From 13abd00685664ada99159adcfe0c4af9c889e96f Mon Sep 17 00:00:00 2001 From: Alexandre Peixoto Ferreira Date: Sun, 24 Sep 2023 21:46:41 -0500 Subject: sd-dhcp-client: reject NAKs from servers that we did not send an offer to (#29290) To support multiple DHCP servers in a network. --- src/libsystemd-network/sd-dhcp-client.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'src') diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c index cfdee5d6b4..79f308f652 100644 --- a/src/libsystemd-network/sd-dhcp-client.c +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -1591,9 +1591,14 @@ static int client_parse_message( case DHCP_STATE_REQUESTING: case DHCP_STATE_RENEWING: case DHCP_STATE_REBINDING: - if (r == DHCP_NAK) + if (r == DHCP_NAK) { + if (client->lease && client->lease->server_address != lease->server_address) + return log_dhcp_client_errno(client, SYNTHETIC_ERRNO(ENOMSG), + "NAK from unexpected server, ignoring: %s", + strna(error_message)); return log_dhcp_client_errno(client, SYNTHETIC_ERRNO(EADDRNOTAVAIL), "NAK: %s", strna(error_message)); + } if (r != DHCP_ACK) return log_dhcp_client_errno(client, SYNTHETIC_ERRNO(ENOMSG), "received message was not an ACK, ignoring."); -- cgit v1.2.3