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, 662 insertions, 0 deletions

diff --git a/security/apparmor/file.c b/security/apparmor/file.c
new file mode 100644
index 000000000..9119ddda6
--- /dev/null
+++ b/security/apparmor/file.c
@@ -0,0 +1,662 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor mediation of files
+ *
+ * Copyright (C) 1998-2008 Novell/SUSE
+ * Copyright 2009-2010 Canonical Ltd.
+ */
+
+#include <linux/tty.h>
+#include <linux/fdtable.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+
+#include "include/apparmor.h"
+#include "include/audit.h"
+#include "include/cred.h"
+#include "include/file.h"
+#include "include/match.h"
+#include "include/net.h"
+#include "include/path.h"
+#include "include/policy.h"
+#include "include/label.h"
+
+static u32 map_mask_to_chr_mask(u32 mask)
+{
+	u32 m = mask & PERMS_CHRS_MASK;
+
+	if (mask & AA_MAY_GETATTR)
+		m |= MAY_READ;
+	if (mask & (AA_MAY_SETATTR | AA_MAY_CHMOD | AA_MAY_CHOWN))
+		m |= MAY_WRITE;
+
+	return m;
+}
+
+/**
+ * file_audit_cb - call back for file specific audit fields
+ * @ab: audit_buffer  (NOT NULL)
+ * @va: audit struct to audit values of  (NOT NULL)
+ */
+static void file_audit_cb(struct audit_buffer *ab, void *va)
+{
+	struct common_audit_data *sa = va;
+	kuid_t fsuid = current_fsuid();
+	char str[10];
+
+	if (aad(sa)->request & AA_AUDIT_FILE_MASK) {
+		aa_perm_mask_to_str(str, sizeof(str), aa_file_perm_chrs,
+				    map_mask_to_chr_mask(aad(sa)->request));
+		audit_log_format(ab, " requested_mask=\"%s\"", str);
+	}
+	if (aad(sa)->denied & AA_AUDIT_FILE_MASK) {
+		aa_perm_mask_to_str(str, sizeof(str), aa_file_perm_chrs,
+				    map_mask_to_chr_mask(aad(sa)->denied));
+		audit_log_format(ab, " denied_mask=\"%s\"", str);
+	}
+	if (aad(sa)->request & AA_AUDIT_FILE_MASK) {
+		audit_log_format(ab, " fsuid=%d",
+				 from_kuid(&init_user_ns, fsuid));
+		audit_log_format(ab, " ouid=%d",
+				 from_kuid(&init_user_ns, aad(sa)->fs.ouid));
+	}
+
+	if (aad(sa)->peer) {
+		audit_log_format(ab, " target=");
+		aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
+				FLAG_VIEW_SUBNS, GFP_KERNEL);
+	} else if (aad(sa)->fs.target) {
+		audit_log_format(ab, " target=");
+		audit_log_untrustedstring(ab, aad(sa)->fs.target);
+	}
+}
+
+/**
+ * aa_audit_file - handle the auditing of file operations
+ * @profile: the profile being enforced  (NOT NULL)
+ * @perms: the permissions computed for the request (NOT NULL)
+ * @op: operation being mediated
+ * @request: permissions requested
+ * @name: name of object being mediated (MAYBE NULL)
+ * @target: name of target (MAYBE NULL)
+ * @tlabel: target label (MAY BE NULL)
+ * @ouid: object uid
+ * @info: extra information message (MAYBE NULL)
+ * @error: 0 if operation allowed else failure error code
+ *
+ * Returns: %0 or error on failure
+ */
+int aa_audit_file(struct aa_profile *profile, struct aa_perms *perms,
+		  const char *op, u32 request, const char *name,
+		  const char *target, struct aa_label *tlabel,
+		  kuid_t ouid, const char *info, int error)
+{
+	int type = AUDIT_APPARMOR_AUTO;
+	DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_TASK, AA_CLASS_FILE, op);
+
+	sa.u.tsk = NULL;
+	aad(&sa)->request = request;
+	aad(&sa)->name = name;
+	aad(&sa)->fs.target = target;
+	aad(&sa)->peer = tlabel;
+	aad(&sa)->fs.ouid = ouid;
+	aad(&sa)->info = info;
+	aad(&sa)->error = error;
+	sa.u.tsk = NULL;
+
+	if (likely(!aad(&sa)->error)) {
+		u32 mask = perms->audit;
+
