tailscale

Commit Graph

Author	SHA1	Message	Date
Joe Tsai	61886e031e	ssh/tailssh: fix double race condition with non-pty command (#8405 ) There are two race conditions in output handling. The first race condition is due to a misuse of exec.Cmd.StdoutPipe. The documentation explicitly forbids concurrent use of StdoutPipe with exec.Cmd.Wait (see golang/go#60908) because Wait will close both sides of the pipe once the process ends without any guarantees that all data has been read from the pipe. To fix this, we allocate the os.Pipes ourselves and manage cleanup ourselves when the process has ended. The second race condition is because sshSession.run waits upon exec.Cmd to finish and then immediately proceeds to call ss.Exit, which will close all output streams going to the SSH client. This may interrupt any asynchronous io.Copy still copying data. To fix this, we close the write-side of the os.Pipes after the process has finished (and before calling ss.Exit) and synchronously wait for the io.Copy routines to finish. Fixes #7601 Signed-off-by: Joe Tsai <joetsai@digital-static.net> Co-authored-by: Maisem Ali <maisem@tailscale.com>	1 year ago
Brad Fitzpatrick	32b8f25ed1	Revert "ssh/tailssh: change to user directory when running login/command" This reverts commit `dc5bc32d8f`. It broke tests. (sadly, ones which we have disabled on CI, but go test ./ssh/tailssh broke)	1 year ago
Derek Burdick	dc5bc32d8f	ssh/tailssh: change to user directory when running login/command On redhat 9 and similarly locked down systems, root user does not have access to a users directory. This fix does not set a directory for the incubator process and instead sets the directory when the actual process requested by remote user is executed. Fixes #8118 Signed-off-by: Derek Burdick <derek-burdick@users.noreply.github.com>	1 year ago
Maisem Ali	2ae670eb71	ssh/tailssh: work around lack of scontext in SELinux Trying to SSH when SELinux is enforced results in errors like: ``` ➜ ~ ssh ec2-user@<ip> Last login: Thu Jun 1 22:51:44 from <ip2> ec2-user: no shell: Permission denied Connection to <ip> closed. ``` while the `/var/log/audit/audit.log` has ``` type=AVC msg=audit(1685661291.067:465): avc: denied { transition } for pid=5296 comm="login" path="/usr/bin/bash" dev="nvme0n1p1" ino=2564 scontext=system_u:system_r:unconfined_service_t:s0 tcontext=unconfined_u:unconfined_r:unconfined_t:s0 tclass=process permissive=0 ``` The right fix here would be to somehow install the appropriate context when tailscale is installed on host, but until we figure out a way to do that stop using the `login` cmd in these situations. Updates #4908 Signed-off-by: Maisem Ali <maisem@tailscale.com>	1 year ago
Maisem Ali	2e0aa151c9	ssh/tailssh: add support for remote/reverse port forwarding This basically allows running services on the SSH client and reaching them from the SSH server during the session. Updates #6575 Signed-off-by: Maisem Ali <maisem@tailscale.com>	1 year ago
Derek Burdick	d3c8c3dd00	ssh/tailssh: Max Username Length 256 for linux Max username length is increased to 256 on linux to match /usr/include/bits/local_lim.h Fixes #8277 Signed-off-by: Derek Burdick <derek-burdick@users.noreply.github.com>	1 year ago
Charlotte Brandhorst-Satzkorn	4e86857313	ssh/tailssh: add ssh session recording failed event type This change introduces a SSHSessionRecordingFailed event type that is used when a session recording fails to start or fails during a session, and the on failure indicates that it should fail open. Updates tailscale/corp#9967 Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>	2 years ago
Brad Fitzpatrick	a4fd4fd845	ssh/tailssh: fix regression after LDAP support `58ab66ec51` added LDAP support for #4945 by shelling out to getdent. It was supposed to fall back to the old method when getdent wasn't found, but some variable name confusion (uid vs username) meant the old path wasn't calling the right lookup function (user.LookupId instead of user.Lookup). Which meant that changed probably also broke FreeBSD and macOS SSH support in addition to the reported OpenWRT regression. The gokrazy support didn't look right either. Fixes #8180 Change-Id: I273bbe96fe98b2517fbf0335fd476b483c051554 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Maisem Ali	0ca8bf1e26	ssh/tailssh: close tty on session close We were only closing on side of the pty/tty pair. Close the other side too. Thanks to @fritterhoff for reporting and debugging the issue! Fixes #8119 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Brad Fitzpatrick	a743b66f9d	ssh/tailssh: move some user-related code into new user.go The previous commit `58ab66e` added ssh/tailssh/user.go as part of working on #4945. So move some more user-related code over to it. Updates #cleanup Change-Id: I24de66df25ffb8f867e1a0a540d410f9ef16d7b0 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Brad Fitzpatrick	58ab66ec51	ssh/tailssh: support LDAP users for Tailscale SSH Fixes #4945 Change-Id: Ie013cb47684cb87928a44f92c66352310bfe53f1 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Charlotte Brandhorst-Satzkorn	29ded8f9f9	ssh/tailssh,tailcfg: add connID to ssheventnotifyrequest and castheader This change adds a ConnectionID field to both SSHEventNotifyRequest and CastHeader that identifies the ID of a connection to the SSH server. Updates tailscale/corp#9967 Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>	2 years ago
