1 files changed, 463 insertions, 0 deletions

diff --git a/security/lsm_audit.c b/security/lsm_audit.c
new file mode 100644
index 000000000..75cc3f8d2
--- /dev/null
+++ b/security/lsm_audit.c
@@ -0,0 +1,463 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * common LSM auditing functions
+ *
+ * Based on code written for SELinux by :
+ *			Stephen Smalley, <sds@tycho.nsa.gov>
+ * 			James Morris <jmorris@redhat.com>
+ * Author : Etienne Basset, <etienne.basset@ensta.org>
+ */
+
+#include <linux/types.h>
+#include <linux/stddef.h>
+#include <linux/kernel.h>
+#include <linux/gfp.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <net/sock.h>
+#include <linux/un.h>
+#include <net/af_unix.h>
+#include <linux/audit.h>
+#include <linux/ipv6.h>
+#include <linux/ip.h>
+#include <net/ip.h>
+#include <net/ipv6.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/dccp.h>
+#include <linux/sctp.h>
+#include <linux/lsm_audit.h>
+#include <linux/security.h>
+
+/**
+ * ipv4_skb_to_auditdata : fill auditdata from skb
+ * @skb : the skb
+ * @ad : the audit data to fill
+ * @proto : the layer 4 protocol
+ *
+ * return  0 on success
+ */
+int ipv4_skb_to_auditdata(struct sk_buff *skb,
+		struct common_audit_data *ad, u8 *proto)
+{
+	int ret = 0;
+	struct iphdr *ih;
+
+	ih = ip_hdr(skb);
+	ad->u.net->v4info.saddr = ih->saddr;
+	ad->u.net->v4info.daddr = ih->daddr;
+
+	if (proto)
+		*proto = ih->protocol;
+	/* non initial fragment */
+	if (ntohs(ih->frag_off) & IP_OFFSET)
+		return 0;
+
+	switch (ih->protocol) {
+	case IPPROTO_TCP: {
+		struct tcphdr *th = tcp_hdr(skb);
+
+		ad->u.net->sport = th->source;
+		ad->u.net->dport = th->dest;
+		break;
+	}
+	case IPPROTO_UDP: {
+		struct udphdr *uh = udp_hdr(skb);
+
+		ad->u.net->sport = uh->source;
+		ad->u.net->dport = uh->dest;
+		break;
+	}
+	case IPPROTO_DCCP: {
+		struct dccp_hdr *dh = dccp_hdr(skb);
+
+		ad->u.net->sport = dh->dccph_sport;
+		ad->u.net->dport = dh->dccph_dport;
+		break;
+	}
+	case IPPROTO_SCTP: {
+		struct sctphdr *sh = sctp_hdr(skb);
+
+		ad->u.net->sport = sh->source;
+		ad->u.net->dport = sh->dest;
+		break;
+	}
+	default:
+		ret = -EINVAL;
+	}
+	return ret;
+}
+#if IS_ENABLED(CONFIG_IPV6)
+/**
+ * ipv6_skb_to_auditdata : fill auditdata from skb
+ * @skb : the skb
+ * @ad : the audit data to fill
+ * @proto : the layer 4 protocol
+ *
+ * return  0 on success
+ */
+int ipv6_skb_to_auditdata(struct sk_buff *skb,
+		struct common_audit_data *ad, u8 *proto)
+{
+	int offset, ret = 0;
+	struct ipv6hdr *ip6;
+	u8 nexthdr;
+	__be16 frag_off;
+
+	ip6 = ipv6_hdr(skb);
+	ad->u.net->v6info.saddr = ip6->saddr;
+	ad->u.net->v6info.daddr = ip6->daddr;
+	/* IPv6 can have several extension header before the Transport header
+	 * skip them */
+	offset = skb_network_offset(skb);
+	offset += sizeof(*ip6);
+	nexthdr = ip6->nexthdr;
+	offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
+	if (offset < 0)
+		return 0;
+	if (proto)
+		*proto = nexthdr;
+	switch (nexthdr) {
+	case IPPROTO_TCP: {
+		struct tcphdr _tcph, *th;
+
+		th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
+		if (th == NULL)
+			break;
+
+		ad->u.net->sport = th->source;
+		ad->u.net->dport = th->dest;
+		break;
+	}
+	case IPPROTO_UDP: {
+		struct udphdr _udph, *uh;
+
+		uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
+		if (uh == NULL)
+			break;
+
+		ad->u.net->sport = uh->source;
+		ad->u.net->dport = uh->dest;
+		break;
+	}
+	case IPPROTO_DCCP: {
+		struct dccp_hdr _dccph, *dh;
+
+		dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
+		if (dh == NULL)
+			break;
+
+		ad->u.net->sport = dh->dccph_sport;
+		ad->u.net->dport = dh->dccph_dport;
+		break;
+	}
+	case IPPROTO_SCTP: {
+		struct sctphdr _sctph, *sh;
+
+		sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
+		if (sh == NULL)
+			break;
+		ad->u.net->sport = sh->source;
+		ad->u.net->dport = sh->dest;
+		break;
+	}
+	default:
+		ret = -EINVAL;
+	}
+	return ret;
+}
+#endif
+
+
+static inline void print_ipv6_addr(struct audit_buffer *ab,
+				   const struct in6_addr *addr, __be16 port,
+				   char *name1, char *name2)
+{
+	if (!ipv6_addr_any(addr))
+		audit_log_format(ab, " %s=%pI6c", name1, addr);
+	if (port)
+		audit_log_format(ab, " %s=%d", name2, ntohs(port));
+}
+
+static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
+				   __be16 port, char *name1, char *name2)
+{
+	if (addr)
+		audit_log_format(ab, " %s=%pI4", name1, &addr);
+	if (port)
+		audit_log_format(ab, " %s=%d", name2, ntohs(port));
+}
+
+/**
+ * dump_common_audit_data - helper to dump common audit data
+ * @a : common audit data
+ *
+ */
+static void dump_common_audit_data(struct audit_buffer *ab,
+				   struct common_audit_data *a)
+{
+	char comm[sizeof(current->comm)];
+
+	/*
+	 * To keep stack sizes in check force programers to notice if they
+	 * start making this union too large!  See struct lsm_network_audit
+	 * as an example of how to deal with large data.
