ipn, safesocket: use Windows token in LocalAPI
On Windows, the idiomatic way to check access on a named pipe is for the server to impersonate the client on its current OS thread, perform access checks using the client's access token, and then revert the OS thread's access token back to its true self. The access token is a better representation of the client's rights than just a username/userid check, as it represents the client's effective rights at connection time, which might differ from their normal rights. This patch updates safesocket to do the aforementioned impersonation, extract the token handle, and then revert the impersonation. We retain the token handle for the remaining duration of the connection (the token continues to be valid even after we have reverted back to self). Since the token is a property of the connection, I changed ipnauth to wrap the concrete net.Conn to include the token. I then plumbed that change through ipnlocal, ipnserver, and localapi as necessary. I also added a PermitLocalAdmin flag to the localapi Handler which I intend to use for controlling access to a few new localapi endpoints intended for configuring auto-update. Updates https://github.com/tailscale/tailscale/issues/755 Signed-off-by: Aaron Klotz <aaron@tailscale.com>
This commit is contained in:
Aaron Klotz
parent
ef596aed9b
commit
95671b71a6
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|
@ -2,11 +2,6 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
|
|||
|
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filippo.io/edwards25519 from github.com/hdevalence/ed25519consensus
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filippo.io/edwards25519/field from filippo.io/edwards25519
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W 💣 github.com/Microsoft/go-winio from tailscale.com/safesocket
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W 💣 github.com/Microsoft/go-winio/internal/fs from github.com/Microsoft/go-winio
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W 💣 github.com/Microsoft/go-winio/internal/socket from github.com/Microsoft/go-winio
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W github.com/Microsoft/go-winio/internal/stringbuffer from github.com/Microsoft/go-winio/internal/fs
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W github.com/Microsoft/go-winio/pkg/guid from github.com/Microsoft/go-winio+
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W 💣 github.com/alexbrainman/sspi from github.com/alexbrainman/sspi/internal/common+
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W github.com/alexbrainman/sspi/internal/common from github.com/alexbrainman/sspi/negotiate
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W 💣 github.com/alexbrainman/sspi/negotiate from tailscale.com/net/tshttpproxy
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|
|
@ -43,6 +38,11 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
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LD github.com/prometheus/procfs from github.com/prometheus/client_golang/prometheus
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LD github.com/prometheus/procfs/internal/fs from github.com/prometheus/procfs
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LD github.com/prometheus/procfs/internal/util from github.com/prometheus/procfs
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W 💣 github.com/tailscale/go-winio from tailscale.com/safesocket
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W 💣 github.com/tailscale/go-winio/internal/fs from github.com/tailscale/go-winio
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W 💣 github.com/tailscale/go-winio/internal/socket from github.com/tailscale/go-winio
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W github.com/tailscale/go-winio/internal/stringbuffer from github.com/tailscale/go-winio/internal/fs
|
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W github.com/tailscale/go-winio/pkg/guid from github.com/tailscale/go-winio+
|
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L 💣 github.com/tailscale/netlink from tailscale.com/util/linuxfw
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L 💣 github.com/vishvananda/netlink/nl from github.com/tailscale/netlink
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L github.com/vishvananda/netns from github.com/tailscale/netlink+
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|
|
@ -111,7 +111,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
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💣 tailscale.com/net/tshttpproxy from tailscale.com/derp/derphttp+
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tailscale.com/net/wsconn from tailscale.com/cmd/derper+
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tailscale.com/paths from tailscale.com/client/tailscale
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tailscale.com/safesocket from tailscale.com/client/tailscale
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💣 tailscale.com/safesocket from tailscale.com/client/tailscale
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tailscale.com/syncs from tailscale.com/cmd/derper+
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tailscale.com/tailcfg from tailscale.com/client/tailscale+
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tailscale.com/tka from tailscale.com/client/tailscale+
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|
|
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@ -2,11 +2,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
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filippo.io/edwards25519 from github.com/hdevalence/ed25519consensus
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filippo.io/edwards25519/field from filippo.io/edwards25519
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W 💣 github.com/Microsoft/go-winio from tailscale.com/safesocket
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W 💣 github.com/Microsoft/go-winio/internal/fs from github.com/Microsoft/go-winio
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W 💣 github.com/Microsoft/go-winio/internal/socket from github.com/Microsoft/go-winio
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W github.com/Microsoft/go-winio/internal/stringbuffer from github.com/Microsoft/go-winio/internal/fs
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W github.com/Microsoft/go-winio/pkg/guid from github.com/Microsoft/go-winio+
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W 💣 github.com/alexbrainman/sspi from github.com/alexbrainman/sspi/negotiate+
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W github.com/alexbrainman/sspi/internal/common from github.com/alexbrainman/sspi/negotiate
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W 💣 github.com/alexbrainman/sspi/negotiate from tailscale.com/net/tshttpproxy
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@ -47,6 +42,11 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
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github.com/skip2/go-qrcode from tailscale.com/cmd/tailscale/cli
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github.com/skip2/go-qrcode/bitset from github.com/skip2/go-qrcode+
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github.com/skip2/go-qrcode/reedsolomon from github.com/skip2/go-qrcode
