putty/sshmac.c

44 строки
1.1 KiB
C

/*
* Centralised parts of the SSH-2 MAC API, which don't need to vary
* with the MAC implementation.
*/
#include <assert.h>
#include "ssh.h"
bool ssh2_mac_verresult(ssh2_mac *mac, const void *candidate)
{
unsigned char correct[64]; /* at least as big as all known MACs */
bool toret;
assert(mac->vt->len <= sizeof(correct));
ssh2_mac_genresult(mac, correct);
toret = smemeq(correct, candidate, mac->vt->len);
smemclr(correct, sizeof(correct));
return toret;
}
static void ssh2_mac_prepare(ssh2_mac *mac, const void *blk, int len,
unsigned long seq)
{
ssh2_mac_start(mac);
put_uint32(mac, seq);
put_data(mac, blk, len);
}
void ssh2_mac_generate(ssh2_mac *mac, void *blk, int len, unsigned long seq)
{
ssh2_mac_prepare(mac, blk, len, seq);
ssh2_mac_genresult(mac, (unsigned char *)blk + len);
}
bool ssh2_mac_verify(
ssh2_mac *mac, const void *blk, int len, unsigned long seq)
{
ssh2_mac_prepare(mac, blk, len, seq);
return ssh2_mac_verresult(mac, (const unsigned char *)blk + len);
}