agent: Add support for RSA signatures with SHA256 and SHA512

This commit is contained in:
Tobias Brunner
2018-10-26 09:55:07 +02:00
parent 1b510c0467
commit 5e03675a19
@@ -81,6 +81,14 @@ enum agent_msg_type_t {
SSH_AGENT_SIGN_RESPONSE = 14,
};
/**
* Flags for signatures
*/
enum agent_signature_flags_t {
SSH_AGENT_FLAG_SHA2_256 = 2,
SSH_AGENT_FLAG_SHA2_512 = 4,
};
/**
* read a byte from a blob
*/
@@ -217,12 +225,29 @@ static bool read_key(private_agent_private_key_t *this, public_key_t *pubkey)
}
static bool scheme_supported(private_agent_private_key_t *this,
signature_scheme_t scheme)
signature_scheme_t scheme, uint32_t *flags,
char **prefix)
{
switch (this->pubkey->get_type(this->pubkey))
{
case KEY_RSA:
return scheme == SIGN_RSA_EMSA_PKCS1_SHA1;
switch (scheme)
{
case SIGN_RSA_EMSA_PKCS1_SHA1:
*prefix = "ssh-rsa";
return TRUE;
case SIGN_RSA_EMSA_PKCS1_SHA2_256:
*flags |= SSH_AGENT_FLAG_SHA2_256;
*prefix = "rsa-sha2-256";
return TRUE;
case SIGN_RSA_EMSA_PKCS1_SHA2_512:
*flags |= SSH_AGENT_FLAG_SHA2_512;
*prefix = "rsa-sha2-512";
return TRUE;
default:
break;
}
return FALSE;
case KEY_ECDSA:
return scheme == SIGN_ECDSA_256 ||
scheme == SIGN_ECDSA_384 ||
@@ -236,11 +261,11 @@ METHOD(private_key_t, sign, bool,
private_agent_private_key_t *this, signature_scheme_t scheme, void *params,
chunk_t data, chunk_t *signature)
{
uint32_t len, flags;
char buf[2048];
uint32_t len, flags = 0;
char buf[2048], *prefix = NULL;
chunk_t blob;
if (!scheme_supported(this, scheme))
if (!scheme_supported(this, scheme, &flags, &prefix))
{
DBG1(DBG_LIB, "signature scheme %N not supported by ssh-agent",
signature_scheme_names, scheme);
@@ -272,7 +297,7 @@ METHOD(private_key_t, sign, bool,
return FALSE;
}
flags = htonl(0);
flags = htonl(flags);
if (write(this->socket, &flags, sizeof(flags)) != sizeof(flags))
{
DBG1(DBG_LIB, "writing to ssh-agent failed");
@@ -290,9 +315,15 @@ METHOD(private_key_t, sign, bool,
}
/* parse length */
blob = read_string(&blob);
/* check sig type */
if (chunk_equals(read_string(&blob), chunk_from_str("ssh-rsa")))
{ /* for RSA the signature has no special encoding */
/* verify type */
if (prefix && !chunk_equals(read_string(&blob), chunk_from_str(prefix)))
{
DBG1(DBG_LIB, "ssh-agent didn't return requested %s signature", prefix);
return FALSE;
}
if (this->pubkey->get_type(this->pubkey) == KEY_RSA)
{ /* for RSA, the signature has no special encoding */
blob = read_string(&blob);
if (blob.len)
{
@@ -301,7 +332,7 @@ METHOD(private_key_t, sign, bool,
}
}
else
{ /* anything else is treated as ECSDA for now */
{ /* parse ECDSA signatures */
blob = read_string(&blob);
if (blob.len)
{