Implement Zlib compression, in both SSH1 and SSH2.

[originally from svn r792]

Makefile

@@ -69,7 +69,7 @@ MOBJ2 = tree234.$(OBJ)
 ##-- objects putty pscp plink
 OBJS1 = sshcrc.$(OBJ) sshdes.$(OBJ) sshmd5.$(OBJ) sshrsa.$(OBJ) sshrand.$(OBJ)
 OBJS2 = sshsha.$(OBJ) sshblowf.$(OBJ) noise.$(OBJ) sshdh.$(OBJ) sshdss.$(OBJ)
-OBJS3 = sshbn.$(OBJ) sshpubk.$(OBJ) ssh.$(OBJ) pageantc.$(OBJ)
+OBJS3 = sshbn.$(OBJ) sshpubk.$(OBJ) ssh.$(OBJ) pageantc.$(OBJ) sshzlib.$(OBJ)
 ##-- objects pageant
 PAGE1 = pageant.$(OBJ) sshrsa.$(OBJ) sshpubk.$(OBJ) sshdes.$(OBJ) sshbn.$(OBJ)
 PAGE2 = sshmd5.$(OBJ) version.$(OBJ) tree234.$(OBJ)
@@ -229,6 +229,7 @@ sshdh.$(OBJ): sshdh.c ssh.h
 sshdss.$(OBJ): sshdss.c ssh.h
 sshbn.$(OBJ): sshbn.c ssh.h
 sshpubk.$(OBJ): sshpubk.c ssh.h
+sshzlib.$(OBJ): sshzlib.c ssh.h
 scp.$(OBJ): scp.c putty.h network.h winstuff.h
 version.$(OBJ): version.c
 be_all.$(OBJ): be_all.c

putty.h

@@ -140,6 +140,7 @@ typedef struct {
     /* SSH options */
     char remote_cmd[512];
     int nopty;
+    int compression;
     int agentfwd;
     enum { CIPHER_3DES, CIPHER_BLOWFISH, CIPHER_DES } cipher;
     char keyfile[FILENAME_MAX];

settings.c

@@ -66,6 +66,7 @@ void save_settings (char *section, int do_host, Config *cfg) {
     }
     write_setting_s (sesskey, "UserName", cfg->username);
     write_setting_i (sesskey, "NoPTY", cfg->nopty);
+    write_setting_i (sesskey, "Compression", cfg->compression);
     write_setting_i (sesskey, "AgentFwd", cfg->agentfwd);
     write_setting_s (sesskey, "RemoteCmd", cfg->remote_cmd);
     write_setting_s (sesskey, "Cipher", cfg->cipher == CIPHER_BLOWFISH ? "blowfish" :
@@ -186,6 +187,7 @@ void load_settings (char *section, int do_host, Config *cfg) {
     }
     gpps (sesskey, "UserName", "", cfg->username, sizeof(cfg->username));
     gppi (sesskey, "NoPTY", 0, &cfg->nopty);
+    gppi (sesskey, "Compression", 0, &cfg->compression);
     gppi (sesskey, "AgentFwd", 0, &cfg->agentfwd);
     gpps (sesskey, "RemoteCmd", "", cfg->remote_cmd, sizeof(cfg->remote_cmd));
     {

ssh.c

@@ -51,6 +51,7 @@
 #define SSH1_CMSG_EXIT_CONFIRMATION               33   /* 0x21 */
 #define SSH1_MSG_IGNORE                           32   /* 0x20 */
 #define SSH1_MSG_DEBUG                            36   /* 0x24 */
+#define SSH1_CMSG_REQUEST_COMPRESSION             37   /* 0x25 */
 #define SSH1_CMSG_AUTH_TIS                        39   /* 0x27 */
 #define SSH1_SMSG_AUTH_TIS_CHALLENGE              40   /* 0x28 */
 #define SSH1_CMSG_AUTH_TIS_RESPONSE               41   /* 0x29 */
@@ -186,10 +187,19 @@ const static struct ssh_mac *macs[] = {
 const static struct ssh_mac *buggymacs[] = {
     &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none };
 
