This allows for peeking at the length of the next message on a netlink socket
without pulling it off the socket's buffer/queue, allowing tools like 'ip' to
work.
This CL also fixes an issue where dump_done_errno was not included in the
NLMSG_DONE messages payload.
Issue #769
PiperOrigin-RevId: 274068637
Strengthen the header.IPv4.IsValid check to correctly check
for IHL/TotalLength fields. Also add a check to make sure
fragmentOffsets + size of the fragment do not cause a wrap
around for the end of the fragment.
PiperOrigin-RevId: 274049313
The signalfd descriptors otherwise always show as available. This can lead
programs to spin, assuming they are looking to see what signals are pending.
Updates #139
PiperOrigin-RevId: 274017890
Also ensure that all flipcall transport errors not returned by p9 (converted to
EIO by the client, or dropped on the floor by channel server goroutines) are
logged.
PiperOrigin-RevId: 272963663
The behavior for sending and receiving local broadcast (255.255.255.255)
traffic is as follows:
Outgoing
--------
* A broadcast packet sent on a socket that is bound to an interface goes out
that interface
* A broadcast packet sent on an unbound socket follows the route table to
select the outgoing interface
+ if an explicit route entry exists for 255.255.255.255/32, use that one
+ else use the default route
* Broadcast packets are looped back and delivered following the rules for
incoming packets (see next). This is the same behavior as for multicast
packets, except that it cannot be disabled via sockopt.
Incoming
--------
* Sockets wishing to receive broadcast packets must bind to either INADDR_ANY
(0.0.0.0) or INADDR_BROADCAST (255.255.255.255). No other socket receives
broadcast packets.
* Broadcast packets are multiplexed to all sockets matching it. This is the
same behavior as for multicast packets.
* A socket can bind to 255.255.255.255:<port> and then receive its own
broadcast packets sent to 255.255.255.255:<port>
In addition, this change implicitly fixes an issue with multicast reception. If
two sockets want to receive a given multicast stream and one is bound to ANY
while the other is bound to the multicast address, only one of them will
receive the traffic.
PiperOrigin-RevId: 272792377
The input file descriptor is always a regular file, so sendfile can't lose any
data if it will not be able to write them to the output file descriptor.
Reported-by: syzbot+22d22330a35fa1c02155@syzkaller.appspotmail.com
PiperOrigin-RevId: 272730357
Right now, we can find more than one process with the 1 PID in /proc.
$ for i in `seq 10`; do
> unshare -fp sleep 1000 &
> done
$ ls /proc
1 1 1 1 12 18 24 29 6 loadavg net sys version
1 1 1 1 16 20 26 32 cpuinfo meminfo self thread-self
1 1 1 1 17 21 28 36 filesystems mounts stat uptime
PiperOrigin-RevId: 272506593
gVisor does not currently implement the functionality that would result in
AT_SECURE = 1, but Linux includes AT_SECURE = 0 in the normal case, so we
should do the same.
PiperOrigin-RevId: 272311488
Kernel.cpuClockTicker increments kernel.cpuClock, which tasks use as a clock to
track their CPU usage. This improves latency in the syscall path by avoid
expensive monotonic clock calls on every syscall entry/exit.
However, this timer fires every 10ms. Thus, when all tasks are idle (i.e.,
blocked or stopped), this forces a sentry wakeup every 10ms, when we may
otherwise be able to sleep until the next app-relevant event. These wakeups
cause the sentry to utilize approximately 2% CPU when the application is
otherwise idle.
Updates to clock are not strictly necessary when the app is idle, as there are
no readers of cpuClock. This commit reduces idle CPU by disabling the timer
when tasks are completely idle, and computing its effects at the next wakeup.
Rather than disabling the timer as soon as the app goes idle, we wait until the
next tick, which provides a window for short sleeps to sleep and wakeup without
doing the (relatively) expensive work of disabling and enabling the timer.
PiperOrigin-RevId: 272265822
Linux changed this behavior in 16e72e9b30986ee15f17fbb68189ca842c32af58
(v4.11). Previously, extra pages were always mapped RW. Now, those pages will
be executable if the segment specified PF_X. They still must be writeable.
