizeof(*msg) + msg->data_len), data_size);
+		rc = -EINVAL;
+		goto out;
+	}
+	rc = ecryptfs_process_response(daemon, msg, seq);
+	if (rc)
+		printk(KERN_ERR
+		       "Error processing response message; rc = [%d]\n", rc);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_miscdev_write - handle write to daemon miscdev handle
+ * @file: File for misc dev handle
+ * @buf: Buffer containing user data
+ * @count: Amount of data in @buf
+ * @ppos: Pointer to offset in file (ignored)
+ *
+ * Returns the number of bytes read from @buf
+ */
+static ssize_t
+ecryptfs_miscdev_write(struct file *file, const char __user *buf,
+		       size_t count, loff_t *ppos)
+{
+	__be32 counter_nbo;
+	u32 seq;
+	size_t packet_size, packet_size_length;
+	char *data;
+	unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
+	ssize_t rc;
+
+	if (count == 0) {
+		return 0;
+	} else if (count == MIN_NON_MSG_PKT_SIZE) {
+		/* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
+		goto memdup;
+	} else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) {
+		printk(KERN_WARNING "%s: Acceptable packet size range is "
+		       "[%d-%zu], but amount of data written is [%zu].\n",
+		       __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
+		return -EINVAL;
+	}
+
+	if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
+			   sizeof(packet_size_peek))) {
+		printk(KERN_WARNING "%s: Error while inspecting packet size\n",
+		       __func__);
+		return -EFAULT;
+	}
+
+	rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
+					  &packet_size_length);
+	if (rc) {
+		printk(KERN_WARNING "%s: Error parsing packet length; "
+		       "rc = [%zd]\n", __func__, rc);
+		return rc;
+	}
+
+	if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
+	    != count) {
+		printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
+		       packet_size);
+		return -EINVAL;
+	}
+
+memdup:
+	data = memdup_user(buf, count);
+	if (IS_ERR(data)) {
+		printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
+		       __func__, PTR_ERR(data));
+		return PTR_ERR(data);
+	}
+	switch (data[PKT_TYPE_OFFSET]) {
+	case ECRYPTFS_MSG_RESPONSE:
+		if (count < (MIN_MSG_PKT_SIZE
+			     + sizeof(struct ecryptfs_message))) {
+			printk(KERN_WARNING "%s: Minimum acceptable packet "
+			       "size is [%zd], but amount of data written is "
+			       "only [%zd]. Discarding response packet.\n",
+			       __func__,
+			       (MIN_MSG_PKT_SIZE
+				+ sizeof(struct ecryptfs_message)), count);
+			rc = -EINVAL;
+			goto out_free;
+		}
+		memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
+		seq = be32_to_cpu(counter_nbo);
+		rc = ecryptfs_miscdev_response(file->private_data,
+				&data[PKT_LEN_OFFSET + packet_size_length],
+				packet_size, seq);
+		if (rc) {
+			printk(KERN_WARNING "%s: Failed to deliver miscdev "
+			       "response to requesting operation; rc = [%zd]\n",
+			       __func__, rc);
+			goto out_free;
+		}
+		break;
+	case ECRYPTFS_MSG_HELO:
+	case ECRYPTFS_MSG_QUIT:
+		break;
+	default:
+		ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
+				"message of unrecognized type [%d]\n",
+				data[0]);
+		rc = -EINVAL;
+		goto out_free;
+	}
+	rc = count;
+out_free:
+	kfree(data);
+	return rc;
+}
+
+
+static const struct file_operations ecryptfs_miscdev_fops = {
+	.owner   = THIS_MODULE,
+	.open    = ecryptfs_miscdev_open,
+	.poll    = ecryptfs_miscdev_poll,
+	.read    = ecryptfs_miscdev_read,
+	.write   = ecryptfs_miscdev_write,
+	.release = ecryptfs_miscdev_release,
+	.llseek  = noop_llseek,
+};
+
+static struct miscdevice ecryptfs_miscdev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name  = "ecryptfs",
+	.fops  = &ecryptfs_miscdev_fops
+};
+
+/**
+ * ecryptfs_init_ecryptfs_miscdev
+ *
+ * Messages sent to the userspace daemon from the kernel are placed on
+ * a queue associated with the daemon. The next read against the
+ * miscdev handle by that daemon will return the oldest message placed
+ * on the message queue for the daemon.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int __init ecryptfs_init_ecryptfs_miscdev(void)
+{
+	int rc;
+
+	atomic_set(&ecryptfs_num_miscdev_opens, 0);
+	rc = misc_register(&ecryptfs_miscdev);
+	if (rc)
+		printk(KERN_ERR "%s: Failed to register miscellaneous device "
+		       "for communications with userspace daemons; rc = [%d]\n",
+		       __func__, rc);
+	return rc;
+}
+
+/**
+ * ecryptfs_destroy_ecryptfs_miscdev
+ *
+ * All of the daemons must be exorcised prior to calling this
+ * function.
+ */
+void ecryptfs_destroy_ecryptfs_miscdev(void)
+{
+	BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
+	misc_deregister(&ecryptfs_miscdev);
+}