Charlotte Brandhorst-Satzkorn	68307c1411	ssh/tailssh: send ssh event notifications on recording failures This change sends an SSHEventNotificationRequest over noise when a SSH session is set to fail closed and the session is unable to start because a recorder is not available or a session is terminated because connection to the recorder is ended. Each of these scenarios have their own event type. Updates tailscale/corp#9967 Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>	2 years ago
Brad Fitzpatrick	6e967446e4	tsd: add package with System type to unify subsystem init, discovery This is part of an effort to clean up tailscaled initialization between tailscaled, tailscaled Windows service, tsnet, and the mac GUI. Updates #8036 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Maisem Ali	be190e990f	ssh/tailssh: restore support for recording locally We removed it earlier in `916aa782af`, but we still want to support it for some time longer. Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Tom DNetto	c5bf868940	ssh/tailssh: improve debug logging around revoked sessions Updates https://github.com/tailscale/corp/issues/10943 Signed-off-by: Tom DNetto <tom@tailscale.com>	2 years ago
Maisem Ali	1b8a0dfe5e	ssh/tailssh: also handle recording upload failure during writes Previously we would error out when the recording server disappeared after the in memory buffer filled up for the io.Copy. This makes it so that we handle failing open correctly in that path. Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	7778d708a6	ssh/tailssh: handle dialing multiple recorders and failing open This adds support to try dialing out to multiple recorders each with a 5s timeout and an overall 30s timeout. It also starts respecting the actions `OnRecordingFailure` field if set, if it is not set it fails open. Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Andrew Dunham	280255acae	various: add golangci-lint, fix issues (#7905 ) This adds an initial and intentionally minimal configuration for golang-ci, fixes the issues reported, and adds a GitHub Action to check new pull requests against this linter configuration. Signed-off-by: Andrew Dunham <andrew@du.nham.ca> Change-Id: I8f38fbc315836a19a094d0d3e986758b9313f163	2 years ago
Maisem Ali	d42d570066	ssh/tailssh: handle output matching better in tests (#7799 )	2 years ago
Brad Fitzpatrick	2c0bda6e2e	ssh/tailssh: make Tailscale SSH work on gokrazy Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Maisem Ali	e04acabfde	ssh/tailssh: fix race in errors returned when starting recorder There were two code paths that could fail depending on how fast the recorder responses. This fixes that by returning the correct error from both paths. Fixes #7707 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	5ba57e4661	ssh/tailssh: add tests for recording failure Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	09d0b632d4	ssh/tailssh: add session recording test for non-pty sessions Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	583e86b7df	ssh/tailssh: handle session recording when running in userspace mode Previously it would dial out using the http.DefaultClient, however that doesn't work when tailscaled is running in userspace mode (e.g. when testing). Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	8a246487c2	ssh/tailssh: enable recording of non-pty sessions Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	8765568373	ssh/tailssh: add docs to CastHeader fields Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Will Norris	57a008a1e1	all: pass log IDs as the proper type rather than strings This change focuses on the backend log ID, which is the mostly commonly used in the client. Tests which don't seem to make use of the log ID just use the zero value. Signed-off-by: Will Norris <will@tailscale.com>	2 years ago
Andrew Dunham	13377e6458	ssh/tailssh: always assert our final uid/gid Move the assertions about our post-privilege-drop UID/GID out of the conditional if statement and always run them; I haven't been able to find a case where this would fail. Defensively add an envknob to disable this feature, however, which we can remove after the 1.40 release. Updates #7616 Signed-off-by: Andrew Dunham <andrew@du.nham.ca> Change-Id: Iaec3dba9248131920204bd6c6d34bbc57a148185	2 years ago
Andrew Dunham	9de8287d47	ssh/tailssh: lock OS thread during incubator This makes it less likely that we trip over bugs like golang/go#1435. Updates #7616 Signed-off-by: Andrew Dunham <andrew@du.nham.ca> Change-Id: Ic28c03c3ad8ed5274a795c766b767fa876029f0e	2 years ago
Maisem Ali	c350cd1f06	ssh/tailssh: use background context for uploading recordings Otherwise we see errors like ``` ssh-session(sess-20230322T005655-5562985593): recording: error sending recording to <addr>:80: Post "http://<addr>:80/record": context canceled ``` The ss.ctx is closed when the session closes, but we don't want to break the upload at that time. Instead we want to wait for the session to close the writer when it finishes, which it is already doing. Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	d92047cc30	ssh/tailssh: allow recorders to be configured on the first or final action Currently we only send down recorders in first action, allow the final action to replace them but not to drop them. Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	7a97e64ef0	ssh/tailssh: add more metadata to recording header Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	916aa782af	ssh/tailssh: stream SSH recordings to configured recorders Updates tailscale/corp#9967 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Andrew Dunham	39b289578e	ssh/tailssh: make uid an int instead of uint64 Follow-up to #7615 Signed-off-by: Andrew Dunham <andrew@du.nham.ca> Change-Id: Ib4256bff276f6d5cf95838d8e39c87b3643bde37	2 years ago
