Develop Reference

C# Renci SshNet The server response contains a null character at position 0x0000002A

i have multiple Raspberries running with SSH server:
(OpenSSH_7.4p1 Raspbian-10+deb9u7, OpenSSL 1.0.2u 20 Dec 2019).
And if i try to connect via Renci SshNet, i get the following error message:
Renci.SshNet.Common.SshConnectionException: "The server response
contains a null character at position 0x0000002A:
00000000 53 53 48 2D 32 2E 30 2D 4F 70 65 6E 53 53 48 5F
SSH-2.0-OpenSSH_ 00000010 37 2E 34 70 31 20 52 61 73 70 62 69 61 6E
2D 31 7.4p1 Raspbian-1 00000020 30 2B 64 65 62 39 75 37 0A 00
0+deb9u7..
A server must not send a null character before the Protocol Version
Exchange is complete.
More information is available here:
https://www.rfc-editor.org/rfc/rfc4253#section-4.2"
SshClient scClient = new SshClient("123.123.123.123", "pi", "raspberry");
scClient.Connect();
is it possible to change the behavior of the ssh server,
or even better; can i tell renci ssh to ignore these protocol errors?

I think it's a problem of the latest SSH.NET NuGet Package. Currently the newest is 2020.0.0. And the one prior to that is 2020.0.0-beta1.
2020.0.0 gives me this problem, 2020.0.0-beta1 does not.
I will report this issue on https://github.com/sshnet/SSH.NET/issues
EDIT:
2020.0.1 just got published. That doesn't seem to have this problem. I recommend you to try that version.

I broke compatibility with Dotfuscator...please help me understand how

I've used Visual Studio 2010 to create Windows programs using C# for over 18 months now. For at least 12 of those months, I've been using the community edition of Dotfuscator to obfuscate all my programs. So far it's worked beautifully.
My latest project was released in its initial beta, compiled with Visual Studio 2010 for .NET Framework 4.0. That was obfuscated fine.
Since then I imported that to Visual Studio 2013, moved it to .NET Framework 4.5.1 and then kept working on my debugging version. When I was ready for another beta release to my users, I come to realize that the obfuscated version crashes in its release state. The unobsfucated version in release form does not crash. If I put the obfuscated EXE to replace the debugging version, Visual Studio gives me a warning but then runs the program just fine. No crash.
Even though I have an UnhandledException handler in Program.cs, the program just crashes and Windows gives me nothing more than a assembly line reference. Nothing I can use to narrow down the cause.
I have since moved the program back to Visual Studio 2010, .NET Framework 4.0, .NET Framework 4.0 Client Profile, tried all variations of settings in Dotfuscator. Tried the Pro Edition of Dotfuscator (14 day trial). Nothing. After obfuscation, crash with no usable information. Even if I excluse everything, so 0.0% is renamed, still get a crash.
I have some encryption information that needs to remain obfuscated as it has been for the past year or so. So I need to get obfuscation working. And I simply can't figure out what happened, or what I did, to make it stop working.
I would highly appreciate some guidance on what could have been. Thank you in advance.
EDIT: Here are the very basic and not very helpful error messages. I can follow a stack trace if one were provided. I also have my code covered in generous amounts of error catchers, plus a general AppDomain.CurrentDomain.UnhandledException handler. Still, this is all I get:
http://www.keepitfishy.com/files/crash1.jpg
http://www.keepitfishy.com/files/crash2.jpg
and this is part of the assembly code I get when I try to debug with Visual Studio, I marked the line that is supposed to be the culprit:
7362CEF1 E8 15 05 00 00 call 7362D40B
7362CEF6 59 pop ecx
7362CEF7 68 09 04 00 C0 push 0C0000409h
7362CEFC E8 16 05 00 00 call 7362D417
7362CF01 59 pop ecx
7362CF02 5D pop ebp
7362CF03 C3 ret
7362CF04 55 push ebp
7362CF05 8B EC mov ebp,esp
7362CF07 81 EC 24 03 00 00 sub esp,324h
7362CF0D 6A 17 push 17h
7362CF0F E8 37 DE C3 FF call 7326AD4B
7362CF14 85 C0 test eax,eax
7362CF16 74 05 je 7362CF1D
7362CF18 6A 02 push 2
7362CF1A 59 pop ecx
[error line]7362CF1B CD 29 int 29h[error line]
7362CF1D A3 58 61 75 73 mov dword ptr ds:[73756158h],eax
7362CF22 89 0D 54 61 75 73 mov dword ptr ds:[73756154h],ecx
7362CF28 89 15 50 61 75 73 mov dword ptr ds:[73756150h],edx
7362CF2E 89 1D 4C 61 75 73 mov dword ptr ds:[7375614Ch],ebx
7362CF34 89 35 48 61 75 73 mov dword ptr ds:[73756148h],esi
7362CF3A 89 3D 44 61 75 73 mov dword ptr ds:[73756144h],edi
7362CF40 8C 15 70 61 75 73 mov word ptr ds:[73756170h],ss
7362CF46 8C 0D 64 61 75 73 mov word ptr ds:[73756164h],cs
7362CF4C 8C 1D 40 61 75 73 mov word ptr ds:[73756140h],ds
7362CF52 8C 05 3C 61 75 73 mov word ptr ds:[7375613Ch],es
7362CF58 8C 25 38 61 75 73 mov word ptr ds:[73756138h],fs
7362CF5E 8C 2D 34 61 75 73 mov word ptr ds:[73756134h],gs
7362CF64 9C pushfd
7362CF65 8F 05 68 61 75 73 pop dword ptr ds:[73756168h]
7362CF6B 8B 45 00 mov eax,dword ptr [ebp]
7362CF6E A3 5C 61 75 73 mov dword ptr ds:[7375615Ch],eax
7362CF73 8B 45 04 mov eax,dword ptr [ebp+4]
7362CF76 A3 60 61 75 73 mov dword ptr ds:[73756160h],eax
7362CF7B 8D 45 08 lea eax,[ebp+8]
7362CF7E A3 6C 61 75 73 mov dword ptr ds:[7375616Ch],eax
7362CF83 8B 85 DC FC FF FF mov eax,dword ptr [ebp-324h]
If anyone can help me decipher that, I can perhaps track down the cause. Thanks.

