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    Subject[241/264] netlink: validate NLA_MSECS length
    3.1-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Johannes Berg <johannes.berg@intel.com>

    commit c30bc94758ae2a38a5eb31767c1985c0aae0950b upstream.

    L2TP for example uses NLA_MSECS like this:
    policy:
    [L2TP_ATTR_RECV_TIMEOUT] = { .type = NLA_MSECS, },
    code:
    if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
    cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);

    As nla_get_msecs() is essentially nla_get_u64() plus the
    conversion to a HZ-based value, this will not properly
    reject attributes from userspace that aren't long enough
    and might overrun the message.

    Add NLA_MSECS to the attribute minlen array to check the
    size properly.

    Cc: Thomas Graf <tgraf@suug.ch>
    Signed-off-by: Johannes Berg <johannes.berg@intel.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    lib/nlattr.c | 1 +
    1 file changed, 1 insertion(+)

    --- a/lib/nlattr.c
    +++ b/lib/nlattr.c
    @@ -20,6 +20,7 @@ static const u16 nla_attr_minlen[NLA_TYP
    [NLA_U16] = sizeof(u16),
    [NLA_U32] = sizeof(u32),
    [NLA_U64] = sizeof(u64),
    + [NLA_MSECS] = sizeof(u64),
    [NLA_NESTED] = NLA_HDRLEN,
    };




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