Commit 915275ba authored by Paul Bakker's avatar Paul Bakker
Browse files

- Revamped x509_verify() and the SSL f_vrfy callback implementations

parent 819370c7
......@@ -43,6 +43,7 @@ Changes
* Revamped session resumption handling
* Generalized external private key implementation handling (like PKCS#11)
in SSL/TLS
* Revamped x509_verify() and the SSL f_vrfy callback implementations
Bugfix
* Fixed handling error in mpi_cmp_mpi() on longer B values (found by
......
......@@ -397,7 +397,7 @@ struct _ssl_context
void (*f_dbg)(void *, int, const char *);
int (*f_recv)(void *, unsigned char *, size_t);
int (*f_send)(void *, const unsigned char *, size_t);
int (*f_vrfy)(void *, x509_cert *, int, int);
int (*f_vrfy)(void *, x509_cert *, int, int *);
int (*f_get_cache)(void *, ssl_session *);
int (*f_set_cache)(void *, const ssl_session *);
int (*f_sni)(void *, ssl_context *, const unsigned char *, size_t);
......@@ -601,18 +601,16 @@ void ssl_set_authmode( ssl_context *ssl, int authmode );
/**
* \brief Set the verification callback (Optional).
*
* If set, the verification callback is called once for every
* certificate in the chain. The verification function has the
* following parameter: (void *parameter, x509_cert certificate,
* int certifcate_depth, int preverify_ok). It should
* return 0 on SUCCESS.
* If set, the verify callback is called for each
* certificate in the chain. For implementation
* information, please see \c x509parse_verify()
*
* \param ssl SSL context
* \param f_vrfy verification function
* \param p_vrfy verification parameter
*/
void ssl_set_verify( ssl_context *ssl,
int (*f_vrfy)(void *, x509_cert *, int, int),
int (*f_vrfy)(void *, x509_cert *, int, int *),
void *p_vrfy );
/**
......
......@@ -77,6 +77,7 @@
#define BADCRL_EXPIRED 0x20 /**< CRL is expired. */
#define BADCERT_MISSING 0x40 /**< Certificate was missing. */
#define BADCERT_SKIP_VERIFY 0x80 /**< Certificate verification was skipped. */
#define BADCERT_OTHER 0x0100 /**< Other reason (can be used by verify callback) */
/* \} name */
/* \} addtogroup x509_module */
......@@ -310,7 +311,7 @@ typedef struct _x509_cert
int ext_types; /**< Bit string containing detected and parsed extensions */
int ca_istrue; /**< Optional Basic Constraint extension value: 1 if this certificate belongs to a CA, 0 otherwise. */
int max_pathlen; /**< Optional Basic Constraint extension value: The maximum path length to the root certificate. */
int max_pathlen; /**< Optional Basic Constraint extension value: The maximum path length to the root certificate. Path length is 1 higher than RFC 5280 'meaning', so 1+ */
unsigned char key_usage; /**< Optional key usage extension value: See the values below */
......@@ -671,6 +672,20 @@ int x509parse_time_expired( const x509_time *time );
/**
* \brief Verify the certificate signature
*
* The verify callback is a user-supplied callback that
* can clear / modify / add flags for a certificate. If set,
* the verification callback is called for each
* certificate in the chain (from the trust-ca down to the
* presented crt). The parameters for the callback are:
* (void *parameter, x509_cert *crt, int certificate_depth,
* int *flags). With the flags representing current flags for
* that specific certificate and the certificate depth from
* the top (Trust CA depth = 0).
*
* All flags left after returning from the callback
* are also returned to the application. The function should
* return 0 for anything but a fatal error.
*
* \param crt a certificate to be verified
* \param trust_ca the trusted CA chain
* \param ca_crl the CRL chain for trusted CA's
......@@ -687,14 +702,14 @@ int x509parse_time_expired( const x509_time *time );
* BADCERT_REVOKED --
* BADCERT_CN_MISMATCH --
* BADCERT_NOT_TRUSTED
*
* \note TODO: add two arguments, depth and crl
* or another error in case of a fatal error encountered
* during the verification process.
*/
int x509parse_verify( x509_cert *crt,
x509_cert *trust_ca,
x509_crl *ca_crl,
const char *cn, int *flags,
int (*f_vrfy)(void *, x509_cert *, int, int),
int (*f_vrfy)(void *, x509_cert *, int, int *),
void *p_vrfy );
/**
......
......@@ -2959,7 +2959,7 @@ void ssl_set_authmode( ssl_context *ssl, int authmode )
}
void ssl_set_verify( ssl_context *ssl,
int (*f_vrfy)(void *, x509_cert *, int, int),
int (*f_vrfy)(void *, x509_cert *, int, int *),
void *p_vrfy )
{
ssl->f_vrfy = f_vrfy;
......