Based off of the error dialog you posted, you are having stack issues in native code:
From MSDN:
0xC0000409 STATUS_STACK_BUFFER_OVERRUN
The system detected an
overrun of a stack-based buffer in this application. This overrun
could potentially allow a malicious user to gain control of this application.
Tracking down what is causing the overrun may be as simple as looking at the stack trace when the exception is thrown. Even though VS is not showing you code, it may still be able to identify the module and function on the top off the call stack.
If the issue is from corruption of the stack which has long since passed, you may need to approach the issue not from .Net, but as any other native application.
If you are not the author of any native components in your application, you may have a P/Invoke signature which is incorrect, be allocating an incorrectly sized buffer or struct which is passed to a P/Invoked function, or otherwise be calling native code incorrectly. Check your P/Invokes and make sure you have MDAs enabled.

Calling WAMS from Windows Forms application, freezes

I have a simple Windows Azure Mobile Service. I can get data from it by IOS, now I want to do it from Windows Forms application. My problem, it is not working. It is very strange, because when I call the same code from unit test from the same solution, it works, but when from a Windows Forms app, it freezes. Project targets .net 4.5 and references WAMS client lib by nuget.
Here is my code:
var testTable = WAMSService.MobileService.GetTable<HBCDataLib.WAMS.Test>();
var testResult = testTable.Take(1000).ToListAsync().Result;
By investigating it by Fiddler, i can see this:
CONNECT xy.azure-mobile.net:443 HTTP/1.1
Host: xy.azure-mobile.net
Connection: Keep-Alive
A SSLv3-compatible ClientHello handshake was found. Fiddler extracted the parameters below.
Version: 3.1 (TLS/1.0)
Random: 52 A0 0F 12 01 B1 9A 53 9A 2C 43 13 BD AD 44 6E 9D FB 2E A1 92 FC 5A C0 15 EB 72 30 B9 29 C4 B6
SessionID: empty
Extensions:
renegotiation_info 00
server_name xy.azure-mobile.net
elliptic_curves 00 05 00 18 00 20
ec_point_formats 01 00
SessionTicket TLS empty
Ciphers:
[002F] TLS_RSA_AES_128_SHA
[0035] TLS_RSA_AES_256_SHA
[0005] SSL_RSA_WITH_RC4_128_SHA
[000A] SSL_RSA_WITH_3DES_EDE_SHA
[C013] TLS1_CK_ECDHE_RSA_WITH_AES_128_CBC_SHA
[C014] TLS1_CK_ECDHE_RSA_WITH_AES_256_CBC_SHA
[C009] TLS1_CK_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
[C00A] TLS1_CK_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
[0032] TLS_DHE_DSS_WITH_AES_128_SHA
[0038] TLS_DHE_DSS_WITH_AES_256_SHA
[0013] SSL_DHE_DSS_WITH_3DES_EDE_SHA
[0004] SSL_RSA_WITH_RC4_128_MD5
Compression:
[00] NO_COMPRESSION
It is trivial, and works from unit test from the same solution. So, is it restricted (?!) to call WAMS from Windows forms app? Or what could be the problem?
Thanks in advance!

