4

我正在为 iOS 做 unix 服务器 ssh 仿真。在谈判过程中，我遇到了许多障碍，并且仍在与这些障碍作斗争。最新的一个是关于 SSH2_MSG_KEX_DH_GEX_REPLY 数据包数据，我收到错误的数据包长度（可能是多余的填充）。整个流程的包描述如下：

Client : connection with aix.polarhome.com with port 775 (changed port for ssh) using GCDAsyncSocket
Server : SSH-2.0-OpenSSH_6.0
Client : send SSH-2.0-OpenSSH_6.0

(Rest packet will follow BPP protocol)
Server : SSH2_MSG_KEXINIT with set of supported algorithms
Client : SSH2_MSG_KEXINIT with set of common algorithms 

Client : SSH2_MSG_KEX_DH_GEX_REQUEST_OLD 
         code: 
    SignedByte sendByte[1920];
    int writeIndex = 0;

    minGroupLength = 1024;
    prefGroupLength = 1024;
    maxGroupLength = 4096;

    sendByte[writeIndex++] = SSH2_MSG_KEX_DH_GEX_REQUEST_OLD;

    [self write32BitInteger:prefGroupLength toPacket:sendByte fromIndex:writeIndex];
    writeIndex += 4;

    [self sendSSHBinaryPacketPayload:sendByte toLength:writeIndex];
    writeIndex = 0;

Server : SSH2_MSG_KEX_DH_GEX_GROUP

client -> fetch values of p and g 
         compute value of e (1 < e < (p-1)/2)

Client : SSH2_MSG_KEX_DH_GEX_INIT
         Code
SignedByte sendByte[1920];
    int writeIndex = 0;

NSInteger eByteCount = [[e description] stringByReplacingOccurrencesOfString:@" " withString:@""].length/2;

sendByte[writeIndex++] = SSH2_MSG_KEX_DH_GEX_INIT;

[self write32BitInteger:eByteCount toPacket:sendByte fromIndex:writeIndex];
writeIndex += 4;

Byte eBytes[eByteCount];
NSInteger length = [self getBytes:eBytes fromBigInteger:e];
for (int i = 0; i < length; i++) {
    sendByte[writeIndex++] = eBytes[i];
}

[self sendSSHBinaryPacketPayload:sendByte toLength:writeIndex];
writeIndex = 0;

Server : SSH2_MSG_KEX_DH_GEX_REPLY
Total length : 720 
Packet length (4 bytes): 00 00 02 bc (700 which should be 720 - 4 = 716) Don't Know why this 700?

client -> read host key and verify it
         read value of f
         read signature and verify it

Client : SSH2_MSG_NEWKEYS

现在在发送最后一个数据包服务器模拟并且没有数据返回 SSH2_MSG_NEWKEYS 之后。

我查看了其他 ssh 模拟器的代码，但没有一个有帮助。我完全无能为力，我该怎么办，请帮忙，我真的很沮丧。

4

1 回答 1

0

每@revinder在评论中：

我解决了我自己的服务器发送两个数据包合并为一个，SSH2_MSG_KEX_DH_GEX_REPLY 和 SSH2_MSG_NEWKEYS。

于 2015-09-10T18:50:54.783 回答