+static void ssh_comp_none_init(void) { }
+static int ssh_comp_none_block(unsigned char *block, int len,
+			       unsigned char **outblock, int *outlen) {
+    return 0;
+}
 const static struct ssh_compress ssh_comp_none = {
-    "none"
+    "none",
+    ssh_comp_none_init, ssh_comp_none_block,
+    ssh_comp_none_init, ssh_comp_none_block
 };
-const static struct ssh_compress *compressions[] = { &ssh_comp_none };
+extern const struct ssh_compress ssh_zlib;
+const static struct ssh_compress *compressions[] = {
+    &ssh_zlib, &ssh_comp_none };
 
 /*
  * 2-3-4 tree storing channels.
@@ -226,6 +236,7 @@ static SHA_State exhash;
 static Socket s = NULL;
 
 static unsigned char session_key[32];
+static int ssh1_compressing;
 static const struct ssh_cipher *cipher = NULL;
 static const struct ssh_cipher *cscipher = NULL;
 static const struct ssh_cipher *sccipher = NULL;
@@ -373,9 +384,6 @@ next_packet:
     debug(("\r\n"));
 #endif
 
-    pktin.type = pktin.data[st->pad];
-    pktin.body = pktin.data + st->pad + 1;
-
     st->realcrc = crc32(pktin.data, st->biglen-4);
     st->gotcrc = GET_32BIT(pktin.data+st->biglen-4);
     if (st->gotcrc != st->realcrc) {
@@ -383,6 +391,39 @@ next_packet:
         crReturn(0);
     }
 
+    pktin.body = pktin.data + st->pad + 1;
+
+    if (ssh1_compressing) {
+	unsigned char *decompblk;
+	int decomplen;
+#if 0
+	int i;
+	debug(("Packet payload pre-decompression:\n"));
+	for (i = -1; i < pktin.length; i++)
+	    debug(("  %02x", (unsigned char)pktin.body[i]));
+	debug(("\r\n"));
+#endif
+	zlib_decompress_block(pktin.body-1, pktin.length+1,
+			      &decompblk, &decomplen);
+
+	if (pktin.maxlen < st->pad + decomplen) {
+	    pktin.maxlen = st->pad + decomplen;
+	    pktin.data = realloc(pktin.data, pktin.maxlen+APIEXTRA);
+	    if (!pktin.data)
+		fatalbox("Out of memory");
+	}
+
+	memcpy(pktin.body-1, decompblk, decomplen);
+	free(decompblk);
+	pktin.length = decomplen-1;
+#if 0
+	debug(("Packet payload post-decompression:\n"));
+	for (i = -1; i < pktin.length; i++)
+	    debug(("  %02x", (unsigned char)pktin.body[i]));
+	debug(("\r\n"));
+#endif
+    }
+
     if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
         pktin.type == SSH1_SMSG_STDERR_DATA ||
         pktin.type == SSH1_MSG_DEBUG ||
@@ -395,6 +436,8 @@ next_packet:
         }
     }
 
+    pktin.type = pktin.body[-1];
+
     if (pktin.type == SSH1_MSG_DEBUG) {
 	/* log debug message */
 	char buf[80];
@@ -515,6 +558,34 @@ next_packet:
     }
     st->incoming_sequence++;               /* whether or not we MACed */
 
+    /*
+     * Decompress packet payload.
+     */
+    {
+	unsigned char *newpayload;
+	int newlen;
+	if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5,
+					 &newpayload, &newlen)) {
+	    if (pktin.maxlen < newlen+5) {
+		pktin.maxlen = newlen+5;
+		pktin.data = (pktin.data == NULL ? malloc(pktin.maxlen+APIEXTRA) :
+			      realloc(pktin.data, pktin.maxlen+APIEXTRA));
+		if (!pktin.data)
+		    fatalbox("Out of memory");
+	    }
+	    pktin.length = 5 + newlen;
+	    memcpy(pktin.data+5, newpayload, newlen);
+#if 0
+	    debug(("Post-decompression payload:\r\n"));
+	    for (st->i = 0; st->i < newlen; st->i++)
+		debug(("  %02x", (unsigned char)pktin.data[5+st->i]));
+	    debug(("\r\n"));
+#endif
+
+	    free(newpayload);
+	}
+    }
+
     pktin.savedpos = 6;
     pktin.type = pktin.data[5];
 
