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Access all hashes and MACs through the standard API.

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All the hash-specific state structures, and the functions that
directly accessed them, are now local to the source files implementing
the hashes themselves. Everywhere we previously used those types or
functions, we're now using the standard ssh_hash or ssh2_mac API.

The 'simple' functions (hmacmd5_simple, SHA_Simple etc) are now a pair
of wrappers in sshauxcrypt.c, each of which takes an algorithm
structure and can do the same conceptual thing regardless of what it
is.
This commit is contained in:
Simon Tatham
2019-01-20 16:15:14 +00:00
parent acdcf2bfaa
commit 0d2d20aad0
19 changed files with 232 additions and 274 deletions
Download Patch File Download Diff File Expand all files Collapse all files

92
sshpubk.c
View File

@ -31,7 +31,6 @@ static int rsa_ssh1_load_main(FILE * fp, RSAKey *key, bool pub_only,
strbuf *buf;
int ciphertype;
int ret = 0;
struct MD5Context md5c;
ptrlen comment;
BinarySource src[1];
@ -96,9 +95,7 @@ static int rsa_ssh1_load_main(FILE * fp, RSAKey *key, bool pub_only,
if (enclen & 7)
goto end;
MD5Init(&md5c);
put_data(&md5c, passphrase, strlen(passphrase));
MD5Final(keybuf, &md5c);
hash_simple(&ssh_md5, ptrlen_from_asciz(passphrase), keybuf);
des3_decrypt_pubkey(keybuf, buf->u + src->pos, enclen);
smemclr(keybuf, sizeof(keybuf)); /* burn the evidence */
}
@ -363,12 +360,11 @@ bool rsa_ssh1_savekey(const Filename *filename, RSAKey *key,
* Now encrypt the encrypted portion.
*/
if (passphrase) {
struct MD5Context md5c;
unsigned char keybuf[16];
MD5Init(&md5c);
put_data(&md5c, passphrase, strlen(passphrase));
MD5Final(keybuf, &md5c);
ssh_hash *h = ssh_hash_new(&ssh_md5);
put_data(h, passphrase, strlen(passphrase));
ssh_hash_final(h, keybuf);
des3_encrypt_pubkey(keybuf, buf->u + estart, buf->len - estart);
smemclr(keybuf, sizeof(keybuf)); /* burn the evidence */
}
@ -588,6 +584,19 @@ const ssh_keyalg *find_pubkey_alg(const char *name)
return find_pubkey_alg_len(ptrlen_from_asciz(name));
}
static void ssh2_ppk_derivekey(ptrlen passphrase, uint8_t *key)
{
ssh_hash *h;
h = ssh_hash_new(&ssh_sha1);
put_uint32(h, 0);
put_datapl(h, passphrase);
ssh_hash_final(h, key + 0);
h = ssh_hash_new(&ssh_sha1);
put_uint32(h, 1);
put_datapl(h, passphrase);
ssh_hash_final(h, key + 20);
}
ssh2_userkey *ssh2_load_userkey(
const Filename *filename, const char *passphrase, const char **errorstr)
{
@ -708,21 +717,13 @@ ssh2_userkey *ssh2_load_userkey(
*/
if (cipher) {
unsigned char key[40];
SHA_State s;
if (!passphrase)
goto error;
if (private_blob->len % cipherblk)
goto error;
SHA_Init(&s);
put_uint32(&s, 0);
put_data(&s, passphrase, passlen);
SHA_Final(&s, key + 0);
SHA_Init(&s);
put_uint32(&s, 1);
put_data(&s, passphrase, passlen);
SHA_Final(&s, key + 20);
ssh2_ppk_derivekey(ptrlen_from_asciz(passphrase), key);
aes256_decrypt_pubkey(key, private_blob->u, private_blob->len);
}
@ -752,23 +753,27 @@ ssh2_userkey *ssh2_load_userkey(
}
if (is_mac) {
SHA_State s;
ssh_hash *hash;
ssh2_mac *mac;
unsigned char mackey[20];
