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-rw-r--r--security/lsm_audit.c463
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);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 15:59:53 +0000