mirror of
https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
synced 2024-10-19 18:09:05 +00:00
4acdbdbe50
If a connection tracking helper tells us to expect a connection, and we're already expecting that connection, we simply free the one they gave us and return success. The problem is that NAT helpers (eg. FTP) have to allocate the expectation first (to see what port is available) then rewrite the packet. If that rewrite fails, they try to remove the expectation, but it was freed in ip_conntrack_expect_related. This is one example of a larger problem: having registered the expectation, the pointer is no longer ours to use. Reference counting is needed for ctnetlink anyway, so introduce it now. To have a single "put" path, we need to grab the reference to the connection on creation, rather than open-coding it in the caller. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
157 lines
3.8 KiB
C
157 lines
3.8 KiB
C
/* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Version: 0.0.7
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*
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* Thu 21 Mar 2002 Harald Welte <laforge@gnumonks.org>
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* - port to newnat API
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*
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*/
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#include <linux/module.h>
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#include <linux/ip.h>
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#include <linux/udp.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
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#include <linux/netfilter_ipv4/ip_conntrack_tftp.h>
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#include <linux/moduleparam.h>
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MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
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MODULE_DESCRIPTION("tftp connection tracking helper");
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MODULE_LICENSE("GPL");
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#define MAX_PORTS 8
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static int ports[MAX_PORTS];
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static int ports_c;
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module_param_array(ports, int, &ports_c, 0400);
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MODULE_PARM_DESC(ports, "port numbers of tftp servers");
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#if 0
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#define DEBUGP(format, args...) printk("%s:%s:" format, \
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__FILE__, __FUNCTION__ , ## args)
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#else
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#define DEBUGP(format, args...)
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#endif
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unsigned int (*ip_nat_tftp_hook)(struct sk_buff **pskb,
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enum ip_conntrack_info ctinfo,
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struct ip_conntrack_expect *exp);
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EXPORT_SYMBOL_GPL(ip_nat_tftp_hook);
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static int tftp_help(struct sk_buff **pskb,
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struct ip_conntrack *ct,
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enum ip_conntrack_info ctinfo)
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{
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struct tftphdr _tftph, *tfh;
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struct ip_conntrack_expect *exp;
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unsigned int ret = NF_ACCEPT;
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tfh = skb_header_pointer(*pskb,
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(*pskb)->nh.iph->ihl*4+sizeof(struct udphdr),
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sizeof(_tftph), &_tftph);
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if (tfh == NULL)
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return NF_ACCEPT;
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switch (ntohs(tfh->opcode)) {
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/* RRQ and WRQ works the same way */
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case TFTP_OPCODE_READ:
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case TFTP_OPCODE_WRITE:
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DEBUGP("");
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DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
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DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
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exp = ip_conntrack_expect_alloc(ct);
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if (exp == NULL)
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return NF_DROP;
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exp->tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
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exp->mask.src.ip = 0xffffffff;
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exp->mask.dst.ip = 0xffffffff;
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exp->mask.dst.u.udp.port = 0xffff;
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exp->mask.dst.protonum = 0xff;
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exp->expectfn = NULL;
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DEBUGP("expect: ");
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DUMP_TUPLE(&exp->tuple);
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DUMP_TUPLE(&exp->mask);
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if (ip_nat_tftp_hook)
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ret = ip_nat_tftp_hook(pskb, ctinfo, exp);
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else if (ip_conntrack_expect_related(exp) != 0)
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ret = NF_DROP;
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ip_conntrack_expect_put(exp);
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break;
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case TFTP_OPCODE_DATA:
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case TFTP_OPCODE_ACK:
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DEBUGP("Data/ACK opcode\n");
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break;
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case TFTP_OPCODE_ERROR:
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DEBUGP("Error opcode\n");
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break;
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default:
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DEBUGP("Unknown opcode\n");
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}
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return NF_ACCEPT;
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}
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static struct ip_conntrack_helper tftp[MAX_PORTS];
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static char tftp_names[MAX_PORTS][10];
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static void fini(void)
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{
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int i;
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for (i = 0 ; i < ports_c; i++) {
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DEBUGP("unregistering helper for port %d\n",
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ports[i]);
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ip_conntrack_helper_unregister(&tftp[i]);
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}
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}
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static int __init init(void)
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{
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int i, ret;
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char *tmpname;
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if (ports_c == 0)
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ports[ports_c++] = TFTP_PORT;
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for (i = 0; i < ports_c; i++) {
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/* Create helper structure */
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memset(&tftp[i], 0, sizeof(struct ip_conntrack_helper));
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tftp[i].tuple.dst.protonum = IPPROTO_UDP;
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tftp[i].tuple.src.u.udp.port = htons(ports[i]);
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tftp[i].mask.dst.protonum = 0xFF;
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tftp[i].mask.src.u.udp.port = 0xFFFF;
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tftp[i].max_expected = 1;
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tftp[i].timeout = 5 * 60; /* 5 minutes */
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tftp[i].me = THIS_MODULE;
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tftp[i].help = tftp_help;
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tmpname = &tftp_names[i][0];
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if (ports[i] == TFTP_PORT)
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sprintf(tmpname, "tftp");
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else
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sprintf(tmpname, "tftp-%d", i);
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tftp[i].name = tmpname;
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DEBUGP("port #%d: %d\n", i, ports[i]);
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ret=ip_conntrack_helper_register(&tftp[i]);
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if (ret) {
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printk("ERROR registering helper for port %d\n",
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ports[i]);
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fini();
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return(ret);
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}
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}
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return(0);
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}
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module_init(init);
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module_exit(fini);
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