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path: root/src/syscall/exec_linux.go
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2019-03-08syscall: add all ambient capabilities into permitted and inheritable setsAndrei Vagin
According to the prctl man page, each capability from the ambient set must already be present in both the permitted and the inheritable sets of the process. exec_linux_test suggests configuring the capabilities in the parent process. This doesn't look nice, because: * Capabilities are a per-thread attribute, so we need to use LockOSThread. * Need to restore capabilities after creating a process. * Doesn't work with user namespaces, because a process gets capabilities when a namespace is created. Fixes #23152 Change-Id: Iba23e530fc7b9f5182d602fe855f82218f354219 Reviewed-on: https://go-review.googlesource.com/c/go/+/156577 Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-03-06syscall: fix hang when using Unshareflags: CLONE_NEWUSER with uid/gid ↵Michael Stapelberg
mapping (linux) Note that this particular combination of properties still fails (EPERM), but it no longer hangs. Updates #29789 Change-Id: I29b15b85a25a7acd7ae89ffc5fed074bcdfe0a12 Reviewed-on: https://go-review.googlesource.com/c/go/+/158297 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-12-27syscall: document LockOSThread with GNU/Linux SysProcAttr.PtraceIan Lance Taylor
Fixes #28315 Change-Id: Ie02c72d02ad2f66c9cdbbba579a304641f327672 Reviewed-on: https://go-review.googlesource.com/c/155138 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-02-13syscall: support syscalls without error return on LinuxTobias Klauser
Add the rawSyscallNoError wrapper function which is used for Linux syscalls that don't return an error and convert all applicable occurences of RawSyscall to use it instead. Fixes #22924 Change-Id: Iff1eddb54573d459faa01471f10398b3d38528dd Reviewed-on: https://go-review.googlesource.com/84485 Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-23syscall: move ptrace setup to right before execJess Frazelle
This will prevent any ptrace calls from getting trace output from the runtime itself setting up after fork. Fixes #21428. Change-Id: I9d835bd5a8f404394eb6237679f2111a72e5bc17 Reviewed-on: https://go-review.googlesource.com/55811 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Avelino <t@avelino.xxx>
2017-06-28syscall: add AmbientCaps to linux SysProcAttrMichael Stapelberg
Fixes #19713 Change-Id: Id1ca61b35bca2a4bea23dd64c7fb001a3a14fd88 Reviewed-on: https://go-review.googlesource.com/43512 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-06-20syscall: mark forkAndExecInChild1 noinlineAustin Clements
This certainly won't get inlined right now, but in the spirit of making this more robust, we have to disable inlining because inlining would defeat the purpose of separating forkAndExecInChild1 into a separate function. Updates #20732. Change-Id: I736c3f909cc42c5f5783740c2e19ba4827c7c2ec Reviewed-on: https://go-review.googlesource.com/46174 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-06-20syscall: use CLONE_VFORK safelyAustin Clements
Currently, CLONE_VFORK is used without much regard to the stack. This is dangerous, because anything the child does to the stack is visible to the parent. For example, if the compiler were to reuse named stack slots (which it currently doesn't do), it would be easy for the child running in the same stack frame as the parent to corrupt local variables that the parent then depended on. We're not sure of anything specific going wrong in this code right now, but it is at best a ticking time bomb. CLONE_VFORK can only safely be used if we ensure the child does not execute in any of the active stack frames of the parent. This commit implements this by arranging for the parent to return immediately from the frame the child will operate in, and for the child to never return to the frame the parent will operate in. Fixes #20732. Change-Id: Iad5b4ddc2b994c082bd278bfd52ef53bd38c037f Reviewed-on: https://go-review.googlesource.com/46173 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-06-14runtime, syscall: reset signal handlers to default in childIan Lance Taylor