@@ -524,7 +595,7 @@ next_packet:
     crFinish(0);
 }
 
-static void s_wrpkt_start(int type, int len) {
+static void ssh1_pktout_size(int len) {
     int pad, biglen;
 
     len += 5;			       /* type and CRC */
@@ -546,20 +617,46 @@ static void s_wrpkt_start(int type, int len) {
 	if (!pktout.data)
 	    fatalbox("Out of memory");
     }
-
-    pktout.type = type;
     pktout.body = pktout.data+4+pad+1;
 }
 
+static void s_wrpkt_start(int type, int len) {
+    ssh1_pktout_size(len);
+    pktout.type = type;
+}
+
 static void s_wrpkt(void) {
     int pad, len, biglen, i;
     unsigned long crc;
 
+    pktout.body[-1] = pktout.type;
+
+    if (ssh1_compressing) {
+	unsigned char *compblk;
+	int complen;
+#if 0
+	debug(("Packet payload pre-compression:\n"));
+	for (i = -1; i < pktout.length; i++)
+	    debug(("  %02x", (unsigned char)pktout.body[i]));
+	debug(("\r\n"));
+#endif
+	zlib_compress_block(pktout.body-1, pktout.length+1,
+			    &compblk, &complen);
+	ssh1_pktout_size(complen-1);
+	memcpy(pktout.body-1, compblk, complen);
+	free(compblk);
+#if 0
+	debug(("Packet payload post-compression:\n"));
+	for (i = -1; i < pktout.length; i++)
+	    debug(("  %02x", (unsigned char)pktout.body[i]));
+	debug(("\r\n"));
+#endif
+    }
+
     len = pktout.length + 5;	       /* type and CRC */
     pad = 8 - (len%8);
     biglen = len + pad;
 
-    pktout.body[-1] = pktout.type;
     for (i=0; i<pad; i++)
 	pktout.data[i+4] = random_byte();
     crc = crc32(pktout.data+4, biglen-4);
@@ -767,6 +864,26 @@ static void ssh2_pkt_send(void) {
     int cipherblk, maclen, padding, i;
     static unsigned long outgoing_sequence = 0;
 
+    /*
+     * Compress packet payload.
+     */
+#if 0
+    debug(("Pre-compression payload:\r\n"));
+    for (i = 5; i < pktout.length; i++)
+	debug(("  %02x", (unsigned char)pktout.data[i]));
+    debug(("\r\n"));
+#endif
+    {
+	unsigned char *newpayload;
+	int newlen;
+	if (cscomp && cscomp->compress(pktout.data+5, pktout.length-5,
+				       &newpayload, &newlen)) {
+	    pktout.length = 5;
+	    ssh2_pkt_adddata(newpayload, newlen);
+	    free(newpayload);
+	}
+    }
+
     /*
      * Add padding. At least four bytes, and must also bring total
      * length (minus MAC) up to a multiple of the block size.
@@ -1637,6 +1754,21 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
 	logevent("Allocated pty");
     }
 
+    if (cfg.compression) {
+        send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
+        do { crReturnV; } while (!ispkt);
+        if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
+            bombout(("Protocol confusion"));
+            crReturnV;
+        } else if (pktin.type == SSH1_SMSG_FAILURE) {
+            c_write("Server refused to compress\r\n", 32);
+        }
+	logevent("Started compression");
+	ssh1_compressing = TRUE;
+	zlib_compress_init();
+	zlib_decompress_init();
+    }
+
     if (*cfg.remote_cmd)
         send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END);
     else
@@ -1845,12 +1977,13 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
     static unsigned char exchange_hash[20];
     static unsigned char keyspace[40];
     static const struct ssh_cipher *preferred_cipher;
+    static const struct ssh_compress *preferred_comp;
 
     crBegin;
     random_init();
 
     /*
-     * Set up the preferred cipher.
+     * Set up the preferred cipher and compression.
      */
     if (cfg.cipher == CIPHER_BLOWFISH) {
         preferred_cipher = &ssh_blowfish_ssh2;
@@ -1863,6 +1996,10 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
         /* Shouldn't happen, but we do want to initialise to _something_. */
         preferred_cipher = &ssh_3des_ssh2;
     }
+    if (cfg.compression)
+	preferred_comp = &ssh_zlib;
+    else
+	preferred_comp = &ssh_comp_none;
 