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W 💣 github.com/tailscale/go-winio from tailscale.com/safesocket
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W 💣 github.com/tailscale/go-winio/internal/fs from github.com/tailscale/go-winio
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W 💣 github.com/tailscale/go-winio/internal/socket from github.com/tailscale/go-winio
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W github.com/tailscale/go-winio/internal/stringbuffer from github.com/tailscale/go-winio/internal/fs
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W github.com/tailscale/go-winio/pkg/guid from github.com/tailscale/go-winio+
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github.com/tailscale/goupnp from github.com/tailscale/goupnp/dcps/internetgateway2+
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github.com/tailscale/goupnp/dcps/internetgateway2 from tailscale.com/net/portmapper
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github.com/tailscale/goupnp/httpu from github.com/tailscale/goupnp+
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|
|
@ -116,7 +116,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
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💣 tailscale.com/net/tshttpproxy from tailscale.com/derp/derphttp+
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tailscale.com/net/wsconn from tailscale.com/control/controlhttp+
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tailscale.com/paths from tailscale.com/cmd/tailscale/cli+
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tailscale.com/safesocket from tailscale.com/cmd/tailscale/cli+
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💣 tailscale.com/safesocket from tailscale.com/cmd/tailscale/cli+
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tailscale.com/syncs from tailscale.com/net/netcheck+
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tailscale.com/tailcfg from tailscale.com/cmd/tailscale/cli+
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tailscale.com/tka from tailscale.com/client/tailscale+
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|
|
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|
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@ -2,11 +2,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
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filippo.io/edwards25519 from github.com/hdevalence/ed25519consensus
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filippo.io/edwards25519/field from filippo.io/edwards25519
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W 💣 github.com/Microsoft/go-winio from tailscale.com/safesocket
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W 💣 github.com/Microsoft/go-winio/internal/fs from github.com/Microsoft/go-winio
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W 💣 github.com/Microsoft/go-winio/internal/socket from github.com/Microsoft/go-winio
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W github.com/Microsoft/go-winio/internal/stringbuffer from github.com/Microsoft/go-winio/internal/fs
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W github.com/Microsoft/go-winio/pkg/guid from github.com/Microsoft/go-winio+
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W 💣 github.com/alexbrainman/sspi from github.com/alexbrainman/sspi/internal/common+
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W github.com/alexbrainman/sspi/internal/common from github.com/alexbrainman/sspi/negotiate
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W 💣 github.com/alexbrainman/sspi/negotiate from tailscale.com/net/tshttpproxy
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@ -136,6 +131,11 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
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LD github.com/pkg/sftp from tailscale.com/ssh/tailssh
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LD github.com/pkg/sftp/internal/encoding/ssh/filexfer from github.com/pkg/sftp
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W 💣 github.com/tailscale/certstore from tailscale.com/control/controlclient
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W 💣 github.com/tailscale/go-winio from tailscale.com/safesocket
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W 💣 github.com/tailscale/go-winio/internal/fs from github.com/tailscale/go-winio
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W 💣 github.com/tailscale/go-winio/internal/socket from github.com/tailscale/go-winio
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W github.com/tailscale/go-winio/internal/stringbuffer from github.com/tailscale/go-winio/internal/fs
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W github.com/tailscale/go-winio/pkg/guid from github.com/tailscale/go-winio+
|
||||
github.com/tailscale/golang-x-crypto/acme from tailscale.com/ipn/ipnlocal
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LD github.com/tailscale/golang-x-crypto/chacha20 from github.com/tailscale/golang-x-crypto/ssh
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LD 💣 github.com/tailscale/golang-x-crypto/internal/alias from github.com/tailscale/golang-x-crypto/chacha20
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|
|
@ -297,7 +297,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
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💣 tailscale.com/portlist from tailscale.com/ipn/ipnlocal
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tailscale.com/posture from tailscale.com/ipn/ipnlocal
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tailscale.com/proxymap from tailscale.com/tsd+
|
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tailscale.com/safesocket from tailscale.com/client/tailscale+
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||||
💣 tailscale.com/safesocket from tailscale.com/client/tailscale+
|
||||
tailscale.com/smallzstd from tailscale.com/control/controlclient+
|
||||
LD 💣 tailscale.com/ssh/tailssh from tailscale.com/cmd/tailscaled
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tailscale.com/syncs from tailscale.com/net/netcheck+
|
||||
|
|
@ -352,7 +352,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
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|||
💣 tailscale.com/util/osdiag from tailscale.com/cmd/tailscaled+
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||||
W 💣 tailscale.com/util/osdiag/internal/wsc from tailscale.com/util/osdiag
|
||||
tailscale.com/util/osshare from tailscale.com/ipn/ipnlocal+
|
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W tailscale.com/util/pidowner from tailscale.com/ipn/ipnauth
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||||
tailscale.com/util/race from tailscale.com/net/dns/resolver
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tailscale.com/util/racebuild from tailscale.com/logpolicy
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tailscale.com/util/rands from tailscale.com/ipn/ipnlocal+
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|
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3
go.mod
3
go.mod
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@ -4,7 +4,6 @@ go 1.21
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require (
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filippo.io/mkcert v1.4.4
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github.com/Microsoft/go-winio v0.6.1