Block all signals during a fork. In the parent process, after the fork, restore the signal mask. In the child process, reset all currently handled signals to the default handler, and then restore the signal mask. The effect of this is that the child will be operating using the same signal regime as the program it is about to exec, as exec resets all non-ignored signals to the default, and preserves the signal mask. We do this so that in the case of a signal sent to the process group, the child process will not try to run a signal handler while in the precarious state after a fork. Fixes #18600. Change-Id: I9f39aaa3884035908d687ee323c975f349d5faaa Reviewed-on: https://go-review.googlesource.com/45471 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2017-05-31syscall: allow processes steal a controlling terminal on LinuxJulio Montes
The current implementation of forkAndExecInChild for Linux does not allow spawned processes steal the controlling terminal from a different session group. This patch passes 1 as the argument to TIOCSCTTY in order to allow spawned processes steal controlling terminals. Fixes #20454 Change-Id: I171b8981509d648b07f89bddc1e9d45cb70e00e6 Reviewed-on: https://go-review.googlesource.com/44343 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org>
2017-04-25syscall: fix ordering of Unshare and chroot on LinuxRonald G. Minnich
When unshare specifies a new namespace, the syscall package changes / to make namespace changes private. If a chroot is specified, the unshare must be done first. If the chroot is done first then the unshare will not specify the correct /. A new test is included which test combining chroot and CLONE_NEWNS; it fails without the patch and works with it. Fixes #20103 Change-Id: I86022803c784bd418a30383321f3d64103d95c62 Reviewed-on: https://go-review.googlesource.com/41626 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-03-23os/exec: handle Unshareflags with CLONE_NEWNSRonald G. Minnich
In some newer Linux distros, systemd forces all mount namespaces to be shared, starting at /. This disables the CLONE_NEWNS flag in unshare(2) and clone(2). While this problem is most commonly seen on systems with systemd, it can happen anywhere, due to how Linux namespaces now work. Hence, to create a private mount namespace, it is not sufficient to just set CLONE_NEWS; you have to call mount(2) to change the behavior of namespaces, i.e. mount("none", "/", NULL, MS_REC|MS_PRIVATE, NULL) This is tested and working and we can now correctly start child process with private namespaces on Linux distros that use systemd. The new test works correctly on Ubuntu 16.04.2 LTS. It fails if I comment out the new Mount, and succeeds otherwise. In each case it correctly cleans up after itself. Fixes #19661 Change-Id: I52240b59628e3772b529d9bbef7166606b0c157d Reviewed-on: https://go-review.googlesource.com/38471 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-03-22syscall: use CLONE_VFORK and CLONE_VMRichard Musiol
This greatly improves the latency of starting a child process when the Go process is using a lot of memory. Even though the kernel uses copy-on-write, preparation for that can take up to several 100ms under certain conditions. All other goroutines are suspended while starting a subprocess so this latency directly affects total throughput. With CLONE_VM the child process shares the same memory with the parent process. On its own this would lead to conflicting use of the same memory, so CLONE_VFORK is used to suspend the parent process until the child releases the memory when switching to to the new program binary via the exec syscall. When the parent process continues to run, one has to consider the changes to memory that the child process did, namely the return address of the syscall function needs to be restored from a register. A simple benchmark has shown a difference in latency of 16ms vs. 0.5ms at 10GB memory usage. However, much higher latencies of several 100ms have been observed in real world scenarios. For more information see comments on #5838. Fixes #5838 Change-Id: I6377d7bd8dcd00c85ca0c52b6683e70ce2174ba6 Reviewed-on: https://go-review.googlesource.com/37439 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-17syscall: only call setgroups if we need toWander Lairson Costa
If the caller set ups a Credential in os/exec.Command, os/exec.Command.Start will end up calling setgroups(2), even if no supplementary groups were given. Only root can call setgroups(2) on BSD kernels, which causes Start to fail for non-root users when they try to set uid and gid for the new process. We fix by introducing a new field to syscall.Credential named NoSetGroups, and setgroups(2) is only called if it is false. We make this field with inverted logic to preserve backward compatibility. RELNOTES=yes Change-Id: I3cff1f21c117a1430834f640ef21fd4e87e06804 Reviewed-on: https://go-review.googlesource.com/36697 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-11-09syscall: use 32-bit setuid/setgid syscalls on linux/{386,arm}Brad Fitzpatrick
