Libsmb2 is a userspace client library for accessing SMB2/SMB3 shares on a network. It is high performance and fully async. It supports both zero-copy for SMB READ/WRITE commands as well as compounded commands.

Libsmb2 is distributed under the LGPLv2.1 licence.

API

Libsmb2 implements three different APIs for accessing remote SMB shares :

1, High level synchronous posix-like API. This is a simple API for accessing a share. The functions in this API are modelled to be be similar to the corresponding POSIX functions. This API is described in libsmb.h

2, High level async posix-like API. This is a high performance, fully non-blocking and async API. The functions in this API are modelled to be be similar to the corresponding POSIX functions. This is the recommended API. This API is described in libsmb.h

3, Low level async RAW API. This is a low level API that provides direct access to the SMB2 PDUs and data structures. This API is described in libsmb-raw.h

SMB URL Format

The SMB URL format is currently a small subset of the URL format that is defined/used by the Samba project. The goal is to eventually support the full URL format, thus making URLs interchangable between Samba utilities and Libsmb2 but we are not there yet.

smb://[;][@][:]/[/path][?arg=val[&arg=val]*]

is either a hostname, an IPv4 or an IPv6 address.

Aruments supported by libsmb2 are : sec= : Mechanism to use to authenticate to the server. Default is any available mech, but can be overridden by : krb5: Use Kerberos using credentials from kinit. krb5cc: Use Kerberos using credentials from credentials cache. ntlmssp : Only use NTLMSSP vers= : Which SMB version to negotiate: 2: Negotiate any version of SMB2 3: Negotiate any version of SMB3 2.02, 2.10, 3.00, 3.02, 3.1.1 : negotiate a specific version. Default is to negotiate any SMB2 or SMB3 version. seal : Enable SMB3 encryption. sign : Require SMB2/3 signing. timeout : Timeout in seconds when to cancel a command. Default it 0: No timeout.

NOTE:- When using krb5cc mode use smb2_set_domain() and smb2_set_password() in the examples and applications

Authentication

Libsmb2 provides has builtin support for NTLMSSP username/password authentication. It can also, optionally, be built with (MIT) Kerberos authentication.

Libsmb2 will try to build with Kerberos if these libraries are present. You can force a build without Kerberos support by using the flag --without-libkrb5 to configure. In this case only NTLMSSP authentication will be available.

MIT KERBEROS

Authentication is implemented using MIT Kerberos and it supports both KRB5 for authentication against Active Directory as well as NTLMSSP (optional).

MIT Kerberos can be configured to also provide NTLMSSP authentication, as an alternative to the builtin NTLMSSP implementation using an external mech plugin. To use this Kerberos/NTLMSSP module you will need to build and install GSS-NTLMSSP from [https://github.com/simo5/gss-ntlmssp] If you are uncertain you can skip this module and just use the NTLMSSP module that is provided by libsmb2.

NTLM Authentication

NTLM credentials are stored in a text file of the form : DOMAIN:USERNAME:PASSWORD with one line per username. You need to set up the environment variable NTLM_USER_FILE to point to this file. You need one entry in this file for each local user account you want to be able to use libsmb2 for accessing a remote share.

By default, NTLM authentication will use the username for the current process. This can be overridden by specifying a different username in the SMB URL : smb://[email protected]/share?sec=ntlmssp

KRB5 Authentication

Kerberos authentication can be used when the linux workstation as well as the file server are part of Active Directory.

You should be able to authenticate to the file server using krb5 by specifying sec=krb5 in the URL : smb://server/share?sec=krb5

The application needs to set the username, password and the domain fqdn in the context using smb2_set_user(), smb2_set_password() and smb2_set_domain() respectively.

NTLM Credentials

This applies to both the builtin NTLMSSP implementation as well as when using Kerberos with the NTLMSSP mech plugin.

NTLM credentials are stored in a text file of the form : DOMAIN:USERNAME:PASSWORD with one line per username. You need to set up the environment variable NTLM_USER_FILE to point to this file. You need one entry in this file for each local user account you want to be able to use libsmb2 for accessing a remote share.

By default, NTLM authentication will use the username for the current process. This can be overridden by specifying a different username in the SMB URL : smb://[email protected]/share?sec=ntlmssp

Alternatively you can provide the username and password from your application by calling : smb2_set_user(smb2, ); smb2_set_password(smb2, );

SMB2/3 SIGNING

Signing is supported with KRB5, with the builtin ntlmssp support and with gss-ntlmssp mech plugin.

SMB3 Encryption

Encryption is only supported with KRB5 or with the builtin ntlmssp support. Encryption is not supported when the gss-ntlmssp mech plugin is used. Encryption can be enabled either using the "seal" URL argument or by calling smb3_set_seal(smb2, 1);

BUILDING LIBSMB2

Windows

You have to install CMake (https://cmake.org/) and Visual Studio (https://www.visualstudio.com/) to build libsmb2 for Windows (including Universal Windows Platform).

Please follow the next steps to build shared library:

mkdir build
cd build
cmake -G "Visual Studio 15 2017" ..
cmake --build . --config RelWithDebInfo

Static library:

mkdir build
cd build
cmake -G "Visual Studio 15 2017" -DBUILD_SHARED_LIBS=0 ..
cmake --build . --config RelWithDebInfo

macOS, iOS, tvOS, watchOS

You can use AMSMB2 (https://github.com/amosavian/AMSMB2) universal framework which incorporates precompiled libsmb2 for Apple devices.

It is written in Swift but can be used in both Swift and Objective-C codes.

If you want to rebuild libsmb2 in AMSMB2, please follow these steps:

git clone https://github.com/amosavian/AMSMB2
cd AMSMB2/buildtools
./build.sh

Precompiled binaries don't include Kerberos support by default. If you want build libraries with Kerberos support, execute this script instead:

./build-with-krb5.sh

ESP32

libsmb2 is pre-configured for the ESP32 micro-controller using the esp-idf toolchain (Arduino is not supported). Simply clone this project in the 'components' directory of the ESP32 project and it will automatically be included in the build process.

Playstation2

EE, Emotion-Engine, is the main CPU for the PS2. To compile libsmb2 for the PS2 EE, first install the PS2 toolchain and PS2 SDK and set it up.

To build libsmb2.a, a version of libsmb2 for the EE tcpip stack: $ cd lib $ make -f Makefile.PS2_EE clean $ make -f Makefile.PS2_EE install

IOP, IO-Processor is the secondary CPU for the PS2. To compile libsmb2 for the PS2 IOP, first install the PS2 toolchain and PS2 SDK and set it up.

Then to build libsmb2, run $ cd lib $ make -f Makefile.PS2_IOP clean $ make -f Makefile.PS2_IOP install

PlayStation 3

PPU, PowerPC, is the main CPU for the PS3. To compile libsmb2 for the PS3 PPU, first install the PS3 toolchain and PSL1GHT SDK and set it up.

Then to build libsmb2, run $ cd lib $ make -f Makefile.PS3_PPU install

The process will copy the resulting libsmb2.a and the include/smb2 headers to your PSL1GHT SDK portlibs folder.