X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=netlink.c;h=6384c02220720721d9f8a123e83d976a0e21c9ac;hp=76ac91c31679f2d89e39fadd77fbe7764e818a28;hb=55bc97e626e0f31e04b190528b25c6e026942610;hpb=389070fed67552c613ce5afd3cdb436f8f8c538f diff --git a/netlink.c b/netlink.c index 76ac91c..6384c02 100644 --- a/netlink.c +++ b/netlink.c @@ -98,15 +98,14 @@ their use. */ #include +#include +#include #include "secnet.h" #include "util.h" #include "ipaddr.h" #include "netlink.h" #include "process.h" -#define OPT_SOFTROUTE 1 -#define OPT_ALLOWROUTE 2 - #define ICMP_TYPE_ECHO_REPLY 0 #define ICMP_TYPE_UNREACHABLE 3 @@ -121,7 +120,7 @@ their use. #define ICMP_CODE_TTL_EXCEEDED 0 /* Generic IP checksum routine */ -static inline uint16_t ip_csum(uint8_t *iph,uint32_t count) +static inline uint16_t ip_csum(uint8_t *iph,int32_t count) { register uint32_t sum=0; @@ -145,7 +144,7 @@ static inline uint16_t ip_csum(uint8_t *iph,uint32_t count) * By Jorge Cwik , adapted for linux by * Arnt Gulbrandsen. */ -static inline uint16_t ip_fast_csum(uint8_t *iph, uint32_t ihl) { +static inline uint16_t ip_fast_csum(uint8_t *iph, int32_t ihl) { uint32_t sum; __asm__ __volatile__( @@ -175,8 +174,9 @@ static inline uint16_t ip_fast_csum(uint8_t *iph, uint32_t ihl) { return sum; } #else -static inline uint16_t ip_fast_csum(uint8_t *iph, uint32_t ihl) +static inline uint16_t ip_fast_csum(uint8_t *iph, int32_t ihl) { + assert(ihl < INT_MAX/4); return ip_csum(iph,ihl*4); } #endif @@ -238,7 +238,7 @@ static struct icmphdr *netlink_icmp_tmpl(struct netlink *st, struct icmphdr *h; BUF_ALLOC(&st->icmp,"netlink_icmp_tmpl"); - buffer_init(&st->icmp,st->max_start_pad); + buffer_init(&st->icmp,calculate_max_start_pad()); h=buf_append(&st->icmp,sizeof(*h)); h->iph.version=4; @@ -262,7 +262,7 @@ static struct icmphdr *netlink_icmp_tmpl(struct netlink *st, /* Fill in the ICMP checksum field correctly */ static void netlink_icmp_csum(struct icmphdr *h) { - uint32_t len; + int32_t len; len=ntohs(h->iph.tot_len)-(4*h->iph.ihl); h->check=0; @@ -293,6 +293,7 @@ static bool_t netlink_icmp_may_reply(struct buffer_if *buf) struct icmphdr *icmph; uint32_t source; + if (buf->size < (int)sizeof(struct icmphdr)) return False; iph=(struct iphdr *)buf->start; icmph=(struct icmphdr *)buf->start; if (iph->protocol==1) { @@ -338,6 +339,7 @@ static bool_t netlink_icmp_may_reply(struct buffer_if *buf) */ static uint16_t netlink_icmp_reply_len(struct buffer_if *buf) { + if (buf->size < (int)sizeof(struct iphdr)) return 0; struct iphdr *iph=(struct iphdr *)buf->start; uint16_t hlen,plen; @@ -354,11 +356,11 @@ static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf, struct netlink_client *client, uint8_t type, uint8_t code) { - struct iphdr *iph=(struct iphdr *)buf->start; struct icmphdr *h; uint16_t len; if (netlink_icmp_may_reply(buf)) { + struct iphdr *iph=(struct iphdr *)buf->start; len=netlink_icmp_reply_len(buf); h=netlink_icmp_tmpl(st,ntohl(iph->saddr),len); h->type=type; h->code=code; @@ -381,19 +383,52 @@ static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf, * 3. Checksums correctly. * 4. Doesn't have a bogus length */ -static bool_t netlink_check(struct netlink *st, struct buffer_if *buf) +static bool_t netlink_check(struct netlink *st, struct buffer_if *buf, + char *errmsgbuf, int errmsgbuflen) { +#define BAD(...) do{ \ + snprintf(errmsgbuf,errmsgbuflen,__VA_ARGS__); \ + return False; \ + }while(0) + + if (buf->size < (int)sizeof(struct iphdr)) BAD("len %"PRIu32"",buf->size); struct iphdr *iph=(struct iphdr *)buf->start; - uint32_t len; + int32_t len; - if (iph->ihl < 5 || iph->version != 4) return False; - if (buf->size < iph->ihl*4) return False; - if (ip_fast_csum((uint8_t *)iph, iph->ihl)!