This is a note to let you know that I've just added the patch titled
packet: validate variable length ll headers
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
packet-validate-variable-length-ll-headers.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Sat Apr 16 10:02:53 PDT 2016
From: Willem de Bruijn <willemb@xxxxxxxxxx>
Date: Wed, 9 Mar 2016 21:58:34 -0500
Subject: packet: validate variable length ll headers
From: Willem de Bruijn <willemb@xxxxxxxxxx>
[ Upstream commit 9ed988cd591500c040b2a6257bc68543e08ceeef ]
Replace link layer header validation check ll_header_truncate with
more generic dev_validate_header.
Validation based on hard_header_len incorrectly drops valid packets
in variable length protocols, such as AX25. dev_validate_header
calls header_ops.validate for such protocols to ensure correctness
below hard_header_len.
See also http://comments.gmane.org/gmane.linux.network/401064
Fixes 9c7077622dd9 ("packet: make packet_snd fail on len smaller than l2 header")
Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/packet/af_packet.c | 37 ++++++++++++++++---------------------
1 file changed, 16 insertions(+), 21 deletions(-)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1916,6 +1916,10 @@ retry:
goto retry;
}
+ if (!dev_validate_header(dev, skb->data, len)) {
+ err = -EINVAL;
+ goto out_unlock;
+ }
if (len > (dev->mtu + dev->hard_header_len + extra_len) &&
!packet_extra_vlan_len_allowed(dev, skb)) {
err = -EMSGSIZE;
@@ -2326,18 +2330,6 @@ static void tpacket_destruct_skb(struct
sock_wfree(skb);
}
-static bool ll_header_truncated(const struct net_device *dev, int len)
-{
- /* net device doesn't like empty head */
- if (unlikely(len < dev->hard_header_len)) {
- net_warn_ratelimited("%s: packet size is too short (%d < %d)\n",
- current->comm, len, dev->hard_header_len);
- return true;
- }
-
- return false;
-}
-
static void tpacket_set_protocol(const struct net_device *dev,
struct sk_buff *skb)
{
@@ -2420,19 +2412,19 @@ static int tpacket_fill_skb(struct packe
if (unlikely(err < 0))
return -EINVAL;
} else if (dev->hard_header_len) {
- if (ll_header_truncated(dev, tp_len))
- return -EINVAL;
+ int hdrlen = min_t(int, dev->hard_header_len, tp_len);
skb_push(skb, dev->hard_header_len);
- err = skb_store_bits(skb, 0, data,
- dev->hard_header_len);
+ err = skb_store_bits(skb, 0, data, hdrlen);
if (unlikely(err))
return err;
+ if (!dev_validate_header(dev, skb->data, hdrlen))
+ return -EINVAL;
if (!skb->protocol)
tpacket_set_protocol(dev, skb);
- data += dev->hard_header_len;
- to_write -= dev->hard_header_len;
+ data += hdrlen;
+ to_write -= hdrlen;
}
offset = offset_in_page(data);
@@ -2763,9 +2755,6 @@ static int packet_snd(struct socket *soc
offset = dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len);
if (unlikely(offset < 0))
goto out_free;
- } else {
- if (ll_header_truncated(dev, len))
- goto out_free;
}
/* Returns -EFAULT on error */
@@ -2773,6 +2762,12 @@ static int packet_snd(struct socket *soc
if (err)
goto out_free;
+ if (sock->type == SOCK_RAW &&
+ !dev_validate_header(dev, skb->data, len)) {
+ err = -EINVAL;
+ goto out_free;
+ }
+
sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
if (!gso_type && (len > dev->mtu + reserve + extra_len) &&
Patches currently in stable-queue which might be from willemb@xxxxxxxxxx are
queue-4.4/ax25-add-link-layer-header-validation-function.patch
queue-4.4/net-validate-variable-length-ll-headers.patch
queue-4.4/packet-validate-variable-length-ll-headers.patch
queue-4.4/macvtap-always-pass-ethernet-header-in-linear.patch
queue-4.4/ipv6-udp-fix-udp_mib_ignoredmulti-updates.patch
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