Commit 8dcfc9e3 authored by Rusty Russell's avatar Rusty Russell Committed by David S. Miller

[NETFILTER]: Linearize iptables matches.

Adjusts the IPTables matches to handle non-linear packets.
Untested: ipt_ah and ipt_esp.
parent 4b5fb65e
......@@ -35,14 +35,16 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ahhdr *ah = hdr;
struct ahhdr ah;
const struct ipt_ah *ahinfo = matchinfo;
if (offset == 0 && datalen < sizeof(struct ahhdr)) {
/* Must not be a fragment. */
if (offset)
return 0;
if (skb_copy_bits(skb, skb->nh.iph->ihl*4, &ah, sizeof(ah)) < 0) {
/* We've been asked to examine this packet, and we
can't. Hence, no choice but to drop. */
duprintf("Dropping evil AH tinygram.\n");
......@@ -50,10 +52,8 @@ match(const struct sk_buff *skb,
return 0;
}
/* Must not be a fragment. */
return !offset
&& spi_match(ahinfo->spis[0], ahinfo->spis[1],
ntohl(ah->spi),
return spi_match(ahinfo->spis[0], ahinfo->spis[1],
ntohl(ah.spi),
!!(ahinfo->invflags & IPT_AH_INV_SPI));
}
......
......@@ -14,8 +14,6 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_conntrack_info *sinfo = matchinfo;
......
......@@ -19,8 +19,7 @@ MODULE_LICENSE("GPL");
static int match(const struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, const void *matchinfo,
int offset, const void *hdr, u_int16_t datalen,
int *hotdrop)
int offset, int *hotdrop)
{
const struct ipt_dscp_info *info = matchinfo;
const struct iphdr *iph = skb->nh.iph;
......
......@@ -19,34 +19,40 @@ MODULE_DESCRIPTION("IP tables ECN matching module");
MODULE_LICENSE("GPL");
static inline int match_ip(const struct sk_buff *skb,
const struct iphdr *iph,
const struct ipt_ecn_info *einfo)
{
return ((iph->tos&IPT_ECN_IP_MASK) == einfo->ip_ect);
return ((skb->nh.iph->tos&IPT_ECN_IP_MASK) == einfo->ip_ect);
}
static inline int match_tcp(const struct sk_buff *skb,
const struct iphdr *iph,
const struct ipt_ecn_info *einfo)
const struct ipt_ecn_info *einfo,
int *hotdrop)
{
struct tcphdr *tcph = (void *)iph + iph->ihl*4;
struct tcphdr tcph;
/* In practice, TCP match does this, so can't fail. But let's
be good citizens. */
if (skb_copy_bits(skb, skb->nh.iph->ihl*4, &tcph, sizeof(tcph)) < 0) {
*hotdrop = 0;
return 0;
}
if (einfo->operation & IPT_ECN_OP_MATCH_ECE) {
if (einfo->invert & IPT_ECN_OP_MATCH_ECE) {
if (tcph->ece == 1)
if (tcph.ece == 1)
return 0;
} else {
if (tcph->ece == 0)
if (tcph.ece == 0)
return 0;
}
}
if (einfo->operation & IPT_ECN_OP_MATCH_CWR) {
if (einfo->invert & IPT_ECN_OP_MATCH_CWR) {
if (tcph->cwr == 1)
if (tcph.cwr == 1)
return 0;
} else {
if (tcph->cwr == 0)
if (tcph.cwr == 0)
return 0;
}
}
......@@ -56,20 +62,18 @@ static inline int match_tcp(const struct sk_buff *skb,
static int match(const struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, const void *matchinfo,
int offset, const void *hdr, u_int16_t datalen,
int *hotdrop)
int offset, int *hotdrop)
{
const struct ipt_ecn_info *info = matchinfo;
const struct iphdr *iph = skb->nh.iph;
if (info->operation & IPT_ECN_OP_MATCH_IP)
if (!match_ip(skb, iph, info))
if (!match_ip(skb, info))
return 0;
if (info->operation & (IPT_ECN_OP_MATCH_ECE|IPT_ECN_OP_MATCH_CWR)) {
if (iph->protocol != IPPROTO_TCP)
if (skb->nh.iph->protocol != IPPROTO_TCP)
return 0;
if (!match_tcp(skb, iph, info))
if (!match_tcp(skb, info, hotdrop))
return 0;
}
......