Fixes #17092 Change-Id: Ib14e4db13116ebbe4d72c414fb979d27a06d6174 Reviewed-on: https://go-review.googlesource.com/33011 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-10-19syscall: for ForkExec on Linux, always use 32-bit setgroups system callRuss Cox
Fixes #17092. Change-Id: If203d802a919e00594ddc1282782fc59a083fd63 Reviewed-on: https://go-review.googlesource.com/31458 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-06-02syscall: call setgroups for no groups on GNU/LinuxAlexander Morozov
Skip setgroups only for one particular case: GidMappings != nil and GidMappingsEnableSetgroup == false and list of supplementary groups is empty. This patch returns pre-1.5 behavior for simple exec and still allows to use GidMappings with non-empty Credential. Change-Id: Ia91c77e76ec5efab7a7f78134ffb529910108fc1 Reviewed-on: https://go-review.googlesource.com/23524 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-06-01syscall: rename SysProcAttr.Unshare to UnshareflagsAlexander Morozov
For symmetry with Cloneflags and it looks slightly weird because there is syscall.Unshare method. Change-Id: I3d710177ca8f27c05b344407f212cbbe3435094b Reviewed-on: https://go-review.googlesource.com/23612 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Rob Pike <r@golang.org>
2016-05-20syscall: add Unshare flags to SysProcAttr on LinuxJess Frazelle
This patch adds Unshare flags to SysProcAttr for Linux systems. Fixes #1954 Change-Id: Id819c3f92b1474e5a06dd8d55f89d74a43eb770c Reviewed-on: https://go-review.googlesource.com/23233 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-03-29syscall: fix accidental close of exec status pipe in StartProcessRichard Miller
In syscall.forkAndExecInChild, blocks of code labelled Pass 1 and Pass 2 permute the file descriptors (if necessary) which are passed to the child process. If Pass 1 begins with fds = {0,2,1}, nextfd = 4 and pipe = 4, then the statement labelled "don't stomp on pipe" is too late -- the pipe (which will be needed to pass exec status back to the parent) will have been closed by the preceding DUP call. Moving the "don't stomp" test earlier ensures that the pipe is protected. Fixes #14979 Change-Id: I890c311527f6aa255be48b3277c1e84e2049ee22 Reviewed-on: https://go-review.googlesource.com/21184 Run-TryBot: David du Colombier <0intro@gmail.com> Reviewed-by: David du Colombier <0intro@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-03-21syscall: change clone argument order on s390xMichael Munday
The Linux ABI takes arguments in a different order on s390x. Change-Id: Ic9cfcc22a5ea3d8ef77d4dd0b915fc266ff3e5f7 Reviewed-on: https://go-review.googlesource.com/20960 Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
2016-03-02all: single space after period.Brad Fitzpatrick
The tree's pretty inconsistent about single space vs double space after a period in documentation. Make it consistently a single space, per earlier decisions. This means contributors won't be confused by misleading precedence. This CL doesn't use go/doc to parse. It only addresses // comments. It was generated with: $ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])') $ go test go/doc -update Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7 Reviewed-on: https://go-review.googlesource.com/20022 Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Dave Day <djd@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-10-20cmd/compile, syscall: use go:norace comment for forkAndExecInChildIan Lance Taylor
Use a go:norace comment rather than having the compiler know the special name syscall.forkAndExecInChild. Change-Id: I69bc6aa6fc40feb2148d23f269ff32453696fb28 Reviewed-on: https://go-review.googlesource.com/16097 Reviewed-by: Minux Ma <minux@golang.org>
2015-08-27syscall: don't call Setgroups if Credential.Groups is emptyAlexander Morozov
Setgroups with zero-length groups is no-op for changing groups and supposed to be used only for determining curent groups length. Also because we deny setgroups by default if use GidMappings we have unnecessary error from that no-op syscall. Change-Id: I8f74fbca9190a3dcbbef1d886c518e01fa05eb62 Reviewed-on: https://go-review.googlesource.com/13938 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-06-12syscall: add GidMappingsEnableSetgroups to Linux SysProcAttrAlexander Morozov
