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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /security/selinux/xfrm.c
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
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(). ...
Diffstat (limited to 'security/selinux/xfrm.c')
-rw-r--r--security/selinux/xfrm.c473
1 files changed, 473 insertions, 0 deletions
diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
new file mode 100644
index 000000000..c576832fe
--- /dev/null
+++ b/security/selinux/xfrm.c
@@ -0,0 +1,473 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * NSA Security-Enhanced Linux (SELinux) security module
+ *
+ * This file contains the SELinux XFRM hook function implementations.
+ *
+ * Authors: Serge Hallyn <sergeh@us.ibm.com>
+ * Trent Jaeger <jaegert@us.ibm.com>
+ *
+ * Updated: Venkat Yekkirala <vyekkirala@TrustedCS.com>
+ *
+ * Granular IPSec Associations for use in MLS environments.
+ *
+ * Copyright (C) 2005 International Business Machines Corporation
+ * Copyright (C) 2006 Trusted Computer Solutions, Inc.
+ */
+
+/*
+ * USAGE:
+ * NOTES:
+ * 1. Make sure to enable the following options in your kernel config:
+ * CONFIG_SECURITY=y
+ * CONFIG_SECURITY_NETWORK=y
+ * CONFIG_SECURITY_NETWORK_XFRM=y
+ * CONFIG_SECURITY_SELINUX=m/y
+ * ISSUES:
+ * 1. Caching packets, so they are not dropped during negotiation
+ * 2. Emulating a reasonable SO_PEERSEC across machines
+ * 3. Testing addition of sk_policy's with security context via setsockopt
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/security.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <linux/skbuff.h>
+#include <linux/xfrm.h>
+#include <net/xfrm.h>
+#include <net/checksum.h>
+#include <net/udp.h>
+#include <linux/atomic.h>
+
+#include "avc.h"
+#include "objsec.h"
+#include "xfrm.h"
+
+/* Labeled XFRM instance counter */
+atomic_t selinux_xfrm_refcount __read_mostly = ATOMIC_INIT(0);
+
+/*
+ * Returns true if the context is an LSM/SELinux context.
+ */
+static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx)
+{
+ return (ctx &&
+ (ctx->ctx_doi == XFRM_SC_DOI_LSM) &&
+ (ctx->ctx_alg == XFRM_SC_ALG_SELINUX));
+}
+
+/*
+ * Returns true if the xfrm contains a security blob for SELinux.
+ */
+static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
+{
+ return selinux_authorizable_ctx(x->security);
+}
+
+/*
+ * Allocates a xfrm_sec_state and populates it using the supplied security
+ * xfrm_user_sec_ctx context.
+ */
+static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp,
+ struct xfrm_user_sec_ctx *uctx,
+ gfp_t gfp)
+{
+ int rc;
+ const struct task_security_struct *tsec = selinux_cred(current_cred());
+ struct xfrm_sec_ctx *ctx = NULL;
+ u32 str_len;
+
+ if (ctxp == NULL || uctx == NULL ||
+ uctx->ctx_doi != XFRM_SC_DOI_LSM ||
+ uctx->ctx_alg != XFRM_SC_ALG_SELINUX)
+ return -EINVAL;
+
+ str_len = uctx->ctx_len;
+ if (str_len >= PAGE_SIZE)
+ return -ENOMEM;
+
+ ctx = kmalloc(struct_size(ctx, ctx_str, str_len + 1), gfp);
+ if (!ctx)
+ return -ENOMEM;
+
+ ctx->ctx_doi = XFRM_SC_DOI_LSM;
+ ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
+ ctx->ctx_len = str_len;
+ memcpy(ctx->ctx_str, &uctx[1], str_len);
+ ctx->ctx_str[str_len] = '\0';
+ rc = security_context_to_sid(&selinux_state, ctx->ctx_str, str_len,
+ &ctx->ctx_sid, gfp);
+ if (rc)
+ goto err;
+
+ rc = avc_has_perm(&selinux_state,
+ tsec->sid, ctx->ctx_sid,
+ SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT, NULL);
+ if (rc)
+ goto err;
+
+ *ctxp = ctx;
+ atomic_inc(&selinux_xfrm_refcount);
+ return 0;
+
+err:
+ kfree(ctx);
+ return rc;
+}
+
+/*
+ * Free the xfrm_sec_ctx structure.
+ */
+static void selinux_xfrm_free(struct xfrm_sec_ctx *ctx)
+{
+ if (!ctx)
+ return;
+
+ atomic_dec(&selinux_xfrm_refcount);
+ kfree(ctx);
+}
+
+/*
+ * Authorize the deletion of a labeled SA or policy rule.
+ */
+static int selinux_xfrm_delete(struct xfrm_sec_ctx *ctx)
+{
+ const struct task_security_struct *tsec = selinux_cred(current_cred());
+
+ if (!ctx)
+ return 0;
+
+ return avc_has_perm(&selinux_state,
+ tsec->sid, ctx->ctx_sid,
+ SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT,
+ NULL);
+}
+
+/*
+ * LSM hook implementation that authorizes that a flow can use a xfrm policy
+ * rule.
