[crypto] Add x509_truncate() to truncate a certificate chain

Downloading a cross-signed certificate chain to partially replace
(rather than simply extend) an existing chain will require the ability
to discard all certificates after a specified link in the chain.

Extract the relevant logic from x509_free_chain() and expose it
separately as x509_truncate().

Signed-off-by: Michael Brown <mcb30@ipxe.org>
pull/154/merge
Michael Brown 2024-02-13 16:27:31 +00:00
parent e10dfe5dc7
commit 3e721e0c08
3 changed files with 37 additions and 9 deletions

View File

@ -1603,19 +1603,12 @@ int x509_check_name ( struct x509_certificate *cert, const char *name ) {
static void x509_free_chain ( struct refcnt *refcnt ) {
struct x509_chain *chain =
container_of ( refcnt, struct x509_chain, refcnt );
struct x509_link *link;
struct x509_link *tmp;
DBGC2 ( chain, "X509 chain %p freed\n", chain );
/* Free each link in the chain */
list_for_each_entry_safe ( link, tmp, &chain->links, list ) {
x509_put ( link->cert );
list_del ( &link->list );
free ( link );
}
/* Free chain */
x509_truncate ( chain, NULL );
assert ( list_empty ( &chain->links ) );
free ( chain );
}
@ -1696,6 +1689,27 @@ int x509_append_raw ( struct x509_chain *chain, const void *data,
return rc;
}
/**
* Truncate X.509 certificate chain
*
* @v chain X.509 certificate chain
* @v link Link after which to truncate chain, or NULL
*/
void x509_truncate ( struct x509_chain *chain, struct x509_link *link ) {
struct x509_link *tmp;
/* Truncate entire chain if no link is specified */
if ( ! link )
link = list_entry ( &chain->links, struct x509_link, list );
/* Free each link in the chain */
list_for_each_entry_safe_continue ( link, tmp, &chain->links, list ) {
x509_put ( link->cert );
list_del ( &link->list );
free ( link );
}
}
/**
* Identify X.509 certificate by subject
*

View File

@ -391,6 +391,7 @@ extern int x509_append ( struct x509_chain *chain,
struct x509_certificate *cert );
extern int x509_append_raw ( struct x509_chain *chain, const void *data,
size_t len );
extern void x509_truncate ( struct x509_chain *chain, struct x509_link *link );
extern int x509_auto_append ( struct x509_chain *chain,
struct x509_chain *certs );
extern int x509_validate_chain ( struct x509_chain *chain, time_t time,

View File

@ -984,6 +984,7 @@ static void x509_validate_chain_fail_okx ( struct x509_test_chain *chn,
*
*/
static void x509_test_exec ( void ) {
struct x509_link *link;
/* Parse all certificates */
x509_certificate_ok ( &root_crt );
@ -1089,6 +1090,18 @@ static void x509_test_exec ( void ) {
x509_validate_chain_fail_ok ( &useless_chain, test_ca_expired,
&empty_store, &test_root );
/* Check chain truncation */
link = list_last_entry ( &server_chain.chain->links,
struct x509_link, list );
ok ( link->cert == root_crt.cert );
link = list_prev_entry ( link, &server_chain.chain->links, list );
ok ( link->cert == intermediate_crt.cert );
x509_validate_chain_ok ( &server_chain, test_time,
&empty_store, &test_root );
x509_truncate ( server_chain.chain, link );
x509_validate_chain_fail_ok ( &server_chain, test_time,
&empty_store, &test_root );
/* Sanity check */
assert ( list_empty ( &empty_store.links ) );