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github.com/akutz/memconn v0.1.0
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github.com/alexbrainman/sspi v0.0.0-20231016080023-1a75b4708caa
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github.com/andybalholm/brotli v1.0.5
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@ -104,6 +103,7 @@ require (
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)
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require (
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github.com/Microsoft/go-winio v0.6.1 // indirect
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github.com/google/gnostic-models v0.6.9-0.20230804172637-c7be7c783f49 // indirect
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github.com/gorilla/securecookie v1.1.1 // indirect
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)
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@ -321,6 +321,7 @@ require (
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github.com/stretchr/testify v1.8.4 // indirect
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github.com/subosito/gotenv v1.4.2 // indirect
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github.com/t-yuki/gocover-cobertura v0.0.0-20180217150009-aaee18c8195c // indirect
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github.com/tailscale/go-winio v0.0.0-20231025203758-c4f33415bf55
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github.com/tdakkota/asciicheck v0.2.0 // indirect
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github.com/tetafro/godot v1.4.11 // indirect
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github.com/timakin/bodyclose v0.0.0-20230421092635-574207250966 // indirect
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|
|
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2
go.sum
2
go.sum
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@ -868,6 +868,8 @@ github.com/tailscale/certstore v0.1.1-0.20231020161753-77811a65f4ff h1:vnxdYZUJb
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|||
github.com/tailscale/certstore v0.1.1-0.20231020161753-77811a65f4ff/go.mod h1:XrBNfAFN+pwoWuksbFS9Ccxnopa15zJGgXRFN90l3K4=
|
||||
github.com/tailscale/depaware v0.0.0-20210622194025-720c4b409502 h1:34icjjmqJ2HPjrSuJYEkdZ+0ItmGQAQ75cRHIiftIyE=
|
||||
github.com/tailscale/depaware v0.0.0-20210622194025-720c4b409502/go.mod h1:p9lPsd+cx33L3H9nNoecRRxPssFKUwwI50I3pZ0yT+8=
|
||||
github.com/tailscale/go-winio v0.0.0-20231025203758-c4f33415bf55 h1:Gzfnfk2TWrk8Jj4P4c1a3CtQyMaTVCznlkLZI++hok4=
|
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github.com/tailscale/go-winio v0.0.0-20231025203758-c4f33415bf55/go.mod h1:4k4QO+dQ3R5FofL+SanAUZe+/QfeK0+OIuwDIRu2vSg=
|
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github.com/tailscale/goexpect v0.0.0-20210902213824-6e8c725cea41 h1:/V2rCMMWcsjYaYO2MeovLw+ClP63OtXgCF2Y1eb8+Ns=
|
||||
github.com/tailscale/goexpect v0.0.0-20210902213824-6e8c725cea41/go.mod h1:/roCdA6gg6lQyw/Oz6gIIGu3ggJKYhF+WC/AQReE5XQ=
|
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github.com/tailscale/golang-x-crypto v0.0.0-20230713185742-f0b76a10a08e h1:JyeJF/HuSwvxWtsR1c0oKX1lzaSH5Wh4aX+MgiStaGQ=
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@ -5,7 +5,9 @@
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package ipnauth
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import (
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"errors"
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"fmt"
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"io"
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"net"
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"net/netip"
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"os"
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@ -25,6 +27,35 @@ import (
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"tailscale.com/version/distro"
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)
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// ErrNotImplemented is returned by ConnIdentity.WindowsToken when it is not
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// implemented for the current GOOS.
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var ErrNotImplemented = errors.New("not implemented for GOOS=" + runtime.GOOS)
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// WindowsToken represents the current security context of a Windows user.
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type WindowsToken interface {
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io.Closer
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// EqualUIDs reports whether other refers to the same user ID as the receiver.
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EqualUIDs(other WindowsToken) bool
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// IsAdministrator reports whether the receiver is a member of the built-in
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// Administrators group, or else an error. Use IsElevated to determine whether
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// the receiver is actually utilizing administrative rights.
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IsAdministrator() (bool, error)
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// IsUID reports whether the receiver's user ID matches uid.
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IsUID(uid ipn.WindowsUserID) bool
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// UID returns the ipn.WindowsUserID associated with the receiver, or else
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// an error.
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UID() (ipn.WindowsUserID, error)
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// IsElevated reports whether the receiver is currently executing as an
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// elevated administrative user.
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IsElevated() bool
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// UserDir returns the special directory identified by folderID as associated
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// with the receiver. folderID must be one of the KNOWNFOLDERID values from
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// the x/sys/windows package, serialized as a stringified GUID.
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UserDir(folderID string) (string, error)
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// Username returns the user name associated with the receiver.
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Username() (string, error)
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}
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// ConnIdentity represents the owner of a localhost TCP or unix socket connection
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// connecting to the LocalAPI.
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type ConnIdentity struct {
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// Used on Windows:
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// TODO(bradfitz): merge these into the peercreds package and
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// use that for all.
