From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tonda Subject: TCP port firewall controlled by UDP packets Date: Fri, 12 Aug 2011 01:42:52 +0200 Message-ID: <1313106172-18455-1-git-send-email-as@strmilov.cz> To: davem@davemloft.net, kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org If unsure, say N. + +config TCPFIREWALL + tristate "TCP Firewall controlled by UDP queries" + depends on m diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -51,3 +51,4 @@ obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \ xfrm4_output.o +obj-$(CONFIG_TCPFIREWALL) += tcpfirewall/ diff --git a/net/ipv4/tcpfirewall/Makefile b/net/ipv4/tcpfirewall/Makefile --- a/net/ipv4/tcpfirewall/Makefile +++ b/net/ipv4/tcpfirewall/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_TCPFIREWALL) += tcpfirewall.o diff --git a/net/ipv4/tcpfirewall/tcpfirewall.c b/net/ipv4/tcpfirewall/tcpfirewall.c --- a/net/ipv4/tcpfirewall/tcpfirewall.c +++ b/net/ipv4/tcpfirewall/tcpfirewall.c @@ -0,0 +1,451 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct net_protocol { + int (*handler)(struct sk_buff *skb); + void (*err_handler)(struct sk_buff *skb, u32 info); + int (*gso_send_check)(struct sk_buff *skb); + struct sk_buff *(*gso_segment)(struct sk_buff *skb, + u32 features); + struct sk_buff **(*gro_receive)(struct sk_buff **head, + struct sk_buff *skb); + int (*gro_complete)(struct sk_buff *skb); + unsigned int no_policy:1, + netns_ok:1; +}; + +MODULE_LICENSE("GPL"); + +static unsigned long inet_protos = 0x01234567; + +struct net_protocol **_inet_protos; + +module_param(inet_protos, ulong, 0); + +static int *otviraky; +static int *zaviraky; + +static int pocetotviraku; +static int pocetzaviraku; +static int stav; +static int packetcounter; +static int tcpport; +static int open; +static int firewall; + +int (*tcpv4recv) (struct sk_buff *skb); +int (*udprecv) (struct sk_buff *skb); + +int udpcontroller(struct sk_buff *skb) +{ + const struct udphdr *uh; + + if (skb->pkt_type != PACKET_HOST) { + kfree_skb(skb); + return 0; + } + + if (!pskb_may_pull(skb, sizeof(struct tcphdr))) { + kfree_skb(skb); + return 0; + } + + uh = udp_hdr(skb); + + if (pocetotviraku == 0) + return udprecv(skb); + + if (!open) { + if (uh->dest == otviraky[stav]) { + ++stav; + packetcounter = 0; + + if (stav == pocetotviraku) { + open = 1; + stav = 0; + } + } else { + if (packetcounter <= 16) { + ++packetcounter; + if (packetcounter > 16) + stav = 0; + } + } + } else { + if (uh->dest == zaviraky[stav]) { + ++stav; + packetcounter = 0; + + if (stav == pocetzaviraku) { + open = 0; + stav = 0; + } + } else { + if (packetcounter <= 16) { + ++packetcounter; + if (packetcounter > 16) + stav = 0; + } + } + } + + + return udprecv(skb); +} + +int tcpfirewall(struct sk_buff *skb) +{ + const struct tcphdr *th; + + if (skb->pkt_type != PACKET_HOST) { + kfree_skb(skb); + return 0; + } + + if (!pskb_may_pull(skb, sizeof(struct tcphdr))) { + kfree_skb(skb); + return 0; + } + + th = tcp_hdr(skb); + + if (th->dest == tcpport) { + if (firewall == 1 && !open) { + /*tcpv4sendreset(NULL, skb);*/ + kfree_skb(skb); + return 0; + } + } + + return tcpv4recv(skb); +} + +static struct net_protocol *zalohatcp; +static struct net_protocol *zalohaudp; +static struct net_protocol mytcp; +static struct net_protocol