#include <stdio.h>
#include <stdlib.h>
+#include <assert.h>
#include "ssh.h"
(x)=='+' ? 62 : \
(x)=='/' ? 63 : 0 )
-static int loadrsakey_main(FILE *fp, struct RSAKey *key, struct RSAAux *aux,
+static int loadrsakey_main(FILE *fp, struct RSAKey *key,
char **commentptr, char *passphrase) {
unsigned char buf[16384];
unsigned char keybuf[16];
*/
i += makeprivate(buf+i, key);
if (len-i < 0) goto end;
- if (aux) {
- i += ssh1_read_bignum(buf+i, &aux->iqmp);
- if (len-i < 0) goto end;
- i += ssh1_read_bignum(buf+i, &aux->q);
- if (len-i < 0) goto end;
- i += ssh1_read_bignum(buf+i, &aux->p);
- if (len-i < 0) goto end;
- }
+ i += ssh1_read_bignum(buf+i, &key->iqmp);
+ if (len-i < 0) goto end;
+ i += ssh1_read_bignum(buf+i, &key->q);
+ if (len-i < 0) goto end;
+ i += ssh1_read_bignum(buf+i, &key->p);
+ if (len-i < 0) goto end;
ret = 1;
end:
return ret;
}
-int loadrsakey(char *filename, struct RSAKey *key, struct RSAAux *aux,
- char *passphrase) {
+int loadrsakey(char *filename, struct RSAKey *key, char *passphrase) {
FILE *fp;
unsigned char buf[64];
*/
if (fgets(buf, sizeof(buf), fp) &&
!strcmp(buf, rsa_signature)) {
- return loadrsakey_main(fp, key, aux, NULL, passphrase);
+ return loadrsakey_main(fp, key, NULL, passphrase);
}
/*
*/
if (fgets(buf, sizeof(buf), fp) &&
!strcmp(buf, rsa_signature)) {
- return loadrsakey_main(fp, NULL, NULL, comment, NULL);
+ return loadrsakey_main(fp, NULL, comment, NULL);
}
fclose(fp);
return 0; /* wasn't the right kind of file */
/*
* Save an RSA key file. Return nonzero on success.
*/
-int saversakey(char *filename, struct RSAKey *key, struct RSAAux *aux,
- char *passphrase) {
+int saversakey(char *filename, struct RSAKey *key, char *passphrase) {
unsigned char buf[16384];
unsigned char keybuf[16];
struct MD5Context md5c;
* q, then p.
*/
p += ssh1_write_bignum(p, key->private_exponent);
- p += ssh1_write_bignum(p, aux->iqmp);
- p += ssh1_write_bignum(p, aux->q);
- p += ssh1_write_bignum(p, aux->p);
+ p += ssh1_write_bignum(p, key->iqmp);
+ p += ssh1_write_bignum(p, key->q);
+ p += ssh1_write_bignum(p, key->p);
/*
* Now write zeros until the encrypted portion is a multiple of
} else
return 0;
}
+
+/* ----------------------------------------------------------------------
+ * SSH2 private key load/store functions.
+ */
+
+/*
+ * PuTTY's own format for SSH2 keys is as follows:
+ *
+ * The file is text. Lines are terminated by CRLF, although CR-only
+ * and LF-only are tolerated on input.
+ *
+ * The first line says "PuTTY-User-Key-File-1: " plus the name of the
+ * algorithm ("ssh-dss", "ssh-rsa" etc. Although, of course, this
+ * being PuTTY, "ssh-dss" is not supported.)
+ *
+ * The next line says "Encryption: " plus an encryption type.
+ * Currently the only supported encryption types are "aes256-cbc"
+ * and "none".
+ *
+ * The next line says "Comment: " plus the comment string.
+ *
+ * Next there is a line saying "Public-Lines: " plus a number N.
+ * The following N lines contain a base64 encoding of the public
+ * part of the key. This is encoded as the standard SSH2 public key
+ * blob (with no initial length): so for RSA, for example, it will
+ * read
+ *
+ * string "ssh-rsa"
+ * mpint exponent
+ * mpint modulus
+ *
+ * Next, there is a line saying "Private-Lines: " plus a number N,
+ * and then N lines containing the (potentially encrypted) private
+ * part of the key. For the key type "ssh-rsa", this will be
+ * composed of
+ *
+ * mpint private_exponent
+ * mpint p (the larger of the two primes)
+ * mpint q (the smaller prime)
+ * mpint iqmp (the inverse of q modulo p)
+ * data padding (to reach a multiple of the cipher block size)
+ *
+ * Finally, there is a line saying "Private-Hash: " plus a hex
+ * representation of a SHA-1 hash of the plaintext version of the
+ * private part, including the final padding.
