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authorWillem de Bruijn <willemb@google.com>2016-03-09 21:58:34 -0500
committerDavid S. Miller <davem@davemloft.net>2016-03-09 22:13:01 -0500
commit9ed988cd591500c040b2a6257bc68543e08ceeef (patch)
tree5044c8b8a7af7aa6c9bf017a51da01f3ca334274
parentea47781c26510e5d97f80f9aceafe9065bd5e3aa (diff)
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packet: validate variable length ll headers
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@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/packet/af_packet.c43
1 files changed, 18 insertions, 25 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index d41b1074cb2d..1ecfa710ca98 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1915,6 +1915,10 @@ 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;
@@ -2393,18 +2397,6 @@ static void tpacket_destruct_skb(struct sk_buff *skb)
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)
{
@@ -2522,16 +2514,20 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
if (unlikely(err < 0))
return -EINVAL;
} else if (copylen) {
+ int hdrlen = min_t(int, copylen, tp_len);
+
skb_push(skb, dev->hard_header_len);
skb_put(skb, copylen - dev->hard_header_len);
- err = skb_store_bits(skb, 0, data, copylen);
+ 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 += copylen;
- to_write -= copylen;
+ data += hdrlen;
+ to_write -= hdrlen;
}
offset = offset_in_page(data);
@@ -2703,13 +2699,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
copylen = __virtio16_to_cpu(vio_le(),
vnet_hdr->hdr_len);
}
- if (dev->hard_header_len) {
- if (ll_header_truncated(dev, tp_len)) {
- tp_len = -EINVAL;
- goto tpacket_error;
- }
- copylen = max_t(int, copylen, dev->hard_header_len);
- }
+ copylen = max_t(int, copylen, dev->hard_header_len);
skb = sock_alloc_send_skb(&po->sk,
hlen + tlen + sizeof(struct sockaddr_ll) +
(copylen - dev->hard_header_len),
@@ -2905,9 +2895,6 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
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 */
@@ -2915,6 +2902,12 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
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 (!vnet_hdr.gso_type && (len > dev->mtu + reserve + extra_len) &&