Andrew Dunham	ccace1f7df	ssh/tailssh: fix privilege dropping on FreeBSD; add tests On FreeBSD and Darwin, changing a process's supplementary groups with setgroups(2) will also change the egid of the process, setting it to the first entry in the provided list. This is distinct from the behaviour on other platforms (and possibly a violation of the POSIX standard). Because of this, on FreeBSD with no TTY, our incubator code would previously not change the process's gid, because it would read the newly-changed egid, compare it against the expected egid, and since they matched, not change the gid. Because we didn't use the 'login' program on FreeBSD without a TTY, this would propagate to a child process. This could be observed by running "id -p" in two contexts. The expected output, and the output returned when running from a SSH shell, is: andrew@freebsd:~ $ id -p uid andrew groups andrew However, when run via "ssh andrew@freebsd id -p", the output would be: $ ssh andrew@freebsd id -p login root uid andrew rgid wheel groups andrew (this could also be observed via "id -g -r" to print just the gid) We fix this by pulling the details of privilege dropping out into their own function and prepending the expected gid to the start of the list on Darwin and FreeBSD. Finally, we add some tests that run a child process, drop privileges, and assert that the final UID/GID/additional groups are what we expect. More information can be found in the following article: https://www.usenix.org/system/files/login/articles/325-tsafrir.pdf Updates #7616 Alternative to #7609 Signed-off-by: Andrew Dunham <andrew@du.nham.ca> Change-Id: I0e6513c31b121108b50fe561c89e5816d84a45b9	2 years ago
Maisem Ali	223713d4a1	tailcfg,all: add and use Node.IsTagged() Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	e69682678f	ssh/tailssh: use context.WithCancelCause It was using a custom implmentation of the context.WithCancelCause, replace usage with stdlib. Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	0582829e00	ssh/tailssh: try launching commands with /usr/bin/login on macOS Updates #4939 Co-authored-by: Adam Eijdenberg <adam@continusec.com> Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	5787989d74	ssh/tailssh: detect user shell correctly on darwin Updates #6213 Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Brad Fitzpatrick	b1248442c3	all: update to Go 1.20, use strings.CutPrefix/Suffix instead of our fork Updates #7123 Updates #5309 Change-Id: I90bcd87a2fb85a91834a0dd4be6e03db08438672 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Maisem Ali	04b57a371e	ipn/ipnlocal: drop not required StateKey parameter This is #cleanup now that #7121 is merged. Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Maisem Ali	5bba65e978	net/memnet: rename from net/nettest This is just #cleanup to resolve a TODO Also add a package doc. Signed-off-by: Maisem Ali <maisem@tailscale.com>	2 years ago
Will Norris	71029cea2d	all: update copyright and license headers This updates all source files to use a new standard header for copyright and license declaration. Notably, copyright no longer includes a date, and we now use the standard SPDX-License-Identifier header. This commit was done almost entirely mechanically with perl, and then some minimal manual fixes. Updates #6865 Signed-off-by: Will Norris <will@tailscale.com>	2 years ago
Brad Fitzpatrick	1116602d4c	ssh/tailssh: add OpenBSD support for Tailscale SSH And bump go.mod for https://github.com/u-root/u-root/pull/2593 Change-Id: I36ec94c5b2b76d671cb739f1e9a1a43ca1d9d1b1 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Brad Fitzpatrick	be67b8e75b	ssh/tailssh: fix Tailscale SSH to non-root tailscaled Fix regression from `337c77964b` where tailscaled started calling Setgroups. Prior to that, SSH to a non-root tailscaled was working. Instead, ignore any failure calling Setgroups if the groups are already correct. Fixes #6888 Change-Id: I561991ddb37eaf2620759c6bcaabd36e0fb2a22d Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Brad Fitzpatrick	8047dfa2dc	ssh/tailssh: unify some of the incubator_* GOOS files into incubator.go In prep for fix for #6888 Change-Id: I79f780c6467a9b7ac03017b27d412d6b0d2f7e6b Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Brad Fitzpatrick	84eaef0bbb	ssh/tailssh: don't swallow process exit code in be-child Thanks to @nshalman and @Soypete for debugging! Updates #6054 Change-Id: I74550cc31f8a257b37351b8152634c768e1e0a8a Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Brad Fitzpatrick	f837d179b9	ssh/tailssh: fix typo in error message "look up" is the verb. "lookup" is a noun. Change-Id: I81c99e12c236488690758fb5c121e7e4e1622a36 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago
Brad Fitzpatrick	651e0d8aad	ssh/tailssh: add envknob for default PATH As backup plan, just in case the earlier fix's logic wasn't correct and we want to experiment in the field or have users have a quicker fix. Updates #5285 Change-Id: I7447466374d11f8f609de6dfbc4d9a944770826d Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	2 years ago

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149 Commits (0a86705d59367efeb45ee72a636cd4ff752b5216)