+ */
+int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid)
+{
+ int rc;
+
+ /* All flows should be treated as polmatch'ing an otherwise applicable
+ * "non-labeled" policy. This would prevent inadvertent "leaks". */
+ if (!ctx)
+ return 0;
+
+ /* Context sid is either set to label or ANY_ASSOC */
+ if (!selinux_authorizable_ctx(ctx))
+ return -EINVAL;
+
+ rc = avc_has_perm(&selinux_state,
+ fl_secid, ctx->ctx_sid,
+ SECCLASS_ASSOCIATION, ASSOCIATION__POLMATCH, NULL);
+ return (rc == -EACCES ? -ESRCH : rc);
+}
+
+/*
+ * LSM hook implementation that authorizes that a state matches
+ * the given policy, flow combo.
+ */
+int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x,
+ struct xfrm_policy *xp,
+ const struct flowi_common *flic)
+{
+ u32 state_sid;
+ u32 flic_sid;
+
+ if (!xp->security)
+ if (x->security)
+ /* unlabeled policy and labeled SA can't match */
+ return 0;
+ else
+ /* unlabeled policy and unlabeled SA match all flows */
+ return 1;
+ else
+ if (!x->security)
+ /* unlabeled SA and labeled policy can't match */
+ return 0;
+ else
+ if (!selinux_authorizable_xfrm(x))
+ /* Not a SELinux-labeled SA */
+ return 0;
+
+ state_sid = x->security->ctx_sid;
+ flic_sid = flic->flowic_secid;
+
+ if (flic_sid != state_sid)
+ return 0;
+
+ /* We don't need a separate SA Vs. policy polmatch check since the SA
+ * is now of the same label as the flow and a flow Vs. policy polmatch
+ * check had already happened in selinux_xfrm_policy_lookup() above. */
+ return (avc_has_perm(&selinux_state, flic_sid, state_sid,
+ SECCLASS_ASSOCIATION, ASSOCIATION__SENDTO,
+ NULL) ? 0 : 1);
+}
+
+static u32 selinux_xfrm_skb_sid_egress(struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+ struct xfrm_state *x;
+
+ if (dst == NULL)
+ return SECSID_NULL;
+ x = dst->xfrm;
+ if (x == NULL || !selinux_authorizable_xfrm(x))
+ return SECSID_NULL;
+
+ return x->security->ctx_sid;
+}
+
+static int selinux_xfrm_skb_sid_ingress(struct sk_buff *skb,
+ u32 *sid, int ckall)
+{
+ u32 sid_session = SECSID_NULL;
+ struct sec_path *sp = skb_sec_path(skb);
+
+ if (sp) {
+ int i;
+
+ for (i = sp->len - 1; i >= 0; i--) {
+ struct xfrm_state *x = sp->xvec[i];
+ if (selinux_authorizable_xfrm(x)) {
+ struct xfrm_sec_ctx *ctx = x->security;
+
+ if (sid_session == SECSID_NULL) {
+ sid_session = ctx->ctx_sid;
+ if (!ckall)
+ goto out;
+ } else if (sid_session != ctx->ctx_sid) {
+ *sid = SECSID_NULL;
+ return -EINVAL;
+ }
+ }
+ }
+ }
+
+out:
+ *sid = sid_session;
+ return 0;
+}
+
+/*
+ * LSM hook implementation that checks and/or returns the xfrm sid for the
+ * incoming packet.
+ */
+int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
+{
+ if (skb == NULL) {
+ *sid = SECSID_NULL;
+ return 0;
+ }
+ return selinux_xfrm_skb_sid_ingress(skb, sid, ckall);
+}
+
+int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
+{
+ int rc;
+
+ rc = selinux_xfrm_skb_sid_ingress(skb, sid, 0);
+ if (rc == 0 && *sid == SECSID_NULL)
+ *sid = selinux_xfrm_skb_sid_egress(skb);
+
+ return rc;
+}
+
+/*
+ * LSM hook implementation that allocs and transfers uctx spec to xfrm_policy.
+ */
+int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
+ struct xfrm_user_sec_ctx *uctx,
+ gfp_t gfp)
+{
+ return selinux_xfrm_alloc_user(ctxp, uctx, gfp);
+}
+
+/*
+ * LSM hook implementation that copies security data structure from old to new
+ * for policy cloning.
+ */
+int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
+ struct xfrm_sec_ctx **new_ctxp)
+{
+ struct xfrm_sec_ctx *new_ctx;
+
+ if (!old_ctx)
+ return 0;
+
+ new_ctx = kmemdup(old_ctx, sizeof(*old_ctx) + old_ctx->ctx_len,
+ GFP_ATOMIC);
+ if (!new_ctx)
+ return -ENOMEM;
+ atomic_inc(&selinux_xfrm_refcount);
+ *new_ctxp = new_ctx;
+
+ return 0;
+}
+
+/*
+ * LSM hook implementation that frees xfrm_sec_ctx security information.