+		if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL))
+			mask = 0xffff;
+
+		/* mask off perms that are not being force audited */
+		aad(&sa)->request &= mask;
+
+		if (likely(!aad(&sa)->request))
+			return 0;
+		type = AUDIT_APPARMOR_AUDIT;
+	} else {
+		/* only report permissions that were denied */
+		aad(&sa)->request = aad(&sa)->request & ~perms->allow;
+		AA_BUG(!aad(&sa)->request);
+
+		if (aad(&sa)->request & perms->kill)
+			type = AUDIT_APPARMOR_KILL;
+
+		/* quiet known rejects, assumes quiet and kill do not overlap */
+		if ((aad(&sa)->request & perms->quiet) &&
+		    AUDIT_MODE(profile) != AUDIT_NOQUIET &&
+		    AUDIT_MODE(profile) != AUDIT_ALL)
+			aad(&sa)->request &= ~perms->quiet;
+
+		if (!aad(&sa)->request)
+			return aad(&sa)->error;
+	}
+
+	aad(&sa)->denied = aad(&sa)->request & ~perms->allow;
+	return aa_audit(type, profile, &sa, file_audit_cb);
+}
+
+static int path_name(const char *op, struct aa_label *label,
+		     const struct path *path, int flags, char *buffer,
+		     const char **name, struct path_cond *cond, u32 request)
+{
+	struct aa_profile *profile;
+	const char *info = NULL;
+	int error;
+
+	error = aa_path_name(path, flags, buffer, name, &info,
+			     labels_profile(label)->disconnected);
+	if (error) {
+		fn_for_each_confined(label, profile,
+			aa_audit_file(profile, &nullperms, op, request, *name,
+				      NULL, NULL, cond->uid, info, error));
+		return error;
+	}
+
+	return 0;
+}
+
+/**
+ * aa_lookup_fperms - convert dfa compressed perms to internal perms
+ * @dfa: dfa to lookup perms for   (NOT NULL)
+ * @state: state in dfa
+ * @cond:  conditions to consider  (NOT NULL)
+ *
+ * TODO: convert from dfa + state to permission entry
+ *
+ * Returns: a pointer to a file permission set
+ */
+struct aa_perms default_perms = {};
+struct aa_perms *aa_lookup_fperms(struct aa_policydb *file_rules,
+				 aa_state_t state, struct path_cond *cond)
+{
+	unsigned int index = ACCEPT_TABLE(file_rules->dfa)[state];
+
+	if (!(file_rules->perms))
+		return &default_perms;
+
+	if (uid_eq(current_fsuid(), cond->uid))
+		return &(file_rules->perms[index]);
+
+	return &(file_rules->perms[index + 1]);
+}
+
+/**
+ * aa_str_perms - find permission that match @name
+ * @dfa: to match against  (MAYBE NULL)
+ * @state: state to start matching in
+ * @name: string to match against dfa  (NOT NULL)
+ * @cond: conditions to consider for permission set computation  (NOT NULL)
+ * @perms: Returns - the permissions found when matching @name
+ *
+ * Returns: the final state in @dfa when beginning @start and walking @name
+ */
+aa_state_t aa_str_perms(struct aa_policydb *file_rules, aa_state_t start,
+			const char *name, struct path_cond *cond,
+			struct aa_perms *perms)
+{
+	aa_state_t state;
+	state = aa_dfa_match(file_rules->dfa, start, name);
+	*perms = *(aa_lookup_fperms(file_rules, state, cond));
+
+	return state;
+}
+
+static int __aa_path_perm(const char *op, struct aa_profile *profile,
+			  const char *name, u32 request,
+			  struct path_cond *cond, int flags,
+			  struct aa_perms *perms)
+{
+	struct aa_ruleset *rules = list_first_entry(&profile->rules,
+						    typeof(*rules), list);
+	int e = 0;
+
+	if (profile_unconfined(profile))
+		return 0;
+	aa_str_perms(&(rules->file), rules->file.start[AA_CLASS_FILE],
+		     name, cond, perms);
+	if (request & ~perms->allow)
+		e = -EACCES;
+	return aa_audit_file(profile, perms, op, request, name, NULL, NULL,
+			     cond->uid, NULL, e);
