From 5e28599a6e45eb8ce7e50510b06c3a34ebf1a8fa Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Thu, 4 Oct 2007 14:43:09 -0700 Subject: [PATCH] [CCID2]: Sequence number wraparound issues This replaces several uses of standard arithmetic with the DCCP sequence number arithmetic functions. The problem here is that the sequence number wrap-around was not taken into consideration. * Condition "seqp->ccid2s_seq <= prev->ccid2s_seq" has been replaced by dccp_delta_seqno(seqp->ccid2s_seq, prev->ccid2s_seq) >= 0 since if seqp is `before' prev, then the delta_seqno() is positive. * The test whether sequence numbers `a' and `b' are consecutive has the form dccp_delta_seqno(a, b) == 1 * Increment of ccid2hctx_rpseq could be done using dccp_inc_seqno(), but since here the incremented ccid2hctx_rpseq == seqno, used assignment instead. Signed-off-by: Gerrit Renker Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller --- net/dccp/ccids/ccid2.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c index 1dff4188f3f5..426008e3b7e3 100644 --- a/net/dccp/ccids/ccid2.c +++ b/net/dccp/ccids/ccid2.c @@ -59,7 +59,8 @@ static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx) pipe++; /* packets are sent sequentially */ - BUG_ON(seqp->ccid2s_seq <= prev->ccid2s_seq); + BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq, + prev->ccid2s_seq ) >= 0); BUG_ON(time_before(seqp->ccid2s_sent, prev->ccid2s_sent)); @@ -562,8 +563,8 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) hctx->ccid2hctx_rpseq = seqno; } else { /* check if packet is consecutive */ - if ((hctx->ccid2hctx_rpseq + 1) == seqno) - hctx->ccid2hctx_rpseq++; + if (dccp_delta_seqno(hctx->ccid2hctx_rpseq, seqno) == 1) + hctx->ccid2hctx_rpseq = seqno; /* it's a later packet */ else if (after48(seqno, hctx->ccid2hctx_rpseq)) { hctx->ccid2hctx_rpdupack++; -- 2.20.1