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gnrc_icmpv6_error: check IPv6 header before starting to build

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Check for:

 - if it exists (critical error condition -- non-IPv6 headers should
   not trigger these functions) => assert
 - if it has a multicast source (that shouldn't really happen but
   people might try weird stuff ;-)
 - if it has an unspecified source (can't determine receiver of error
   message => don't send it, don't build it)
This commit is contained in:
Martine Lenders 2018-11-17 01:53:10 +01:00
parent 447e1b8eb8
commit ef1132384a
2 changed files with 57 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
sys/include/net/gnrc/icmpv6/error.h
View File

@ -39,6 +39,9 @@ extern "C" {
*
* @pre @p orig_pkt contains a packet snip of type @ref GNRC_NETTYPE_IPV6
*
* @note Won't send if source address of @p orig_pkt is unspecified or
* multicast
*
* @param[in] code The [code for the message](@ref net_icmpv6_error_dst_unr_codes).
* @param[in] orig_pkt The invoking packet.
*/
@ -49,6 +52,9 @@ void gnrc_icmpv6_error_dst_unr_send(uint8_t code, const gnrc_pktsnip_t *orig_pkt
*
* @pre @p orig_pkt contains a packet snip of type @ref GNRC_NETTYPE_IPV6
*
* @note Won't send if source address of @p orig_pkt is unspecified or
* multicast
*
* @param[in] mtu The maximum transission unit of the next-hop link.
* @param[in] orig_pkt The invoking packet.
*/
@ -60,6 +66,9 @@ void gnrc_icmpv6_error_pkt_too_big_send(uint32_t mtu,
*
* @pre @p orig_pkt contains a packet snip of type @ref GNRC_NETTYPE_IPV6
*
* @note Won't send if source address of @p orig_pkt is unspecified or
* multicast
*
* @param[in] code The [code for the message](@ref net_icmpv6_error_time_exc_codes).
* @param[in] orig_pkt The invoking packet.
*/
@ -72,6 +81,8 @@ void gnrc_icmpv6_error_time_exc_send(uint8_t code,
* @pre @p orig_pkt is in receive order.
* @pre @p orig_pkt contains a packet snip of type @ref GNRC_NETTYPE_IPV6
*
* @note Won't send if source address of @p orig_pkt is unspecified or
* multicast
*
* @param[in] code The [code for the message](@ref net_icmpv6_error_param_prob_codes).
* @param[in] ptr Pointer to the errorneous octet in @p orig_pkt.

61
sys/net/gnrc/network_layer/icmpv6/error/gnrc_icmpv6_error.c
View File

@ -192,16 +192,16 @@ static gnrc_pktsnip_t *_param_prob_build(uint8_t code, void *ptr,
return pkt;
}
static void _send(gnrc_pktsnip_t *pkt, const gnrc_pktsnip_t *orig_pkt)
static void _send(gnrc_pktsnip_t *pkt, const gnrc_pktsnip_t *orig_pkt,
gnrc_pktsnip_t *ipv6)
{
if (pkt != NULL) {
/* discarding const qualifier is safe here */
gnrc_pktsnip_t *ipv6 = gnrc_pktsnip_search_type((gnrc_pktsnip_t *)orig_pkt,
GNRC_NETTYPE_IPV6);
gnrc_pktsnip_t *netif = gnrc_pktsnip_search_type((gnrc_pktsnip_t *)orig_pkt,
GNRC_NETTYPE_NETIF);
assert(ipv6 != NULL);
ipv6_hdr_t *ipv6_hdr = ipv6->data;
/* overwrite ipv6 parameter pointer ... we don't need it after this */
ipv6 = gnrc_ipv6_hdr_build(pkt, NULL, &ipv6_hdr->src);
if (ipv6 == NULL) {
DEBUG("gnrc_icmpv6_error: No space in packet buffer left\n");
@ -237,39 +237,70 @@ static void _send(gnrc_pktsnip_t *pkt, const gnrc_pktsnip_t *orig_pkt)
}
}
static gnrc_pktsnip_t *_check_ipv6_hdr(const gnrc_pktsnip_t *orig_pkt)
{
/* discarding const qualifier is safe here */
gnrc_pktsnip_t *ipv6 = gnrc_pktsnip_search_type((gnrc_pktsnip_t *)orig_pkt,
GNRC_NETTYPE_IPV6);
assert(ipv6 != NULL);
const ipv6_hdr_t *ipv6_hdr = ipv6->data;
if (ipv6_addr_is_unspecified(&ipv6_hdr->src) ||
ipv6_addr_is_multicast(&ipv6_hdr->src)) {
ipv6 = NULL;
}
return ipv6;
}
void gnrc_icmpv6_error_dst_unr_send(uint8_t code, const gnrc_pktsnip_t *orig_pkt)
{
gnrc_pktsnip_t *pkt = _dst_unr_build(code, orig_pkt);
gnrc_pktsnip_t *ipv6 = _check_ipv6_hdr(orig_pkt);
DEBUG("gnrc_icmpv6_error: trying to send destination unreachable error\n");
_send(pkt, orig_pkt);
if (ipv6 != NULL) {
gnrc_pktsnip_t *pkt = _dst_unr_build(code, orig_pkt);
DEBUG("gnrc_icmpv6_error: trying to send destination unreachable error\n");
_send(pkt, orig_pkt, ipv6);
}
}
void gnrc_icmpv6_error_pkt_too_big_send(uint32_t mtu,
const gnrc_pktsnip_t *orig_pkt)
{
gnrc_pktsnip_t *pkt = _pkt_too_big_build(mtu, orig_pkt);
gnrc_pktsnip_t *ipv6 = _check_ipv6_hdr(orig_pkt);
DEBUG("gnrc_icmpv6_error: trying to send packet too big error\n");
_send(pkt, orig_pkt);
if (ipv6 != NULL) {
gnrc_pktsnip_t *pkt = _pkt_too_big_build(mtu, orig_pkt);
DEBUG("gnrc_icmpv6_error: trying to send packet too big error\n");
_send(pkt, orig_pkt, ipv6);
}
}
void gnrc_icmpv6_error_time_exc_send(uint8_t code,
const gnrc_pktsnip_t *orig_pkt)
{
gnrc_pktsnip_t *pkt = _time_exc_build(code, orig_pkt);
gnrc_pktsnip_t *ipv6 = _check_ipv6_hdr(orig_pkt);
DEBUG("gnrc_icmpv6_error: trying to send time exceeded error\n");
_send(pkt, orig_pkt);
if (ipv6 != NULL) {
gnrc_pktsnip_t *pkt = _time_exc_build(code, orig_pkt);
DEBUG("gnrc_icmpv6_error: trying to send time exceeded error\n");
_send(pkt, orig_pkt, ipv6);
}
}
void gnrc_icmpv6_error_param_prob_send(uint8_t code, void *ptr,
const gnrc_pktsnip_t *orig_pkt)
{
gnrc_pktsnip_t *pkt = _param_prob_build(code, ptr, orig_pkt);
gnrc_pktsnip_t *ipv6 = _check_ipv6_hdr(orig_pkt);
DEBUG("gnrc_icmpv6_error: trying to send parameter problem error\n");
_send(pkt, orig_pkt);
if (ipv6 != NULL) {
gnrc_pktsnip_t *pkt = _param_prob_build(code, ptr, orig_pkt);
DEBUG("gnrc_icmpv6_error: trying to send parameter problem error\n");
_send(pkt, orig_pkt, ipv6);
}
}
/** @} */