[PATCH 1/2] security/smack implement logging V2
Eric Paris
eparis at redhat.com
Mon Apr 6 18:53:53 UTC 2009
On Sun, 2009-04-05 at 10:47 +0200, Etienne Basset wrote:
> 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 at numericable.fr>
> ---
> diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
> new file mode 100644
> index 0000000..df54ad6
> --- /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 at ensta.org>
> + *
> + * All credits to : Stephen Smalley, <sds at epoch.ncsc.mil>
> + * All BUGS to : Etienne BASSET <etienne.basset at ensta.org>
> + */
> +#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 <asm/system.h>
I believe they say to always put asm/ after all linux/
> +#include <linux/key.h>
> +#include <linux/skbuff.h>
> +
> +
> +/* Auxiliary data to use in generating the audit record. */
> +struct common_audit_data {
> + char type;
> +#define AVC_AUDIT_DATA_FS 1
> +#define AVC_AUDIT_DATA_NET 2
> +#define AVC_AUDIT_DATA_CAP 3
> +#define AVC_AUDIT_DATA_IPC 4
> +#define AVC_AUDIT_DATA_TASK 5
> +#define AVC_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 {
> + 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 AVC audit data structure. */
> +#define COMMON_AUDIT_DATA_INIT(_d, _t) \
> + { memset((_d), 0, sizeof(struct common_audit_data)); \
> + (_d)->type = AVC_AUDIT_DATA_##_t; (_d)->function = __func__; }
> +
> +void common_lsm_audit(struct common_audit_data *a);
> +
> +#endif
> diff --git a/security/Makefile b/security/Makefile
> index fa77021..bd208b8 100644
> --- a/security/Makefile
> +++ b/security/Makefile
> @@ -15,7 +15,7 @@ obj-$(CONFIG_SECURITY) += security.o capability.o
> obj-$(CONFIG_SECURITYFS) += inode.o
> # Must precede capability.o in order to stack properly.
> obj-$(CONFIG_SECURITY_SELINUX) += selinux/built-in.o
> -obj-$(CONFIG_SECURITY_SMACK) += smack/built-in.o
> +obj-$(CONFIG_SECURITY_SMACK) += smack/built-in.o lsm_audit.o
> obj-$(CONFIG_SECURITY_TOMOYO) += tomoyo/built-in.o
> obj-$(CONFIG_SECURITY_ROOTPLUG) += root_plug.o
> obj-$(CONFIG_CGROUP_DEVICE) += device_cgroup.o
> diff --git a/security/lsm_audit.c b/security/lsm_audit.c
> new file mode 100644
> index 0000000..9056848
> --- /dev/null
> +++ b/security/lsm_audit.c
> @@ -0,0 +1,390 @@
> +/*
> + * common LSM auditing functions
> + *
> + * Based on code written for SELinux by :
> + * Stephen Smalley, <sds at epoch.ncsc.mil>
> + * James Morris <jmorris at redhat.com>
> + * Author : Etienne Basset, <etienne.basset at 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/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 avc_print_ipv6_addr(struct audit_buffer *ab,
> + struct in6_addr *addr, __be16 port,
> + char *name1, char *name2)
avc_ is an SELinux'ism that doesn't make much sense. I'm fine with just
print_ipv6_addr or audit_ipv6_addr or output_ipv6_addr....
> +{
> + 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 avc_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)
odd place for a "\t " if you aren't going to line up the arguments,
just use tabs. Couple other "\t " oddities...
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