+ int size;
+ int c;
+
+ size = 128;
+ text = snewn(size, char);
+ len = 0;
+ text[len] = '\0';
+
+ while (1) {
+ c = fgetc(fp);
+ if (c == '\r' || c == '\n' || c == EOF) {
+ if (c != EOF) {
+ c = fgetc(fp);
+ if (c != '\r' && c != '\n')
+ ungetc(c, fp);
+ }
+ return text;
+ }
+ if (len + 1 >= size) {
+ size += 128;
+ text = sresize(text, size, char);
+ }
+ text[len++] = c;
+ text[len] = '\0';
+ }
+}
+
+int base64_decode_atom(char *atom, unsigned char *out)
+{
+ int vals[4];
+ int i, v, len;
+ unsigned word;
+ char c;
+
+ for (i = 0; i < 4; i++) {
+ c = atom[i];
+ if (c >= 'A' && c <= 'Z')
+ v = c - 'A';
+ else if (c >= 'a' && c <= 'z')
+ v = c - 'a' + 26;
+ else if (c >= '0' && c <= '9')
+ v = c - '0' + 52;
+ else if (c == '+')
+ v = 62;
+ else if (c == '/')
+ v = 63;
+ else if (c == '=')
+ v = -1;
+ else
+ return 0; /* invalid atom */
+ vals[i] = v;
+ }
+
+ if (vals[0] == -1 || vals[1] == -1)
+ return 0;
+ if (vals[2] == -1 && vals[3] != -1)
+ return 0;
+
+ if (vals[3] != -1)
+ len = 3;
+ else if (vals[2] != -1)
+ len = 2;
+ else
+ len = 1;
+
+ word = ((vals[0] << 18) |
+ (vals[1] << 12) | ((vals[2] & 0x3F) << 6) | (vals[3] & 0x3F));
+ out[0] = (word >> 16) & 0xFF;
+ if (len > 1)
+ out[1] = (word >> 8) & 0xFF;
+ if (len > 2)
+ out[2] = word & 0xFF;
+ return len;
+}
+
+static unsigned char *read_blob(FILE * fp, int nlines, int *bloblen)
+{
+ unsigned char *blob;
+ char *line;
+ int linelen, len;
+ int i, j, k;
+
+ /* We expect at most 64 base64 characters, ie 48 real bytes, per line. */
+ blob = snewn(48 * nlines, unsigned char);
+ len = 0;
+ for (i = 0; i < nlines; i++) {
+ line = read_body(fp);
+ if (!line) {
+ sfree(blob);
+ return NULL;
+ }
+ linelen = strlen(line);
+ if (linelen % 4 != 0 || linelen > 64) {
+ sfree(blob);
+ sfree(line);
+ return NULL;
+ }
+ for (j = 0; j < linelen; j += 4) {
+ k = base64_decode_atom(line + j, blob + len);
+ if (!k) {
+ sfree(line);
+ sfree(blob);
+ return NULL;
+ }
+ len += k;
+ }
+ sfree(line);
+ }
+ *bloblen = len;
+ return blob;
+}
+
+/*
+ * Magic error return value for when the passphrase is wrong.
