Anon functions aren't accepted as AuthCallback

[mrvik]

Hey, after writing some code, seems like there is a problem on the SetAuthCallback function.

Stack trace:

(I) smb-web-client Jan  7 19:31:05 Got a request type 1: {Type:1 Username:Asd Password:sdfsdfsdf}
INFO: Current debug levels:
  all: 99
  tdb: 99
  printdrivers: 99
  lanman: 99
  smb: 99
  rpc_parse: 99
  rpc_srv: 99
  rpc_cli: 99
  passdb: 99
  sam: 99
  auth: 99
  winbind: 99
  vfs: 99
  idmap: 99
  quota: 99
  acls: 99
  locking: 99
  msdfs: 99
  dmapi: 99
  registry: 99
  scavenger: 99
  dns: 99
  ldb: 99
  tevent: 99
  auth_audit: 99
  auth_json_audit: 99
  kerberos: 99
  drs_repl: 99
  smb2: 99
  smb2_credits: 99
  dsdb_audit: 99
  dsdb_json_audit: 99
  dsdb_password_audit: 99
  dsdb_password_json_audit: 99
  dsdb_transaction_audit: 99
  dsdb_transaction_json_audit: 99
  dsdb_group_audit: 99
  dsdb_group_json_audit: 99
panic: runtime error: cgo argument has Go pointer to Go pointer

goroutine 10 [running]:
github.com/mvo5/libsmbclient-go.(*Client).SetAuthCallback.func1(0xc000252120, 0xc000242040)
        /home/mrvik/go/pkg/mod/github.com/mvo5/libsmbclient-go@v0.0.0-20190424080658-d00e6e47f104/libsmbclient.go:117 +0xfd
github.com/mvo5/libsmbclient-go.(*Client).SetAuthCallback(0xc000252120, 0xc0000dc420)
        /home/mrvik/go/pkg/mod/github.com/mvo5/libsmbclient-go@v0.0.0-20190424080658-d00e6e47f104/libsmbclient.go:117 +0xf1
gitlab.com/mrvik/smb-web-client/sambaManager.getClient(0xc0000de130, 0x3, 0xc0000de133, 0x9, 0x857e80)
        /home/mrvik/git/rpi/smb-web-client/sambaManager/sambaExec.go:11 +0xf4
gitlab.com/mrvik/smb-web-client/sambaManager.TryAuthenticate(0x8d24ce, 0x9, 0xc0000de130, 0x3, 0xc0000de133, 0x9, 0x954100, 0x0, 0x0)
        /home/mrvik/git/rpi/smb-web-client/sambaManager/sambaExec.go:16 +0x8b
gitlab.com/mrvik/smb-web-client/sambaManager.handleRequest(0xc0002520e0)
        /home/mrvik/git/rpi/smb-web-client/sambaManager/sambaManager.go:67 +0x2f8
gitlab.com/mrvik/smb-web-client/sambaManager.Init.func1(0x959e00, 0xc00006c3c0, 0xc00006e360, 0x95bf40, 0xc00006c300)
        /home/mrvik/git/rpi/smb-web-client/sambaManager/sambaManager.go:31 +0x96
created by gitlab.com/mrvik/smb-web-client/sambaManager.Init
        /home/mrvik/git/rpi/smb-web-client/sambaManager/sambaManager.go:23 +0x13a
exit status 2

Go code:

package sambaManager;

import(
    "fmt"
    "github.com/mvo5/libsmbclient-go"
)

func getClient(user, password string) *libsmbclient.Client{
    client:=libsmbclient.New();
    client.SetDebug(99);
    client.SetAuthCallback(func(_,_ string)(string,string,string){return "", user, password});
    return client;
}

//Try to authenticate a user against the SMB server
func TryAuthenticate(host, user, password string)(ok bool, err error){
    client:=getClient(user, password);
    defer client.Close();
    userDir:=fmt.Sprintf("smb://%s/%s/", host, user); //Test for user home dir (should have the homes section enabled)
    _, err=client.Opendir(userDir);
    ok=err==nil;
    return;
}

[mvo5]

Hey, thanks for your bugreport. I have an example smb explorer app in the tree, I moved it into 'cmd/smb/main.go` now. Could you please check if that also crashes in the same way? Please check https://github.com/mvo5/libsmbclient-go/blob/master/cmd/smb/main.go#L54 for an example usage. maybe the issue is that you use an anonymous func(). But it's ~5y since I wrote this code so I'm a bit rusty :) I kind of abandoned it after I found that libsmbclient is not thread safe at all.

Fwiw - with the example in main.go I don't get crashes.

[mrvik]

Fwiw - with the example in main.go I don't get crashes.

Yes, this annoyed me at first, I tried to copy your fn from https://github.com/mvo5/libsmbclient-go/blob/master/cmd/smb/main.go#L54 and pass it instead of my anon function and it worked.

Seems like anon functions aren't working (not related to GC nor goroutine thread locking as far as I tested). The real issue seems anon functions definitively, I'm updating the title

Thanks for your fast reply.