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Move all the auxiliary cipher functions into a new module.

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All those functions like aes256_encrypt_pubkey and des_decrypt_xdmauth
previously lived in the same source files as the ciphers they were
based on, and provided an alternative API to the internals of that
cipher's implementation. But there was no _need_ for them to have that
privileged access to the internals, because they didn't do anything
you couldn't access through the standard API. It was just a historical
oddity with no real benefit, whose main effect is to make refactoring
painful.

So now all of those functions live in a new file sshauxcrypt.c, and
they all work through the same vtable system as all other cipher
clients, by making an instance of the right cipher and configuring it
in the appropriate way. This should make them completely independent
of any internal changes to the cipher implementations they're based
on.
This commit is contained in:
Simon Tatham
2019-01-18 06:51:12 +00:00
parent 986508a570
commit 07db7f89b2
4 changed files with 157 additions and 137 deletions
Download Patch File Download Diff File Expand all files Collapse all files

106
sshdes.c
View File

@ -927,112 +927,6 @@ static void des_decrypt_blk(ssh_cipher *cipher, void *blk, int len)
des_cbc_decrypt(blk, len, &ctx->context);
}
void des3_decrypt_pubkey(const void *vkey, void *vblk, int len)
{
const unsigned char *key = (const unsigned char *)vkey;
unsigned char *blk = (unsigned char *)vblk;
DESContext ourkeys[3];
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[2]);
des_3cbc_decrypt(blk, len, ourkeys);
smemclr(ourkeys, sizeof(ourkeys));
}
void des3_encrypt_pubkey(const void *vkey, void *vblk, int len)
{
const unsigned char *key = (const unsigned char *)vkey;
unsigned char *blk = (unsigned char *)vblk;
DESContext ourkeys[3];
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[2]);
des_3cbc_encrypt(blk, len, ourkeys);
smemclr(ourkeys, sizeof(ourkeys));
}
void des3_decrypt_pubkey_ossh(const void *vkey, const void *viv,
void *vblk, int len)
{
const unsigned char *key = (const unsigned char *)vkey;
const unsigned char *iv = (const unsigned char *)viv;
unsigned char *blk = (unsigned char *)vblk;
DESContext ourkeys[3];
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 16),
GET_32BIT_MSB_FIRST(key + 20), &ourkeys[2]);
ourkeys[0].iv0 = GET_32BIT_MSB_FIRST(iv);
ourkeys[0].iv1 = GET_32BIT_MSB_FIRST(iv+4);
des_cbc3_decrypt(blk, len, ourkeys);
smemclr(ourkeys, sizeof(ourkeys));
}
void des3_encrypt_pubkey_ossh(const void *vkey, const void *viv,
void *vblk, int len)
{
const unsigned char *key = (const unsigned char *)vkey;
const unsigned char *iv = (const unsigned char *)viv;
unsigned char *blk = (unsigned char *)vblk;
DESContext ourkeys[3];
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 16),
GET_32BIT_MSB_FIRST(key + 20), &ourkeys[2]);
ourkeys[0].iv0 = GET_32BIT_MSB_FIRST(iv);
ourkeys[0].iv1 = GET_32BIT_MSB_FIRST(iv+4);
des_cbc3_encrypt(blk, len, ourkeys);
smemclr(ourkeys, sizeof(ourkeys));
}
static void des_keysetup_xdmauth(const void *vkeydata, DESContext *dc)
{
const unsigned char *keydata = (const unsigned char *)vkeydata;
unsigned char key[8];
int i, nbits, j;
unsigned int bits;
bits = 0;
nbits = 0;
j = 0;
for (i = 0; i < 8; i++) {
if (nbits < 7) {
bits = (bits << 8) | keydata[j];
nbits += 8;
j++;
}
key[i] = (bits >> (nbits - 7)) << 1;
bits &= ~(0x7F << (nbits - 7));
nbits -= 7;
}
des_key_setup(GET_32BIT_MSB_FIRST(key), GET_32BIT_MSB_FIRST(key + 4), dc);
}
void des_encrypt_xdmauth(const void *keydata, void *blk, int len)
{
DESContext dc;
des_keysetup_xdmauth(keydata, &dc);
des_cbc_encrypt(blk, len, &dc);
}
void des_decrypt_xdmauth(const void *keydata, void *blk, int len)
{
DESContext dc;
des_keysetup_xdmauth(keydata, &dc);
des_cbc_decrypt(blk, len, &dc);
}
const ssh_cipheralg ssh_3des_ssh2 = {
des3_ssh2_new, des3_ssh2_free, des3_ssh2_setiv, des3_ssh2_setkey,
des3_ssh2_encrypt_blk, des3_ssh2_decrypt_blk, NULL, NULL,