+ *
+ * If the key is encrypted, the encryption key is derived from the
+ * passphrase by means of a succession of SHA-1 hashes. Each hash
+ * is the hash of:
+ *
+ * uint32 sequence-number
+ * string passphrase
+ *
+ * where the sequence-number increases from zero. As many of these
+ * hashes are used as necessary.
+ */
+
+static int read_header(FILE *fp, char *header) {
+ int len = 39;
+ int c;
+
+ while (len > 0) {
+ c = fgetc(fp);
+ if (c == '\n' || c == '\r' || c == EOF)
+ return 0; /* failure */
+ if (c == ':') {
+ c = fgetc(fp);
+ if (c != ' ')
+ return 0;
+ *header = '\0';
+ return 1; /* success! */
+ }
+ if (len == 0)
+ return 0; /* failure */
+ *header++ = c;
+ len--;
+ }
+ return 0; /* failure */
+}
+
+static char *read_body(FILE *fp) {
+ char *text;
+ int len;
+ int size;
+ int c;
+
+ size = 128;
+ text = smalloc(size);
+ len = 0;
+ text[len] = '\0';
+
+ while (1) {
+ c = fgetc(fp);
+ if (c == '\r' || c == '\n') {
+ c = fgetc(fp);
+ if (c != '\r' && c != '\n' && c != EOF)
+ ungetc(c, fp);
+ return text;
+ }
+ if (c == EOF) {
+ sfree(text);
+ return NULL;
+ }
+ if (len + 1 > size) {
+ size += 128;
+ text = srealloc(text, size);
+ }
+ 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 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 = smalloc(48 * nlines);
+ 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
+};
+
+struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) {
+ FILE *fp;
+ char header[40], *b, *comment, *hash;
+ 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;
+
+ ret = NULL; /* return NULL for most errors */
+ comment = hash = NULL;
+ public_blob = private_blob = NULL;
+
+ fp = fopen(filename, "rb");
+ if (!fp)
+ goto error;
+
+ /* Read the first header line which contains the key type. */
+ if (!read_header(fp, header) || 0!=strcmp(header, "PuTTY-User-Key-File-1"))
+ goto error;
+ if ((b = read_body(fp)) == NULL)
+ goto error;
+ /* Select key algorithm structure. Currently only ssh-rsa. */
+ if (!strcmp(b, "ssh-rsa"))
+ alg = &ssh_rsa;
+ else {
+ 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;
+ if (!strcmp(b, "aes256-cbc")) {
+ cipher = 1; cipherblk = 16;
+ } else if (!strcmp(b, "none")) {
+ cipher = 0; cipherblk = 1;
+ } else {
+ sfree(b);
+ goto error;
+ }
+ sfree(b);
+
+ /* 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-Hash header line. */
+ if (!read_header(fp, header) || 0!=strcmp(header, "Private-Hash"))
+ goto error;
+ if ((hash = read_body(fp)) == NULL)
+ goto error;
+
+ fclose(fp);
+ fp = NULL;
+
+ /*
+ * Decrypt the private blob.
+ */
+ if (cipher) {
+ unsigned char key[40];
+ SHA_State s;
+ int passlen;
+
+ if (!passphrase)
+ goto error;
+ if (private_blob_len % cipherblk)
+ goto error;
+
+ passlen = strlen(passphrase);
+
+ 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 private hash.
+ */
+ {
+ char realhash[41];
+ unsigned char binary[20];
+ SHA_State s;
+
+ SHA_Simple(private_blob, private_blob_len, binary);
+ for (i = 0; i < 20; i++)
+ sprintf(realhash+2*i, "%02x", binary[i]);
+
+ if (strcmp(hash, realhash)) {
+ /* An incorrect hash is an unconditional Error if the key is
+ * unencrypted. Otherwise, it means Wrong Passphrase. */
+ ret = cipher ? SSH2_WRONG_PASSPHRASE : NULL;
+ goto error;
+ }
+ }
+ sfree(hash);
+
+ /*
+ * Create and return the key.
+ */
+ ret = smalloc(sizeof(struct ssh2_userkey));
+ ret->alg = alg;
+ ret->comment = comment;
+ ret->data = alg->createkey(public_blob, public_blob_len,
+ private_blob, private_blob_len);
+ sfree(public_blob);
+ sfree(private_blob);
+ return ret;
+
+ /*
+ * Error processing.
+ */
+ error:
+ if (fp) fclose(fp);
+ if (comment) sfree(comment);
+ if (hash) sfree(hash);
+ if (public_blob) sfree(public_blob);
+ if (private_blob) sfree(private_blob);
+ return ret;
+}
+
+char *ssh2_userkey_loadpub(char *filename, char **algorithm, int *pub_blob_len) {
+ FILE *fp;
+ char header[40], *b;
+ const struct ssh_signkey *alg;
+ int cipher, cipherblk;
+ unsigned char *public_blob;
+ int public_blob_len;
+ int i;
+
+ public_blob = NULL;
+
+ fp = fopen(filename, "rb");
+ if (!fp)
+ goto error;
+
+ /* Read the first header line which contains the key type. */
+ if (!read_header(fp, header) || 0!=strcmp(header, "PuTTY-User-Key-File-1"))
+ goto error;
+ if ((b = read_body(fp)) == NULL)
+ goto error;
+ /* Select key algorithm structure. Currently only ssh-rsa. */
+ if (!strcmp(b, "ssh-rsa"))
+ alg = &ssh_rsa;
+ else {
+ 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 ((b = read_body(fp)) == NULL)
+ goto error;
+ sfree(b); /* we don't care */
+
+ /* 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;
+
+ fclose(fp);
+ *pub_blob_len = public_blob_len;
+ *algorithm = alg->name;
+ return public_blob;
+
+ /*
+ * Error processing.
+ */
+ error:
+ if (fp) fclose(fp);
+ if (public_blob) sfree(public_blob);
+ return NULL;
+}
+
+int ssh2_userkey_encrypted(char *filename, char **commentptr) {
+ FILE *fp;
+ char header[40], *b, *comment;
+ int ret;
+
+ if (commentptr) *commentptr = NULL;
+
+ fp = fopen(filename, "rb");
+ if (!fp)
+ return 0;
+ if (!read_header(fp, header) || 0!=strcmp(header, "PuTTY-User-Key-File-1")) {
+ fclose(fp); return 0;
+ }
+ if ((b = read_body(fp)) == NULL) {
+ fclose(fp); return 0;
+ }
+ sfree(b); /* we don't care about key type here */
+ /* Read the Encryption header line. */
+ if (!read_header(fp, header) || 0!=strcmp(header, "Encryption")) {
+ fclose(fp); return 0;
+ }
+ if ((b = read_body(fp)) == NULL) {
+ fclose(fp); return 0;
+ }
+
+ /* Read the Comment header line. */
+ if (!read_header(fp, header) || 0!=strcmp(header, "Comment")) {
+ fclose(fp); sfree(b); return 1;
+ }
+ if ((comment = read_body(fp)) == NULL) {
+ fclose(fp); sfree(b); return 1;
+ }
+
+ if (commentptr) *commentptr = comment;
+
+ fclose(fp);
+ if (!strcmp(b, "aes256-cbc"))
+ ret = 1;
+ else
+ ret = 0;
+ sfree(b);
+ return ret;
+}
+
+int base64_lines(int datalen) {
+ /* When encoding, we use 64 chars/line, which equals 48 real chars. */
+ return (datalen+47) / 48;
+}
+
+void base64_encode_atom(unsigned char *data, int n, char *out) {
+ static const char base64_chars[] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+ unsigned word;
+
+ word = data[0] << 16;
+ if (n > 1)
+ word |= data[1] << 8;
+ if (n > 2)
+ word |= data[2];
+ out[0] = base64_chars[(word >> 18) & 0x3F];
+ out[1] = base64_chars[(word >> 12) & 0x3F];
+ if (n > 1)
+ out[2] = base64_chars[(word >> 6) & 0x3F];
+ else
+ out[2] = '=';
+ if (n > 2)
+ out[3] = base64_chars[word & 0x3F];
+ else
+ out[3] = '=';
+}
+
+void base64_encode(FILE *fp, unsigned char *data, int datalen) {
+ int linelen = 0;
+ char out[4];
+ int n;
+
+ while (datalen > 0) {
+ if (linelen >= 64) {
+ linelen = 0;
+ fputc('\n', fp);
+ }
+ n = (datalen < 3 ? datalen : 3);
+ base64_encode_atom(data, n, out);
+ data += n;
+ datalen -= n;
+ fwrite(out, 1, 4, fp);
+ linelen += 4;
+ }
+ fputc('\n', fp);
+}
+
+int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, char *passphrase) {
+ FILE *fp;
+ unsigned char *pub_blob, *priv_blob, *priv_blob_encrypted;
+ int pub_blob_len, priv_blob_len, priv_encrypted_len;
+ int passlen;
+ int cipherblk;
+ int i;
+ char *cipherstr;
+ unsigned char priv_hash[20];
+
+ /*
+ * Fetch the key component blobs.
+ */
+ pub_blob = key->alg->public_blob(key->data, &pub_blob_len);
+ priv_blob = key->alg->private_blob(key->data, &priv_blob_len);
+ if (!pub_blob || !priv_blob) {
+ sfree(pub_blob);
+ sfree(priv_blob);
+ return 0;
+ }
+
+ /*
+ * Determine encryption details, and encrypt the private blob.
+ */
+ if (passphrase) {
+ cipherstr = "aes256-cbc";
+ cipherblk = 16;
+ } else {
+ cipherstr = "none";
+ cipherblk = 1;
+ }
+ priv_encrypted_len = priv_blob_len + cipherblk - 1;
+ priv_encrypted_len -= priv_encrypted_len % cipherblk;
+ priv_blob_encrypted = smalloc(priv_encrypted_len);
+ memset(priv_blob_encrypted, 0, priv_encrypted_len);
+ memcpy(priv_blob_encrypted, priv_blob, priv_blob_len);
+ /* Create padding based on the SHA hash of the unpadded blob. This prevents
+ * too easy a known-plaintext attack on the last block. */
+ SHA_Simple(priv_blob, priv_blob_len, priv_hash);
+ assert(priv_encrypted_len - priv_blob_len < 20);
+ memcpy(priv_blob_encrypted + priv_blob_len, priv_hash,
+ priv_encrypted_len - priv_blob_len);
+
+ /* Now create the _real_ private hash. */
+ SHA_Simple(priv_blob_encrypted, priv_encrypted_len, priv_hash);
+
+ if (passphrase) {
+ char key[40];
+ SHA_State s;
+
+ passlen = strlen(passphrase);
+
+ 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_encrypt_pubkey(key, priv_blob_encrypted, priv_encrypted_len);
+ }
+
+ fp = fopen(filename, "w");
+ if (!fp)
+ return 0;
+ fprintf(fp, "PuTTY-User-Key-File-1: %s\n", key->alg->name);
+ fprintf(fp, "Encryption: %s\n", cipherstr);
+ fprintf(fp, "Comment: %s\n", key->comment);
+ fprintf(fp, "Public-Lines: %d\n", base64_lines(pub_blob_len));
+ base64_encode(fp, pub_blob, pub_blob_len);
+ fprintf(fp, "Private-Lines: %d\n", base64_lines(priv_encrypted_len));
+ base64_encode(fp, priv_blob_encrypted, priv_encrypted_len);
+ fprintf(fp, "Private-Hash: ");
+ for (i = 0; i < 20; i++)
+ fprintf(fp, "%02x", priv_hash[i]);
+ fprintf(fp, "\n");
+ fclose(fp);
+ return 1;
+}
+
+/* ----------------------------------------------------------------------
+ * A function to determine which version of SSH to try on a private
+ * key file. Returns 0 on failure, 1 or 2 on success.
+ */
+int keyfile_version(char *filename) {
+ FILE *fp;
+ int i;
+
+ fp = fopen(filename, "r");
+ if (!fp)
+ return 0;
+ i = fgetc(fp);
+ fclose(fp);
+ if (i == 'S')
+ return 1; /* "SSH PRIVATE KEY FORMAT" etc */
+ if (i == 'P') /* "PuTTY-User-Key-File" etc */
+ return 2;
+ return 0; /* unrecognised or EOF */
+}
projects / u / mdw / putty / blobdiff