diff options
author | Michal Kubeček <mkubecek@suse.cz> | 2015-03-02 18:27:11 +0100 |
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committer | David S. Miller <davem@davemloft.net> | 2015-03-02 22:19:29 -0500 |
commit | acf8dd0a9d0b9e4cdb597c2f74802f79c699e802 (patch) | |
tree | 32e7fcfb666b6019f9c4aab4bfe095353657e920 /drivers/net/ethernet | |
parent | 096b1c172853163b865884446f73977b27eb034d (diff) |
udp: only allow UFO for packets from SOCK_DGRAM sockets
If an over-MTU UDP datagram is sent through a SOCK_RAW socket to a
UFO-capable device, ip_ufo_append_data() sets skb->ip_summed to
CHECKSUM_PARTIAL unconditionally as all GSO code assumes transport layer
checksum is to be computed on segmentation. However, in this case,
skb->csum_start and skb->csum_offset are never set as raw socket
transmit path bypasses udp_send_skb() where they are usually set. As a
result, driver may access invalid memory when trying to calculate the
checksum and store the result (as observed in virtio_net driver).
Moreover, the very idea of modifying the userspace provided UDP header
is IMHO against raw socket semantics (I wasn't able to find a document
clearly stating this or the opposite, though). And while allowing
CHECKSUM_NONE in the UFO case would be more efficient, it would be a bit
too intrusive change just to handle a corner case like this. Therefore
disallowing UFO for packets from SOCK_DGRAM seems to be the best option.
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet')
0 files changed, 0 insertions, 0 deletions