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audit: normalize NETFILTER_PKT 

Eliminate flipping in and out of message fields, dropping fields in the
process.

Sample raw message format IPv4 UDP:
type=NETFILTER_PKT msg=audit(1487874761.386:228):  mark=0xae8a2732 saddr=127.0.0.1 daddr=127.0.0.1 proto=17^]
Sample raw message format IPv6 ICMP6:
type=NETFILTER_PKT msg=audit(1487874761.381:227):  mark=0x223894b7 saddr=::1 daddr=::1 proto=58^]

Issue: https://github.com/linux-audit/audit-kernel/issues/11
Test case: https://github.com/linux-audit/audit-testsuite/issues/43

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Richard Guy Briggs 2017-05-02 10:16:04 -04:00 committed by Paul Moore
parent 0cb88b6ff0
commit 2173c519d5
1 changed files with 28 additions and 98 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

126
net/netfilter/xt_AUDIT.c
View File

@ -31,146 +31,76 @@ MODULE_ALIAS("ip6t_AUDIT");
MODULE_ALIAS("ebt_AUDIT"); MODULE_ALIAS("ebt_AUDIT");
MODULE_ALIAS("arpt_AUDIT"); MODULE_ALIAS("arpt_AUDIT");
static void audit_proto(struct audit_buffer *ab, struct sk_buff *skb, static bool audit_ip4(struct audit_buffer *ab, struct sk_buff *skb)
unsigned int proto, unsigned int offset)
{
switch (proto) {
case IPPROTO_TCP:
case IPPROTO_UDP:
case IPPROTO_UDPLITE: {
const __be16 *pptr;
__be16 _ports[2];
pptr = skb_header_pointer(skb, offset, sizeof(_ports), _ports);
if (pptr == NULL) {
audit_log_format(ab, " truncated=1");
return;
}
audit_log_format(ab, " sport=%hu dport=%hu",
ntohs(pptr[0]), ntohs(pptr[1]));
}
break;
case IPPROTO_ICMP:
case IPPROTO_ICMPV6: {
const u8 *iptr;
u8 _ih[2];
iptr = skb_header_pointer(skb, offset, sizeof(_ih), &_ih);
if (iptr == NULL) {
audit_log_format(ab, " truncated=1");
return;
}
audit_log_format(ab, " icmptype=%hhu icmpcode=%hhu",
iptr[0], iptr[1]);
}
break;
}
}
static void audit_ip4(struct audit_buffer *ab, struct sk_buff *skb)
{ {
struct iphdr _iph; struct iphdr _iph;
const struct iphdr *ih; const struct iphdr *ih;
ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_iph), &_iph); ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_iph), &_iph);
if (!ih) { if (!ih)
audit_log_format(ab, " truncated=1"); return false;
return;
}
audit_log_format(ab, " saddr=%pI4 daddr=%pI4 ipid=%hu proto=%hhu", audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu",
&ih->saddr, &ih->daddr, ntohs(ih->id), ih->protocol); &ih->saddr, &ih->daddr, ih->protocol);
if (ntohs(ih->frag_off) & IP_OFFSET) { return true;
audit_log_format(ab, " frag=1");
return;
}
audit_proto(ab, skb, ih->protocol, ih->ihl * 4);
} }
static void audit_ip6(struct audit_buffer *ab, struct sk_buff *skb) static bool audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
{ {
struct ipv6hdr _ip6h; struct ipv6hdr _ip6h;
const struct ipv6hdr *ih; const struct ipv6hdr *ih;
u8 nexthdr; u8 nexthdr;
__be16 frag_off; __be16 frag_off;
int offset;
ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h); ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
if (!ih) { if (!ih)
audit_log_format(ab, " truncated=1"); return false;
return;
}
nexthdr = ih->nexthdr; nexthdr = ih->nexthdr;
offset = ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), &nexthdr, &frag_off);
&nexthdr, &frag_off);
audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu", audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
&ih->saddr, &ih->daddr, nexthdr); &ih->saddr, &ih->daddr, nexthdr);
if (offset) return true;
audit_proto(ab, skb, nexthdr, offset);
} }
static unsigned int static unsigned int
audit_tg(struct sk_buff *skb, const struct xt_action_param *par) audit_tg(struct sk_buff *skb, const struct xt_action_param *par)
{ {
const struct xt_audit_info *info = par->targinfo;
struct audit_buffer *ab; struct audit_buffer *ab;
int fam = -1;
if (audit_enabled == 0) if (audit_enabled == 0)
goto errout; goto errout;
ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT); ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
if (ab == NULL) if (ab == NULL)
goto errout; goto errout;
audit_log_format(ab, "action=%hhu hook=%u len=%u inif=%s outif=%s", audit_log_format(ab, "mark=%#x", skb->mark);
info->type, xt_hooknum(par), skb->len,
xt_in(par) ? xt_inname(par) : "?",
xt_out(par) ? xt_outname(par) : "?");
if (skb->mark)
audit_log_format(ab, " mark=%#x", skb->mark);
if (skb->dev && skb->dev->type == ARPHRD_ETHER) {
audit_log_format(ab, " smac=%pM dmac=%pM macproto=0x%04x",
eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
ntohs(eth_hdr(skb)->h_proto));
if (xt_family(par) == NFPROTO_BRIDGE) {
switch (eth_hdr(skb)->h_proto) {
case htons(ETH_P_IP):
audit_ip4(ab, skb);
break;
case htons(ETH_P_IPV6):
audit_ip6(ab, skb);
break;
}
}
}
switch (xt_family(par)) { switch (xt_family(par)) {
case NFPROTO_IPV4: case NFPROTO_BRIDGE:
audit_ip4(ab, skb); switch (eth_hdr(skb)->h_proto) {
case htons(ETH_P_IP):
fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
break;
case htons(ETH_P_IPV6):
fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
break;
}
break;
case NFPROTO_IPV4:
fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
break; break;
case NFPROTO_IPV6: case NFPROTO_IPV6:
audit_ip6(ab, skb); fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
break; break;
} }
#ifdef CONFIG_NETWORK_SECMARK if (fam == -1)
if (skb->secmark) audit_log_format(ab, " saddr=? daddr=? proto=-1");
audit_log_secctx(ab, skb->secmark);
#endif
audit_log_end(ab); audit_log_end(ab);