myudp; + +static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buffer) +{ + if (!strcmp(attr->name, "firewall")) { + if (firewall) + buffer[0] = '1'; + else + buffer[0] = '0'; + + buffer[1] = '\n'; + return 2; + } + + if (!strcmp(attr->name, "tcpport")) { + sprintf(buffer, "%d\n", ntohs(tcpport)); + return strlen(buffer)+1; + } + + if (!strcmp(attr->name, "openers")) { + int i; + char *znak; + if (pocetotviraku == 0) + return 0; + buffer[0] = '\0'; + znak = kmalloc(10, GFP_KERNEL); + for (i = 0; i < pocetotviraku; ++i) { + sprintf(znak, "%d ", ntohs(otviraky[i])); + strcat(buffer, znak); + } + kfree(znak); + buffer[strlen(buffer)-1] = '\n'; + return strlen(buffer); + } + + if (!strcmp(attr->name, "closers")) { + int i; + char *znak; + if (pocetzaviraku == 0) + return 0; + buffer[0] = '\0'; + znak = kmalloc(10, GFP_KERNEL); + for (i = 0; i < pocetzaviraku; ++i) { + sprintf(znak, "%d ", ntohs(zaviraky[i])); + strcat(buffer, znak); + } + kfree(znak); + buffer[strlen(buffer)-1] = '\n'; + return strlen(buffer); + } + + if (!strcmp(attr->name, "open")) { + if (open) + buffer[0] = '1'; + else + buffer[0] = '0'; + + buffer[1] = '\n'; + return 2; + } + + if (!strcmp(attr->name, "state")) { + sprintf(buffer, "%d\n", stav); + return strlen(buffer)+1; + } + + if (!strcmp(attr->name, "counter")) { + sprintf(buffer, "%d\n", packetcounter); + return strlen(buffer)+1; + } + + return 0; +} + +static ssize_t store(struct kobject *kobj, struct attribute *attr, + const char *buffer, size_t size) +{ + int i; + char *cislo; + if (!strcmp(attr->name, "firewall")) { + if (size > 0 && buffer[0] == '1') + firewall = 1; + else + firewall = 0; + stav = 0; + return size; + } + + if (!strcmp(attr->name, "tcpport")) { + cislo = kmalloc(size+1, GFP_KERNEL); + for (i = 0; i < size; ++i) + cislo[i] = buffer[i]; + cislo[size] = '\0'; + if (kstrtoint(cislo, 10, &i) < 0) + i = -1; + if (i > 0 && i < 65536) + tcpport = htons(i); + kfree(cislo); + stav = 0; + return size; + } + + if (!strcmp(attr->name, "openers")) { + int udpport, i; + int *noveotviraky; + int *stareotviraky; + cislo = kmalloc(size+1, GFP_KERNEL); + for (i = 0; i < size; ++i) + cislo[i] = buffer[i]; + cislo[size] = '\0'; + + if (!strcmp(cislo, "reset") || !strcmp(cislo, "reset\n")) { + if (pocetotviraku) + kfree(otviraky); + pocetotviraku = 0; + } + + if (kstrtoint(cislo, 10, &i) < 0) + i = -1; + kfree(cislo); + + if (i > 0 && i < 65536 && (pocetotviraku == 0 || + otviraky[pocetotviraku-1] != i)) + udpport = htons(i); + else + return size; + + if (pocetotviraku < 10) { + noveotviraky = kmalloc((pocetotviraku+1)*sizeof(int), + GFP_KERNEL); + + for (i = 0; i < pocetotviraku; ++i) + noveotviraky[i] = otviraky[i]; + + noveotviraky[pocetotviraku] = udpport; + stareotviraky = otviraky; + otviraky = noveotviraky; + if (pocetotviraku) + kfree(stareotviraky); + + ++pocetotviraku; + } + stav = 0; + return size; + } + + if (!strcmp(attr->name, "closers")) { + int udpport, i; + int *novezaviraky; + int *starezaviraky; + cislo = kmalloc(size+1, GFP_KERNEL); + for (i = 0; i < size; ++i) + cislo[i] = buffer[i]; + cislo[size] = '\0'; + + if (!strcmp(cislo, "reset") || !strcmp(cislo, "reset\n")) { + if (pocetzaviraku) + kfree(zaviraky); + pocetzaviraku = 0; + } + + if (kstrtoint(cislo, 10, &i) < 0) + i = -1; + kfree(cislo); + + if (i > 0 && i < 