     /*
      * Be prepared to work around the buggy MAC problem.
@@ -1925,16 +2062,18 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
     }
     /* List client->server compression algorithms. */
     ssh2_pkt_addstring_start();
-    for (i = 0; i < lenof(compressions); i++) {
+    for (i = 0; i < lenof(compressions)+1; i++) {
-        ssh2_pkt_addstring_str(compressions[i]->name);
+        const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
-        if (i < lenof(compressions)-1)
+        ssh2_pkt_addstring_str(c->name);
+        if (i < lenof(compressions))
             ssh2_pkt_addstring_str(",");
     }
     /* List server->client compression algorithms. */
     ssh2_pkt_addstring_start();
-    for (i = 0; i < lenof(compressions); i++) {
+    for (i = 0; i < lenof(compressions)+1; i++) {
-        ssh2_pkt_addstring_str(compressions[i]->name);
+        const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
-        if (i < lenof(compressions)-1)
+        ssh2_pkt_addstring_str(c->name);
+        if (i < lenof(compressions))
             ssh2_pkt_addstring_str(",");
     }
     /* List client->server languages. Empty list. */
@@ -2007,16 +2146,18 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
         }
     }
     ssh2_pkt_getstring(&str, &len);    /* client->server compression */
-    for (i = 0; i < lenof(compressions); i++) {
+    for (i = 0; i < lenof(compressions)+1; i++) {
-        if (in_commasep_string(compressions[i]->name, str, len)) {
+        const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
-            cscomp_tobe = compressions[i];
+        if (in_commasep_string(c->name, str, len)) {
+            cscomp_tobe = c;
             break;
         }
     }
     ssh2_pkt_getstring(&str, &len);    /* server->client compression */
-    for (i = 0; i < lenof(compressions); i++) {
+    for (i = 0; i < lenof(compressions)+1; i++) {
-        if (in_commasep_string(compressions[i]->name, str, len)) {
+        const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
-            sccomp_tobe = compressions[i];
+        if (in_commasep_string(c->name, str, len)) {
+            sccomp_tobe = c;
             break;
         }
     }
@@ -2105,6 +2246,8 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
     scmac = scmac_tobe;
     cscomp = cscomp_tobe;
     sccomp = sccomp_tobe;
+    cscomp->compress_init();
+    sccomp->decompress_init();
     /*
      * Set IVs after keys.
      */

ssh.h

@@ -137,6 +137,12 @@ struct ssh_hostkey {
 
 struct ssh_compress {
     char *name;
+    void (*compress_init)(void);
+    int (*compress)(unsigned char *block, int len,
+		    unsigned char **outblock, int *outlen);
+    void (*decompress_init)(void);
+    int (*decompress)(unsigned char *block, int len,
+		      unsigned char **outblock, int *outlen);
 };
 
 #ifndef MSCRYPTOAPI
@@ -197,3 +203,13 @@ int rsa_generate(struct RSAKey *key, struct RSAAux *aux, int bits,
                  progfn_t pfn, void *pfnparam);
 Bignum primegen(int bits, int modulus, int residue,
                 int phase, progfn_t pfn, void *pfnparam);
+
+/*
+ * zlib compression.
+ */
+void zlib_compress_init(void);
+void zlib_decompress_init(void);
+int zlib_compress_block(unsigned char *block, int len,
+			unsigned char **outblock, int *outlen);
+int zlib_decompress_block(unsigned char *block, int len,
+			  unsigned char **outblock, int *outlen);

win_res.rc

@@ -31,24 +31,24 @@ BEGIN
 END
 
 /* Accelerators used: aco */
-IDD_MAINBOX DIALOG DISCARDABLE 0, 0, 280, 232
+IDD_MAINBOX DIALOG DISCARDABLE 0, 0, 280, 242
 STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENU
 CAPTION "PuTTY Configuration"
 FONT 8, "MS Sans Serif"
 BEGIN
-    DEFPUSHBUTTON "&Open", IDOK, 184, 215, 44, 14
+    DEFPUSHBUTTON "&Open", IDOK, 184, 225, 44, 14
-    PUSHBUTTON "&Cancel", IDCANCEL, 231, 215, 44, 14
+    PUSHBUTTON "&Cancel", IDCANCEL, 231, 225, 44, 14
-    PUSHBUTTON "&About", IDC_ABOUT, 3, 215, 44, 14, NOT WS_TABSTOP
+    PUSHBUTTON "&About", IDC_ABOUT, 3, 225, 44, 14, NOT WS_TABSTOP
 END
 
