From 867d6ae2c9cec6a0f6f3a7472cf8397693f6cc35 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Stefan=20Br=C3=BCns?= Date: Thu, 27 Aug 2015 23:53:26 +0200 Subject: [PATCH] net: reject Bootp/DHCP packets with bad OP value MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Rename check_packet to check_reply_packet to make its function more obvious. The check for DHCP_* values is completely off, as it should compare against DHCP option 53 (Message Type). Only valid value for any Bootp/DHCP reply is BOOTREPLY. Signed-off-by: Stefan Brüns Acked-by: Joe Hershberger --- net/bootp.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/net/bootp.c b/net/bootp.c index fbdc7cb..3fac7f3 100644 --- a/net/bootp.c +++ b/net/bootp.c @@ -109,7 +109,8 @@ static bool bootp_match_id(ulong id) return false; } -static int check_packet(uchar *pkt, unsigned dest, unsigned src, unsigned len) +static int check_reply_packet(uchar *pkt, unsigned dest, unsigned src, + unsigned len) { struct bootp_hdr *bp = (struct bootp_hdr *)pkt; int retval = 0; @@ -118,11 +119,7 @@ static int check_packet(uchar *pkt, unsigned dest, unsigned src, unsigned len) retval = -1; else if (len < sizeof(struct bootp_hdr) - OPT_FIELD_SIZE) retval = -2; - else if (bp->bp_op != OP_BOOTREQUEST && - bp->bp_op != OP_BOOTREPLY && - bp->bp_op != DHCP_OFFER && - bp->bp_op != DHCP_ACK && - bp->bp_op != DHCP_NAK) + else if (bp->bp_op != OP_BOOTREPLY) retval = -3; else if (bp->bp_htype != HWT_ETHER) retval = -4; @@ -343,7 +340,7 @@ static void bootp_handler(uchar *pkt, unsigned dest, struct in_addr sip, bp = (struct bootp_hdr *)pkt; /* Filter out pkts we don't want */ - if (check_packet(pkt, dest, src, len)) + if (check_reply_packet(pkt, dest, src, len)) return; /* @@ -960,7 +957,7 @@ static void dhcp_handler(uchar *pkt, unsigned dest, struct in_addr sip, src, dest, len, dhcp_state); /* Filter out pkts we don't want */ - if (check_packet(pkt, dest, src, len)) + if (check_reply_packet(pkt, dest, src, len)) return; debug("DHCPHandler: got DHCP packet: (src=%d, dst=%d, len=%d) state: "