65536 && (pocetzaviraku == 0 || + zaviraky[pocetzaviraku-1] != i)) + udpport = htons(i); + else + return size; + + if (pocetzaviraku < 10) { + novezaviraky = kmalloc((pocetzaviraku+1)*sizeof(int), + GFP_KERNEL); + + for (i = 0; i < pocetzaviraku; ++i) + novezaviraky[i] = zaviraky[i]; + + novezaviraky[pocetzaviraku] = udpport; + starezaviraky = zaviraky; + zaviraky = novezaviraky; + if (pocetzaviraku) + kfree(starezaviraky); + + ++pocetzaviraku; + } + stav = 0; + return size; + } + + if (!strcmp(attr->name, "open")) { + if (size > 0 && buffer[0] == '1') + open = 1; + else + open = 0; + + stav = 0; + return size; + } + + return 0; +} + +static const struct sysfs_ops so = { + .show = show, + .store = store, +}; + +static struct kobj_type khid = { + .sysfs_ops = &so, +}; + +static struct kobject kobj; + +static const struct attribute fw = { + .name = "firewall", + .mode = S_IRWXU, +}; + +static const struct attribute opn = { + .name = "open", + .mode = S_IRWXU, +}; + +static const struct attribute tcpp = { + .name = "tcpport", + .mode = S_IRWXU, +}; + +static const struct attribute openers = { + .name = "openers", + .mode = S_IRWXU, +}; + +static const struct attribute closers = { + .name = "closers", + .mode = S_IRWXU, +}; + +static const struct attribute stat = { + .name = "state", + .mode = S_IRUSR, +}; + +static const struct attribute counte = { + .name = "counter", + .mode = S_IRUSR, +}; + +static int __init start(void) +{ + if (inet_protos == 0x01234567) { + printk(KERN_WARNING "inet_protos parameter was not"); + printk(KERN_WARNING " specified!\nread its value from"); + printk(KERN_WARNING " System_map file file, and insert"); + printk(KERN_WARNING " the module again!\n"); + return -1; + } + + pocetotviraku = 0; + pocetzaviraku = 0; + stav = -1; + packetcounter = 0; + tcpport = 0; + open = 1; + firewall = 0; + + memset(&kobj, 0, sizeof(struct kobject)); + + _inet_protos = (struct net_protocol **)inet_protos; + + kobject_init(&kobj, &khid); + if (kobject_add(&kobj, NULL, "tcpfirewall") < 0) + printk(KERN_ERR "kobject_add failed"); + + if (sysfs_create_file(&kobj, &fw) < 0) + printk(KERN_ERR "sysfs_create_file failed"); + if (sysfs_create_file(&kobj, &opn) < 0) + printk(KERN_ERR "sysfs_create_file failed"); + if (sysfs_create_file(&kobj, &tcpp) < 0) + printk(KERN_ERR "sysfs_create_file failed"); + if (sysfs_create_file(&kobj, &openers) < 0) + printk(KERN_ERR "sysfs_create_file failed"); + if (sysfs_create_file(&kobj, &closers) < 0) + printk(KERN_ERR "sysfs_create_file failed"); + if (sysfs_create_file(&kobj, &stat) < 0) + printk(KERN_ERR "sysfs_create_file failed"); + if (sysfs_create_file(&kobj, &counte) < 0) + printk(KERN_ERR "sysfs_create_file failed"); + + zalohatcp = _inet_protos[IPPROTO_TCP]; + zalohaudp = _inet_protos[IPPROTO_UDP]; + mytcp = *zalohatcp; + myudp = *zalohaudp; + tcpv4recv = mytcp.handler; + udprecv = myudp.handler; + mytcp.handler = tcpfirewall; + myudp.handler = udpcontroller; + _inet_protos[IPPROTO_TCP] = &mytcp; + _inet_protos[IPPROTO_UDP] = &myudp; + return 0; +} + +static void konec(void) +{ + _inet_protos[IPPROTO_TCP] = zalohatcp; + _inet_protos[IPPROTO_UDP] = zalohaudp; + + if (pocetotviraku) + kfree(otviraky); + if (pocetzaviraku) + kfree(zaviraky); + + kobject_del(&kobj); +} + +module_init(start); +module_exit(konec);