=0) return False; + if (iph->ihl < 5) BAD("ihl %u",iph->ihl); + if (iph->version != 4) BAD("version %u",iph->version); + if (buf->size < iph->ihl*4) BAD("size %"PRId32"<%u*4",buf->size,iph->ihl); + if (ip_fast_csum((uint8_t *)iph, iph->ihl)!=0) BAD("csum"); len=ntohs(iph->tot_len); /* There should be no padding */ - if (buf->size!=len || len<(iph->ihl<<2)) return False; + if (buf->size!=len) BAD("len %"PRId32"!=%"PRId32,buf->size,len); + if (len<(iph->ihl<<2)) BAD("len %"PRId32"<(%u<<2)",len,iph->ihl); /* XXX check that there's no source route specified */ return True; + +#undef BAD +} + +/* Deliver a packet _to_ client; used after we have decided + * what to do with it (and just to check that the client has + * actually registered a delivery function with us). */ +static void netlink_client_deliver(struct netlink *st, + struct netlink_client *client, + uint32_t source, uint32_t dest, + struct buffer_if *buf) +{ + if (!client->deliver) { + string_t s,d; + s=ipaddr_to_string(source); + d=ipaddr_to_string(dest); + Message(M_ERR,"%s: dropping %s->%s, client not registered\n", + st->name,s,d); + free(s); free(d); + BUF_FREE(buf); + return; + } + client->deliver(client->dst, buf); + client->outcount++; } /* Deliver a packet. "client" is the _origin_ of the packet, not its @@ -403,6 +438,13 @@ static void netlink_packet_deliver(struct netlink *st, struct netlink_client *client, struct buffer_if *buf) { + if (buf->size < (int)sizeof(struct iphdr)) { + Message(M_ERR,"%s: trying to deliver a too-short packet" + " from %s!\n",st->name, client?client->name:"(local)"); + BUF_FREE(buf); + return; + } + struct iphdr *iph=(struct iphdr *)buf->start; uint32_t dest=ntohl(iph->daddr); uint32_t source=ntohl(iph->saddr); @@ -501,9 +543,8 @@ static void netlink_packet_deliver(struct netlink *st, } else { if (best_quality>0) { /* XXX Fragment if required */ - st->routes[best_match]->deliver( - st->routes[best_match]->dst, buf); - st->routes[best_match]->outcount++; + netlink_client_deliver(st,st->routes[best_match], + source,dest,buf); BUF_ASSERT_FREE(buf); } else { /* Generate ICMP destination unreachable */ @@ -520,6 +561,7 @@ static void netlink_packet_forward(struct netlink *st, struct netlink_client *client, struct buffer_if *buf) { + if (buf->size < (int)sizeof(struct iphdr)) return; struct iphdr *iph=(struct iphdr *)buf->start; BUF_ASSERT_USED(buf); @@ -549,6 +591,12 @@ static void netlink_packet_local(struct netlink *st, st->localcount++; + if (buf->size < (int)sizeof(struct icmphdr)) { + Message(M_WARNING,"%s: short packet addressed to secnet; " + "ignoring it\n",st->name); + BUF_FREE(buf); + return; + } h=(struct icmphdr *)buf->start; if ((ntohs(h->iph.frag_off)&0xbfff)!=0) { @@ -592,14 +640,19 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *client, { uint32_t source,dest; struct iphdr *iph; + char errmsgbuf[50]; + const char *sourcedesc=client?client->name:"host"; BUF_ASSERT_USED(buf); - if (!netlink_check(st,buf)) { - Message(M_WARNING,"%s: bad IP packet from %s\n", - st->name,client?client->name:"host"); + + if (!netlink_check(st,buf,errmsgbuf,sizeof(errmsgbuf))) { + Message(M_WARNING,"%s: bad IP packet from %s: %s\n", + st->name,sourcedesc, + errmsgbuf); BUF_FREE(buf); return; } + assert(buf->size >= (int)sizeof(struct icmphdr)); iph=(struct iphdr *)buf->start; source=ntohl(iph->saddr); @@ -646,7 +699,7 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *client, if (client) { st->deliver_to_host(st->dst,buf); } else { - st->clients->deliver(st->clients->dst,buf); + netlink_client_deliver(st,st->clients,source,dest,buf); } BUF_ASSERT_FREE(buf); return; @@ -693,7 +746,7 @@ static void netlink_set_quality(void *sst, uint32_t quality) static void netlink_output_subnets(struct netlink *st, uint32_t loglevel, struct subnet_list *snets) { - uint32_t i; + int32_t i; string_t net; for (i=0; ientries; i++) { @@ -761,17 +814,19 @@ static void netlink_phase_hook(void *sst, uint32_t new_phase) { struct netlink *st=sst; struct netlink_client *c; - uint32_t i; + int32_t i; /* All the networks serviced by the various tunnels should now * have been registered. We build a routing table by sorting the * clients by priority. */ - st->routes=safe_malloc(st->n_clients*sizeof(*st->routes), - "netlink_phase_hook"); + st->routes=safe_malloc_ary(sizeof(*st->routes),st->n_clients, + "netlink_phase_hook"); /* Fill the table */ i=0; - for (c=st->clients; c; c=c->next) + for (c=st->clients; c; c=c->next) { + assert(iroutes[i++]=c; + } /* Sort the table in descending order of priority */ qsort(st->routes,st->n_clients,sizeof(*st->routes), netlink_compare_client_priority); @@ -786,28 +841,7 @@ static void netlink_signal_handler(void *sst, int signum) netlink_dump_routes(st,True); } -static void netlink_inst_output_config(void *sst, struct buffer_if *buf) -{ -/* struct netlink_client *c=sst; */ -/* struct netlink *st=c->nst; */ - - /* For now we don't output anything */ - BUF_ASSERT_USED(buf); -} - -static bool_t netlink_inst_check_config(void *sst, struct buffer_if *buf) -{ -/* struct netlink_client *c=sst; */ -/* struct netlink *st=c->nst; */ - - BUF_ASSERT_USED(buf); - /* We need to eat all of the configuration information from the buffer - for backward compatibility. */ - buf->size=0; - return True; -} - -static void netlink_inst_set_mtu(void *sst, uint32_t new_mtu) +static void netlink_inst_set_mtu(void *sst, int32_t new_mtu) { struct netlink_client *c=sst; @@ -815,14 +849,10 @@ static void netlink_inst_set_mtu(void *sst, uint32_t new_mtu) } static void netlink_inst_reg(void *sst, netlink_deliver_fn *deliver, - void *dst, uint32_t max_start_pad, - uint32_t max_end_pad) + void *dst) { struct netlink_client *c=sst; - struct netlink *st=c->nst; - if (max_start_pad > st->max_start_pad) st->max_start_pad=max_start_pad; - if (max_end_pad > st->max_end_pad) st->max_end_pad=max_end_pad; c->deliver=deliver; c->dst=dst; } @@ -843,7 +873,8 @@ static closure_t *netlink_inst_create(struct netlink *st, struct netlink_client *c; string_t name; struct ipset *networks; - uint32_t options,priority,mtu; + uint32_t options,priority; + int32_t mtu; list_t *l; name=dict_read_string(dict, "name", True, st->name, loc); @@ -892,8 +923,6 @@ static closure_t *netlink_inst_create(struct netlink *st, c->ops.reg=netlink_inst_reg; c->ops.deliver=netlink_inst_incoming; c->ops.set_quality=netlink_set_quality; - c->ops.output_config=netlink_inst_output_config; - c->ops.check_config=netlink_inst_check_config; c->ops.set_mtu=netlink_inst_set_mtu; c->nst=st; @@ -903,7 +932,7 @@ static closure_t *netlink_inst_create(struct netlink *st, c->deliver=NULL; c->dst=NULL; c->name=name; - c->link_quality=LINK_QUALITY_DOWN; + c->link_quality=LINK_QUALITY_UNUSED; c->mtu=mtu?mtu:st->mtu; c->options=options; c->outcount=0; @@ -911,6 +940,7 @@ static closure_t *netlink_inst_create(struct netlink *st, c->kup=False; c->next=st->clients; st->clients=c; + assert(st->n_clients < INT_MAX); st->n_clients++; return &c->cl; @@ -950,8 +980,6 @@ netlink_deliver_fn *netlink_init(struct netlink *st, st->cl.type=CL_PURE; st->cl.apply=netlink_inst_apply; st->cl.interface=st; - st->max_start_pad=0; - st->max_end_pad=0; st->clients=NULL; st->routes=NULL; st->n_clients=0;