+ */
+struct ssh2_userkey ssh2_wrong_passphrase = {
+ NULL, NULL, NULL
+};
+
+const struct ssh_signkey *find_pubkey_alg(const char *name)
+{
+ if (!strcmp(name, "ssh-rsa"))
+ return &ssh_rsa;
+ else if (!strcmp(name, "ssh-dss"))
+ return &ssh_dss;
+ else
+ return NULL;
+}
+
+struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
+ char *passphrase, const char **errorstr)
+{
+ FILE *fp;
+ char header[40], *b, *encryption, *comment, *mac;
+ const struct ssh_signkey *alg;
+ struct ssh2_userkey *ret;
+ int cipher, cipherblk;
+ unsigned char *public_blob, *private_blob;
+ int public_blob_len, private_blob_len;
+ int i, is_mac, old_fmt;
+ int passlen = passphrase ? strlen(passphrase) : 0;
+ const char *error = NULL;
+
+ ret = NULL; /* return NULL for most errors */
+ encryption = comment = mac = NULL;
+ public_blob = private_blob = NULL;
+
+ fp = f_open(filename, "rb", FALSE);
+ if (!fp) {
+ error = "can't open file";
+ goto error;
+ }
+
+ /* Read the first header line which contains the key type. */
+ if (!read_header(fp, header))
+ goto error;
+ if (0 == strcmp(header, "PuTTY-User-Key-File-2")) {
+ old_fmt = 0;
+ } else if (0 == strcmp(header, "PuTTY-User-Key-File-1")) {
+ /* this is an old key file; warn and then continue */
+ old_keyfile_warning();
+ old_fmt = 1;
+ } else if (0 == strncmp(header, "PuTTY-User-Key-File-", 20)) {
+ /* this is a key file FROM THE FUTURE; refuse it, but with a
+ * more specific error message than the generic one below */
+ error = "PuTTY key format too new";
+ goto error;
+ } else {
+ error = "not a PuTTY SSH-2 private key";
+ goto error;
+ }
+ error = "file format error";
+ if ((b = read_body(fp)) == NULL)
+ goto error;
+ /* Select key algorithm structure. */
+ alg = find_pubkey_alg(b);
+ if (!alg) {
+ sfree(b);
+ goto error;
+ }
+ sfree(b);
+
+ /* Read the Encryption header line. */
+ if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))
+ goto error;
+ if ((encryption = read_body(fp)) == NULL)
+ goto error;
+ if (!strcmp(encryption, "aes256-cbc")) {
+ cipher = 1;
+ cipherblk = 16;
+ } else if (!strcmp(encryption, "none")) {
+ cipher = 0;
+ cipherblk = 1;
+ } else {
+ goto error;
+ }
+
+ /* Read the Comment header line. */
+ if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))
+ goto error;
+ if ((comment = read_body(fp)) == NULL)
+ goto error;
+
+ /* Read the Public-Lines header line and the public blob. */
+ if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))
+ goto error;
+ if ((b = read_body(fp)) == NULL)
+ goto error;
+ i = atoi(b);
+ sfree(b);
+ if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)
+ goto error;
+
+ /* Read the Private-Lines header line and the Private blob. */
+ if (!read_header(fp, header) || 0 != strcmp(header, "Private-Lines"))
+ goto error;
+ if ((b = read_body(fp)) == NULL)
+ goto error;
+ i = atoi(b);
+ sfree(b);
+ if ((private_blob = read_blob(fp, i, &private_blob_len)) == NULL)
+ goto error;
+
+ /* Read the Private-MAC or Private-Hash header line. */
+ if (!read_header(fp, header))
+ goto error;
+ if (0 == strcmp(header, "Private-MAC")) {
+ if ((mac = read_body(fp)) == NULL)
+ goto error;
+ is_mac = 1;
+ } else if (0 == strcmp(header, "Private-Hash") && old_fmt) {
+ if ((mac = read_body(fp)) == NULL)
+ goto error;
+ is_mac = 0;
+ } else
+ goto error;
+
+ fclose(fp);
+ fp = NULL;
+
+ /*
+ * Decrypt the private blob.
+ */
+ if (cipher) {
+ unsigned char key[40];
+ SHA_State s;
+
+ if (!passphrase)
+ goto error;
+ if (private_blob_len % cipherblk)
+ goto error;
+
+ SHA_Init(&s);
+ SHA_Bytes(&s, "\0\0\0\0", 4);
+ SHA_Bytes(&s, passphrase, passlen);
+ SHA_Final(&s, key + 0);
+ SHA_Init(&s);
+ SHA_Bytes(&s, "\0\0\0\1", 4);
+ SHA_Bytes(&s, passphrase, passlen);
+ SHA_Final(&s, key + 20);
+ aes256_decrypt_pubkey(key, private_blob, private_blob_len);
+ }
+
+ /*
+ * Verify the MAC.