char header[] = "putty-private-key-file-mac-key";
SHA_Init(&s);
put_data(&s, header, sizeof(header)-1);
hash = ssh_hash_new(&ssh_sha1);
put_data(hash, header, sizeof(header)-1);
if (cipher && passphrase)
put_data(&s, passphrase, passlen);
SHA_Final(&s, mackey);
put_data(hash, passphrase, passlen);
ssh_hash_final(hash, mackey);
hmac_sha1_simple(mackey, 20, macdata->s,
macdata->len, binary);
mac = ssh2_mac_new(&ssh_hmac_sha1, NULL);
ssh2_mac_setkey(mac, make_ptrlen(mackey, 20));
ssh2_mac_start(mac);
put_data(mac, macdata->s, macdata->len);
ssh2_mac_genresult(mac, binary);
ssh2_mac_free(mac);
smemclr(mackey, sizeof(mackey));
smemclr(&s, sizeof(s));
} else {
SHA_Simple(macdata->s, macdata->len, binary);
hash_simple(&ssh_sha1, ptrlen_from_strbuf(macdata), binary);
}
if (free_macdata)
@ -1241,7 +1246,6 @@ bool ssh2_save_userkey(
strbuf *pub_blob, *priv_blob;
unsigned char *priv_blob_encrypted;
int priv_encrypted_len;
int passlen;
int cipherblk;
int i;
const char *cipherstr;
@ -1272,7 +1276,7 @@ bool ssh2_save_userkey(
memcpy(priv_blob_encrypted, priv_blob->u, 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->u, priv_blob->len, priv_mac);
hash_simple(&ssh_sha1, ptrlen_from_strbuf(priv_blob), priv_mac);
assert(priv_encrypted_len - priv_blob->len < 20);
memcpy(priv_blob_encrypted + priv_blob->len, priv_mac,
priv_encrypted_len - priv_blob->len);
@ -1280,7 +1284,6 @@ bool ssh2_save_userkey(
/* Now create the MAC. */
{
strbuf *macdata;
SHA_State s;
unsigned char mackey[20];
char header[] = "putty-private-key-file-mac-key";
@ -1291,37 +1294,24 @@ bool ssh2_save_userkey(
put_string(macdata, pub_blob->s, pub_blob->len);
put_string(macdata, priv_blob_encrypted, priv_encrypted_len);
SHA_Init(&s);
put_data(&s, header, sizeof(header)-1);
ssh_hash *h = ssh_hash_new(&ssh_sha1);
put_data(h, header, sizeof(header)-1);
if (passphrase)
put_data(&s, passphrase, strlen(passphrase));
SHA_Final(&s, mackey);
hmac_sha1_simple(mackey, 20, macdata->s,
macdata->len, priv_mac);
put_data(h, passphrase, strlen(passphrase));
ssh_hash_final(h, mackey);
mac_simple(&ssh_hmac_sha1, make_ptrlen(mackey, 20),
ptrlen_from_strbuf(macdata), priv_mac);
strbuf_free(macdata);
smemclr(mackey, sizeof(mackey));
smemclr(&s, sizeof(s));
}
if (passphrase) {
unsigned char key[40];
SHA_State s;
passlen = strlen(passphrase);
SHA_Init(&s);
put_uint32(&s, 0);
put_data(&s, passphrase, passlen);
SHA_Final(&s, key + 0);
SHA_Init(&s);
put_uint32(&s, 1);
put_data(&s, passphrase, passlen);
SHA_Final(&s, key + 20);
aes256_encrypt_pubkey(key, priv_blob_encrypted,
priv_encrypted_len);
ssh2_ppk_derivekey(ptrlen_from_asciz(passphrase), key);
aes256_encrypt_pubkey(key, priv_blob_encrypted, priv_encrypted_len);
smemclr(key, sizeof(key));
smemclr(&s, sizeof(s));
}
fp = f_open(filename, "w", true);
@ -1496,7 +1486,7 @@ char *ssh2_fingerprint_blob(const void *blob, int bloblen)
/*
* The fingerprint hash itself is always just the MD5 of the blob.
*/
MD5Simple(blob, bloblen, digest);
hash_simple(&ssh_md5, make_ptrlen(blob, bloblen), digest);
for (i = 0; i < 16; i++)
sprintf(fingerprint_str + i*3, "%02x%s", digest[i], i==15 ? "" : ":");