diff options
Diffstat (limited to '')
| -rw-r--r-- | security/lsm_audit.c | 470 |
1 files changed, 470 insertions, 0 deletions
diff --git a/security/lsm_audit.c b/security/lsm_audit.c new file mode 100644 index 000000000..d6fea68d2 --- /dev/null +++ b/security/lsm_audit.c @@ -0,0 +1,470 @@ +/* + * 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> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2, + * as published by the Free Software Foundation. + */ + +#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> + +/** + * 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); + if (ih == NULL) + return -EINVAL; + + 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); + if (th == NULL) + break; + + ad->u.net->sport = th->source; + ad->u.net->dport = th->dest; + break; + } + case IPPROTO_UDP: { + struct udphdr *uh = udp_hdr(skb); + if (uh == NULL) + break; + + ad->u.net->sport = uh->source; + ad->u.net->dport = uh->dest; + break; + } + case IPPROTO_DCCP: { + struct dccp_hdr *dh = dccp_hdr(skb); + if (dh == NULL) + break; + + ad->u.net->sport = dh->dccph_sport; + ad->u.net->dport = dh->dccph_dport; + break; + } + case IPPROTO_SCTP: { + struct sctphdr *sh = sctp_hdr(skb); + if (sh == NULL) + break; + 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); + if (ip6 == NULL) + return -EINVAL; + ad->u.net->v6info.saddr = ip6->saddr; + ad->u.net->v6info.daddr = ip6->daddr; + ret = 0; + /* 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, + 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, " 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; + + inode = a->u.inode; + dentry = d_find_alias(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); + dput(dentry); + } + 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_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) { + 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; + } /* 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); +} |