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pid int
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userID ipn.WindowsUserID
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user *user.User
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pid int
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}
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// WindowsUserID returns the local machine's userid of the connection
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if envknob.GOOS() != "windows" {
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return ""
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}
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if ci.userID != "" {
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return ci.userID
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if tok, err := ci.WindowsToken(); err == nil {
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defer tok.Close()
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if uid, err := tok.UID(); err == nil {
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return uid
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}
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}
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// For Linux tests running as Windows:
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const isBroken = true // TODO(bradfitz,maisem): fix tests; this doesn't work yet
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return ""
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}
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func (ci *ConnIdentity) User() *user.User { return ci.user }
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func (ci *ConnIdentity) Pid() int { return ci.pid }
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func (ci *ConnIdentity) IsUnixSock() bool { return ci.isUnixSock }
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func (ci *ConnIdentity) Creds() *peercred.Creds { return ci.creds }
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ci.creds, _ = peercred.Get(c)
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return ci, nil
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}
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// WindowsToken is unsupported when GOOS != windows and always returns
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// ErrNotImplemented.
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func (ci *ConnIdentity) WindowsToken() (WindowsToken, error) {
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return nil, ErrNotImplemented
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}
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@ -6,53 +6,157 @@ package ipnauth
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import (
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"fmt"
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"net"
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"syscall"
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"runtime"
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"unsafe"
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"golang.org/x/sys/windows"
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"tailscale.com/ipn"
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"tailscale.com/safesocket"
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"tailscale.com/types/logger"
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"tailscale.com/util/pidowner"
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)
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var (
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kernel32 = syscall.NewLazyDLL("kernel32.dll")
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||||
procGetNamedPipeClientProcessId = kernel32.NewProc("GetNamedPipeClientProcessId")
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)
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func getNamedPipeClientProcessId(h windows.Handle) (pid uint32, err error) {
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r1, _, err := procGetNamedPipeClientProcessId.Call(uintptr(h), uintptr(unsafe.Pointer(&pid)))
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if r1 > 0 {
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return pid, nil
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}
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||||
return 0, err
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||||
}
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||||
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||||
// GetConnIdentity extracts the identity information from the connection
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||||
// based on the user who owns the other end of the connection.
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// If c is not backed by a named pipe, an error is returned.
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||||
func GetConnIdentity(logf logger.Logf, c net.Conn) (ci *ConnIdentity, err error) {
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||||
ci = &ConnIdentity{conn: c}
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h, ok := c.(interface {
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||||
Fd() uintptr
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||||
})
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||||
wcc, ok := c.(*safesocket.WindowsClientConn)
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||||
if !ok {
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||||
return ci, fmt.Errorf("not a windows handle: %T", c)
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||||
return nil, fmt.Errorf("not a WindowsClientConn: %T", c)
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||||
}
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||||
pid, err := getNamedPipeClientProcessId(windows.Handle(h.Fd()))
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||||
