This patch creates auditing functions usable by LSM to audit security events. It provides standard dumping of FS, NET, task etc ... events (code borrowed from SELinux) and provides 2 callbacks to define LSM specific auditing, which should be flexible enough to convert SELinux too. Signed-off-by: Etienne Basset <etienne.basset(a)numericable.fr&gt;

--- include/linux/lsm_audit.h | 111 +++++++++++++ security/lsm_audit.c | 386 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 497 insertions(+), 0 deletions(-) diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h new file mode 100644 index 0000000..e461b2c --- /dev/null +++ b/include/linux/lsm_audit.h @@ -0,0 +1,111 @@ +/* + * Common LSM logging functions + * Heavily borrowed from selinux/avc.h + * + * Author : Etienne BASSET <etienne.basset(a)ensta.org&gt; + * + * All credits to : Stephen Smalley, <sds(a)epoch.ncsc.mil&gt; + * All BUGS to : Etienne BASSET <etienne.basset(a)ensta.org&gt; + */ +#ifndef _LSM_COMMON_LOGGING_ +#define _LSM_COMMON_LOGGING_ + +#include <linux/stddef.h> +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/kdev_t.h> +#include <linux/spinlock.h> +#include <linux/init.h> +#include <linux/audit.h> +#include <linux/in6.h> +#include <linux/path.h> +#include <linux/key.h> +#include <linux/skbuff.h> +#include <asm/system.h> + + +/* Auxiliary data to use in generating the audit record. */ +struct common_audit_data { + char type; +#define LSM_AUDIT_DATA_FS 1 +#define LSM_AUDIT_DATA_NET 2 +#define LSM_AUDIT_DATA_CAP 3 +#define LSM_AUDIT_DATA_IPC 4 +#define LSM_AUDIT_DATA_TASK 5 +#define LSM_AUDIT_DATA_KEY 6 + struct task_struct *tsk; + union { + struct { + struct path path; + struct inode *inode; + } fs; + struct { + int netif; + struct sock *sk; + u16 family; + __be16 dport; + __be16 sport; + union { + struct { + __be32 daddr; + __be32 saddr; + } v4; + struct { + struct in6_addr daddr; + struct in6_addr saddr; + } v6; + } fam; + } net; + int cap; + int ipc_id; + struct task_struct *tsk; +#ifdef CONFIG_KEYS + struct { + key_serial_t key; + char *key_desc; + } key_struct; +#endif + } u; + const char *function; + /* this union contains LSM specific data */ + union { + /* SMACK data */ + struct smack_audit_data { + char *subject; + char *object; + char *request; + int result; + } smack_audit_data; + /* SELinux data */ + struct { + u32 ssid; + u32 tsid; + u16 tclass; + u32 requested; + u32 audited; + struct av_decision *avd; + int result; + } selinux_audit_data; + } lsm_priv; + /* these callback will be implemented by a specific LSM */ + void (*lsm_pre_audit)(struct audit_buffer *, void *); + void (*lsm_post_audit)(struct audit_buffer *, void *); +}; + +#define v4info fam.v4 +#define v6info fam.v6 + +int ipv4_skb_to_auditdata(struct sk_buff *skb, + struct common_audit_data *ad, u8 *proto); + +int ipv6_skb_to_auditdata(struct sk_buff *skb, + struct common_audit_data *ad, u8 *proto); + +/* Initialize an LSM audit data structure. */ +#define COMMON_AUDIT_DATA_INIT(_d, _t) \ + { memset((_d), 0, sizeof(struct common_audit_data)); \ + (_d)->type = LSM_AUDIT_DATA_##_t; (_d)->function = __func__; } + +void common_lsm_audit(struct common_audit_data *a); + +#endif diff --git a/security/lsm_audit.c b/security/lsm_audit.c new file mode 100644 index 0000000..b47a933 --- /dev/null +++ b/security/lsm_audit.c @@ -0,0 +1,386 @@ +/* + * common LSM auditing functions + * + * Based on code written for SELinux by : + * Stephen Smalley, <sds(a)epoch.ncsc.mil&gt; + * James Morris <jmorris(a)redhat.com&gt; + * Author : Etienne Basset, <etienne.basset(a)ensta.org&gt; + * + * 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/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 defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) +/** + * 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; + + ip6 = ipv6_hdr(skb); + if (ip6 == NULL) + return -EINVAL; + ipv6_addr_copy(&ad->u.net.v6info.saddr, &ip6->saddr); + ipv6_addr_copy(&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); + 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=%pI6", 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) +{ + struct inode *inode = NULL; + struct task_struct *tsk = current; + + if (a->tsk) + tsk = a->tsk; + if (tsk && tsk->pid) { + audit_log_format(ab, " pid=%d comm=", tsk->pid); + audit_log_untrustedstring(ab, tsk->comm); + } + + switch (a->type) { + 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_FS: + if (a->u.fs.path.dentry) { + struct dentry *dentry = a->u.fs.path.dentry; + if (a->u.fs.path.mnt) { + audit_log_d_path(ab, "path=", &a->u.fs.path); + } else { + audit_log_format(ab, " name="); + audit_log_untrustedstring(ab, + dentry->d_name.name); + } + inode = dentry->d_inode; + } else if (a->u.fs.inode) { + struct dentry *dentry; + inode = a->u.fs.inode; + dentry = d_find_alias(inode); + if (dentry) { + audit_log_format(ab, " name="); + audit_log_untrustedstring(ab, + dentry->d_name.name); + dput(dentry); + } + } + if (inode) + audit_log_format(ab, " dev=%s ino=%lu", + inode->i_sb->s_id, + inode->i_ino); + break; + case LSM_AUDIT_DATA_TASK: + tsk = a->u.tsk; + if (tsk && tsk->pid) { + audit_log_format(ab, " pid=%d comm=", tsk->pid); + audit_log_untrustedstring(ab, tsk->comm); + } + break; + case LSM_AUDIT_DATA_NET: + if (a->u.net.sk) { + struct sock *sk = a->u.net.sk; + struct unix_sock *u; + 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->rcv_saddr, + inet->sport, + "laddr", "lport"); + print_ipv4_addr(ab, inet->daddr, + inet->dport, + "faddr", "fport"); + break; + } + case AF_INET6: { + struct inet_sock *inet = inet_sk(sk); + struct ipv6_pinfo *inet6 = inet6_sk(sk); + + print_ipv6_addr(ab, &inet6->rcv_saddr, + inet->sport, + "laddr", "lport"); + print_ipv6_addr(ab, &inet6->daddr, + inet->dport, + "faddr", "fport"); + break; + } + case AF_UNIX: + u = unix_sk(sk); + if (u->dentry) { + struct path path = { + .dentry = u->dentry, + .mnt = u->mnt + }; + audit_log_d_path(ab, "path=", &path); + break; + } + if (!u->addr) + break; + len = u->addr->len-sizeof(short); + p = &u->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 + } /* switch (a->type) */ +} + +/** + * common_lsm_audit - generic LSM auditing function + * @a: auxiliary audit data + * + * setup the audit buffer for common security information + * uses callback to print LSM specific information + */ +void common_lsm_audit(struct common_audit_data *a) +{ + struct audit_buffer *ab; + + if (a == NULL) + return; + /* we use GFP_ATOMIC so we won't sleep */ + ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC); + + if (ab == NULL) + return; + + if (a->lsm_pre_audit) + a->lsm_pre_audit(ab, a); + + dump_common_audit_data(ab, a); + + if (a->lsm_post_audit) + a->lsm_post_audit(ab, a); + + audit_log_end(ab); +} -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html