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[dhcp_relay] Check payload size to prevent buffer overflow in dhcpv6 option #9740

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Merged
merged 10 commits into from
Jan 28, 2022
Merged

[dhcp_relay] Check payload size to prevent buffer overflow in dhcpv6 option #9740

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3cec21a
check payload size to prevent buffer overflow in dhcpv6 option
kellyyeh Jan 12, 2022
fd79af7
Merge branch 'Azure:master' into dhcp6relay-bufferoverflow
kellyyeh Jan 26, 2022
3e77339
Update bound check
kellyyeh Jan 26, 2022
5774092
Remove redundant check
kellyyeh Jan 27, 2022
d84faff
Remove extra space
kellyyeh Jan 27, 2022
2886874
Enhance first bound check
kellyyeh Jan 27, 2022
0fd77c4
Bound check data size received
kellyyeh Jan 27, 2022
0444593
Enhance option size check
kellyyeh Jan 28, 2022
e9072c6
Fix spacing
kellyyeh Jan 28, 2022
b39ec2c
Fix logic
kellyyeh Jan 28, 2022
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7 changes: 5 additions & 2 deletions src/dhcp6relay/src/relay.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -493,14 +493,17 @@ void relay_client(int sock, const uint8_t *msg, int32_t len, const ip6_hdr *ip_h
auto position = current_position + sizeof(struct dhcpv6_option);
auto dhcpv6msg = parse_dhcpv6_hdr(position);

while ((current_position - msg) != len) {
while ((current_position - msg) < len) {
auto option = parse_dhcpv6_opt(current_position, &tmp);
current_position = tmp;
if (current_position - msg > len || ntohs(option->option_length) > sizeof(buffer) - (current_buffer_position - buffer)) {
break;
}
switch (ntohs(option->option_code)) {
case OPTION_RELAY_MSG:
memcpy(current_buffer_position, ((uint8_t *)option) + sizeof(struct dhcpv6_option), ntohs(option->option_length));
current_buffer_position += ntohs(option->option_length);
type = dhcpv6msg->msg_type;;
type = dhcpv6msg->msg_type;
break;
default:
break;
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