ci.pid, err = wcc.ClientPID()
|
||||
if err != nil {
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||||
return ci, fmt.Errorf("getNamedPipeClientProcessId: %v", err)
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||||
return nil, err
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||||
}
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||||
ci.pid = int(pid)
|
||||
uid, err := pidowner.OwnerOfPID(ci.pid)
|
||||
if err != nil {
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||||
return ci, fmt.Errorf("failed to map connection's pid to a user (WSL?): %w", err)
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||||
}
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||||
ci.userID = ipn.WindowsUserID(uid)
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||||
u, err := LookupUserFromID(logf, uid)
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||||
if err != nil {
|
||||
return ci, fmt.Errorf("failed to look up user from userid: %w", err)
|
||||
}
|
||||
ci.user = u
|
||||
return ci, nil
|
||||
}
|
||||
|
||||
type token struct {
|
||||
t windows.Token
|
||||
}
|
||||
|
||||
func (t *token) UID() (ipn.WindowsUserID, error) {
|
||||
sid, err := t.uid()
|
||||
if err != nil {
|
||||
return "", fmt.Errorf("failed to look up user from token: %w", err)
|
||||
}
|
||||
|
||||
return ipn.WindowsUserID(sid.String()), nil
|
||||
}
|
||||
|
||||
func (t *token) Username() (string, error) {
|
||||
sid, err := t.uid()
|
||||
if err != nil {
|
||||
return "", fmt.Errorf("failed to look up user from token: %w", err)
|
||||
}
|
||||
|
||||
username, domain, _, err := sid.LookupAccount("")
|
||||
if err != nil {
|
||||
return "", fmt.Errorf("failed to look up username from SID: %w", err)
|
||||
}
|
||||
|
||||
return fmt.Sprintf(`%s\%s`, domain, username), nil
|
||||
}
|
||||
|
||||
func (t *token) IsAdministrator() (bool, error) {
|
||||
baSID, err := windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
|
||||
if err != nil {
|
||||
return false, err
|
||||
}
|
||||
|
||||
return t.t.IsMember(baSID)
|
||||
}
|
||||
|
||||
func (t *token) IsElevated() bool {
|
||||
return t.t.IsElevated()
|
||||
}
|
||||
|
||||
func (t *token) UserDir(folderID string) (string, error) {
|
||||
guid, err := windows.GUIDFromString(folderID)
|
||||
if err != nil {
|
||||
return "", err
|
||||
}
|
||||
|
||||
return t.t.KnownFolderPath((*windows.KNOWNFOLDERID)(unsafe.Pointer(&guid)), 0)
|
||||
}
|
||||
|
||||
func (t *token) Close() error {
|
||||
if t.t == 0 {
|
||||
return nil
|
||||
}
|
||||
if err := t.t.Close(); err != nil {
|
||||
return err
|
||||
}
|
||||
t.t = 0
|
||||
runtime.SetFinalizer(t, nil)
|
||||
return nil
|
||||
}
|
||||
|
||||
func (t *token) EqualUIDs(other WindowsToken) bool {
|
||||
if t != nil && other == nil || t == nil && other != nil {
|
||||
return false
|
||||
}
|
||||
ot, ok := other.(*token)
|
||||
if !ok {
|
||||
return false
|
||||
}
|
||||
if t == ot {
|
||||
return true
|
||||
}
|
||||
uid, err := t.uid()
|
||||
if err != nil {
|
||||
return false
|
||||
}
|
||||
oUID, err := ot.uid()
|
||||
if err != nil {
|
||||
return false
|
||||
}
|
||||
return uid.Equals(oUID)
|
||||
}
|
||||
|
||||
func (t *token) uid() (*windows.SID, error) {
|
||||
tu, err := t.t.GetTokenUser()
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
return tu.User.Sid, nil
|
||||
}
|
||||
|
||||
func (t *token) IsUID(uid ipn.WindowsUserID) bool {
|
||||
tUID, err := t.UID()
|
||||
if err != nil {
|
||||
return false
|
||||
}
|
||||
|
||||
return tUID == uid
|
||||
}
|
||||
|
||||
// WindowsToken returns the WindowsToken representing the security context
|
||||
// of the connection's client.
|
||||
func (ci *ConnIdentity) WindowsToken() (WindowsToken, error) {
|
||||
var wcc *safesocket.WindowsClientConn
|
||||
var ok bool
|
||||
if wcc, ok = ci.conn.(*safesocket.WindowsClientConn); !ok {
|
||||
return nil, fmt.Errorf("not a WindowsClientConn: %T", ci.conn)
|
||||
}
|
||||
|
||||
// We duplicate the token's handle so that the WindowsToken we return may have
|
||||
// a lifetime independent from the original connection.
|
||||
var h windows.Handle
|
||||
if err := windows.DuplicateHandle(
|
||||
windows.CurrentProcess(),
|
||||
windows.Handle(wcc.Token()),
|
||||
windows.CurrentProcess(),
|
||||
&h,
|
||||
0,
|
||||
false,
|
||||
windows.DUPLICATE_SAME_ACCESS,
|
||||
); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
result := &token{t: windows.Token(h)}
|
||||
runtime.SetFinalizer(result, func(t *token) { t.Close() })
|
||||
return result, nil
|
||||
}
|
||||
|
|
|
|||
|
|
@ -261,6 +261,7 @@ type LocalBackend struct {
|
|||
componentLogUntil map[string]componentLogState
|
||||
// c2nUpdateStatus is the status of c2n-triggered client update.
|
||||
c2nUpdateStatus updateStatus
|
||||
currentUser ipnauth.WindowsToken
|
||||
|
||||
// ServeConfig fields. (also guarded by mu)
|
||||
lastServeConfJSON mem.RO // last JSON that was parsed into serveConfig
|
||||
|
|
@ -2722,7 +2723,7 @@ func (b *LocalBackend) shouldUploadServices() bool {
|
|||
return !p.ShieldsUp() && b.netMap.CollectServices
|
||||
}
|
||||
|
||||
// SetCurrentUserID is used to implement support for multi-user systems (only
|
||||
// SetCurrentUser is used to implement support for multi-user systems (only
|
||||
// Windows 2022-11-25). On such systems, the uid is used to determine which
|
||||
// user's state should be used. The current user is maintained by active
|
||||
// connections open to the backend.
|
||||
|
|
@ -2737,18 +2738,35 @@ func (b *LocalBackend) shouldUploadServices() bool {
|
|||
// unattended mode. The user must disable unattended mode before the user can be
|
||||
// changed.
|
||||
//
|
||||
// On non-multi-user systems, the uid should be set to empty string.
|
||||
func (b *LocalBackend) SetCurrentUserID(uid ipn.WindowsUserID) {
|
||||
// On non-multi-user systems, the token should be set to nil.
|
||||
//
|
||||
// SetCurrentUser returns the ipn.WindowsUserID associated with token
|
||||
// when successful.
