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,并且仍在与之抗争。最新消息之一是有关SSH2_MSG_KEX_DH_GEX_REPLY数据包的数据,在该数据包中我收到了错误的数据包长度(可能是多余的填充)。整个过程的报文描述如下:

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,在发送完最后一个数据包服务器模拟之后,没有数据返回SSH2_MSG_NEWKEYS。

我研究了其他ssh模拟器的代码,但没有一个有帮助。
我完全一无所知,我该怎么办,请帮忙,我真的很沮丧。

最佳答案

每个@revinder在评论中:

我解决了它,我自己的服务器发送了两个合并为SSH2_MSG_KEX_DH_GEX_REPLY和SSH2_MSG_NEWKEYS的数据包。

10-06 13:07