......@@ -35,14 +35,16 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct esphdr *esp = hdr;
struct esphdr esp;
const struct ipt_esp *espinfo = matchinfo;
if (offset == 0 && datalen < sizeof(struct esphdr)) {
/* Must not be a fragment. */
if (offset)
return 0;
if (skb_copy_bits(skb, skb->nh.iph->ihl*4, &esp, sizeof(esp)) < 0) {
/* We've been asked to examine this packet, and we
can't. Hence, no choice but to drop. */
duprintf("Dropping evil ESP tinygram.\n");
......@@ -50,10 +52,8 @@ match(const struct sk_buff *skb,
return 0;
}
/* Must not be a fragment. */
return !offset
&& spi_match(espinfo->spis[0], espinfo->spis[1],
ntohl(esp->spi),
return spi_match(espinfo->spis[0], espinfo->spis[1],
ntohl(esp.spi),
!!(espinfo->invflags & IPT_ESP_INV_SPI));
}
......
......@@ -28,8 +28,6 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_helper_info *info = matchinfo;
......
......@@ -15,8 +15,6 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_length_info *info = matchinfo;
......
......@@ -47,8 +47,6 @@ ipt_limit_match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
struct ipt_rateinfo *r = ((struct ipt_rateinfo *)matchinfo)->master;
......
......@@ -12,8 +12,6 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_mac_info *info = matchinfo;
......
......@@ -11,8 +11,6 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_mark_info *info = matchinfo;
......
......@@ -39,15 +39,18 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct udphdr *udp = hdr;
u16 ports[2];
const struct ipt_multiport *multiinfo = matchinfo;
/* Must be big enough to read ports. */
if (offset == 0 && datalen < sizeof(struct udphdr)) {
/* Must not be a fragment. */
if (offset)
return 0;
/* Must be big enough to read ports (both UDP and TCP have
them at the start). */
if (skb_copy_bits(skb, skb->nh.iph->ihl*4, ports, sizeof(ports)) < 0) {
/* We've been asked to examine this packet, and we
can't. Hence, no choice but to drop. */
duprintf("ipt_multiport:"
......@@ -56,11 +59,9 @@ match(const struct sk_buff *skb,
return 0;
}
/* Must not be a fragment. */
return !offset
&& ports_match(multiinfo->ports,
return ports_match(multiinfo->ports,
multiinfo->flags, multiinfo->count,
ntohs(udp->source), ntohs(udp->dest));
ntohs(ports[0]), ntohs(ports[1]));
}
/* Called when user tries to insert an entry of this type. */
......
......@@ -115,8 +115,6 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_owner_info *info = matchinfo;
......@@ -170,8 +168,11 @@ checkentry(const char *tablename,
return 0;
}
if (matchsize != IPT_ALIGN(sizeof(struct ipt_owner_info)))
if (matchsize != IPT_ALIGN(sizeof(struct ipt_owner_info))) {
printk("Matchsize %u != %u\n", matchsize,
IPT_ALIGN(sizeof(struct ipt_owner_info)));
return 0;
}
return 1;
}
......
......@@ -13,8 +13,6 @@ static int match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_pkttype_info *info = matchinfo;
......
......@@ -13,8 +13,6 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_state_info *sinfo = matchinfo;
......