|
||||
func (b *LocalBackend) SetCurrentUser(token ipnauth.WindowsToken) (ipn.WindowsUserID, error) {
|
||||
var uid ipn.WindowsUserID
|
||||
if token != nil {
|
||||
var err error
|
||||
uid, err = token.UID()
|
||||
if err != nil {
|
||||
return "", err
|
||||
}
|
||||
}
|
||||
|
||||
b.mu.Lock()
|
||||
if b.pm.CurrentUserID() == uid {
|
||||
b.mu.Unlock()
|
||||
return
|
||||
return uid, nil
|
||||
}
|
||||
if err := b.pm.SetCurrentUserID(uid); err != nil {
|
||||
b.mu.Unlock()
|
||||
return
|
||||
return uid, nil
|
||||
}
|
||||
if b.currentUser != nil {
|
||||
b.currentUser.Close()
|
||||
}
|
||||
b.currentUser = token
|
||||
b.resetForProfileChangeLockedOnEntry()
|
||||
return uid, nil
|
||||
}
|
||||
|
||||
func (b *LocalBackend) CheckPrefs(p *ipn.Prefs) error {
|
||||
|
|
@ -4112,6 +4130,10 @@ func (b *LocalBackend) ResetForClientDisconnect() {
|
|||
|
||||
b.setNetMapLocked(nil)
|
||||
b.pm.Reset()
|
||||
if b.currentUser != nil {
|
||||
b.currentUser.Close()
|
||||
b.currentUser = nil
|
||||
}
|
||||
b.keyExpired = false
|
||||
b.authURL = ""
|
||||
b.authURLSticky = ""
|
||||
|
|
|
|||
|
|
@ -202,6 +202,7 @@ func (s *Server) serveHTTP(w http.ResponseWriter, r *http.Request) {
|
|||
lah := localapi.NewHandler(lb, s.logf, s.netMon, s.backendLogID)
|
||||
lah.PermitRead, lah.PermitWrite = s.localAPIPermissions(ci)
|
||||
lah.PermitCert = s.connCanFetchCerts(ci)
|
||||
lah.CallerIsLocalAdmin = s.connIsLocalAdmin(ci)
|
||||
lah.ServeHTTP(w, r)
|
||||
return
|
||||
}
|
||||
|
|
@ -242,8 +243,30 @@ func (s *Server) checkConnIdentityLocked(ci *ipnauth.ConnIdentity) error {
|
|||
for _, active = range s.activeReqs {
|
||||
break
|
||||
}
|
||||
if active != nil && ci.WindowsUserID() != active.WindowsUserID() {
|
||||
return inUseOtherUserError{fmt.Errorf("Tailscale already in use by %s, pid %d", active.User().Username, active.Pid())}
|
||||
if active != nil {
|
||||
chkTok, err := ci.WindowsToken()
|
||||
if err == nil {
|
||||
defer chkTok.Close()
|
||||
} else if !errors.Is(err, ipnauth.ErrNotImplemented) {
|
||||
return err
|
||||
}
|
||||
|
||||
activeTok, err := active.WindowsToken()
|
||||
if err == nil {
|
||||
defer activeTok.Close()
|
||||
} else if !errors.Is(err, ipnauth.ErrNotImplemented) {
|
||||
return err
|
||||
}
|
||||
|
||||
if chkTok != nil && !chkTok.EqualUIDs(activeTok) {
|
||||
var b strings.Builder
|
||||
b.WriteString("Tailscale already in use")
|
||||
if username, err := activeTok.Username(); err == nil {
|
||||
fmt.Fprintf(&b, " by %s", username)
|
||||
}
|
||||
fmt.Fprintf(&b, ", pid %d", active.Pid())
|
||||
return inUseOtherUserError{errors.New(b.String())}
|
||||
}
|
||||
}
|
||||
}
|
||||
if err := s.mustBackend().CheckIPNConnectionAllowed(ci); err != nil {
|
||||
|
|
@ -341,6 +364,31 @@ func (s *Server) connCanFetchCerts(ci *ipnauth.ConnIdentity) bool {
|
|||
return false
|
||||
}
|
||||
|
||||
// connIsLocalAdmin reports whether ci has administrative access to the local
|
||||
// machine, for whatever that means with respect to the current OS.
|
||||
//
|
||||
// This returns true only on Windows machines when the client user is a
|
||||
// member of the built-in Administrators group (but not necessarily elevated).
|
||||
// This is useful because, on Windows, tailscaled itself always runs with
|
||||
// elevated rights: we want to avoid privilege escalation for certain mutative operations.
|
||||
func (s *Server) connIsLocalAdmin(ci *ipnauth.ConnIdentity) bool {
|
||||
tok, err := ci.WindowsToken()
|
||||
if err != nil {
|
||||
if !errors.Is(err, ipnauth.ErrNotImplemented) {
|
||||
s.logf("ipnauth.ConnIdentity.WindowsToken() error: %v", err)
|
||||
}
|
||||
return false
|
||||
}
|
||||
defer tok.Close()
|
||||
|
||||
isAdmin, err := tok.IsAdministrator()
|
||||
if err != nil {
|
||||
s.logf("ipnauth.WindowsToken.IsAdministrator() error: %v", err)
|
||||
return false
|
||||
}
|
||||
return isAdmin
|
||||
}
|
||||
|
||||
// addActiveHTTPRequest adds c to the server's list of active HTTP requests.
|
||||
//
|
||||
// If the returned error may be of type inUseOtherUserError.
|
||||
|
|
@ -372,14 +420,25 @@ func (s *Server) addActiveHTTPRequest(req *http.Request, ci *ipnauth.ConnIdentit
|
|||
|
||||
mak.Set(&s.activeReqs, req, ci)
|
||||
|
||||
if uid := ci.WindowsUserID(); uid != "" && len(s.activeReqs) == 1 {
|
||||
// Tell the LocalBackend about the identity we're now running as.