How to use a CNG (or AES-NI enabled instruction set) in .NET?

I Currently perform a large amount of encryption/decryption of text in c# using AES.
With a pure software system it can take quite a processor hit for a decent amount of time for the lots of datasets required to be decrypted. I know Intel have came out with their AES-NI instruction set and AMD has come out with similar.
I'm using .NET 4.0, I know that the windows CNG framework makes use of these instruction sets, but it does not appear that AesManaged in the .NET world does the same.
There is a fantastic project "CLR Security" which makes a gateway from .NET 3.5 to the windows CNG, however it hasn't been maintained in a year and I'd rather not (if possible) jump on a dying project.
There is a CNGProvider class in .NET 4 but there doesn't appear to be adequate documentation to cobble together a working decryption from it for AES.
Does anyone have experience with the topic they could point me in the right direction on how to get AES-NI implemented in a pure .NET environment, using pre-made classes, without having to do a p/invoke directly from c#? (It'd be fine if there was a wrapper class doing it, as long as it was maintained).

What about AesCryptoServiceProvider? It says that uses CAPI, and so
hopefully CNG if available. – Rup
This comment has helped tremendously, after doing some digging it looks like AesCryptoServiceProvider will use AES-NI if available. I cannot find any 'official' documentation from Microsoft on this however. When running simple timing benchmarks the difference is ~15x faster so either the API itself is massively optimized (which for a 15x increase is pretty nice optimization) or it uses the AES-NI instruction set.
Unfortunately I don't have a non AES-NI box to test on, but if I ever get one I'll update this thread with results.
So I'm pretty confident this is the API to use for AES-NI but cannot guarantee without further testing.