 /* Accelerators used: ac */
-IDD_RECONF DIALOG DISCARDABLE 0, 0, 280, 232
+IDD_RECONF DIALOG DISCARDABLE 0, 0, 280, 242
 STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENU
 CAPTION "PuTTY Reconfiguration"
 FONT 8, "MS Sans Serif"
 BEGIN
-    DEFPUSHBUTTON "&Apply", IDOK, 184, 215, 44, 14
+    DEFPUSHBUTTON "&Apply", IDOK, 184, 225, 44, 14
-    PUSHBUTTON "&Cancel", IDCANCEL, 231, 215, 44, 14
+    PUSHBUTTON "&Cancel", IDCANCEL, 231, 225, 44, 14
 END
 
 /* Accelerators used: co */

windlg.c

@@ -326,6 +326,7 @@ enum { IDCX_ABOUT = IDC_ABOUT, IDCX_TVSTATIC, IDCX_TREEVIEW, controlstartvalue,
     IDC_AGENTFWD,
     IDC_CMDSTATIC,
     IDC_CMDEDIT,
+    IDC_COMPRESS,
     sshpanelend,
 
     selectionpanelstart,
@@ -486,6 +487,7 @@ static void init_dlg_ctrls(HWND hwnd) {
     SetDlgItemText (hwnd, IDC_TTEDIT, cfg.termtype);
     SetDlgItemText (hwnd, IDC_LOGEDIT, cfg.username);
     CheckDlgButton (hwnd, IDC_NOPTY, cfg.nopty);
+    CheckDlgButton (hwnd, IDC_COMPRESS, cfg.compression);
     CheckDlgButton (hwnd, IDC_BUGGYMAC, cfg.buggymac);
     CheckDlgButton (hwnd, IDC_AGENTFWD, cfg.agentfwd);
     CheckRadioButton (hwnd, IDC_CIPHER3DES, IDC_CIPHERDES,
@@ -631,7 +633,7 @@ static int GenericMainDlgProc (HWND hwnd, UINT msg,
 	    SendMessage(tvstatic, WM_SETFONT, font, MAKELPARAM(TRUE, 0));
 
             r.left = 3; r.right = r.left + 75;
-            r.top = 13; r.bottom = r.top + 196;
+            r.top = 13; r.bottom = r.top + 206;
             MapDialogRect(hwnd, &r);
             treeview = CreateWindowEx(WS_EX_CLIENTEDGE, WC_TREEVIEW, "",
                                       WS_CHILD | WS_VISIBLE |
@@ -972,6 +974,7 @@ static int GenericMainDlgProc (HWND hwnd, UINT msg,
                 beginbox(&cp, "Protocol options",
                          IDC_BOX_SSH3, IDC_BOXT_SSH3);
 		checkbox(&cp, "Don't allocate a &pseudo-terminal", IDC_NOPTY);
+		checkbox(&cp, "Enable compr&ession", IDC_COMPRESS);
 		radioline(&cp, "Preferred SSH protocol version:",
 			  IDC_SSHPROTSTATIC, 2,
 			  "&1", IDC_SSHPROT1, "&2", IDC_SSHPROT2, NULL);
@@ -1497,6 +1500,11 @@ static int GenericMainDlgProc (HWND hwnd, UINT msg,
 		HIWORD(wParam) == BN_DOUBLECLICKED)
 		cfg.nopty = IsDlgButtonChecked (hwnd, IDC_NOPTY);
 	    break;
+	  case IDC_COMPRESS:
+	    if (HIWORD(wParam) == BN_CLICKED ||
+		HIWORD(wParam) == BN_DOUBLECLICKED)
+		cfg.compression = IsDlgButtonChecked (hwnd, IDC_COMPRESS);
+	    break;
 	  case IDC_BUGGYMAC:
 	    if (HIWORD(wParam) == BN_CLICKED ||
 		HIWORD(wParam) == BN_DOUBLECLICKED)