......@@ -3004,15 +3004,19 @@ static int x509parse_verifycrl(x509_cert *crt, x509_cert *ca,
int hash_id;
unsigned char hash[64];
if( ca == NULL )
return( flags );
/*
* TODO: What happens if no CRL is present?
* Suggestion: Revocation state should be unknown if no CRL is present.
* For backwards compatibility this is not yet implemented.
*/
while( ca != NULL && crl_list != NULL && crl_list->version != 0 )
while( crl_list != NULL )
{
if( crl_list->issuer_raw.len != ca->subject_raw.len ||
if( crl_list->version == 0 ||
crl_list->issuer_raw.len != ca->subject_raw.len ||
memcmp( crl_list->issuer_raw.p, ca->subject_raw.p,
crl_list->issuer_raw.len ) != 0 )
{
......@@ -3086,6 +3090,168 @@ int x509_wildcard_verify( const char *cn, x509_buf *name )
return( 0 );
}
static int x509parse_verify_top(
x509_cert *child, x509_cert *trust_ca,
x509_crl *ca_crl, int *path_cnt, int *flags,
int (*f_vrfy)(void *, x509_cert *, int, int *),
void *p_vrfy )
{
int hash_id, ret;
int ca_flags = 0;
unsigned char hash[64];
if( x509parse_time_expired( &child->valid_to ) )
*flags |= BADCERT_EXPIRED;
/*
* Child is the top of the chain. Check against the trust_ca list.
*/
*flags |= BADCERT_NOT_TRUSTED;
while( trust_ca != NULL )
{
if( trust_ca->version == 0 ||
child->issuer_raw.len != trust_ca->subject_raw.len ||
memcmp( child->issuer_raw.p, trust_ca->subject_raw.p,
child->issuer_raw.len ) != 0 )
{
trust_ca = trust_ca->next;
continue;
}
if( trust_ca->max_pathlen > 0 &&
trust_ca->max_pathlen < *path_cnt )
{
trust_ca = trust_ca->next;
continue;
}
hash_id = child->sig_alg;
x509_hash( child->tbs.p, child->tbs.len, hash_id, hash );
if( rsa_pkcs1_verify( &trust_ca->rsa, RSA_PUBLIC, hash_id,
0, hash, child->sig.p ) != 0 )
{
trust_ca = trust_ca->next;
continue;
}
/*
* Top of chain is signed by a trusted CA
*/
*flags &= ~BADCERT_NOT_TRUSTED;
break;
}
if( trust_ca != NULL )
{
/* Check trusted CA's CRL for then chain's top crt */
*flags |= x509parse_verifycrl( child, trust_ca, ca_crl );
if( x509parse_time_expired( &trust_ca->valid_to ) )
ca_flags |= BADCERT_EXPIRED;
hash_id = trust_ca->sig_alg;
x509_hash( trust_ca->tbs.p, trust_ca->tbs.len, hash_id, hash );
if( rsa_pkcs1_verify( &trust_ca->rsa, RSA_PUBLIC, hash_id,
0, hash, trust_ca->sig.p ) != 0 )
{
ca_flags |= BADCERT_NOT_TRUSTED;
}
if( NULL != f_vrfy )
{
if( ( ret = f_vrfy( p_vrfy, trust_ca, 0, &ca_flags ) ) != 0 )
return( ret );
}
}
/* Call callback on top cert */
if( NULL != f_vrfy )
{
if( ( ret = f_vrfy(p_vrfy, child, 1, flags ) ) != 0 )
return( ret );
}
*path_cnt = 2;
*flags |= ca_flags;
return( 0 );
}
static int x509parse_verify_child(
x509_cert *child, x509_cert *parent, x509_cert *trust_ca,
x509_crl *ca_crl, int *path_cnt, int *flags,
int (*f_vrfy)(void *, x509_cert *, int, int *),
void *p_vrfy )
{
int hash_id, ret;
int parent_flags = 0;
unsigned char hash[64];
x509_cert *grandparent;
if( x509parse_time_expired( &child->valid_to ) )
*flags |= BADCERT_EXPIRED;
hash_id = child->sig_alg;
x509_hash( child->tbs.p, child->tbs.len, hash_id, hash );
if( rsa_pkcs1_verify( &parent->rsa, RSA_PUBLIC, hash_id, 0, hash,
child->sig.p ) != 0 )
*flags |= BADCERT_NOT_TRUSTED;
/* Check trusted CA's CRL for the given crt */
*flags |= x509parse_verifycrl(child, parent, ca_crl);
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;
}
(*path_cnt)++;
if( grandparent != NULL )
{
/*
* Part of the chain
*/
