lkml.org 
[lkml]   [2020]   [Mar]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.4 18/72] net: sched: correct flower port blocking
    Date
    From: Jason Baron <jbaron@akamai.com>

    [ Upstream commit 8a9093c79863b58cc2f9874d7ae788f0d622a596 ]

    tc flower rules that are based on src or dst port blocking are sometimes
    ineffective due to uninitialized stack data. __skb_flow_dissect() extracts
    ports from the skb for tc flower to match against. However, the port
    dissection is not done when when the FLOW_DIS_IS_FRAGMENT bit is set in
    key_control->flags. All callers of __skb_flow_dissect(), zero-out the
    key_control field except for fl_classify() as used by the flower
    classifier. Thus, the FLOW_DIS_IS_FRAGMENT may be set on entry to
    __skb_flow_dissect(), since key_control is allocated on the stack
    and may not be initialized.

    Since key_basic and key_control are present for all flow keys, let's
    make sure they are initialized.

    Fixes: 62230715fd24 ("flow_dissector: do not dissect l4 ports for fragments")
    Co-developed-by: Eric Dumazet <edumazet@google.com>
    Signed-off-by: Eric Dumazet <edumazet@google.com>
    Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
    Signed-off-by: Jason Baron <jbaron@akamai.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    include/net/flow_dissector.h | 9 +++++++++
    net/sched/cls_flower.c | 1 +
    2 files changed, 10 insertions(+)

    --- a/include/net/flow_dissector.h
    +++ b/include/net/flow_dissector.h
    @@ -4,6 +4,7 @@
    #include <linux/types.h>
    #include <linux/in6.h>
    #include <linux/siphash.h>
    +#include <linux/string.h>
    #include <uapi/linux/if_ether.h>

    /**
    @@ -185,4 +186,12 @@ static inline bool flow_keys_have_l4(str

    u32 flow_hash_from_keys(struct flow_keys *keys);

    +static inline void
    +flow_dissector_init_keys(struct flow_dissector_key_control *key_control,
    + struct flow_dissector_key_basic *key_basic)
    +{
    + memset(key_control, 0, sizeof(*key_control));
    + memset(key_basic, 0, sizeof(*key_basic));
    +}
    +
    #endif
    --- a/net/sched/cls_flower.c
    +++ b/net/sched/cls_flower.c
    @@ -127,6 +127,7 @@ static int fl_classify(struct sk_buff *s
    struct fl_flow_key skb_key;
    struct fl_flow_key skb_mkey;

    + flow_dissector_init_keys(&skb_key.control, &skb_key.basic);
    fl_clear_masked_range(&skb_key, &head->mask);
    skb_key.indev_ifindex = skb->skb_iif;
    /* skb_flow_dissect() does not set n_proto in case an unknown protocol,

    \
     
     \ /
      Last update: 2020-03-10 13:43    [W:4.184 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site