cmd: Split unix sockets for admin endpoint addresses (#5696)

* cmd: fix cli when admin endpoint uses new unix socket permission format

Fixes a bug where the following Caddyfile

```Caddyfile
{
	admin unix/admin.sock|0660
}
```

and `caddy reload --config Caddyfile`
would throw the following error instead of reloading it:

```
INFO    using provided configuration    {"config_file": "Caddyfile", "config_adapter": ""}
Error: sending configuration to instance: performing request: Post "http://127.0.0.1/load": dial unix admin.sock|0660: connect: no such file or directory
[ERROR] exit status 1
```

---

This bug also affected `caddy start` and `caddy stop`.

* Move splitter function to internal

---------

Co-authored-by: Matthew Holt <[email protected]>

4 files changed, 73 insertions, 37 deletions

diff --git a/cmd/commandfuncs.go b/cmd/commandfuncs.go
index 68b099ef7..dde870be6 100644
--- a/cmd/commandfuncs.go
+++ b/cmd/commandfuncs.go
@@ -35,6 +35,7 @@ import (
 	"github.com/caddyserver/caddy/v2"
 	"github.com/caddyserver/caddy/v2/caddyconfig"
 	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
+	"github.com/caddyserver/caddy/v2/internal"
 	"go.uber.org/zap"
 )
 
@@ -611,6 +612,16 @@ func AdminAPIRequest(adminAddr, method, uri string, headers http.Header, body io
 	origin := "http://" + parsedAddr.JoinHostPort(0)
 	if parsedAddr.IsUnixNetwork() {
 		origin = "http://127.0.0.1" // bogus host is a hack so that http.NewRequest() is happy
+
+		// the unix address at this point might still contain the optional
+		// unix socket permissions, which are part of the address/host.
+		// those need to be removed first, as they aren't part of the
+		// resulting unix file path
+		addr, _, err := internal.SplitUnixSocketPermissionsBits(parsedAddr.Host)
+		if err != nil {
+			return nil, err
+		}
+		parsedAddr.Host = addr
 	}
 
 	// form the request
diff --git a/internal/sockets.go b/internal/sockets.go
new file mode 100644
index 000000000..761f92051
--- /dev/null
+++ b/internal/sockets.go
@@ -0,0 +1,56 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal
+
+import (
+	"fmt"
+	"io/fs"
+	"strconv"
+	"strings"
+)
+
+// SplitUnixSocketPermissionsBits takes a unix socket address in the
+// unusual "path|bits" format (e.g. /run/caddy.sock|0222) and tries
+// to split it into socket path (host) and permissions bits (port).
+// Colons (":") can't be used as separator, as socket paths on Windows
+// may include a drive letter (e.g. `unix/c:\absolute\path.sock`).
+// Permission bits will default to 0200 if none are specified.
+// Throws an error, if the first carrying bit does not
+// include write perms (e.g. `0422` or `022`).
+// Symbolic permission representation (e.g. `u=w,g=w,o=w`)
+// is not supported and will throw an error for now!
+func SplitUnixSocketPermissionsBits(addr string) (path string, fileMode fs.FileMode, err error) {
+	addrSplit := strings.SplitN(addr, "|", 2)
+
+	if len(addrSplit) == 2 {
+		// parse octal permission bit string as uint32
+		fileModeUInt64, err := strconv.ParseUint(addrSplit[1], 8, 32)
+		if err != nil {
+			return "", 0, fmt.Errorf("could not parse octal permission bits in %s: %v", addr, err)
+		}
+		fileMode = fs.FileMode(fileModeUInt64)
+
+		// FileMode.String() returns a string like `-rwxr-xr--` for `u=rwx,g=rx,o=r` (`0754`)
+		if string(fileMode.String()[2]) != "w" {
+			return "", 0, fmt.Errorf("owner of the socket requires '-w-' (write, octal: '2') permissions at least; got '%s' in %s", fileMode.String()[1:4], addr)
+		}
+
+		return addrSplit[0], fileMode, nil
+	}
+
+	// default to 0200 (symbolic: `u=w,g=,o=`)
+	// if no permission bits are specified
+	return addr, 0200, nil
+}
diff --git a/listeners.go b/listeners.go
index fe5ad0c55..9e761be60 100644
--- a/listeners.go
+++ b/listeners.go
@@ -31,6 +31,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/caddyserver/caddy/v2/internal"
 	"github.com/quic-go/quic-go"
 	"github.com/quic-go/quic-go/http3"
 	"go.uber.org/zap"
@@ -157,7 +158,7 @@ func (na NetworkAddress) listen(ctx context.Context, portOffset uint, config net
 	// is independent of permissions bits
 	if na.IsUnixNetwork() {
 		var err error
-		address, unixFileMode, err = splitUnixSocketPermissionsBits(na.Host)
+		address, unixFileMode, err = internal.SplitUnixSocketPermissionsBits(na.Host)
 		if err != nil {
 			return nil, err
 		}
@@ -319,40 +320,6 @@ func IsUnixNetwork(netw string) bool {
 	return strings.HasPrefix(netw, "unix")
 }
 