ret = x509parse_verify_child( parent, grandparent, trust_ca, ca_crl, path_cnt, &parent_flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
else
{
ret = x509parse_verify_top( parent, trust_ca, ca_crl, path_cnt, &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 );
(*path_cnt)++;
*flags |= parent_flags;
return( 0 );
}
/*
* Verify the certificate validity
*/
......@@ -3093,22 +3259,18 @@ int x509parse_verify( x509_cert *crt,
x509_cert *trust_ca,
x509_crl *ca_crl,
const char *cn, int *flags,
int (*f_vrfy)(void *, x509_cert *, int, int),
int (*f_vrfy)(void *, x509_cert *, int, int *),
void *p_vrfy )
{
size_t cn_len;
int hash_id;
int pathlen;
int ret;
int pathlen = 1;
x509_cert *parent;
x509_name *name;
unsigned char hash[64];
x509_sequence *cur = NULL;
*flags = 0;
if( x509parse_time_expired( &crt->valid_to ) )
*flags = BADCERT_EXPIRED;
if( cn != NULL )
{
name = &crt->subject;
......@@ -3161,13 +3323,11 @@ int x509parse_verify( x509_cert *crt,
}
/*
* Iterate upwards in the given cert chain,
* ignoring any upper cert with CA != TRUE.
* Iterate upwards in the given cert chain, to find our crt parent.
* Ignore any upper cert with CA != TRUE.
*/
parent = crt->next;
pathlen = 1;
while( parent != NULL && parent->version != 0 )
{
if( parent->ca_istrue == 0 ||
......@@ -3178,83 +3338,26 @@ int x509parse_verify( x509_cert *crt,
parent = parent->next;
continue;
}
hash_id = crt->sig_alg;
x509_hash( crt->tbs.p, crt->tbs.len, hash_id, hash );
if( rsa_pkcs1_verify( &parent->rsa, RSA_PUBLIC, hash_id, 0, hash,
crt->sig.p ) != 0 )
*flags |= BADCERT_NOT_TRUSTED;
/* Check trusted CA's CRL for the given crt */
*flags |= x509parse_verifycrl(crt, parent, ca_crl);
/* crt is verified to be a child of the parent cur, call verify callback */
if( NULL != f_vrfy )
{
if( f_vrfy( p_vrfy, crt, pathlen - 1, ( *flags == 0 ) ) != 0 )
return( POLARSSL_ERR_X509_CERT_VERIFY_FAILED );
else
*flags = 0;
}
else if( *flags != 0 )
return( POLARSSL_ERR_X509_CERT_VERIFY_FAILED );
pathlen++;
crt = parent;
parent = crt->next;
break;
}
/*
* Attempt to validate topmost cert with our CA chain.
*/
*flags |= BADCERT_NOT_TRUSTED;
while( trust_ca != NULL && trust_ca->version != 0 )
if( parent != NULL )
{
if( crt->issuer_raw.len != trust_ca->subject_raw.len ||
memcmp( crt->issuer_raw.p, trust_ca->subject_raw.p,
crt->issuer_raw.len ) != 0 )
{
trust_ca = trust_ca->next;
continue;
}
if( trust_ca->max_pathlen > 0 &&
trust_ca->max_pathlen < pathlen )
break;
hash_id = crt->sig_alg;
x509_hash( crt->tbs.p, crt->tbs.len, hash_id, hash );
if( rsa_pkcs1_verify( &trust_ca->rsa, RSA_PUBLIC, hash_id,
0, hash, crt->sig.p ) == 0 )
{
/*
* cert. is signed by a trusted CA
*/
*flags &= ~BADCERT_NOT_TRUSTED;
break;
}
trust_ca = trust_ca->next;
}
/* Check trusted CA's CRL for the given crt */
*flags |= x509parse_verifycrl( crt, trust_ca, ca_crl );
/* Verification succeeded, call callback on top cert */
if( NULL != f_vrfy )
/*
* Part of the chain
*/
ret = x509parse_verify_child( crt, parent, trust_ca, ca_crl, &pathlen, flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
else
{
if( f_vrfy(p_vrfy, crt, pathlen-1, ( *flags == 0 ) ) != 0 )
return( POLARSSL_ERR_X509_CERT_VERIFY_FAILED );
else
*flags = 0;
ret = x509parse_verify_top( crt, trust_ca, ca_crl, &pathlen, flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
else if( *flags != 0 )
if( *flags != 0 )
return( POLARSSL_ERR_X509_CERT_VERIFY_FAILED );
return( 0 );
......