|
||||
lb.SetCurrentUserID(uid)
|
||||
if s.lastUserID != uid {
|
||||
if s.lastUserID != "" {
|
||||
doReset = true
|
||||
if len(s.activeReqs) == 1 {
|
||||
token, err := ci.WindowsToken()
|
||||
if err != nil {
|
||||
if !errors.Is(err, ipnauth.ErrNotImplemented) {
|
||||
s.logf("error obtaining access token: %v", err)
|
||||
}
|
||||
} else {
|
||||
// Tell the LocalBackend about the identity we're now running as.
|
||||
uid, err := lb.SetCurrentUser(token)
|
||||
if err != nil {
|
||||
token.Close()
|
||||
return nil, err
|
||||
}
|
||||
if s.lastUserID != uid {
|
||||
if s.lastUserID != "" {
|
||||
doReset = true
|
||||
}
|
||||
s.lastUserID = uid
|
||||
}
|
||||
s.lastUserID = uid
|
||||
}
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -157,6 +157,17 @@ type Handler struct {
|
|||
// cert fetching access.
|
||||
PermitCert bool
|
||||
|
||||
// CallerIsLocalAdmin is whether the this handler is being invoked as a
|
||||
// result of a LocalAPI call from a user who is a local admin of the current
|
||||
// machine.
|
||||
//
|
||||
// As of 2023-10-26 it is only populated on Windows.
|
||||
//
|
||||
// It can be used to to restrict some LocalAPI operations which should only
|
||||
// be run by an admin and not unprivileged users in a computing environment
|
||||
// managed by IT admins.
|
||||
CallerIsLocalAdmin bool
|
||||
|
||||
b *ipnlocal.LocalBackend
|
||||
logf logger.Logf
|
||||
netMon *netmon.Monitor // optional; nil means interfaces will be looked up on-demand
|
||||
|
|
|
|||
|
|
@ -3,16 +3,27 @@
|
|||
|
||||
package safesocket
|
||||
|
||||
//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go pipe_windows.go
|
||||
|
||||
import (
|
||||
"context"
|
||||
"fmt"
|
||||
"net"
|
||||
"runtime"
|
||||
"syscall"
|
||||
"time"
|
||||
|
||||
"github.com/Microsoft/go-winio"
|
||||
"github.com/tailscale/go-winio"
|
||||
"golang.org/x/sys/windows"
|
||||
)
|
||||
|
||||
func connect(s *ConnectionStrategy) (net.Conn, error) {
|
||||
return winio.DialPipe(s.path, nil)
|
||||
dl := time.Now().Add(20 * time.Second)
|
||||
ctx, cancel := context.WithDeadline(context.Background(), dl)
|
||||
defer cancel()
|
||||
// We use the identification impersonation level so that tailscaled may
|
||||
// obtain information about our token for access control purposes.
|
||||
return winio.DialPipeAccessImpLevel(ctx, s.path, windows.GENERIC_READ|windows.GENERIC_WRITE, winio.PipeImpLevelIdentification)
|
||||
}
|
||||
|
||||
func setFlags(network, address string, c syscall.RawConn) error {
|
||||
|
|
@ -39,5 +50,109 @@ func listen(path string) (net.Listener, error) {
|
|||
if err != nil {
|
||||
return nil, fmt.Errorf("namedpipe.Listen: %w", err)
|
||||
}
|
||||
return lc, nil
|
||||
return &winIOPipeListener{Listener: lc}, nil
|
||||
}
|
||||
|
||||
// WindowsClientConn is an implementation of net.Conn that permits retrieval of
|
||||
// the Windows access token associated with the connection's client. The
|
||||
// embedded net.Conn must be a go-winio PipeConn.
|
||||
type WindowsClientConn struct {
|
||||
net.Conn
|
||||
token windows.Token
|
||||
}
|
||||
|
||||
// winioPipeHandle is fulfilled by the underlying code implementing go-winio's
|
||||
// PipeConn interface.
|
||||
type winioPipeHandle interface {
|
||||
// Fd returns the Windows handle associated with the connection.
|
||||
Fd() uintptr
|
||||
}
|
||||
|
||||
func resolvePipeHandle(c net.Conn) windows.Handle {
|
||||
wph, ok := c.(winioPipeHandle)
|
||||
if !ok {
|
||||
return 0
|
||||
}
|
||||
return windows.Handle(wph.Fd())
|
||||
}
|
||||
|
||||
func (conn *WindowsClientConn) handle() windows.Handle {
|
||||
return resolvePipeHandle(conn.Conn)
|
||||
}
|
||||
|
||||
// ClientPID returns the pid of conn's client, or else an error.
|
||||
func (conn *WindowsClientConn) ClientPID() (int, error) {
|
||||
var pid uint32
|
||||
if err := getNamedPipeClientProcessId(conn.handle(), &pid); err != nil {
|
||||
return -1, fmt.Errorf("GetNamedPipeClientProcessId: %w", err)
|
||||
}
|
||||
return int(pid), nil
|
||||
}
|
||||
|
||||
// Token returns the Windows access token of the client user.