+ */
+ {
+ char realmac[41];
+ unsigned char binary[20];
+ unsigned char *macdata;
+ int maclen;
+ int free_macdata;
+
+ if (old_fmt) {
+ /* MAC (or hash) only covers the private blob. */
+ macdata = private_blob;
+ maclen = private_blob_len;
+ free_macdata = 0;
+ } else {
+ unsigned char *p;
+ int namelen = strlen(alg->name);
+ int enclen = strlen(encryption);
+ int commlen = strlen(comment);
+ maclen = (4 + namelen +
+ 4 + enclen +
+ 4 + commlen +
+ 4 + public_blob_len +
+ 4 + private_blob_len);
+ macdata = snewn(maclen, unsigned char);
+ p = macdata;
+#define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)
+ DO_STR(alg->name, namelen);
+ DO_STR(encryption, enclen);
+ DO_STR(comment, commlen);
+ DO_STR(public_blob, public_blob_len);
+ DO_STR(private_blob, private_blob_len);
+
+ free_macdata = 1;
+ }
+
+ if (is_mac) {
+ SHA_State s;
+ unsigned char mackey[20];
+ char header[] = "putty-private-key-file-mac-key";
+
+ SHA_Init(&s);
+ SHA_Bytes(&s, header, sizeof(header)-1);
+ if (cipher && passphrase)
+ SHA_Bytes(&s, passphrase, passlen);
+ SHA_Final(&s, mackey);
+
+ hmac_sha1_simple(mackey, 20, macdata, maclen, binary);
+
+ smemclr(mackey, sizeof(mackey));
+ smemclr(&s, sizeof(s));
+ } else {
+ SHA_Simple(macdata, maclen, binary);
+ }
+
+ if (free_macdata) {
+ smemclr(macdata, maclen);
+ sfree(macdata);
+ }
+
+ for (i = 0; i < 20; i++)
+ sprintf(realmac + 2 * i, "%02x", binary[i]);
+
+ if (strcmp(mac, realmac)) {
+ /* An incorrect MAC is an unconditional Error if the key is
+ * unencrypted. Otherwise, it means Wrong Passphrase. */
+ if (cipher) {
+ error = "wrong passphrase";
+ ret = SSH2_WRONG_PASSPHRASE;
+ } else {
+ error = "MAC failed";
+ ret = NULL;
+ }
+ goto error;
+ }
+ }
+ sfree(mac);
+
+ /*
+ * Create and return the key.
+ */
+ ret = snew(struct ssh2_userkey);
+ ret->alg = alg;
+ ret->comment = comment;
+ ret->data = alg->createkey(public_blob, public_blob_len,
+ private_blob, private_blob_len);
+ if (!ret->data) {
+ sfree(ret->comment);
+ sfree(ret);
+ ret = NULL;
+ error = "createkey failed";
+ goto error;
+ }
+ sfree(public_blob);
+ sfree(private_blob);
+ sfree(encryption);
+ if (errorstr)
+ *errorstr = NULL;
+ return ret;
+
+ /*
+ * Error processing.
+ */
+ error:
+ if (fp)
+ fclose(fp);
+ if (comment)
+ sfree(comment);
+ if (encryption)
+ sfree(encryption);
+ if (mac)
+ sfree(mac);
+ if (public_blob)
+ sfree(public_blob);
+ if (private_blob)
+ sfree(private_blob);
+ if (errorstr)
+ *errorstr = error;
+ return ret;
+}
+
+unsigned char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
+ int *pub_blob_len, char **commentptr,
+ const char **errorstr)
+{
+ FILE *fp;
+ char header[40], *b;
+ const struct ssh_signkey *alg;
+ unsigned char *public_blob;
+ int public_blob_len;
+ int i;
+ const char *error = NULL;
+ char *comment;
+
+ public_blob = NULL;
+
+ fp = f_open(filename, "rb", FALSE);
+ if (!fp) {
+ error = "can't open file";
+ goto error;
+ }
+
+ /* Read the first header line which contains the key type. */
+ if (!read_header(fp, header)
+ || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&
+ 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {
+ if (0 == strncmp(header, "PuTTY-User-Key-File-", 20))
+ error = "PuTTY key format too new";
+ else
+ error = "not a PuTTY SSH-2 private key";
+ goto error;
+ }
+ error = "file format error";
+ if ((b = read_body(fp)) == NULL)
+ goto error;
+ /* Select key algorithm structure. */
+ alg = find_pubkey_alg(b);
+ if (!alg) {
+ sfree(b);
+ goto error;
+ }
+ sfree(b);
+
+ /* Read the Encryption header line. */
+ if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))
+ goto error;
+ if ((b = read_body(fp)) == NULL)
+ goto error;
+ sfree(b); /* we don't care */
+
+ /* Read the Comment header line. */
+ if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))
+ goto error;
+ if ((comment = read_body(fp)) == NULL)
+ goto error;
+
+ if (commentptr)
+ *commentptr = comment;
+ else
+ sfree(comment);
+
+ /* Read the Public-Lines header line and the public blob. */
+ if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))
+ goto error;
+ if ((b = read_body(fp)) == NULL)
+ goto error;
+ i = atoi(b);
+ sfree(b);
+ if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)
+ goto error;