When execveat is called on an interpreter script, the symlink count for
resolving the script path should be separate from the count for resolving the
the corresponding interpreter. An ELOOP error should not occur if we do not hit
the symlink limit along any individual path, even if the total number of
symlinks encountered exceeds the limit.
Closes#574
PiperOrigin-RevId: 277358474
Set the snd/rcv buffer sizes so that the test is deterministic and runs in a
reasonable amount of time. It also ensures that we disable any auto-tuning of
the send/receive buffer which may happen.
PiperOrigin-RevId: 277337232
When an interpreter script is opened with O_CLOEXEC and the resulting fd is
passed into execveat, an ENOENT error should occur (the script would otherwise
be inaccessible to the interpreter). This matches the actual behavior of
Linux's execveat.
PiperOrigin-RevId: 277306680
Like (AF_INET, SOCK_RAW) sockets, AF_PACKET sockets require CAP_NET_RAW. With
runsc, you'll need to pass `--net-raw=true` to enable them.
Binding isn't supported yet.
PiperOrigin-RevId: 275909366
This change fixes several issues with the fsgofer host UDS support. Notably, it
adds support for SOCK_SEQPACKET and SOCK_DGRAM sockets [1]. It also fixes
unsafe use of unet.Socket, which could cause a panic if Socket.FD is called
when err != nil, and calls to Socket.FD with nothing to prevent the garbage
collector from destroying and closing the socket.
A set of tests is added to exercise host UDS access. This required extracting
most of the syscall test runner into a library that can be used by custom
tests.
Updates #235
Updates #1003
[1] N.B. SOCK_DGRAM sockets are likely not particularly useful, as a server can
only reply to a client that binds first. We don't allow bind, so these are
unlikely to be used.
PiperOrigin-RevId: 275558502
Netstack has its own stats, we use this to fill /proc/net/snmp.
Note that some metrics are not recorded in Netstack, which will be shown
as 0 in the proc file.
Signed-off-by: Jianfeng Tan <[email protected]>
Change-Id: Ie0089184507d16f49bc0057b4b0482094417ebe1
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
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
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: [email protected]
PiperOrigin-RevId: 272730357
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
Refactoring in 0036d1f7eb95bcc52977f15507f00dd07018e7e2 (v4.10) caused Linux to
start unconditionally zeroing the remainder of the last page in the
interpreter. Previously it did not due so if filesz == memsz, and *still* does
not do so when filesz == memsz for loading binaries, only interpreter.
This inconsistency is not worth replicating in gVisor, as it is arguably a bug,
but our tests must ensure we create interpreter ELFs compatible with this new
requirement.
PiperOrigin-RevId: 272266401
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
The test is checking the wrong poll_fd for POLLHUP. The only
reason it passed till now was because it was also checking
for POLLIN which was always true on the other fd from the
previous poll!
PiperOrigin-RevId: 270780401
Previously, when we set hostname:
$ strace hostname abc
...
sethostname("abc", 3) = -1 ENAMETOOLONG (File name too long)
...
According to man 2 sethostname:
"The len argument specifies the number of bytes in name. (Thus, name
does not require a terminating null byte.)"
We wrongly use the CopyStringIn() to check terminating zero byte in
the implementation of sethostname syscall.
To fix this, we use CopyInBytes() instead.
Fixes: #861
Reported-by: chenglang.hy <[email protected]>
Signed-off-by: Jianfeng Tan <[email protected]>
Adresses a deadlock with the rolled back change:
https://github.com/google/gvisor/commit/e72cf7af1fcbef3d9fb9bf102435bb36dd302a63
Creating a session from an orphaned process group was causing a lock to be
acquired twice by a single goroutine. This behavior is addressed, and a test
(OrphanRegression) has been added to pty.cc.
Implemented the following ioctls:
- TIOCSCTTY - set controlling TTY
- TIOCNOTTY - remove controlling tty, maybe signal some other processes
- TIOCGPGRP - get foreground process group. Also enables tcgetpgrp().
