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[dhcp_relay] fix data type in dhcp6relay, add protection in packet data parsing #9036

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Merged
kellyyeh merged 6 commits into from
Oct 22, 2021
Merged

[dhcp_relay] fix data type in dhcp6relay, add protection in packet data parsing #9036

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58139b4
fix recv data length datatype
kellyyeh Oct 21, 2021
ccb6fbe
check if next pointer is current position
kellyyeh Oct 21, 2021
2364cc8
prevent stuck in infinite while loop
kellyyeh Oct 21, 2021
74216d2
address PR comments
kellyyeh Oct 21, 2021
71699a0
return if boundary protection fails
kellyyeh Oct 21, 2021
a7f670c
Address PR comments
kellyyeh Oct 21, 2021
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15 changes: 11 additions & 4 deletions src/dhcp6relay/src/relay.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -515,29 +515,36 @@ void relay_client(int sock, const uint8_t *msg, int32_t len, const ip6_hdr *ip_h
void callback(evutil_socket_t fd, short event, void *arg) {
struct relay_config *config = (struct relay_config *)arg;
static uint8_t message_buffer[4096];
uint32_t len = recv(config->filter, message_buffer, 4096, 0);
int32_t len = recv(config->filter, message_buffer, 4096, 0);
if (len <= 0) {
syslog(LOG_WARNING, "recv: Failed to receive data at filter socket\n");
syslog(LOG_WARNING, "recv: Failed to receive data at filter socket: %s\n", strerror(errno));
return;
}

char* ptr = (char *)message_buffer;
const uint8_t *current_position = (uint8_t *)ptr;
const uint8_t *current_position = (uint8_t *)ptr;
const uint8_t *tmp = NULL;
const uint8_t *prev = NULL;

auto ether_header = parse_ether_frame(current_position, &tmp);
current_position = tmp;

auto ip_header = parse_ip6_hdr(current_position, &tmp);
current_position = tmp;

prev = current_position;
if (ip_header->ip6_ctlun.ip6_un1.ip6_un1_nxt != IPPROTO_UDP) {
const struct ip6_ext *ext_header;
do {
ext_header = (const struct ip6_ext *)current_position;
current_position += ext_header->ip6e_len;
if((current_position == prev) || (current_position >= (uint8_t *)ptr + sizeof(message_buffer))) {
return;
}
prev = current_position;
}
while (ext_header->ip6e_nxt != IPPROTO_UDP);
}
}

auto udp_header = parse_udp(current_position, &tmp);
current_position = tmp;
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