Code in net/ethernet/eth.c does this:
__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
{
...
if (unlikely(!ether_addr_equal_64bits(eth->h_dest,
dev->dev_addr))) {
if (unlikely(is_multicast_ether_addr_64bits(eth->h_dest))) {
if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
skb->pkt_type = PACKET_BROADCAST;
else
skb->pkt_type = PACKET_MULTICAST;
} else {
skb->pkt_type = PACKET_OTHERHOST;
}
}
Multicast and broadcast are distinct and dev->broadcast seems to be ffffffffffff
by default, so add another multicast mac address that will serve as PACKET_MULTICAST.
One observation is that checking for extra cover is very fast
(effectively a memory load), so we can simplify code by removing
th->extra_cover and just check for it always. Additionally, we may
grab some coverage that we would miss otherwise.
Don't sleep for 500 ms at the end if colliding,
we are not going to use the extra coverage in that case anyway.
Check for extra coverage at the end every 100ms to avoid
being killed on timeout before we write any.
Make the 500ms sleep at the end parametrizable.
Enable it for syz_usb syscalls, so we get the same behavior for usb.
But this also allows to get extra coverage for other subsystems.
Some subsystems don't have a good way to detect if we will get any
extra coverage or not. Sleeping for 500ms for all programs slows down
fuzzing too much. So we check for extra coverage at the end for all
programs (cheap anyway), but sleep only for usb program.
This allows to collect extra coverage for vhost and maybe wireguard in future.
Update #806
Create individual file for futex syscall and add description for the new
operation FUTEX_WAIT_MULTIPLE.
Signed-off-by: André Almeida <andrealmeid@collabora.com>
* wireguard: setup some initial devices in a triangle
The fuzzer will wind up undoing some of this, which is fine, but at
least it now has the chance of hitting some other paths it wasn't
before.
Closes: #1599
* wireguard: make code ugly after `make generate` pass
* wireguard: get rid of unused structs that are still interesting
* wireguard: compile in C++ mode with gcc 7
Complex designated initializers are only supported in C++ mode from gcc
8, and for whatever reason syzkaller wants to be compiled in C++ mode.
* wireguard: add braces around debug statements for checker
* wireguard: regenerate go source
We print whole reproducer programs on failure,
if lots of programs fail, this results in thousands
of lines of output, which is esp bad on travis.
Limit amount of output.
The stringnozescapes does not make sense with filename,
also we may need similar escaping for string flags.
Handle escaped strings on ast level instead.
This avoids introducing new type and works seamleassly with flags.
As alternative I've also tried using strconv.Quote/Unquote
but it leads to ugly half-escaped strings:
"\xb0\x80s\xe8\xd4N\x91\xe3ڒ,\"C\x82D\xbb\x88\\i\xe2i\xc8\xe9\xd85\xb1\x14):M\xdcn"
Make hex-encoded strings a separate string format instead.
I bumped input buffer size on Go side in:
a2af37f0 prog: increase encodingexec buffer size
But I forgot to increase the size on the executor side.
Do this and add comments re keeping them in sync.
Unsafe is, well, unsafe.
Plus it fails under the new checkptr mode in go1.14.
Remove use of unsafe.
No statistically significant change in performance:
name old time/op new time/op delta
StoreLoadInt-8 21.2ns ± 5% 21.6ns ± 9% ~ (p=0.136 n=20+20)
Getting coverage working on cross-arch environment is currently
not documented at all. Also coverage presentation in the web-ui
is unclear. This document addition addresses these