+	 */
+	BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2);
+
+	audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
+	audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm)));
+
+	switch (a->type) {
+	case LSM_AUDIT_DATA_NONE:
+		return;
+	case LSM_AUDIT_DATA_IPC:
+		audit_log_format(ab, " ipc_key=%d ", a->u.ipc_id);
+		break;
+	case LSM_AUDIT_DATA_CAP:
+		audit_log_format(ab, " capability=%d ", a->u.cap);
+		break;
+	case LSM_AUDIT_DATA_PATH: {
+		struct inode *inode;
+
+		audit_log_d_path(ab, " path=", &a->u.path);
+
+		inode = d_backing_inode(a->u.path.dentry);
+		if (inode) {
+			audit_log_format(ab, " dev=");
+			audit_log_untrustedstring(ab, inode->i_sb->s_id);
+			audit_log_format(ab, " ino=%lu", inode->i_ino);
+		}
+		break;
+	}
+	case LSM_AUDIT_DATA_FILE: {
+		struct inode *inode;
+
+		audit_log_d_path(ab, " path=", &a->u.file->f_path);
+
+		inode = file_inode(a->u.file);
+		if (inode) {
+			audit_log_format(ab, " dev=");
+			audit_log_untrustedstring(ab, inode->i_sb->s_id);
+			audit_log_format(ab, " ino=%lu", inode->i_ino);
+		}
+		break;
+	}
+	case LSM_AUDIT_DATA_IOCTL_OP: {
+		struct inode *inode;
+
+		audit_log_d_path(ab, " path=", &a->u.op->path);
+
+		inode = a->u.op->path.dentry->d_inode;
+		if (inode) {
+			audit_log_format(ab, " dev=");
+			audit_log_untrustedstring(ab, inode->i_sb->s_id);
+			audit_log_format(ab, " ino=%lu", inode->i_ino);
+		}
+
+		audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd);
+		break;
+	}
+	case LSM_AUDIT_DATA_DENTRY: {
+		struct inode *inode;
+
+		audit_log_format(ab, " name=");
+		spin_lock(&a->u.dentry->d_lock);
+		audit_log_untrustedstring(ab, a->u.dentry->d_name.name);
+		spin_unlock(&a->u.dentry->d_lock);
+
+		inode = d_backing_inode(a->u.dentry);
+		if (inode) {
+			audit_log_format(ab, " dev=");
+			audit_log_untrustedstring(ab, inode->i_sb->s_id);
+			audit_log_format(ab, " ino=%lu", inode->i_ino);
+		}
+		break;
+	}
+	case LSM_AUDIT_DATA_INODE: {
+		struct dentry *dentry;
+		struct inode *inode;
+
+		rcu_read_lock();
+		inode = a->u.inode;
+		dentry = d_find_alias_rcu(inode);
+		if (dentry) {
+			audit_log_format(ab, " name=");
+			spin_lock(&dentry->d_lock);
+			audit_log_untrustedstring(ab, dentry->d_name.name);
+			spin_unlock(&dentry->d_lock);
+		}
+		audit_log_format(ab, " dev=");
+		audit_log_untrustedstring(ab, inode->i_sb->s_id);
+		audit_log_format(ab, " ino=%lu", inode->i_ino);
+		rcu_read_unlock();
+		break;
+	}
+	case LSM_AUDIT_DATA_TASK: {
+		struct task_struct *tsk = a->u.tsk;
+		if (tsk) {
+			pid_t pid = task_tgid_nr(tsk);
+			if (pid) {
+				char comm[sizeof(tsk->comm)];
+				audit_log_format(ab, " opid=%d ocomm=", pid);
+				audit_log_untrustedstring(ab,
+				    memcpy(comm, tsk->comm, sizeof(comm)));
+			}
+		}
+		break;
+	}
+	case LSM_AUDIT_DATA_NET:
+		if (a->u.net->sk) {
+			const struct sock *sk = a->u.net->sk;
+			struct unix_sock *u;
+			struct unix_address *addr;
+			int len = 0;
+			char *p = NULL;
+
+			switch (sk->sk_family) {
+			case AF_INET: {
+				struct inet_sock *inet = inet_sk(sk);
+
+				print_ipv4_addr(ab, inet->inet_rcv_saddr,
+						inet->inet_sport,
+						"laddr", "lport");
+				print_ipv4_addr(ab, inet->inet_daddr,
+						inet->inet_dport,
+						"faddr", "fport");
+				break;
+			}
+#if IS_ENABLED(CONFIG_IPV6)
+			case AF_INET6: {
+				struct inet_sock *inet = inet_sk(sk);
+
+				print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr,
+						inet->inet_sport,
+						"laddr", "lport");
+				print_ipv6_addr(ab, &sk->sk_v6_daddr,
+						inet->inet_dport,
+						"faddr", "fport");
+				break;
+			}
+#endif
+			case AF_UNIX:
+				u = unix_sk(sk);
+				addr = smp_load_acquire(&u->addr);
+				if (!addr)
+					break;
+				if (u->path.dentry) {
+					audit_log_d_path(ab, " path=", &u->path);
+					break;
+				}
+				len = addr->len-sizeof(short);
+				p = &addr->name->sun_path[0];
+				audit_log_format(ab, " path=");
+				if (*p)
+					audit_log_untrustedstring(ab, p);
+				else
+					audit_log_n_hex(ab, p, len);
+				break;
+			}
+		}
+
+		switch (a->u.net->family) {
+		case AF_INET:
+			print_ipv4_addr(ab, a->u.net->v4info.saddr,
+					a->u.net->sport,
+					"saddr", "src");
+			print_ipv4_addr(ab, a->u.net->v4info.daddr,
+					a->u.net->dport,
+					"daddr", "dest");
+			break;
+		case AF_INET6:
+			print_ipv6_addr(ab, &a->u.net->v6info.saddr,
+					a->u.net->sport,
+					"saddr", "src");
+			print_ipv6_addr(ab, &a->u.net->v6info.daddr,
+					a->u.net->dport,
+					"daddr", "dest");
+			break;
+		}
+		if (a->u.net->netif > 0) {
+			struct net_device *dev;
+
+			/* NOTE: we always use init's namespace */
+			dev = dev_get_by_index(&init_net, a->u.net->netif);
+			if (dev) {
+				audit_log_format(ab, " netif=%s", dev->name);
+				dev_put(dev);
+			}
+		}
+		break;
+#ifdef CONFIG_KEYS
+	case LSM_AUDIT_DATA_KEY:
+		audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
+		if (a->u.key_struct.key_desc) {
+			audit_log_format(ab, " key_desc=");
+			audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
+		}
+		break;
+#endif
+	case LSM_AUDIT_DATA_KMOD:
+		audit_log_format(ab, " kmod=");
+		audit_log_untrustedstring(ab, a->u.kmod_name);
+		break;
+	case LSM_AUDIT_DATA_IBPKEY: {
+		struct in6_addr sbn_pfx;
+
+		memset(&sbn_pfx.s6_addr, 0,
+		       sizeof(sbn_pfx.s6_addr));
+		memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix,
+		       sizeof(a->u.ibpkey->subnet_prefix));
+		audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c",
+				 a->u.ibpkey->pkey, &sbn_pfx);
+		break;
+	}
+	case LSM_AUDIT_DATA_IBENDPORT:
+		audit_log_format(ab, " device=%s port_num=%u",
+				 a->u.ibendport->dev_name,
+				 a->u.ibendport->port);
+		break;
+	case LSM_AUDIT_DATA_LOCKDOWN:
+		audit_log_format(ab, " lockdown_reason=\"%s\"",
+				 lockdown_reasons[a->u.reason]);
+		break;
+	case LSM_AUDIT_DATA_ANONINODE:
+		audit_log_format(ab, " anonclass=%s", a->u.anonclass);
+		break;
+	} /* switch (a->type) */
+}
+
+/**
+ * common_lsm_audit - generic LSM auditing function
+ * @a:  auxiliary audit data
+ * @pre_audit: lsm-specific pre-audit callback
+ * @post_audit: lsm-specific post-audit callback
+ *
+ * setup the audit buffer for common security information
+ * uses callback to print LSM specific information
+ */
+void common_lsm_audit(struct common_audit_data *a,
+	void (*pre_audit)(struct audit_buffer *, void *),
+	void (*post_audit)(struct audit_buffer *, void *))
+{
+	struct audit_buffer *ab;
+
+	if (a == NULL)
+		return;
+	/* we use GFP_ATOMIC so we won't sleep */
+	ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN,
+			     AUDIT_AVC);
+
+	if (ab == NULL)
+		return;
+
+	if (pre_audit)
+		pre_audit(ab, a);
+
+	dump_common_audit_data(ab, a);
+
+	if (post_audit)
+		post_audit(ab, a);
+
+	audit_log_end(ab);
+}