- TIOCSPGRP - set foreground process group. Also enabled tcsetpgrp().
Next steps are to actually turn terminal-generated control characters (e.g. C^c)
into signals to the proper process groups, and to send SIGTTOU and SIGTTIN when
appropriate.
PiperOrigin-RevId: 270088599
Note that the exact semantics for these signalfds are slightly different from
Linux. These signalfds are bound to the process at creation time. Reads, polls,
etc. are all associated with signals directed at that task. In Linux, all
signalfd operations are associated with current, regardless of where the
signalfd originated.
In practice, this should not be an issue given how signalfds are used. In order
to fix this however, we will need to plumb the context through all the event
APIs. This gets complicated really quickly, because the waiter APIs are all
netstack-specific, and not generally exposed to the context. Probably not
worthwhile fixing immediately.
PiperOrigin-RevId: 269901749
absl flags are more modern and we can easily depend on them directly.
The repo now successfully builds with --incompatible_load_cc_rules_from_bzl.
PiperOrigin-RevId: 269387081
This also allows the tee(2) implementation to be enabled, since dup can now be
properly supported via WriteTo.
Note that this change necessitated some minor restructoring with the
fs.FileOperations splice methods. If the *fs.File is passed through directly,
then only public API methods are accessible, which will deadlock immediately
since the locking is already done by fs.Splice. Instead, we pass through an
abstract io.Reader or io.Writer, which elide locks and use the underlying
fs.FileOperations directly.
PiperOrigin-RevId: 268805207
A recent Kokoro change pointed to go_tests.cfg (in line with the
other configurations), which unfortunately broke the presubmits.
This change also enabled the KVM tests, which were still using a
remote execution strategy.
This fixes both of these issues and allows presubmits to pass.
One additional test was caught with this case, which seems to
have been broken. It's unclear why this was not being caught.
PiperOrigin-RevId: 268166291
TestNoDuplicates is racy as it tries to read the /proc file system
while the test is running. But it's possible that from the time a
directory entries are read and each entry processed something could
change and in some cases the entry being processed could have been
deleted. In such cases we should not fail the test but just
ignore the error and move on.
PiperOrigin-RevId: 267483094
- Most AIO tests call io_setup(nr_events = 128). sizeof(struct io_event)
(128*32 = 4096). However, the actual size of the mapping created by
io_setup() is determined by:
(from fs/aio.c:ioctx_alloc())
/*
* We keep track of the number of available ringbuffer slots, to prevent
* overflow (reqs_available), and we also use percpu counters for this.
*
* So since up to half the slots might be on other cpu's percpu counters
* and unavailable, double nr_events so userspace sees what they
* expected: additionally, we move req_batch slots to/from percpu
* counters at a time, so make sure that isn't 0:
*/
nr_events = max(nr_events, num_possible_cpus() * 4);
nr_events *= 2;
(from fs/aio.c:aio_setup_ring())
/* Compensate for the ring buffer's head/tail overlap entry */
nr_events += 2; /* 1 is required, 2 for good luck */
size = sizeof(struct aio_ring);
size += sizeof(struct io_event) * nr_events;
nr_pages = PFN_UP(size);
When we mremap() only the first page of a multi-page AIO ring buffer
mapping, fs/aio.c:aio_ring_mremap() updates struct kioctx::mmap_base -
but struct kioctx::mmap_size is untouched, so sys_io_destroy() =>
kill_ioctx() vm_unmaps() the mremapped page, plus some number of pages
after it. Just get the actual size of the mapping from /proc/self/maps.
- Delete test case MremapOver; while it is correct that Linux will not
complain if you overwrite the AIO ring buffer with another mapping, it
won't actually work in the sense that AIO events will not be written to
the new mapping, because Linux stores the struct pages of the ring
buffer in struct kioctx::ring_pages and writes to those through kmap()
rather than using userspace addresses.
- Don't munmap() after mremap(MREMAP_FIXED) returns EFAULT; see new
comment in factored-out test case MremapExpansion.
PiperOrigin-RevId: 267482903