+}
+
+
+static int profile_path_perm(const char *op, struct aa_profile *profile,
+			     const struct path *path, char *buffer, u32 request,
+			     struct path_cond *cond, int flags,
+			     struct aa_perms *perms)
+{
+	const char *name;
+	int error;
+
+	if (profile_unconfined(profile))
+		return 0;
+
+	error = path_name(op, &profile->label, path,
+			  flags | profile->path_flags, buffer, &name, cond,
+			  request);
+	if (error)
+		return error;
+	return __aa_path_perm(op, profile, name, request, cond, flags,
+			      perms);
+}
+
+/**
+ * aa_path_perm - do permissions check & audit for @path
+ * @op: operation being checked
+ * @label: profile being enforced  (NOT NULL)
+ * @path: path to check permissions of  (NOT NULL)
+ * @flags: any additional path flags beyond what the profile specifies
+ * @request: requested permissions
+ * @cond: conditional info for this request  (NOT NULL)
+ *
+ * Returns: %0 else error if access denied or other error
+ */
+int aa_path_perm(const char *op, struct aa_label *label,
+		 const struct path *path, int flags, u32 request,
+		 struct path_cond *cond)
+{
+	struct aa_perms perms = {};
+	struct aa_profile *profile;
+	char *buffer = NULL;
+	int error;
+
+	flags |= PATH_DELEGATE_DELETED | (S_ISDIR(cond->mode) ? PATH_IS_DIR :
+								0);
+	buffer = aa_get_buffer(false);
+	if (!buffer)
+		return -ENOMEM;
+	error = fn_for_each_confined(label, profile,
+			profile_path_perm(op, profile, path, buffer, request,
+					  cond, flags, &perms));
+
+	aa_put_buffer(buffer);
+
+	return error;
+}
+
+/**
+ * xindex_is_subset - helper for aa_path_link
+ * @link: link permission set
+ * @target: target permission set
+ *
+ * test target x permissions are equal OR a subset of link x permissions
+ * this is done as part of the subset test, where a hardlink must have
+ * a subset of permissions that the target has.
+ *
+ * Returns: true if subset else false
+ */
+static inline bool xindex_is_subset(u32 link, u32 target)
+{
+	if (((link & ~AA_X_UNSAFE) != (target & ~AA_X_UNSAFE)) ||
+	    ((link & AA_X_UNSAFE) && !(target & AA_X_UNSAFE)))
+		return false;
+
+	return true;
+}
+
+static int profile_path_link(struct aa_profile *profile,
+			     const struct path *link, char *buffer,
+			     const struct path *target, char *buffer2,
+			     struct path_cond *cond)
+{
+	struct aa_ruleset *rules = list_first_entry(&profile->rules,
+						    typeof(*rules), list);
+	const char *lname, *tname = NULL;
+	struct aa_perms lperms = {}, perms;
+	const char *info = NULL;
+	u32 request = AA_MAY_LINK;
+	aa_state_t state;
+	int error;
+
+	error = path_name(OP_LINK, &profile->label, link, profile->path_flags,
+			  buffer, &lname, cond, AA_MAY_LINK);
+	if (error)
+		goto audit;
+
+	/* buffer2 freed below, tname is pointer in buffer2 */
+	error = path_name(OP_LINK, &profile->label, target, profile->path_flags,
+			  buffer2, &tname, cond, AA_MAY_LINK);
+	if (error)
+		goto audit;
+
+	error = -EACCES;
+	/* aa_str_perms - handles the case of the dfa being NULL */
+	state = aa_str_perms(&(rules->file),
+			     rules->file.start[AA_CLASS_FILE], lname,
+			     cond, &lperms);
+
+	if (!(lperms.allow & AA_MAY_LINK))
+		goto audit;
+
+	/* test to see if target can be paired with link */
+	state = aa_dfa_null_transition(rules->file.dfa, state);
+	aa_str_perms(&(rules->file), state, tname, cond, &perms);
+
+	/* force audit/quiet masks for link are stored in the second entry
+	 * in the link pair.