......@@ -11,24 +11,32 @@
/* Returns 1 if the mss option is set and matched by the range, 0 otherwise */
static inline int
mssoption_match(u_int16_t min, u_int16_t max,
const struct tcphdr *tcp,
u_int16_t datalen,
const struct sk_buff *skb,
int invert,
int *hotdrop)
{
unsigned int i;
const u_int8_t *opt = (u_int8_t *)tcp;
struct tcphdr tcph;
/* tcp.doff is only 4 bits, ie. max 15 * 4 bytes */
u8 opt[15 * 4 - sizeof(tcph)];
unsigned int i, optlen;
/* If we don't have the whole header, drop packet. */
if (tcp->doff * 4 > datalen) {
*hotdrop = 1;
return 0;
}
for (i = sizeof(struct tcphdr); i < tcp->doff * 4; ) {
if ((opt[i] == TCPOPT_MSS)
&& ((tcp->doff * 4 - i) >= TCPOLEN_MSS)
&& (opt[i+1] == TCPOLEN_MSS)) {
if (skb_copy_bits(skb, skb->nh.iph->ihl*4, &tcph, sizeof(tcph)) < 0)
goto dropit;
/* Malformed. */
if (tcph.doff*4 < sizeof(tcph))
goto dropit;
optlen = tcph.doff*4 - sizeof(tcph);
/* Truncated options. */
if (skb_copy_bits(skb, skb->nh.iph->ihl*4+sizeof(tcph), opt, optlen)<0)
goto dropit;
for (i = 0; i < optlen; ) {
if (opt[i] == TCPOPT_MSS
&& (optlen - i) >= TCPOLEN_MSS
&& opt[i+1] == TCPOLEN_MSS) {
u_int16_t mssval;
mssval = (opt[i+2] << 8) | opt[i+3];
......@@ -38,8 +46,11 @@ mssoption_match(u_int16_t min, u_int16_t max,
if (opt[i] < 2) i++;
else i += opt[i+1]?:1;
}
return invert;
dropit:
*hotdrop = 1;
return 0;
}
static int
......@@ -48,15 +59,11 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_tcpmss_match_info *info = matchinfo;
const struct tcphdr *tcph = (void *)skb->nh.iph + skb->nh.iph->ihl*4;
return mssoption_match(info->mss_min, info->mss_max, tcph,
skb->len - skb->nh.iph->ihl*4,
return mssoption_match(info->mss_min, info->mss_max, skb,
info->invert, hotdrop);
}
......
......@@ -11,14 +11,11 @@ match(const struct sk_buff *skb,
const struct net_device *out,
const void *matchinfo,
int offset,
const void *hdr,
u_int16_t datalen,
int *hotdrop)
{
const struct ipt_tos_info *info = matchinfo;
const struct iphdr *iph = skb->nh.iph;
return (iph->tos == info->tos) ^ info->invert;
return (skb->nh.iph->tos == info->tos) ^ info->invert;
}
static int
......
......@@ -19,24 +19,22 @@ MODULE_LICENSE("GPL");
static int match(const struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, const void *matchinfo,
int offset, const void *hdr, u_int16_t datalen,
int *hotdrop)
int offset, int *hotdrop)
{
const struct ipt_ttl_info *info = matchinfo;
const struct iphdr *iph = skb->nh.iph;
switch (info->mode) {
case IPT_TTL_EQ:
return (iph->ttl == info->ttl);
return (skb->nh.iph->ttl == info->ttl);
break;
case IPT_TTL_NE:
return (!(iph->ttl == info->ttl));
return (!(skb->nh.iph->ttl == info->ttl));
break;
case IPT_TTL_LT:
return (iph->ttl < info->ttl);
return (skb->nh.iph->ttl < info->ttl);
break;
case IPT_TTL_GT:
return (iph->ttl > info->ttl);
return (skb->nh.iph->ttl > info->ttl);
break;
default:
printk(KERN_WARNING "ipt_ttl: unknown mode %d\n",
......
This diff is collapsed.
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment