/*
* Verify the certificate validity, with profile
*/
int ttls_x509_crt_verify_with_profile(ttls_x509_crt *crt,
ttls_x509_crt *trust_ca,
ttls_x509_crl *ca_crl,
const ttls_x509_crt_profile *profile,
const char *cn, uint32_t *flags)
{
size_t cn_len;
int ret;
int pathlen = 0, selfsigned = 0;
ttls_x509_crt *parent;
ttls_x509_name *name;
ttls_x509_sequence *cur = NULL;
ttls_pk_type_t pk_type;
*flags = 0;
if (profile == NULL)
{
ret = TTLS_ERR_X509_BAD_INPUT_DATA;
goto exit;
}
if (cn != NULL)
{
name = &crt->subject;
cn_len = strlen(cn);
if (crt->ext_types & TTLS_X509_EXT_SUBJECT_ALT_NAME)
{
cur = &crt->subject_alt_names;
while (cur != NULL)
{
if (cur->buf.len == cn_len
&& !x509_memcasecmp(cn, cur->buf.p, cn_len))
break;
if (cur->buf.len > 2
&& !memcmp(cur->buf.p, "*.", 2)
&& !x509_check_wildcard(cn, &cur->buf))
break;
cur = cur->next;
}
if (cur == NULL)
*flags |= TTLS_X509_BADCERT_CN_MISMATCH;
}
else
{
while (name != NULL)
{
if (!TTLS_OID_CMP(TTLS_OID_AT_CN, &name->oid)) {
if (name->val.len == cn_len
&& !x509_memcasecmp(name->val.p, cn,
cn_len))
break;
if (name->val.len > 2
&& !memcmp(name->val.p, "*.", 2)
&& !x509_check_wildcard(cn,
&name->val))
break;
}
name = name->next;
}
if (name == NULL)
*flags |= TTLS_X509_BADCERT_CN_MISMATCH;
}
}
/* Check the type and size of the key */
pk_type = ttls_pk_get_type(&crt->pk);
if (x509_profile_check_pk_alg(profile, pk_type) != 0)
*flags |= TTLS_X509_BADCERT_BAD_PK;
if (x509_profile_check_key(profile, pk_type, &crt->pk) != 0)
*flags |= TTLS_X509_BADCERT_BAD_KEY;
/* Look for a parent in trusted CAs */
for (parent = trust_ca; parent != NULL; parent = parent->next)
{
if (x509_crt_check_parent(crt, parent, 0, pathlen == 0) == 0)
break;
}
if (parent != NULL)
{
ret = x509_crt_verify_top(crt, parent, ca_crl, profile, pathlen,
selfsigned, flags);
if (ret != 0)
goto exit;
}
else
{
/* Look for a parent upwards the chain */
for (parent = crt->next; parent != NULL; parent = parent->next)
if (x509_crt_check_parent(crt, parent, 0, pathlen == 0) == 0)
break;
/* Are we part of the chain or at the top? */
if (parent != NULL)
{
ret = x509_crt_verify_child(crt, parent, trust_ca,
ca_crl, profile, pathlen,
selfsigned, flags);
if (ret != 0)
goto exit;
}
else
{
ret = x509_crt_verify_top(crt, trust_ca, ca_crl,
profile, pathlen, selfsigned,
flags);
if (ret != 0)
goto exit;
}
}
exit:
/* prevent misuse of the vrfy callback - VERIFY_FAILED would be ignored by
* the SSL module for authmode optional, but non-zero return from the
* callback means a fatal error so it shouldn't be ignored */
if (ret == TTLS_ERR_X509_CERT_VERIFY_FAILED)
ret = TTLS_ERR_X509_FATAL_ERROR;
if (ret != 0)
{
*flags = (uint32_t) -1;
return ret;
}
if (*flags != 0)
return TTLS_ERR_X509_CERT_VERIFY_FAILED;
return 0;
}
/*
* Verify the certificate validity
*/
int x509_crt_verify( x509_crt *crt,
x509_crt *trust_ca,
x509_crl *ca_crl,
const char *cn, int *flags,
int (*f_vrfy)(void *, x509_crt *, int, int *),
void *p_vrfy )
{
size_t cn_len;
int ret;
int pathlen = 0;
x509_crt *parent;
x509_name *name;
x509_sequence *cur = NULL;
*flags = 0;
if( cn != NULL )
{
name = &crt->subject;
cn_len = strlen( cn );
if( crt->ext_types & EXT_SUBJECT_ALT_NAME )
{
cur = &crt->subject_alt_names;
while( cur != NULL )
{
if( cur->buf.len == cn_len &&
x509_name_cmp( cn, cur->buf.p, cn_len ) == 0 )
break;
if( cur->buf.len > 2 &&
memcmp( cur->buf.p, "*.", 2 ) == 0 &&
x509_wildcard_verify( cn, &cur->buf ) )
break;
cur = cur->next;
}
if( cur == NULL )
*flags |= BADCERT_CN_MISMATCH;
}
else
{
while( name != NULL )
{
if( OID_CMP( OID_AT_CN, &name->oid ) )
{
if( name->val.len == cn_len &&
x509_name_cmp( name->val.p, cn, cn_len ) == 0 )
break;
if( name->val.len > 2 &&
memcmp( name->val.p, "*.", 2 ) == 0 &&
x509_wildcard_verify( cn, &name->val ) )
break;
}
name = name->next;
}
if( name == NULL )
*flags |= BADCERT_CN_MISMATCH;
}
}
/*
* Iterate upwards in the given cert chain, to find our crt parent.
* Ignore any upper cert with CA != TRUE.
*/
parent = crt->next;
while( parent != NULL && parent->version != 0 )
{
if( parent->ca_istrue == 0 ||
crt->issuer_raw.len != parent->subject_raw.len ||
memcmp( crt->issuer_raw.p, parent->subject_raw.p,
crt->issuer_raw.len ) != 0 )
{
parent = parent->next;
continue;
}
break;
}
if( parent != NULL )
{
/*
* Part of the chain
*/
ret = x509_crt_verify_child( crt, parent, trust_ca, ca_crl, pathlen, flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
else
{
ret = x509_crt_verify_top( crt, trust_ca, ca_crl, pathlen, flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
if( *flags != 0 )
return( POLARSSL_ERR_X509_CERT_VERIFY_FAILED );
return( 0 );
}
static int
x509_crt_verify_child(ttls_x509_crt *child, ttls_x509_crt *parent,
ttls_x509_crt *trust_ca, ttls_x509_crl *ca_crl,
const ttls_x509_crt_profile *profile,
int path_cnt, int self_cnt, uint32_t *flags)
{
int ret;
uint32_t parent_flags = 0;
unsigned char hash[TTLS_MD_MAX_SIZE];
ttls_x509_crt *grandparent;
const TlsMdInfo *md_info;
/* Counting intermediate self signed certificates */
if ((path_cnt != 0) && x509_name_cmp(&child->issuer, &child->subject) == 0)
self_cnt++;
/* path_cnt is 0 for the first intermediate CA */
if (1 + path_cnt > TTLS_X509_MAX_INTERMEDIATE_CA)
{
/* return immediately as the goal is to avoid unbounded recursion */
return(TTLS_ERR_X509_FATAL_ERROR);
}
if (ttls_x509_time_is_past(&child->valid_to))
*flags |= TTLS_X509_BADCERT_EXPIRED;
if (ttls_x509_time_is_future(&child->valid_from))
*flags |= TTLS_X509_BADCERT_FUTURE;
if (x509_profile_check_md_alg(profile, child->sig_md) != 0)
*flags |= TTLS_X509_BADCERT_BAD_MD;
if (x509_profile_check_pk_alg(profile, child->sig_pk) != 0)
*flags |= TTLS_X509_BADCERT_BAD_PK;
md_info = ttls_md_info_from_type(child->sig_md);
if (md_info == NULL)
{
/*
* Cannot check 'unknown' hash
*/
T_WARN("certificate uses unsupported hash %d\n", child->sig_md);
*flags |= TTLS_X509_BADCERT_NOT_TRUSTED;
}
else
{
ttls_md(md_info, child->tbs.p, child->tbs.len, hash);
if (x509_profile_check_key(profile, child->sig_pk, &parent->pk) != 0)
*flags |= TTLS_X509_BADCERT_BAD_KEY;
if (ttls_pk_verify_ext(child->sig_pk, child->sig_opts, &parent->pk,
child->sig_md, hash, ttls_md_get_size(md_info),
child->sig.p, child->sig.len) != 0)
{
*flags |= TTLS_X509_BADCERT_NOT_TRUSTED;
}
}
#if defined(TTLS_X509_CRL_PARSE_C)
/* Check trusted CA's CRL for the given crt */
*flags |= x509_crt_verifycrl(child, parent, ca_crl, profile);
#endif
/* Look for a grandparent in trusted CAs */
for (grandparent = trust_ca;
grandparent != NULL;
grandparent = grandparent->next)
{
if (x509_crt_check_parent(parent, grandparent,
0, path_cnt == 0) == 0)
break;
}
if (grandparent != NULL)
{
ret = x509_crt_verify_top(parent, grandparent, ca_crl, profile,
path_cnt + 1, self_cnt, &parent_flags);
if (ret != 0)
return ret;
}
else
{
/* Look for a grandparent upwards the chain */
for (grandparent = parent->next;
grandparent != NULL;
grandparent = grandparent->next)
{
/* +2 because the current step is not yet accounted for
* and because max_pathlen is one higher than it should be.
* Also self signed certificates do not count to the limit. */
if (grandparent->max_pathlen > 0 &&
grandparent->max_pathlen < 2 + path_cnt - self_cnt)
{
continue;
}
if (x509_crt_check_parent(parent, grandparent,
0, path_cnt == 0) == 0)
break;
}
/* Is our parent part of the chain or at the top? */
if (grandparent != NULL)
{
ret = x509_crt_verify_child(parent, grandparent,
trust_ca, ca_crl, profile,
path_cnt + 1, self_cnt,
&parent_flags);
if (ret != 0)
return ret;
}
else
{
ret = x509_crt_verify_top(parent, trust_ca, ca_crl,
profile, path_cnt + 1,
self_cnt, &parent_flags);
if (ret != 0)
return ret;
}
}
*flags |= parent_flags;
return 0;
}
static int x509_crt_verify_child(
x509_crt *child, x509_crt *parent, x509_crt *trust_ca,
x509_crl *ca_crl, int path_cnt, int *flags,
int (*f_vrfy)(void *, x509_crt *, int, int *),
void *p_vrfy )
{
int ret;
int parent_flags = 0;
unsigned char hash[POLARSSL_MD_MAX_SIZE];
x509_crt *grandparent;
const md_info_t *md_info;
if( x509_time_expired( &child->valid_to ) )
*flags |= BADCERT_EXPIRED;
md_info = md_info_from_type( child->sig_md );
if( md_info == NULL )
{
/*
* Cannot check 'unknown' hash
*/
*flags |= BADCERT_NOT_TRUSTED;
}
else
{
md( md_info, child->tbs.p, child->tbs.len, hash );
if( pk_can_do( &parent->pk, child->sig_pk ) == 0 ||
pk_verify( &parent->pk, child->sig_md, hash, md_info->size,
child->sig.p, child->sig.len ) != 0 )
{
*flags |= BADCERT_NOT_TRUSTED;
}
}
#if defined(POLARSSL_X509_CRL_PARSE_C)
/* Check trusted CA's CRL for the given crt */
*flags |= x509_crt_verifycrl(child, parent, ca_crl);
#endif
grandparent = parent->next;
while( grandparent != NULL )
{
if( grandparent->version == 0 ||
grandparent->ca_istrue == 0 ||
parent->issuer_raw.len != grandparent->subject_raw.len ||
memcmp( parent->issuer_raw.p, grandparent->subject_raw.p,
parent->issuer_raw.len ) != 0 )
{
grandparent = grandparent->next;
continue;
}
break;
}
if( grandparent != NULL )
{
/*
* Part of the chain
*/
ret = x509_crt_verify_child( parent, grandparent, trust_ca, ca_crl, path_cnt + 1, &parent_flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
else
{
ret = x509_crt_verify_top( parent, trust_ca, ca_crl, path_cnt + 1, &parent_flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
/* child is verified to be a child of the parent, call verify callback */
if( NULL != f_vrfy )
if( ( ret = f_vrfy( p_vrfy, child, path_cnt, flags ) ) != 0 )
return( ret );
*flags |= parent_flags;
return( 0 );
}