......@@ -82,6 +82,45 @@ void my_debug( void *ctx, int level, const char *str )
}
}
/*
* Enabled if debug_level > 1 in code below
*/
int my_verify( void *data, x509_cert *crt, int depth, int *flags )
{
char buf[1024];
((void) data);
printf( "\nVerify requested for (Depth %d):\n", depth );
x509parse_cert_info( buf, sizeof( buf ) - 1, "", crt );
printf( "%s", buf );
if( ( (*flags) & BADCERT_EXPIRED ) != 0 )
printf( " ! server certificate has expired\n" );
if( ( (*flags) & BADCERT_REVOKED ) != 0 )
printf( " ! server certificate has been revoked\n" );
if( ( (*flags) & BADCERT_CN_MISMATCH ) != 0 )
printf( " ! CN mismatch\n" );
if( ( (*flags) & BADCERT_NOT_TRUSTED ) != 0 )
printf( " ! self-signed or not signed by a trusted CA\n" );
if( ( (*flags) & BADCRL_NOT_TRUSTED ) != 0 )
printf( " ! CRL not trusted\n" );
if( ( (*flags) & BADCRL_EXPIRED ) != 0 )
printf( " ! CRL expired\n" );
if( ( (*flags) & BADCERT_OTHER ) != 0 )
printf( " ! other (unknown) flag\n" );
if ( ( *flags ) == 0 )
printf( " This certificate has no flags\n" );
return( 0 );
}
#if defined(POLARSSL_FS_IO)
#define USAGE_IO \
" ca_file=%%s default: \"\" (pre-loaded)\n" \
......@@ -135,7 +174,6 @@ int main( int argc, char *argv[] )
x509_cert clicert;
rsa_context rsa;
int i;
size_t j, n;
char *p, *q;
const int *list;
......@@ -180,14 +218,6 @@ int main( int argc, char *argv[] )
for( i = 1; i < argc; i++ )
{
n = strlen( argv[i] );
for( j = 0; j < n; j++ )
{
if( argv[i][j] >= 'A' && argv[i][j] <= 'Z' )
argv[i][j] |= 0x20;
}
p = argv[i];
if( ( q = strchr( p, '=' ) ) == NULL )
goto usage;
......@@ -371,6 +401,9 @@ int main( int argc, char *argv[] )
printf( " ok\n" );
if( opt.debug_level > 0 )
ssl_set_verify( &ssl, my_verify, NULL );
ssl_set_endpoint( &ssl, SSL_IS_CLIENT );
ssl_set_authmode( &ssl, SSL_VERIFY_OPTIONAL );
......
......@@ -228,11 +228,11 @@ x509_verify:"data_files/cert_sha512.crt":"data_files/test-ca.crt":"data_files/cr
X509 Certificate verification #19 (Valid Cert, denying callback)
depends_on:POLARSSL_SHA4_C:POLARSSL_PEM_C:POLARSSL_FS_IO
x509_verify:"data_files/cert_sha512.crt":"data_files/test-ca.crt":"data_files/crl.pem":NULL:POLARSSL_ERR_X509_CERT_VERIFY_FAILED:0:&verify_none
x509_verify:"data_files/cert_sha512.crt":"data_files/test-ca.crt":"data_files/crl.pem":NULL:POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_OTHER:verify_none
X509 Certificate verification #20 (Not trusted Cert, allowing callback)
depends_on:POLARSSL_PEM_C:POLARSSL_FS_IO
x509_verify:"data_files/server2.crt":"data_files/server1.crt":"data_files/crl_expired.pem":NULL:0:0:&verify_all
x509_verify:"data_files/server2.crt":"data_files/server1.crt":"data_files/crl_expired.pem":NULL:0:0:verify_all
X509 Certificate verification #21 (domain matching wildcard certificate)
depends_on:POLARSSL_PEM_C:POLARSSL_FS_IO
......
......@@ -2,22 +2,22 @@ BEGIN_HEADER
#include <polarssl/x509.h>
#include <polarssl/pem.h>
int verify_none( void *data, x509_cert *crt, int certificate_depth, int preverify_ok )
int verify_none( void *data, x509_cert *crt, int certificate_depth, int *flags )
{
((void) data);
((void) crt);
((void) certificate_depth);
((void) preverify_ok);
return 1;
*flags |= BADCERT_OTHER;
return 0;
}
int verify_all( void *data, x509_cert *crt, int certificate_depth, int preverify_ok )
int verify_all( void *data, x509_cert *crt, int certificate_depth, int *flags )
{
((void) data);
((void) crt);
((void) certificate_depth);
((void) preverify_ok);
*flags = 0;
return 0;
}
......
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