|
||||
func (conn *WindowsClientConn) Token() windows.Token {
|
||||
return conn.token
|
||||
}
|
||||
|
||||
func (conn *WindowsClientConn) Close() error {
|
||||
if conn.token != 0 {
|
||||
conn.token.Close()
|
||||
conn.token = 0
|
||||
}
|
||||
return conn.Conn.Close()
|
||||
}
|
||||
|
||||
type winIOPipeListener struct {
|
||||
net.Listener
|
||||
}
|
||||
|
||||
func (lw *winIOPipeListener) Accept() (net.Conn, error) {
|
||||
conn, err := lw.Listener.Accept()
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
token, err := clientUserAccessToken(conn)
|
||||
if err != nil {
|
||||
conn.Close()
|
||||
return nil, err
|
||||
}
|
||||
|
||||
return &WindowsClientConn{
|
||||
Conn: conn,
|
||||
token: token,
|
||||
}, nil
|
||||
}
|
||||
|
||||
func clientUserAccessToken(c net.Conn) (windows.Token, error) {
|
||||
h := resolvePipeHandle(c)
|
||||
if h == 0 {
|
||||
return 0, fmt.Errorf("not a windows handle: %T", c)
|
||||
}
|
||||
|
||||
// Impersonation touches thread-local state, so we need to lock until the
|
||||
// client access token has been extracted.
|
||||
runtime.LockOSThread()
|
||||
defer runtime.UnlockOSThread()
|
||||
|
||||
if err := impersonateNamedPipeClient(h); err != nil {
|
||||
return 0, err
|
||||
}
|
||||
defer func() {
|
||||
// Revert the current thread's impersonation.
|
||||
if err := windows.RevertToSelf(); err != nil {
|
||||
panic(fmt.Errorf("could not revert impersonation: %w", err))
|
||||
}
|
||||
}()
|
||||
|
||||
// Extract the client's access token from the thread-local state.
|
||||
var token windows.Token
|
||||
if err := windows.OpenThreadToken(windows.CurrentThread(), windows.TOKEN_DUPLICATE|windows.TOKEN_QUERY, true, &token); err != nil {
|
||||
return 0, err
|
||||
}
|
||||
|
||||
return token, nil
|
||||
}
|
||||
|
||||
//sys getNamedPipeClientProcessId(h windows.Handle, clientPid *uint32) (err error) [int32(failretval)==0] = kernel32.GetNamedPipeClientProcessId
|
||||
//sys impersonateNamedPipeClient(h windows.Handle) (err error) [int32(failretval)==0] = advapi32.ImpersonateNamedPipeClient
|
||||
|
|
|
|||
|
|
@ -0,0 +1,62 @@
|
|||
// Code generated by 'go generate'; DO NOT EDIT.
|
||||
|
||||
package safesocket
|
||||
|
||||
import (
|
||||
"syscall"
|
||||
"unsafe"
|
||||
|
||||
"golang.org/x/sys/windows"
|
||||
)
|
||||
|
||||
var _ unsafe.Pointer
|
||||
|
||||
// Do the interface allocations only once for common
|
||||
// Errno values.
|
||||
const (
|
||||
errnoERROR_IO_PENDING = 997
|
||||
)
|
||||
|
||||
var (
|
||||
errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
|
||||
errERROR_EINVAL error = syscall.EINVAL
|
||||
)
|
||||
|
||||
// errnoErr returns common boxed Errno values, to prevent
|
||||
// allocations at runtime.
|
||||
func errnoErr(e syscall.Errno) error {
|
||||
switch e {
|
||||
case 0:
|
||||
return errERROR_EINVAL
|
||||
case errnoERROR_IO_PENDING:
|
||||
return errERROR_IO_PENDING
|
||||
}
|
||||
// TODO: add more here, after collecting data on the common
|
||||
// error values see on Windows. (perhaps when running
|
||||
// all.bat?)
|
||||
return e
|
||||
}
|
||||
|
||||
var (
|
||||
modadvapi32 = windows.NewLazySystemDLL("advapi32.dll")
|
||||
modkernel32 = windows.NewLazySystemDLL("kernel32.dll")
|
||||
|
||||
procImpersonateNamedPipeClient = modadvapi32.NewProc("ImpersonateNamedPipeClient")
|
||||
procGetNamedPipeClientProcessId = modkernel32.NewProc("GetNamedPipeClientProcessId")
|
||||
)
|
||||
|
||||
func impersonateNamedPipeClient(h windows.Handle) (err error) {
|
||||
r1, _, e1 := syscall.Syscall(procImpersonateNamedPipeClient.Addr(), 1, uintptr(h), 0, 0)
|
||||
if int32(r1) == 0 {
|
||||
err = errnoErr(e1)
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
func getNamedPipeClientProcessId(h windows.Handle, clientPid *uint32) (err error) {
|
||||
r1, _, e1 := syscall.Syscall(procGetNamedPipeClientProcessId.Addr(), 2, uintptr(h), uintptr(unsafe.Pointer(clientPid)), 0)
|
||||
if int32(r1) == 0 {
|
||||
err = errnoErr(e1)
|
||||
}
|
||||
return
|
||||
}
|
||||
Loading…
Reference in New Issue