+	 */
+	lperms.audit = perms.audit;
+	lperms.quiet = perms.quiet;
+	lperms.kill = perms.kill;
+
+	if (!(perms.allow & AA_MAY_LINK)) {
+		info = "target restricted";
+		lperms = perms;
+		goto audit;
+	}
+
+	/* done if link subset test is not required */
+	if (!(perms.allow & AA_LINK_SUBSET))
+		goto done_tests;
+
+	/* Do link perm subset test requiring allowed permission on link are
+	 * a subset of the allowed permissions on target.
+	 */
+	aa_str_perms(&(rules->file), rules->file.start[AA_CLASS_FILE],
+		     tname, cond, &perms);
+
+	/* AA_MAY_LINK is not considered in the subset test */
+	request = lperms.allow & ~AA_MAY_LINK;
+	lperms.allow &= perms.allow | AA_MAY_LINK;
+
+	request |= AA_AUDIT_FILE_MASK & (lperms.allow & ~perms.allow);
+	if (request & ~lperms.allow) {
+		goto audit;
+	} else if ((lperms.allow & MAY_EXEC) &&
+		   !xindex_is_subset(lperms.xindex, perms.xindex)) {
+		lperms.allow &= ~MAY_EXEC;
+		request |= MAY_EXEC;
+		info = "link not subset of target";
+		goto audit;
+	}
+
+done_tests:
+	error = 0;
+
+audit:
+	return aa_audit_file(profile, &lperms, OP_LINK, request, lname, tname,
+			     NULL, cond->uid, info, error);
+}
+
+/**
+ * aa_path_link - Handle hard link permission check
+ * @label: the label being enforced  (NOT NULL)
+ * @old_dentry: the target dentry  (NOT NULL)
+ * @new_dir: directory the new link will be created in  (NOT NULL)
+ * @new_dentry: the link being created  (NOT NULL)
+ *
+ * Handle the permission test for a link & target pair.  Permission
+ * is encoded as a pair where the link permission is determined
+ * first, and if allowed, the target is tested.  The target test
+ * is done from the point of the link match (not start of DFA)
+ * making the target permission dependent on the link permission match.
+ *
+ * The subset test if required forces that permissions granted
+ * on link are a subset of the permission granted to target.