+ */
+void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
+{
+ selinux_xfrm_free(ctx);
+}
+
+/*
+ * LSM hook implementation that authorizes deletion of labeled policies.
+ */
+int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
+{
+ return selinux_xfrm_delete(ctx);
+}
+
+/*
+ * LSM hook implementation that allocates a xfrm_sec_state, populates it using
+ * the supplied security context, and assigns it to the xfrm_state.
+ */
+int selinux_xfrm_state_alloc(struct xfrm_state *x,
+ struct xfrm_user_sec_ctx *uctx)
+{
+ return selinux_xfrm_alloc_user(&x->security, uctx, GFP_KERNEL);
+}
+
+/*
+ * LSM hook implementation that allocates a xfrm_sec_state and populates based
+ * on a secid.
+ */
+int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
+ struct xfrm_sec_ctx *polsec, u32 secid)
+{
+ int rc;
+ struct xfrm_sec_ctx *ctx;
+ char *ctx_str = NULL;
+ u32 str_len;
+
+ if (!polsec)
+ return 0;
+
+ if (secid == 0)
+ return -EINVAL;
+
+ rc = security_sid_to_context(&selinux_state, secid, &ctx_str,
+ &str_len);
+ if (rc)
+ return rc;
+
+ ctx = kmalloc(struct_size(ctx, ctx_str, str_len), GFP_ATOMIC);
+ if (!ctx) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ ctx->ctx_doi = XFRM_SC_DOI_LSM;
+ ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
+ ctx->ctx_sid = secid;
+ ctx->ctx_len = str_len;
+ memcpy(ctx->ctx_str, ctx_str, str_len);
+
+ x->security = ctx;
+ atomic_inc(&selinux_xfrm_refcount);
+out:
+ kfree(ctx_str);
+ return rc;
+}
+
+/*
+ * LSM hook implementation that frees xfrm_state security information.
+ */
+void selinux_xfrm_state_free(struct xfrm_state *x)
+{
+ selinux_xfrm_free(x->security);
+}
+
+/*
+ * LSM hook implementation that authorizes deletion of labeled SAs.
+ */
+int selinux_xfrm_state_delete(struct xfrm_state *x)
+{
+ return selinux_xfrm_delete(x->security);
+}
+
+/*
+ * LSM hook that controls access to unlabelled packets. If
+ * a xfrm_state is authorizable (defined by macro) then it was
+ * already authorized by the IPSec process. If not, then
+ * we need to check for unlabelled access since this may not have
+ * gone thru the IPSec process.
+ */
+int selinux_xfrm_sock_rcv_skb(u32 sk_sid, struct sk_buff *skb,
+ struct common_audit_data *ad)
+{
+ int i;
+ struct sec_path *sp = skb_sec_path(skb);
+ u32 peer_sid = SECINITSID_UNLABELED;
+
+ if (sp) {
+ for (i = 0; i < sp->len; i++) {
+ struct xfrm_state *x = sp->xvec[i];
+
+ if (x && selinux_authorizable_xfrm(x)) {
+ struct xfrm_sec_ctx *ctx = x->security;
+ peer_sid = ctx->ctx_sid;
+ break;
+ }
+ }
+ }
+
+ /* This check even when there's no association involved is intended,
+ * according to Trent Jaeger, to make sure a process can't engage in
+ * non-IPsec communication unless explicitly allowed by policy. */
+ return avc_has_perm(&selinux_state,
+ sk_sid, peer_sid,
+ SECCLASS_ASSOCIATION, ASSOCIATION__RECVFROM, ad);
+}
+
+/*
+ * POSTROUTE_LAST hook's XFRM processing:
+ * If we have no security association, then we need to determine
+ * whether the socket is allowed to send to an unlabelled destination.
+ * If we do have a authorizable security association, then it has already been
+ * checked in the selinux_xfrm_state_pol_flow_match hook above.
+ */
+int selinux_xfrm_postroute_last(u32 sk_sid, struct sk_buff *skb,
+ struct common_audit_data *ad, u8 proto)
+{
+ struct dst_entry *dst;
+
+ switch (proto) {
+ case IPPROTO_AH:
+ case IPPROTO_ESP:
+ case IPPROTO_COMP:
+ /* We should have already seen this packet once before it
+ * underwent xfrm(s). No need to subject it to the unlabeled
+ * check. */
+ return 0;
+ default:
+ break;
+ }
+
+ dst = skb_dst(skb);
+ if (dst) {
+ struct dst_entry *iter;
+
+ for (iter = dst; iter != NULL; iter = xfrm_dst_child(iter)) {
+ struct xfrm_state *x = iter->xfrm;
+
+ if (x && selinux_authorizable_xfrm(x))
+ return 0;
+ }
+ }
+
+ /* This check even when there's no association involved is intended,
+ * according to Trent Jaeger, to make sure a process can't engage in
+ * non-IPsec communication unless explicitly allowed by policy. */
+ return avc_has_perm(&selinux_state, sk_sid, SECINITSID_UNLABELED,
+ SECCLASS_ASSOCIATION, ASSOCIATION__SENDTO, ad);
+}