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New mechanism for computing the 6lowpan header length dynamically, depending on how large header the framer creates. Also check the incoming packet for buffer overflow.

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This commit is contained in:
Adam Dunkels 2013-03-17 23:55:01 +01:00
parent cb2336a322
commit 3efa84ecc8
1 changed files with 42 additions and 4 deletions
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44
core/net/sicslowpan.c
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@ -163,7 +163,11 @@ void uip_log(char *msg);
/** \brief Size of the 802.15.4 payload (127byte - 25 for MAC header) */
#ifdef SICSLOWPAN_CONF_MAC_MAX_PAYLOAD
#define MAC_MAX_PAYLOAD SICSLOWPAN_CONF_MAC_MAX_PAYLOAD
#else /* SICSLOWPAN_CONF_MAC_MAX_PAYLOAD */
#define MAC_MAX_PAYLOAD 102
#endif /* SICSLOWPAN_CONF_MAC_MAX_PAYLOAD */
/** \brief Some MAC layers need a minimum payload, which is
@ -1355,6 +1359,8 @@ send_packet(rimeaddr_t *dest)
static uint8_t
output(uip_lladdr_t *localdest)
{
int framer_hdrlen;
/* The MAC address of the destination of the packet */
rimeaddr_t dest;
@ -1422,7 +1428,24 @@ output(uip_lladdr_t *localdest)
}
PRINTFO("sicslowpan output: header of len %d\n", rime_hdr_len);
if(uip_len - uncomp_hdr_len > MAC_MAX_PAYLOAD - rime_hdr_len) {
/* Calculate NETSTACK_FRAMER's header length, that will be added in the NETSTACK_RDC.
* We calculate it here only to make a better decision of whether the outgoing packet
* needs to be fragmented or not. */
#define USE_FRAMER_HDRLEN 1
#if USE_FRAMER_HDRLEN
packetbuf_clear();
packetbuf_set_addr(PACKETBUF_ADDR_RECEIVER, &dest);
framer_hdrlen = NETSTACK_FRAMER.create();
if(framer_hdrlen < 0) {
/* Framing failed, we assume the maximum header length */
framer_hdrlen = 21;
}
packetbuf_clear();
#else /* USE_FRAMER_HDRLEN */
framer_hdrlen = 21;
#endif /* USE_FRAMER_HDRLEN */
if((int)uip_len - (int)uncomp_hdr_len > (int)MAC_MAX_PAYLOAD - framer_hdrlen - (int)rime_hdr_len) {
#if SICSLOWPAN_CONF_FRAG
struct queuebuf *q;
/*
@ -1455,7 +1478,7 @@ output(uip_lladdr_t *localdest)
/* Copy payload and send */
rime_hdr_len += SICSLOWPAN_FRAG1_HDR_LEN;
rime_payload_len = (MAC_MAX_PAYLOAD - rime_hdr_len) & 0xf8;
rime_payload_len = (MAC_MAX_PAYLOAD - framer_hdrlen - rime_hdr_len) & 0xf8;
PRINTFO("(len %d, tag %d)\n", rime_payload_len, my_tag);
memcpy(rime_ptr + rime_hdr_len,
(uint8_t *)UIP_IP_BUF + uncomp_hdr_len, rime_payload_len);
@ -1491,7 +1514,7 @@ output(uip_lladdr_t *localdest)
/* uip_htons((SICSLOWPAN_DISPATCH_FRAGN << 8) | uip_len); */
SET16(RIME_FRAG_PTR, RIME_FRAG_DISPATCH_SIZE,
((SICSLOWPAN_DISPATCH_FRAGN << 8) | uip_len));
rime_payload_len = (MAC_MAX_PAYLOAD - rime_hdr_len) & 0xf8;
rime_payload_len = (MAC_MAX_PAYLOAD - framer_hdrlen - rime_hdr_len) & 0xf8;
while(processed_ip_out_len < uip_len) {
PRINTFO("sicslowpan output: fragment ");
RIME_FRAG_PTR[RIME_FRAG_OFFSET] = processed_ip_out_len >> 3;
@ -1530,6 +1553,7 @@ output(uip_lladdr_t *localdest)
return 0;
#endif /* SICSLOWPAN_CONF_FRAG */
} else {
/*
* The packet does not need to be fragmented
* copy "payload" and send
@ -1709,6 +1733,20 @@ input(void)
return;
}
rime_payload_len = packetbuf_datalen() - rime_hdr_len;
/* Sanity-check size of incoming packet to avoid buffer overflow */
{
int req_size = UIP_LLH_LEN + uncomp_hdr_len + (uint16_t)(frag_offset << 3)
+ rime_payload_len;
if(req_size > sizeof(sicslowpan_buf)) {
PRINTF(
"SICSLOWPAN: packet dropped, minimum required SICSLOWPAN_IP_BUF size: %d+%d+%d+%d=%d (current size: %d)\n",
UIP_LLH_LEN, uncomp_hdr_len, (uint16_t)(frag_offset << 3),
rime_payload_len, req_size, sizeof(sicslowpan_buf));
return;
}
}
memcpy((uint8_t *)SICSLOWPAN_IP_BUF + uncomp_hdr_len + (uint16_t)(frag_offset << 3), rime_ptr + rime_hdr_len, rime_payload_len);
/* update processed_ip_in_len if fragment, sicslowpan_len otherwise */