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icmp: Fix copied length in response packets

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Fixes bug #59364, reported by Yi Guai
This commit is contained in:
Erik Ekman 2021-01-13 20:31:55 +01:00
parent c6777547f6
commit 35550eeab3
2 changed files with 67 additions and 9 deletions
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21
src/core/ipv4/icmp.c
View File

@ -62,7 +62,7 @@
#define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1
#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
/* The amount of data from the original packet to return in a dest-unreachable */
/* The maximum amount of data from the original packet to return in a dest-unreachable */
#define ICMP_DEST_UNREACH_DATASIZE 8
static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code);
@ -344,23 +344,27 @@ icmp_send_response(struct pbuf *p, u8_t type, u8_t code)
struct icmp_hdr *icmphdr;
ip4_addr_t iphdr_src;
struct netif *netif;
u16_t response_pkt_len;
/* increase number of messages attempted to send */
MIB2_STATS_INC(mib2.icmpoutmsgs);
/* ICMP header + IP header + 8 bytes of data */
q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
PBUF_RAM);
/* Keep IP header + up to 8 bytes */
response_pkt_len = IP_HLEN + ICMP_DEST_UNREACH_DATASIZE;
if (p->tot_len < response_pkt_len) response_pkt_len = p->tot_len;
/* ICMP header + part of original packet */
q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_hdr) + response_pkt_len, PBUF_RAM);
if (q == NULL) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n"));
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_send_response: failed to allocate pbuf for ICMP packet.\n"));
MIB2_STATS_INC(mib2.icmpouterrors);
return;
}
LWIP_ASSERT("check that first pbuf can hold icmp message",
(q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
(q->len >= (sizeof(struct icmp_hdr) + response_pkt_len)));
iphdr = (struct ip_hdr *)p->payload;
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_send_response: Sending ICMP type %02X for packet from ", type));
ip4_addr_debug_print_val(ICMP_DEBUG, iphdr->src);
LWIP_DEBUGF(ICMP_DEBUG, (" to "));
ip4_addr_debug_print_val(ICMP_DEBUG, iphdr->dest);
@ -372,8 +376,7 @@ icmp_send_response(struct pbuf *p, u8_t type, u8_t code)
icmphdr->data = 0;
/* copy fields from original packet */
SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload,
IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
pbuf_copy_partial_pbuf(q, p, response_pkt_len, sizeof(struct icmp_hdr));
ip4_addr_copy(iphdr_src, iphdr->src);
#ifdef LWIP_HOOK_IP4_ROUTE_SRC

55
test/unit/ip4/test_ip4.c
View File

@ -1,5 +1,6 @@
#include "test_ip4.h"
#include "lwip/icmp.h"
#include "lwip/ip4.h"
#include "lwip/etharp.h"
#include "lwip/inet_chksum.h"
@ -17,6 +18,8 @@ static struct netif test_netif;
static ip4_addr_t test_ipaddr, test_netmask, test_gw;
static int linkoutput_ctr;
static int linkoutput_byte_ctr;
static int linkoutput_pkt_len;
static u8_t linkoutput_pkt[100];
/* reference internal lwip variable in netif.c */
@ -27,6 +30,8 @@ test_netif_linkoutput(struct netif *netif, struct pbuf *p)
fail_unless(p != NULL);
linkoutput_ctr++;
linkoutput_byte_ctr += p->tot_len;
/* Copy start of packet into buffer */
linkoutput_pkt_len = pbuf_copy_partial(p, linkoutput_pkt, sizeof(linkoutput_pkt), 0);
return ERR_OK;
}
@ -264,6 +269,54 @@ START_TEST(test_ip4addr_aton)
}
END_TEST
/* Test for bug #59364 */
START_TEST(test_ip4_icmp_replylen_short)
{
/* IP packet to 192.168.0.1 using proto 0x22 and 1 byte payload */
const u8_t unknown_proto[] = {
0x45, 0x00, 0x00, 0x15, 0xd4, 0x31, 0x00, 0x00, 0xff, 0x22,
0x66, 0x41, 0xc0, 0xa8, 0x00, 0x02, 0xc0, 0xa8, 0x00, 0x01,
0xaa };
struct pbuf *p;
const int icmp_len = IP_HLEN + sizeof(struct icmp_hdr);
test_netif_add();
test_netif.output = arpless_output;
p = pbuf_alloc(PBUF_IP, sizeof(unknown_proto), PBUF_RAM);
pbuf_take(p, unknown_proto, sizeof(unknown_proto));
fail_unless(ip4_input(p, &test_netif) == ERR_OK);
fail_unless(linkoutput_ctr == 1);
/* Verify outgoing ICMP packet has no extra data */
fail_unless(linkoutput_byte_ctr == icmp_len + sizeof(unknown_proto));
fail_if(memcmp(&linkoutput_pkt[icmp_len], unknown_proto, sizeof(unknown_proto)));
}
END_TEST
START_TEST(test_ip4_icmp_replylen_first_8)
{
/* IP packet to 192.168.0.1 using proto 0x22 and 11 bytes payload */
const u8_t unknown_proto[] = {
0x45, 0x00, 0x00, 0x1f, 0xd4, 0x31, 0x00, 0x00, 0xff, 0x22,
0x66, 0x37, 0xc0, 0xa8, 0x00, 0x02, 0xc0, 0xa8, 0x00, 0x01,
0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9,
0xaa };
struct pbuf *p;
const int icmp_len = IP_HLEN + sizeof(struct icmp_hdr);
const int unreach_len = IP_HLEN + 8;
test_netif_add();
test_netif.output = arpless_output;
p = pbuf_alloc(PBUF_IP, sizeof(unknown_proto), PBUF_RAM);
pbuf_take(p, unknown_proto, sizeof(unknown_proto));
fail_unless(ip4_input(p, &test_netif) == ERR_OK);
fail_unless(linkoutput_ctr == 1);
fail_unless(linkoutput_byte_ctr == icmp_len + unreach_len);
fail_if(memcmp(&linkoutput_pkt[icmp_len], unknown_proto, IP_HLEN + 8));
}
END_TEST
/** Create the suite including all tests for this module */
Suite *
ip4_suite(void)
@ -273,6 +326,8 @@ ip4_suite(void)
TESTFUNC(test_ip4_reass),
TESTFUNC(test_127_0_0_1),
TESTFUNC(test_ip4addr_aton),
TESTFUNC(test_ip4_icmp_replylen_short),
TESTFUNC(test_ip4_icmp_replylen_first_8),
};
return create_suite("IPv4", tests, sizeof(tests)/sizeof(testfunc), ip4_setup, ip4_teardown);
}