Linux 3.19 made a change in the handling of setgroups and the 'gid_map' file to address a security issue. The upshot of the 3.19 changes is that in order to update the 'gid_maps' file, use of the setgroups() system call in this user namespace must first be disabled by writing "deny" to one of the /proc/PID/setgroups files for this namespace. Also added tests for remapping uid_map and gid_map inside new user namespace. Fixes #10626 Change-Id: I4d2539acbab741a37092d277e10f31fc39a8feb7 Reviewed-on: https://go-review.googlesource.com/10670 Run-TryBot: Ian Lance Taylor <iant@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-05-12syscall: relocate linux death signal codeAndrew Williams
Fix bug on Linux SysProcAttr handling: setting both Pdeathsig and Credential caused Pdeathsig to be ignored. This is because the kernel clears the deathsignal field when performing a setuid/setgid system call. Avoid this by moving Pdeathsig handling after Credential handling. Fixes #9686 Change-Id: Id01896ad4e979b8c448e0061f00aa8762ca0ac94 Reviewed-on: https://go-review.googlesource.com/3290 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-05-03syscall: fix little-endian assumptionsShenghou Ma
Change-Id: Ia38256998e544d620a342dabedd9289d61fb0551 Reviewed-on: https://go-review.googlesource.com/9672 Reviewed-by: Dave Cheney <dave@cheney.net> Run-TryBot: Minux Ma <minux@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-03-23syscall: Add Foreground and Pgid to SysProcAttrMichael MacInnis
On Unix, when placing a child in a new process group, allow that group to become the foreground process group. Also, allow a child process to join a specific process group. When setting the foreground process group, Ctty is used as the file descriptor of the controlling terminal. Ctty has been added to the BSD and Solaris SysProcAttr structures and the handling of Setctty changed to match Linux. Change-Id: I18d169a6c5ab8a6a90708c4ff52eb4aded50bc8c Reviewed-on: https://go-review.googlesource.com/5130 Run-TryBot: Ian Lance Taylor <iant@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-03-10syscall: exec_linux.go: support platforms without SYS_DUP2Dave Cheney
Updates #9974 This change is in preparation for merging the arm64 platform. Arm64 does not support SYS_DUP2 at all, so define a new constant to be the minimum dup(2) version supported. This constant defaults to SYS_DUP2 on all existing platforms. Change-Id: If405878105082c7c880f8541c1491970124c9ce4 Reviewed-on: https://go-review.googlesource.com/7123 Reviewed-by: Minux Ma <minux@golang.org> Run-TryBot: Minux Ma <minux@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Dave Cheney <dave@cheney.net>
2014-12-22syscall: check recorded version of ppid instead of 1David Crawshaw
Handles the case where the parent is pid 1 (common in docker containers). Attempted and failed to write a test for this. Fixes #9263. Change-Id: I5c6036446c99e66259a4fab1660b6a594f875020 Reviewed-on: https://go-review.googlesource.com/1372 Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
2014-11-19undo CL 131750044 / 2d6d44ceb80eRuss Cox
Breaks reading from stdin in parent after exec with SysProcAttr{Setpgid: true}. package main import ( "fmt" "os" "os/exec" "syscall" ) func main() { cmd := exec.Command("true") cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true} cmd.Run() fmt.Printf("Hit enter:") os.Stdin.Read(make([]byte, 100)) fmt.Printf("Bye\n") } In go1.3, I type enter at the prompt and the program exits. With the CL being rolled back, the program wedges at the prompt. ««« original CL description syscall: SysProcAttr job control changes Making the child's process group the foreground process group and placing the child in a specific process group involves co-ordination between the parent and child that must be done post-fork but pre-exec. LGTM=iant R=golang-codereviews, gobot, iant, mikioh.mikioh CC=golang-codereviews https://golang.org/cl/131750044 »»» LGTM=minux, dneil R=dneil, minux CC=golang-codereviews, iant, michael.p.macinnis https://golang.org/cl/174450043
2014-10-02syscall: support UID/GID map files for Linux user namespacesMrunal Patel
Fixes #8447. LGTM=iant R=golang-codereviews, bradfitz, iant CC=golang-codereviews https://golang.org/cl/126190043
2014-09-11syscall: SysProcAttr job control changesMichael MacInnis
Making the child's process group the foreground process group and placing the child in a specific process group involves co-ordination between the parent and child that must be done post-fork but pre-exec. LGTM=iant R=golang-codereviews, gobot, iant, mikioh.mikioh CC=golang-codereviews https://golang.org/cl/131750044
2014-09-08build: move package sources from src/pkg to srcRuss Cox
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.
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