linux/include
Willem de Bruijn 5cd8d46ea1 packet: copy user buffers before orphan or clone
tpacket_snd sends packets with user pages linked into skb frags. It
notifies that pages can be reused when the skb is released by setting
skb->destructor to tpacket_destruct_skb.

This can cause data corruption if the skb is orphaned (e.g., on
transmit through veth) or cloned (e.g., on mirror to another psock).

Create a kernel-private copy of data in these cases, same as tun/tap
zerocopy transmission. Reuse that infrastructure: mark the skb as
SKBTX_ZEROCOPY_FRAG, which will trigger copy in skb_orphan_frags(_rx).

Unlike other zerocopy packets, do not set shinfo destructor_arg to
struct ubuf_info. tpacket_destruct_skb already uses that ptr to notify
when the original skb is released and a timestamp is recorded. Do not
change this timestamp behavior. The ubuf_info->callback is not needed
anyway, as no zerocopy notification is expected.

Mark destructor_arg as not-a-uarg by setting the lower bit to 1. The
resulting value is not a valid ubuf_info pointer, nor a valid
tpacket_snd frame address. Add skb_zcopy_.._nouarg helpers for this.

The fix relies on features introduced in commit 52267790ef ("sock:
add MSG_ZEROCOPY"), so can be backported as is only to 4.14.

Tested with from `./in_netns.sh ./txring_overwrite` from
http://github.com/wdebruij/kerneltools/tests

Fixes: 69e3c75f4d ("net: TX_RING and packet mmap")
Reported-by: Anand H. Krishnan <anandhkrishnan@gmail.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-23 11:08:03 -08:00
..
acpi pci-v4.20-changes 2018-10-25 06:50:48 -07:00
asm-generic s390 updates for 4.20-rc2 2018-11-09 06:30:44 -06:00
clocksource
crypto KEYS: asym_tpm: extract key size & public key [ver #2] 2018-10-26 09:30:46 +01:00
drm drm, i915, amdgpu, bridge + core quirk 2018-11-02 10:58:20 -07:00
dt-bindings This time it looks like a quieter release cycle in the clk tree. I guess that's 2018-10-31 11:08:30 -07:00
keys KEYS: Move trusted.h to include/keys [ver #2] 2018-10-26 09:30:47 +01:00
kvm
linux packet: copy user buffers before orphan or clone 2018-11-23 11:08:03 -08:00
math-emu
media media updates for v4.20-rc1 2018-10-31 10:53:29 -07:00
memory
misc
net Revert "sctp: remove sctp_transport_pmtu_check" 2018-11-19 12:42:47 -08:00
pcmcia
ras
rdma First merge window pull request 2018-10-26 07:38:19 -07:00
scsi
soc ARM: SoC driver updates for 4.17 2018-10-29 15:16:01 -07:00
sound ASoC: Updates for v5.0/v4.20 2018-10-22 23:26:37 +02:00
target
trace Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-11-19 09:24:04 -08:00
uapi drm: i915, amdgpu, sun4i, exynos and etnaviv fixes 2018-11-10 13:29:47 -06:00
video
xen CONFIG_XEN_PV breaks xen_create_contiguous_region on ARM 2018-11-02 17:18:34 +01:00