-// Takes a unix socket address in the unusual "path|bits" format
-// (e.g. /run/caddy.sock|0222) and tries to split it into
-// socket path (host) and permissions bits (port). Colons (":")
-// can't be used as separator, as socket paths on Windows may
-// include a drive letter (e.g. `unix/c:\absolute\path.sock`).
-// Permission bits will default to 0200 if none are specified.
-// Throws an error, if the first carrying bit does not
-// include write perms (e.g. `0422` or `022`).
-// Symbolic permission representation (e.g. `u=w,g=w,o=w`)
-// is not supported and will throw an error for now!
-func splitUnixSocketPermissionsBits(addr string) (path string, fileMode fs.FileMode, err error) {
-	addrSplit := strings.SplitN(addr, "|", 2)
-
-	if len(addrSplit) == 2 {
-		// parse octal permission bit string as uint32
-		fileModeUInt64, err := strconv.ParseUint(addrSplit[1], 8, 32)
-		if err != nil {
-			return "", 0, fmt.Errorf("could not parse octal permission bits in %s: %v", addr, err)
-		}
-		fileMode = fs.FileMode(fileModeUInt64)
-
-		// FileMode.String() returns a string like `-rwxr-xr--` for `u=rwx,g=rx,o=r` (`0754`)
-		if string(fileMode.String()[2]) != "w" {
-			return "", 0, fmt.Errorf("owner of the socket requires '-w-' (write, octal: '2') permissions at least; got '%s' in %s", fileMode.String()[1:4], addr)
-		}
-
-		return addrSplit[0], fileMode, nil
-	}
-
-	// default to 0200 (symbolic: `u=w,g=,o=`)
-	// if no permission bits are specified
-	return addr, 0200, nil
-}
-
 // ParseNetworkAddress parses addr into its individual
 // components. The input string is expected to be of
 // the form "network/host:port-range" where any part is
@@ -377,7 +344,7 @@ func ParseNetworkAddressWithDefaults(addr, defaultNetwork string, defaultPort ui
 		network = defaultNetwork
 	}
 	if IsUnixNetwork(network) {
-		_, _, err := splitUnixSocketPermissionsBits(host)
+		_, _, err := internal.SplitUnixSocketPermissionsBits(host)
 		return NetworkAddress{
 			Network: network,
 			Host:    host,
diff --git a/listeners_test.go b/listeners_test.go
index 1b534563d..f8a13cafc 100644
--- a/listeners_test.go
+++ b/listeners_test.go
@@ -17,6 +17,8 @@ package caddy
 import (
 	"reflect"
 	"testing"
+
+	"github.com/caddyserver/caddy/v2/internal"
 )
 
 func TestSplitNetworkAddress(t *testing.T) {
@@ -634,7 +636,7 @@ func TestSplitUnixSocketPermissionsBits(t *testing.T) {
 			expectErr: true,
 		},
 	} {
-		actualPath, actualFileMode, err := splitUnixSocketPermissionsBits(tc.input)
+		actualPath, actualFileMode, err := internal.SplitUnixSocketPermissionsBits(tc.input)
 		if tc.expectErr && err == nil {
 			t.Errorf("Test %d: Expected error but got: %v", i, err)
 		}