How to use a CNG (or AES-NI enabled instruction set) in .NET?
I'm going to focus on the AES-NI instruction set question. I found it to be interesting since I wondered it myself (for use in C and C++).
Microsoft added AES-NI support to Visual Studio 2008 SP1 (_MSC_FULL_VER >= 150030729). The earliest you can observe AES-NI in Microsoft products is circa 2008 since earlier compilers did not support it. That means Server 2008 has it, and possibly Windows Vista via a Service Pack, and above.
According to Does MS Crypto API supports AES and AES-NI processor instructions?, both rsaenh.dll and bcryptprimitives.dll have it. The statements made by IvanP tested on Windows 7 and Windows 10.
However, testing on Windows 8.1 reveals...
# Using a Developer Command prompt so dumpbin is on-path:
> dumpbin /disasm c:\Windows\System32\rsaenh.dll > rsaenh.dll.txt
> dumpbin /disasm c:\Windows\System32\bcryptprimitives.dll > bcryptprimitives.dll.txt
Then:
# Using a GitBash terminal for grep
$ grep -i aes rsaenh.dll.txt
$
And:
$ grep -i aes bcryptprimitives.dll.txt
000000018000234A: 66 0F 3A DF C0 00 aeskeygenassist xmm0,xmm0,0
0000000180002363: 66 0F 38 DB C0 aesimc xmm0,xmm0
000000018000237E: 66 0F 38 DC 41 10 aesenc xmm0,xmmword ptr [rcx+10h]
0000000180002384: 66 0F 38 DC 41 20 aesenc xmm0,xmmword ptr [rcx+20h]
000000018000238A: 66 0F 38 DC 41 30 aesenc xmm0,xmmword ptr [rcx+30h]
0000000180002390: 66 0F 38 DC 41 40 aesenc xmm0,xmmword ptr [rcx+40h]
0000000180002396: 66 0F 38 DC 41 50 aesenc xmm0,xmmword ptr [rcx+50h]
000000018000239C: 66 0F 38 DC 41 60 aesenc xmm0,xmmword ptr [rcx+60h]
00000001800023A2: 66 0F 38 DC 41 70 aesenc xmm0,xmmword ptr [rcx+70h]
00000001800023AF: 66 0F 38 DC 01 aesenc xmm0,xmmword ptr [rcx]
00000001800023B4: 66 0F 38 DC 41 10 aesenc xmm0,xmmword ptr [rcx+10h]
00000001800023C3: 66 41 0F 38 DD 02 aesenclast xmm0,xmmword ptr [r10]
000000018001936E: 66 0F 38 DC 41 10 aesenc xmm0,xmmword ptr [rcx+10h]
0000000180019374: 66 0F 38 DC 41 20 aesenc xmm0,xmmword ptr [rcx+20h]
000000018001937A: 66 0F 38 DC 41 30 aesenc xmm0,xmmword ptr [rcx+30h]
0000000180019380: 66 0F 38 DC 41 40 aesenc xmm0,xmmword ptr [rcx+40h]
0000000180019386: 66 0F 38 DC 41 50 aesenc xmm0,xmmword ptr [rcx+50h]
000000018001938C: 66 0F 38 DC 41 60 aesenc xmm0,xmmword ptr [rcx+60h]
0000000180019392: 66 0F 38 DC 41 70 aesenc xmm0,xmmword ptr [rcx+70h]
000000018001939F: 66 0F 38 DC 01 aesenc xmm0,xmmword ptr [rcx]
00000001800193A4: 66 0F 38 DC 41 10 aesenc xmm0,xmmword ptr [rcx+10h]
00000001800193B3: 66 41 0F 38 DD 02 aesenclast xmm0,xmmword ptr [r10]
000000018001952E: 66 0F 38 DE C4 aesdec xmm0,xmm4
0000000180019533: 66 0F 38 DE CC aesdec xmm1,xmm4
0000000180019538: 66 0F 38 DE D4 aesdec xmm2,xmm4
000000018001953D: 66 0F 38 DE DC aesdec xmm3,xmm4
000000018001954B: 66 0F 38 DF C4 aesdeclast xmm0,xmm4
0000000180019550: 66 0F 38 DF CC aesdeclast xmm1,xmm4
0000000180019555: 66 0F 38 DF D4 aesdeclast xmm2,xmm4
000000018001955A: 66 0F 38 DF DC aesdeclast xmm3,xmm4
000000018002E8B5: 66 0F 38 DE 41 10 aesdec xmm0,xmmword ptr [rcx+10h]
000000018002E8BB: 66 0F 38 DE 41 20 aesdec xmm0,xmmword ptr [rcx+20h]
000000018002E8C1: 66 0F 38 DE 41 30 aesdec xmm0,xmmword ptr [rcx+30h]
000000018002E8C7: 66 0F 38 DE 41 40 aesdec xmm0,xmmword ptr [rcx+40h]
000000018002E8CD: 66 0F 38 DE 41 50 aesdec xmm0,xmmword ptr [rcx+50h]
000000018002E8D3: 66 0F 38 DE 41 60 aesdec xmm0,xmmword ptr [rcx+60h]
000000018002E8D9: 66 0F 38 DE 41 70 aesdec xmm0,xmmword ptr [rcx+70h]
000000018002E8E6: 66 0F 38 DE 01 aesdec xmm0,xmmword ptr [rcx]
000000018002E8EB: 66 0F 38 DE 41 10 aesdec xmm0,xmmword ptr [rcx+10h]
000000018002E8FA: 66 41 0F 38 DF 02 aesdeclast xmm0,xmmword ptr [r10]
000000018003F458: 66 0F 38 DC E8 aesenc xmm5,xmm0
000000018003F45D: 66 0F 38 DC D8 aesenc xmm3,xmm0
000000018003F462: 66 0F 38 DC E0 aesenc xmm4,xmm0
000000018003F467: 66 0F 38 DC F0 aesenc xmm6,xmm0
000000018003F475: 66 0F 38 DD EF aesenclast xmm5,xmm7
000000018003F47A: 66 0F 38 DD DF aesenclast xmm3,xmm7
000000018003F47F: 66 0F 38 DD E7 aesenclast xmm4,xmm7
000000018003F492: 66 0F 38 DD F7 aesenclast xmm6,xmm7
So, on modern Windows, you need to use something that depends on bcryptprimitives.dll. I don't know what .Net primitives enlist bcryptprimitives.dll.
I also checked the following DLLs on Windows 8.1, and there were no AES-NI instructions present:
advapi32.dll
bcrypt.dll
crypt32.dll
cryptbase.dll
cryptcatsvc.dll
cryptdlg.dll
cryptdll.dll
cryptext.dll
cryptnet.dll
cryptowinrt.dll
cryptsp.dll
cryptsvc.dll
There's not much information about the subject on Microsoft's site. I got two hits from csp "aes-ni" site:microsoft.com, and 0 hits for csp "aesni" site:microsoft.com. Whatever is going on, Microsoft is keeping it secret.

