linux-toradex.git/drivers/net/xen-netback, branch v3.2.68

xen-netback: remove pointless clause from if statement

2014-04-30T15:23:17+00:00

[ Upstream commit 0576eddf24df716d8570ef8ca11452a9f98eaab2 ]

This patch removes a test in start_new_rx_buffer() that checks whether
a copy operation is less than MAX_BUFFER_OFFSET in length, since
MAX_BUFFER_OFFSET is defined to be PAGE_SIZE and the only caller of
start_new_rx_buffer() already limits copy operations to PAGE_SIZE or less.

Signed-off-by: Paul Durrant 
Cc: Ian Campbell 
Cc: Wei Liu 
Cc: Sander Eikelenboom 
Reported-By: Sander Eikelenboom 
Tested-By: Sander Eikelenboom 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

xen-netback: use jiffies_64 value to calculate credit timeout

2013-11-28T14:01:59+00:00

[ Upstream commit 059dfa6a93b779516321e5112db9d7621b1367ba ]

time_after_eq() only works if the delta is < MAX_ULONG/2.

For a 32bit Dom0, if netfront sends packets at a very low rate, the time
between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2
and the test for timer_after_eq() will be incorrect. Credit will not be
replenished and the guest may become unable to send packets (e.g., if
prior to the long gap, all credit was exhausted).

Use jiffies_64 variant to mitigate this problem for 32bit Dom0.

Suggested-by: Jan Beulich 
Signed-off-by: Wei Liu 
Reviewed-by: David Vrabel 
Cc: Ian Campbell 
Cc: Jason Luan 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

xen-netback: better names for thresholds

2013-06-19T01:16:44+00:00

commit 376414945d15aa636e65f7e773c1e398b7a21cb9 upstream.

This patch only changes some names to avoid confusion.

In this patch we have:

  MAX_SKB_SLOTS_DEFAULT -> FATAL_SKB_SLOTS_DEFAULT
  max_skb_slots -> fatal_skb_slots
  #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN

The fatal_skb_slots is the threshold to determine whether a packet is
malicious.

XEN_NETBK_LEGACY_SLOTS_MAX is the maximum slots a valid packet can have at
this point. It is defined to be XEN_NETIF_NR_SLOTS_MIN because that's
guaranteed to be supported by all backends.

Suggested-by: Ian Campbell 
Signed-off-by: Wei Liu 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

xen-netback: avoid allocating variable size array on stack

2013-06-19T01:16:44+00:00

commit 59ccb4ebbc35e36a3c143f2d1355deb75c2e628f upstream.

Tune xen_netbk_count_requests to not touch working array beyond limit, so that
we can make working array size constant.

Suggested-by: Jan Beulich 
Signed-off-by: Wei Liu 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

xen-netback: remove redundent parameter in netbk_count_requests

2013-06-19T01:16:44+00:00

commit ac69c26e7accb04ae2cb9ab0872068983a42b3c8 upstream.

Tracking down from the caller, first_idx is always equal to vif->tx.req_cons.
Remove it to avoid confusion.

Suggested-by: Jan Beulich 
Signed-off-by: Wei Liu 
Acked-by: Ian Campbell 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

xen-netback: don't disconnect frontend when seeing oversize packet

2013-06-19T01:16:43+00:00

commit 03393fd5cc2b6cdeec32b704ecba64dbb0feae3c upstream.

Some frontend drivers are sending packets > 64 KiB in length. This length
overflows the length field in the first slot making the following slots have
an invalid length.

Turn this error back into a non-fatal error by dropping the packet. To avoid
having the following slots having fatal errors, consume all slots in the
packet.

This does not reopen the security hole in XSA-39 as if the packet as an
invalid number of slots it will still hit fatal error case.

Signed-off-by: David Vrabel 
Signed-off-by: Wei Liu 
Acked-by: Ian Campbell 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

xen-netback: coalesce slots in TX path and fix regressions

2013-06-19T01:16:43+00:00

commit 2810e5b9a7731ca5fce22bfbe12c96e16ac44b6f upstream.

This patch tries to coalesce tx requests when constructing grant copy
structures. It enables netback to deal with situation when frontend's
MAX_SKB_FRAGS is larger than backend's MAX_SKB_FRAGS.

With the help of coalescing, this patch tries to address two regressions
avoid reopening the security hole in XSA-39.

Regression 1. The reduction of the number of supported ring entries (slots)
per packet (from 18 to 17). This regression has been around for some time but
remains unnoticed until XSA-39 security fix. This is fixed by coalescing
slots.

Regression 2. The XSA-39 security fix turning "too many frags" errors from
just dropping the packet to a fatal error and disabling the VIF. This is fixed
by coalescing slots (handling 18 slots when backend's MAX_SKB_FRAGS is 17)
which rules out false positive (using 18 slots is legit) and dropping packets
using 19 to `max_skb_slots` slots.

To avoid reopening security hole in XSA-39, frontend sending packet using more
than max_skb_slots is considered malicious.

The behavior of netback for packet is thus:

    1-18            slots: valid
   19-max_skb_slots slots: drop and respond with an error
   max_skb_slots+   slots: fatal error

max_skb_slots is configurable by admin, default value is 20.

Also change variable name from "frags" to "slots" in netbk_count_requests.

Please note that RX path still has dependency on MAX_SKB_FRAGS. This will be
fixed with separate patch.

Signed-off-by: Wei Liu 
Acked-by: Ian Campbell 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

xen-netback: fix sparse warning

2013-06-19T01:16:43+00:00

commit 9eaee8beeeb3bca0d9b14324fd9d467d48db784c upstream.

Fix warning about 0 used as NULL.

Signed-off-by: Stephen Hemminger 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

netback: remove redundant assignment

2013-06-19T01:16:42+00:00

commit 16ecba2605a3bbd374cd993e532264e2d8de49e5 upstream.

New value for netbk->mmap_pages[pending_idx] is assigned in
xen_netbk_alloc_page(), no need for a second assignment which
exposes internal to the outside world.

Signed-off-by: Wei Liu 
Acked-by: Ian Campbell 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

xen-netback: remove skb in xen_netbk_alloc_page

2013-06-19T01:16:42+00:00

commit 27f852282ab9a028f57da96d05c26f38c424a315 upstream.

This variable is never used.

Signed-off-by: Wei Liu 
Acked-by: Ian Campbell 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings