--- /dev/null
+/*
+ * Read SSH public keys from files.
+ *
+ * First implementation: only supports unencrypted SSH 1.1 format
+ * RSA keys. Encryption, and SSH 2 DSS keys, to be supported later.
+ */
+
+#include <stdio.h>
+
+#include <stdio.h> /* FIXME */
+#include <stdarg.h> /* FIXME */
+#include <windows.h> /* FIXME */
+#include "putty.h" /* FIXME */
+
+#include "ssh.h"
+
+#define GET_32BIT(cp) \
+ (((unsigned long)(unsigned char)(cp)[0] << 24) | \
+ ((unsigned long)(unsigned char)(cp)[1] << 16) | \
+ ((unsigned long)(unsigned char)(cp)[2] << 8) | \
+ ((unsigned long)(unsigned char)(cp)[3]))
+
+#define rsa_signature "SSH PRIVATE KEY FILE FORMAT 1.1\n"
+
+int loadrsakey(char *filename, struct RSAKey *key, char *passphrase) {
+ FILE *fp;
+ unsigned char buf[16384];
+ unsigned char keybuf[16];
+ int len;
+ int i, j, ciphertype;
+ int ret = 0;
+ struct MD5Context md5c;
+
+ fp = fopen(filename, "rb");
+ if (!fp)
+ goto end;
+
+ /* Slurp the whole file into a buffer. */
+ len = fread(buf, 1, sizeof(buf), fp);
+ fclose(fp);
+ if (len < 0 || len == sizeof(buf))
+ goto end; /* file too big or not read */
+
+ if (len < sizeof(rsa_signature) ||
+ memcmp(buf, rsa_signature, sizeof(rsa_signature)) != 0)
+ goto end; /* failure to have sig at front */
+
+ i = sizeof(rsa_signature);
+
+ /* Next, one byte giving encryption type, and one reserved uint32. */
+ if (len-i < 1)
+ goto end;
+ ciphertype = buf[i];
+ if (ciphertype != 0 && ciphertype != SSH_CIPHER_3DES)
+ goto end;
+ i++;
+ if (len-i < 4)
+ goto end; /* reserved field not present */
+ if (buf[i] != 0 || buf[i+1] != 0 || buf[i+2] != 0 || buf[i+3] != 0)
+ goto end; /* reserved field nonzero, panic! */
+ i += 4;
+
+ /* Now the serious stuff. An ordinary SSH 1 public key. */
+ i += makekey(buf+i, key, NULL, 1);
+ if (len-i < 0)
+ goto end; /* overran */
+
+ /* Next, the comment field. */
+ j = GET_32BIT(buf+i);
+ if (len-i < 4+j) goto end; i += 4+j;
+ /*
+ * FIXME: might need to use this string.
+ */
+
+ /*
+ * Decrypt remainder of buffer.
+ */
+ if (ciphertype) {
+ MD5Init(&md5c);
+ MD5Update(&md5c, passphrase, strlen(passphrase));
+ MD5Final(keybuf, &md5c);
+ des3_decrypt_pubkey(keybuf, buf+i, (len-i+7)&~7);
+ memset(keybuf, 0, sizeof(buf)); /* burn the evidence */
+ }
+
+ /*
+ * We are now in the secret part of the key. The first four
+ * bytes should be of the form a, b, a, b.
+ */
+ if (len-i < 4) goto end;
+ if (buf[i] != buf[i+2] || buf[i+1] != buf[i+3]) { ret = -1; goto end; }
+ i += 4;
+
+ /*
+ * After that, we have one further bignum which is our
+ * decryption modulus, and then we're done.
+ */
+ i += makeprivate(buf+i, key);
+ if (len-i < 0) goto end;
+
+ ret = 1;
+ end:
+ memset(buf, 0, sizeof(buf)); /* burn the evidence */
+ return ret;
+}
+
+/*
+ * See whether an RSA key is encrypted.
+ */
+int rsakey_encrypted(char *filename) {
+ FILE *fp;
+ unsigned char buf[1+sizeof(rsa_signature)];
+ int len;
+
+ fp = fopen(filename, "rb");
+ if (!fp)
+ return 0; /* doesn't even exist */
+
+ /* Slurp the whole file into a buffer. */
+ len = fread(buf, 1, sizeof(buf), fp);
+ fclose(fp);
+ if (len < sizeof(buf))
+ return 0; /* not even valid */
+ if (buf[sizeof(buf)-1])
+ return 1; /* encrypted */
+ return 0;
+}