PiperOrigin-RevId: 272256280
It isn't allowed to splice data from and into the same pipe.
But right now this check is broken, because we don't check that both ends are
pipes.
PiperOrigin-RevId: 272107022
Netstack always picks a random start point everytime PickEphemeralPort
is called. While this is required for UDP so that DNS requests go
out through a randomized set of ports it is not required for TCP. Infact
Linux explicitly hashes the (srcip, dstip, dstport) and a one time secret
initialized at start of the application to get a random offset. But to
ensure it doesn't start from the same point on every scan it uses a static
hint that is incremented by 2 in every call to pick ephemeral ports.
The reason for 2 is Linux seems to split the port ranges where active connects
seem to use even ones while odd ones are used by listening sockets.
This CL implements a similar strategy where we use a hash + hint to generate
the offset to start the search for a free Ephemeral port.
This ensures that we cycle through the available port space in order for
repeated connects to the same destination and significantly reduces the
chance of picking a recently released port.
PiperOrigin-RevId: 272058370
The gofer's CachingInodeOperations implementation contains an optimization for
the common open-read-close pattern when we have a host FD. In this case, the
host kernel will update the timestamp for us to a reasonably close time, so we
don't need an extra RPC to the gofer.
However, when the app explicitly sets the timestamps (via futimes or similar)
then we actually DO need to update the timestamps, because the host kernel
won't do it for us.
To fix this, a new boolean `forceSetTimestamps` was added to
CachineInodeOperations.SetMaskedAttributes. It is only set by
gofer.InodeOperations.SetTimestamps.
PiperOrigin-RevId: 272048146
Before https://golang.org/cl/173160 syscall.RawSyscall would zero out
the last three register arguments to the system call. That no longer happens.
For system calls that take more than three arguments, use RawSyscall6 to
ensure that we pass zero, not random data, for the additional arguments.
PiperOrigin-RevId: 271062527
Non-primary addresses are used for endpoints created to accept multicast and
broadcast packets, as well as "helper" endpoints (0.0.0.0) that allow sending
packets when no proper address has been assigned yet (e.g., for DHCP). These
addresses are not real addresses from a user point of view and should not be
part of the NICInfo() value. Also see b/127321246 for more info.
This switches NICInfo() to call a new NIC.PrimaryAddresses() function. To still
allow an option to get all addresses (mostly for testing) I added
Stack.GetAllAddresses() and NIC.AllAddresses().
In addition, the return value for GetMainNICAddress() was changed for the case
where the NIC has no primary address. Instead of returning an error here,
it now returns an empty AddressWithPrefix() value. The rational for this
change is that it is a valid case for a NIC to have no primary addresses.
Lastly, I refactored the code based on the new additions.
PiperOrigin-RevId: 270971764
How to reproduce:
$ echo "timeout 10 ls" > foo.sh
$ chmod +x foo.sh
$ ./foo.sh
(will hang here for 10 secs, and the output of ls does not show)
When "ls" process writes to stdout, it receives SIGTTOU signal, and
hangs there. Until "timeout" process timeouts, and kills "ls" process.
The expected result is: "ls" writes its output into tty, and terminates
immdedately, then "timeout" process receives SIGCHLD and terminates.
The reason for this failure is that we missed the check for TOSTOP (if
set, background processes will receive the SIGTTOU signal when they do
write).
We use drivers/tty/n_tty.c:n_tty_write() as a reference.
Fixes: #862
Reported-by: chris.zn <chris.zn@antfin.com>
Signed-off-by: Jianfeng Tan <henry.tjf@antfin.com>
Signed-off-by: chenglang.hy <chenglang.hy@antfin.com>
gVisor bot
Kevin Krakauer
Bhasker Hariharan
Ian Lewis
Adin Scannell
Haibo Xu
Ian Gudger
Nicolas Lacasse
Jamie Liu
Chris Kuiper
Andrei Vagin
Michael Pratt
Tamir Duberstein
henry.tjf