+ *
+ * Returns: %0 if allowed else error
+ */
+int aa_path_link(struct aa_label *label, struct dentry *old_dentry,
+		 const struct path *new_dir, struct dentry *new_dentry)
+{
+	struct path link = { .mnt = new_dir->mnt, .dentry = new_dentry };
+	struct path target = { .mnt = new_dir->mnt, .dentry = old_dentry };
+	struct path_cond cond = {
+		d_backing_inode(old_dentry)->i_uid,
+		d_backing_inode(old_dentry)->i_mode
+	};
+	char *buffer = NULL, *buffer2 = NULL;
+	struct aa_profile *profile;
+	int error;
+
+	/* buffer freed below, lname is pointer in buffer */
+	buffer = aa_get_buffer(false);
+	buffer2 = aa_get_buffer(false);
+	error = -ENOMEM;
+	if (!buffer || !buffer2)
+		goto out;
+
+	error = fn_for_each_confined(label, profile,
+			profile_path_link(profile, &link, buffer, &target,
+					  buffer2, &cond));
+out:
+	aa_put_buffer(buffer);
+	aa_put_buffer(buffer2);
+	return error;
+}
+
+static void update_file_ctx(struct aa_file_ctx *fctx, struct aa_label *label,
+			    u32 request)
+{
+	struct aa_label *l, *old;
+
+	/* update caching of label on file_ctx */
+	spin_lock(&fctx->lock);
+	old = rcu_dereference_protected(fctx->label,
+					lockdep_is_held(&fctx->lock));
+	l = aa_label_merge(old, label, GFP_ATOMIC);
+	if (l) {
+		if (l != old) {
+			rcu_assign_pointer(fctx->label, l);
+			aa_put_label(old);
+		} else
+			aa_put_label(l);
+		fctx->allow |= request;
+	}
+	spin_unlock(&fctx->lock);
+}
+
+static int __file_path_perm(const char *op, struct aa_label *label,
+			    struct aa_label *flabel, struct file *file,
+			    u32 request, u32 denied, bool in_atomic)
+{
+	struct aa_profile *profile;
+	struct aa_perms perms = {};
+	vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(file),
+					    file_inode(file));
+	struct path_cond cond = {
+		.uid = vfsuid_into_kuid(vfsuid),
+		.mode = file_inode(file)->i_mode
+	};
+	char *buffer;
+	int flags, error;
+
+	/* revalidation due to label out of date. No revocation at this time */
+	if (!denied && aa_label_is_subset(flabel, label))
+		/* TODO: check for revocation on stale profiles */
+		return 0;
+
+	flags = PATH_DELEGATE_DELETED | (S_ISDIR(cond.mode) ? PATH_IS_DIR : 0);
+	buffer = aa_get_buffer(in_atomic);
+	if (!buffer)
+		return -ENOMEM;
+
+	/* check every profile in task label not in current cache */
+	error = fn_for_each_not_in_set(flabel, label, profile,
+			profile_path_perm(op, profile, &file->f_path, buffer,
+					  request, &cond, flags, &perms));
+	if (denied && !error) {
+		/*
+		 * check every profile in file label that was not tested
+		 * in the initial check above.
+		 *
+		 * TODO: cache full perms so this only happens because of
+		 * conditionals
+		 * TODO: don't audit here
+		 */
+		if (label == flabel)
+			error = fn_for_each(label, profile,
+				profile_path_perm(op, profile, &file->f_path,
+						  buffer, request, &cond, flags,
+						  &perms));
+		else
+			error = fn_for_each_not_in_set(label, flabel, profile,
+				profile_path_perm(op, profile, &file->f_path,
+						  buffer, request, &cond, flags,
+						  &perms));
+	}
+	if (!error)
+		update_file_ctx(file_ctx(file), label, request);
+
+	aa_put_buffer(buffer);
+
+	return error;
+}
+
+static int __file_sock_perm(const char *op, struct aa_label *label,
+			    struct aa_label *flabel, struct file *file,
+			    u32 request, u32 denied)
+{
+	struct socket *sock = (struct socket *) file->private_data;
+	int error;
+
+	AA_BUG(!sock);
+
+	/* revalidation due to label out of date. No revocation at this time */
+	if (!denied && aa_label_is_subset(flabel, label))
+		return 0;
+
+	/* TODO: improve to skip profiles cached in flabel */
+	error = aa_sock_file_perm(label, op, request, sock);
+	if (denied) {
+		/* TODO: improve to skip profiles checked above */
+		/* check every profile in file label to is cached */
+		last_error(error, aa_sock_file_perm(flabel, op, request, sock));
+	}
+	if (!error)
+		update_file_ctx(file_ctx(file), label, request);
+
+	return error;
+}
+
+/**
+ * aa_file_perm - do permission revalidation check & audit for @file
+ * @op: operation being checked
+ * @label: label being enforced   (NOT NULL)
+ * @file: file to revalidate access permissions on  (NOT NULL)
+ * @request: requested permissions
+ * @in_atomic: whether allocations need to be done in atomic context
+ *
+ * Returns: %0 if access allowed else error
+ */
+int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
+		 u32 request, bool in_atomic)
+{
+	struct aa_file_ctx *fctx;
+	struct aa_label *flabel;
+	u32 denied;
+	int error = 0;
+
+	AA_BUG(!label);
+	AA_BUG(!file);
+
+	fctx = file_ctx(file);
+
+	rcu_read_lock();
+	flabel  = rcu_dereference(fctx->label);
+	AA_BUG(!flabel);
+
+	/* revalidate access, if task is unconfined, or the cached cred
+	 * doesn't match or if the request is for more permissions than
+	 * was granted.
+	 *
+	 * Note: the test for !unconfined(flabel) is to handle file
+	 *       delegation from unconfined tasks
+	 */
+	denied = request & ~fctx->allow;
+	if (unconfined(label) || unconfined(flabel) ||
+	    (!denied && aa_label_is_subset(flabel, label))) {
+		rcu_read_unlock();
+		goto done;
+	}
+
+	flabel  = aa_get_newest_label(flabel);
+	rcu_read_unlock();
+	/* TODO: label cross check */
+
+	if (file->f_path.mnt && path_mediated_fs(file->f_path.dentry))
+		error = __file_path_perm(op, label, flabel, file, request,
+					 denied, in_atomic);
+
+	else if (S_ISSOCK(file_inode(file)->i_mode))
+		error = __file_sock_perm(op, label, flabel, file, request,
+					 denied);
+	aa_put_label(flabel);
+
+done:
+	return error;
+}
+
+static void revalidate_tty(struct aa_label *label)
+{
+	struct tty_struct *tty;
+	int drop_tty = 0;
+
+	tty = get_current_tty();
+	if (!tty)
+		return;
+
+	spin_lock(&tty->files_lock);
+	if (!list_empty(&tty->tty_files)) {
+		struct tty_file_private *file_priv;
+		struct file *file;
+		/* TODO: Revalidate access to controlling tty. */
+		file_priv = list_first_entry(&tty->tty_files,
+					     struct tty_file_private, list);
+		file = file_priv->file;
+
+		if (aa_file_perm(OP_INHERIT, label, file, MAY_READ | MAY_WRITE,
+				 IN_ATOMIC))
+			drop_tty = 1;
+	}
+	spin_unlock(&tty->files_lock);
+	tty_kref_put(tty);
+
+	if (drop_tty)
+		no_tty();
+}
+
+static int match_file(const void *p, struct file *file, unsigned int fd)
+{
+	struct aa_label *label = (struct aa_label *)p;
+
+	if (aa_file_perm(OP_INHERIT, label, file, aa_map_file_to_perms(file),
+			 IN_ATOMIC))
+		return fd + 1;
+	return 0;
+}
+
+
+/* based on selinux's flush_unauthorized_files */
+void aa_inherit_files(const struct cred *cred, struct files_struct *files)
+{
+	struct aa_label *label = aa_get_newest_cred_label(cred);
+	struct file *devnull = NULL;
+	unsigned int n;
+
+	revalidate_tty(label);
+
+	/* Revalidate access to inherited open files. */
+	n = iterate_fd(files, 0, match_file, label);
+	if (!n) /* none found? */
+		goto out;
+
+	devnull = dentry_open(&aa_null, O_RDWR, cred);
+	if (IS_ERR(devnull))
+		devnull = NULL;
+	/* replace all the matching ones with this */
+	do {
+		replace_fd(n - 1, devnull, 0);
+	} while ((n = iterate_fd(files, n, match_file, label)) != 0);
+	if (devnull)
+		fput(devnull);
+out:
+	aa_put_label(label);
+}