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    Subject[patch 12/73] IPV4 raw: Strengthen check on validity of iph->ihl
    2.6.23-stable review patch.  If anyone has any objections, please let us know.
    ------------------
    From: Herbert Xu <herbert@gondor.apana.org.au>

    [IPV4] raw: Strengthen check on validity of iph->ihl

    [ Upstream commit: f844c74fe07321953e2dd227fe35280075f18f60 ]

    We currently check that iph->ihl is bounded by the real length and that
    the real length is greater than the minimum IP header length. However,
    we did not check the caes where iph->ihl is less than the minimum IP
    header length.

    This breaks because some ip_fast_csum implementations assume that which
    is quite reasonable.

    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    net/ipv4/raw.c | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    --- a/net/ipv4/raw.c
    +++ b/net/ipv4/raw.c
    @@ -270,6 +270,7 @@ static int raw_send_hdrinc(struct sock *
    int hh_len;
    struct iphdr *iph;
    struct sk_buff *skb;
    + unsigned int iphlen;
    int err;

    if (length > rt->u.dst.dev->mtu) {
    @@ -303,7 +304,8 @@ static int raw_send_hdrinc(struct sock *
    goto error_fault;

    /* We don't modify invalid header */
    - if (length >= sizeof(*iph) && iph->ihl * 4U <= length) {
    + iphlen = iph->ihl * 4;
    + if (iphlen >= sizeof(*iph) && iphlen <= length) {
    if (!iph->saddr)
    iph->saddr = rt->rt_src;
    iph->check = 0;
    --


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