Re: [PATCH V4 2/2] 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(a)redhat.com&gt; --- v4: Write out nfmark unmodified rather than trying to indicate "unset". Collapse/simplify switch/case statements. v3: Don't store interim values, but print immediately. v2: Trim down to 4 fields. Add raw samples. net/netfilter/xt_AUDIT.c | 124 ++++++++++------------------------------------ 1 files changed, 27 insertions(+), 97 deletions(-)

diff --git a/net/netfilter/xt_AUDIT.c b/net/netfilter/xt_AUDIT.c index cdb7cee..582ee54 100644 --- a/net/netfilter/xt_AUDIT.c +++ b/net/netfilter/xt_AUDIT.c @@ -31,146 +31,76 @@ MODULE_ALIAS("ip6t_AUDIT"); MODULE_ALIAS("ebt_AUDIT"); MODULE_ALIAS("arpt_AUDIT"); -static void audit_proto(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) +static bool audit_ip4(struct audit_buffer *ab, struct sk_buff *skb) { struct iphdr _iph; const struct iphdr *ih; ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_iph), &_iph); - if (!ih) { - audit_log_format(ab, " truncated=1"); - return; - } + if (!ih) + return false; - audit_log_format(ab, " saddr=%pI4 daddr=%pI4 ipid=%hu proto=%hhu", - &ih->saddr, &ih->daddr, ntohs(ih->id), ih->protocol); + audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu", + &ih->saddr, &ih->daddr, ih->protocol); - if (ntohs(ih->frag_off) & IP_OFFSET) { - audit_log_format(ab, " frag=1"); - return; - } - - audit_proto(ab, skb, ih->protocol, ih->ihl * 4); + return true; } -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; const struct ipv6hdr *ih; u8 nexthdr; __be16 frag_off; - int offset; ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h); - if (!ih) { - audit_log_format(ab, " truncated=1"); - return; - } + if (!ih) + return false; nexthdr = ih->nexthdr; - offset = ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), - &nexthdr, &frag_off); + ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), &nexthdr, &frag_off); audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu", &ih->saddr, &ih->daddr, nexthdr); - if (offset) - audit_proto(ab, skb, nexthdr, offset); + return true; } static unsigned int audit_tg(struct sk_buff *skb, const struct xt_action_param *par) { - const struct xt_audit_info *info = par->targinfo; struct audit_buffer *ab; + int fam = -1; if (audit_enabled == 0) goto errout; - ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT); if (ab == NULL) goto errout; - audit_log_format(ab, "action=%hhu hook=%u len=%u inif=%s outif=%s", - info->type, par->hooknum, skb->len, - par->in ? par->in->name : "?", - par->out ? par->out->name : "?"); - - 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 (par->family == 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; - } - } - } + audit_log_format(ab, "mark=%#x", skb->mark); switch (par->family) { + case NFPROTO_BRIDGE: + 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: - audit_ip4(ab, skb); + fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1; break; - case NFPROTO_IPV6: - audit_ip6(ab, skb); + fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1; break; } -#ifdef CONFIG_NETWORK_SECMARK - if (skb->secmark) - audit_log_secctx(ab, skb->secmark); -#endif + if (fam == -1) + audit_log_format(ab, " saddr=? daddr=? proto=-1"); audit_log_end(ab); -- 1.7.1 -- Linux-audit mailing list Linux-audit(a)redhat.com https://www.redhat.com/mailman/listinfo/linux-audit

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(a)redhat.com&gt; --- v4: Write out nfmark unmodified rather than trying to indicate "unset". Collapse/simplify switch/case statements. v3: Don't store interim values, but print immediately. v2: Trim down to 4 fields. Add raw samples. net/netfilter/xt_AUDIT.c | 124 ++++++++++------------------------------------ 1 files changed, 27 insertions(+), 97 deletions(-)

diff --git a/net/netfilter/xt_AUDIT.c b/net/netfilter/xt_AUDIT.c index cdb7cee..582ee54 100644 --- a/net/netfilter/xt_AUDIT.c +++ b/net/netfilter/xt_AUDIT.c @@ -31,146 +31,76 @@ MODULE_ALIAS("ip6t_AUDIT"); MODULE_ALIAS("ebt_AUDIT"); MODULE_ALIAS("arpt_AUDIT"); -static void audit_proto(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) +static bool audit_ip4(struct audit_buffer *ab, struct sk_buff *skb) { struct iphdr _iph; const struct iphdr *ih; ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_iph), &_iph); - if (!ih) { - audit_log_format(ab, " truncated=1"); - return; - } + if (!ih) + return false; - audit_log_format(ab, " saddr=%pI4 daddr=%pI4 ipid=%hu proto=%hhu", - &ih->saddr, &ih->daddr, ntohs(ih->id), ih->protocol); + audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu", + &ih->saddr, &ih->daddr, ih->protocol); - if (ntohs(ih->frag_off) & IP_OFFSET) { - audit_log_format(ab, " frag=1"); - return; - } - - audit_proto(ab, skb, ih->protocol, ih->ihl * 4); + return true; } -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; const struct ipv6hdr *ih; u8 nexthdr; __be16 frag_off; - int offset; ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h); - if (!ih) { - audit_log_format(ab, " truncated=1"); - return; - } + if (!ih) + return false; nexthdr = ih->nexthdr; - offset = ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), - &nexthdr, &frag_off); + ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), &nexthdr, &frag_off); audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu", &ih->saddr, &ih->daddr, nexthdr); - if (offset) - audit_proto(ab, skb, nexthdr, offset); + return true; } static unsigned int audit_tg(struct sk_buff *skb, const struct xt_action_param *par) { - const struct xt_audit_info *info = par->targinfo; struct audit_buffer *ab; + int fam = -1; if (audit_enabled == 0) goto errout; - ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT); if (ab == NULL) goto errout; - audit_log_format(ab, "action=%hhu hook=%u len=%u inif=%s outif=%s", - info->type, par->hooknum, skb->len, - par->in ? par->in->name : "?", - par->out ? par->out->name : "?"); - - 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 (par->family == 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; - } - } - } + audit_log_format(ab, "mark=%#x", skb->mark); switch (par->family) { + case NFPROTO_BRIDGE: + 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: - audit_ip4(ab, skb); + fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1; break; - case NFPROTO_IPV6: - audit_ip6(ab, skb); + fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1; break; } -#ifdef CONFIG_NETWORK_SECMARK - if (skb->secmark) - audit_log_secctx(ab, skb->secmark); -#endif + if (fam == -1) + audit_log_format(ab, " saddr=? daddr=? proto=-1"); audit_log_end(ab); -- 1.7.1 -- Linux-audit mailing list Linux-audit(a)redhat.com https://www.redhat.com/mailman/listinfo/linux-audit