How to process first packet panic

[youngcow]

Hi,

This library is very well.
But when I send an incorrect byte in first packet, the process panic.
How should I process this panic?

Thanks.

[bigeagle]

Hi youngcow,

It should make more sense if you put up an example.

Cheers,

[bigeagle]

Hi @youngcow,

Many web frameworks has a "panic recovery" middleware, such as https://github.com/gin-gonic/gin/blob/develop/recovery.go#L25
maybe we can add this middleware to ldapserver.

Cheers,

[woopstar]

Project is idle? Panic error still happens

2017/12/29 18:26:35 Listening on 127.0.0.1:10389
2017/12/29 18:26:36 Connection client [1] from 127.0.0.1:54998 accepted
2017/12/29 18:26:36 client 1 close()
2017/12/29 18:26:36 client 1 close() - stop reading from client
2017/12/29 18:26:36 client 1 close() - Abandon signal sent to processors
2017/12/29 18:26:36 client [1] request processors ended
2017/12/29 18:26:36 client [1] connection closed
panic: Expecting 0x30 as first byte, but got 0x16 instead

goroutine 4 [running]:
github.com/vjeantet/ldapserver.readTagAndLength(0xc4200660c0, 0xc42000c080, 0x30, 0x30, 0xc4200fe0c0, 0x1516ac0, 0x0, 0x0)
	/Sourcecode/github/goipam/packages/src/github.com/vjeantet/ldapserver/packet.go:89 +0x4ad
github.com/vjeantet/ldapserver.readLdapMessageBytes(0xc4200660c0, 0x15147b8, 0xc42002f678, 0x10122c8)
	/Sourcecode/github/goipam/packages/src/github.com/vjeantet/ldapserver/packet.go:54 +0x49
github.com/vjeantet/ldapserver.readMessagePacket(0xc4200660c0, 0xc4200fe0c0, 0x103417b, 0xc42002f6b0)
	/Sourcecode/github/goipam/packages/src/github.com/vjeantet/ldapserver/packet.go:18 +0x2f
github.com/vjeantet/ldapserver.(*client).ReadPacket(0xc420104100, 0x0, 0xc4200fe0c0, 0x0)
	/Sourcecode/github/goipam/packages/src/github.com/vjeantet/ldapserver/client.go:53 +0x33
github.com/vjeantet/ldapserver.(*client).serve(0xc420104100)
	/Sourcecode/github/goipam/packages/src/github.com/vjeantet/ldapserver/client.go:117 +0x1fb
created by github.com/vjeantet/ldapserver.(*Server).serve
	/Sourcecode/github/goipam/packages/src/github.com/vjeantet/ldapserver/server.go:110 +0x4a6

Tested with this

ldapsearch -Z -H ldaps://127.0.0.1:10389 -D "cn=ClientLookup" -w secret -x -b dc=test,dc=domain,dc=com "cn=Andreas Kruger"

[vjeantet]

Not idle

Thanks for the example, it will easier to fix

[woopstar]

For the ease of it, I'm just using the default complex example.

[woopstar]

Do we have any ETA on this? :)

[dcrobbins]

a trivial approach would be to recover client panics, like so:

go func() {
	defer func() {
		if err := recover(); err != nil {
			Logger.Printf("ldap client panic recovered: %v", err)
		}
	}()

	cli.serve()
}()

[marcoacsilva]

Any update?

[marcoacsilva]

A workaround solution for me was to create my own custom Listener, wrapping the server Listener, to validate the first Byte and drop the connection if it's not 0x30 during the Accept phase. It's ugly, but it does the trick.
With this, I only serve LDAP messages, avoiding panic the server.