I had worked in the earliest of chipsets that had these features. At that time Windows 7 didn't have the ability to work with AES. I resorted to the then available Ubuntu and used the Intel doc and with some inline assembly did a cpuid. That served my purpose of a training. Nevertheless one thing I learned is "Intel secure key" was made available almost at the same time as "AES-NI". So if I found RDRAND instruction in the chipset that means I "probably" had AES-NI. So this way the simplest I can do (but not quite documented) is
//PF_RDRAND_INSTRUCTION_AVAILABLE is not documented yet as part of MSDN API as of //this writing
IsProcessorFeaturePresent(PF_RDRAND_INSTRUCTION_AVAILABLE);
We can also use the CPU intrinsics this way
https://learn.microsoft.com/en-us/cpp/intrinsics/cpuid-cpuidex?view=vs-2019
Also see below document for more "proof".
https://csrc.nist.gov/csrc/media/projects/cryptographic-module-validation-program/documents/security-policies/140sp1894.pdf

mono, xsp2, npgsql Could not load assembly

I am writing web service and I have two classes:
<%# WebService Language="C#" Class="CairoParts.ProductsInfoWS.ProductsInfoWS.cs" %>
using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
namespace CairoParts.ProductsInfoWS
{
[WebService(Namespace = "http://localhost:8081/ProductsInfoWS")]
public class ProductsInfoWS : System.Web.Services.WebService
{
[WebMethod]
public List<string> ReceiveFile(byte[] bytes, string fileName, string supplier)
{
}
{
}
and Database.cs:
using System;
using System.Data;
using System.Configuration;
using Npgsql;
namespace CairoParts.ProductsInfoWS
{
public class Database
{
}
}
When i fire xsp2 and type in browser http://localhost:8081/ProductsInfoWS.asmx i get this error:
/usr/lib/mono/2.0/gmcs.exe:22858): WARNING **: The following assembly referenced from /tmp/vadmin-temp-aspnet-0/b8083b1b/assembly/shadow/94001eba/43c949ff_d7c95745_00000001/CairoParts.ProductsInfoWS.dll could not be loaded:
Assembly: Npgsql (assemblyref_index=2)
Version: 2.0.6.0
Public Key: 5d8b90d52f46fda7
The assembly was not found in the Global Assembly Cache, a path listed in the MONO_PATH environment variable, or in the location of the executing assembly (/tmp/vadmin-temp-aspnet-0/b8083b1b/assembly/shadow/94001eba/43c949ff_d7c95745_00000001).
My Npgsql.dll file is in 'bin' directory. Whats wrong...

It could be that the dll Npgsql.dll is strong-name signed and therefore needs to be placed in the global assembly cache (GAC), have you tried copying the dll into the location where the GAC is?
Hope this helps,
Best regards,
Tom.

Run:
monodis --assembly bin/Npgsql.dll
to verify that your assembly has the same version and public key that is referenced from CairoParts.ProductsInfoWS.dll.
In my local Mono installation compiled from sources, I have 3 directories in the gac for Npgsql:
1.0.5000.0__5d8b90d52f46fda7
2.0.0.0__5d8b90d52f46fda7
4.0.0.0__5d8b90d52f46fda7
and none of them has version 2.0.6.0.
Perhaps you need to recompile CairoParts.ProductsInfoWS.dll so that it references the assemblies present in your system.

I recompiled my project and run command that you have suggested, here's the output:
Assembly Table
Name: Npgsql
Hash Algoritm: 0x00008004
Version: 2.0.6.0
Flags: 0x00000001
PublicKey: BlobPtr (0x000020b1)
Dump:
0x00000000: 00 24 00 00 04 80 00 00 94 00 00 00 06 02 00 00
0x00000010: 00 24 00 00 52 53 41 31 00 04 00 00 01 00 01 00
0x00000020: 2B 3C 59 0B 2A 4E 3D 34 7E 68 78 DC 0F F4 D2 1E
0x00000030: B0 56 A5 04 20 25 0C 66 17 04 43 30 70 1D 35 C9
0x00000040: 80 78 A5 DF 97 A6 2D 83 C9 A2 DB 2D 07 25 23 A8
0x00000050: FC 49 13 98 25 4C 6B 89 32 9B 8C 1D CE F4 3A 1E
0x00000060: 7A A1 61 53 BC EA 2A E9 A4 71 14 56 24 82 6F 60
0x00000070: D7 C8 E7 1C D0 25 B5 54 A0 17 7B D9 35 A7 80 96
0x00000080: 29 F0 A7 AF C7 78 EB B4 AD 03 3E 1B F5 12 C1 A9
0x00000090: C6 CE EA 26 B0 77 BC 46 CA C9 38 00 43 5E 77 EE
Culture:
It's look like npgsql versions are ok, but webservice still yields the same error.
I kinda solve this issue by putting Database class in webservice asmx file, but it's more like workaround then a real solution...