From fb8585fc3f9b39153e0bdaf03f00a02dde9c03c6 Mon Sep 17 00:00:00 2001 From: Roel Kluin Date: Tue, 24 Mar 2009 03:27:48 +0000 Subject: [PATCH] ctcm: avoid wraparound in length of incoming data Since the receive code should tolerate any incoming garbage, it should be protected against a potential wraparound when manipulating length values within incoming data. block_len is unsigned, so a too large subtraction will cause a wraparound. Signed-off-by: Roel Kluin Signed-off-by: Ursula Braun Signed-off-by: David S. Miller --- drivers/s390/net/ctcm_fsms.c | 5 ++--- drivers/s390/net/ctcm_main.c | 3 ++- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/s390/net/ctcm_fsms.c b/drivers/s390/net/ctcm_fsms.c index f29c7086fc19..4ded9ac2c5ef 100644 --- a/drivers/s390/net/ctcm_fsms.c +++ b/drivers/s390/net/ctcm_fsms.c @@ -410,9 +410,8 @@ static void chx_rx(fsm_instance *fi, int event, void *arg) priv->stats.rx_length_errors++; goto again; } - block_len -= 2; - if (block_len > 0) { - *((__u16 *)skb->data) = block_len; + if (block_len > 2) { + *((__u16 *)skb->data) = block_len - 2; ctcm_unpack_skb(ch, skb); } again: diff --git a/drivers/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c index 59ce7fb73089..a7a25383db76 100644 --- a/drivers/s390/net/ctcm_main.c +++ b/drivers/s390/net/ctcm_main.c @@ -105,7 +105,8 @@ void ctcm_unpack_skb(struct channel *ch, struct sk_buff *pskb) return; } pskb->protocol = ntohs(header->type); - if (header->length <= LL_HEADER_LENGTH) { + if ((header->length <= LL_HEADER_LENGTH) || + (len <= LL_HEADER_LENGTH)) { if (!(ch->logflags & LOG_FLAG_ILLEGALSIZE)) { CTCM_DBF_TEXT_(ERROR, CTC_DBF_ERROR, "%s(%s): Illegal packet size %d(%d,%d)"