Fixed pathlen contraint enforcement.
diff --git a/library/x509_crt.c b/library/x509_crt.c
index 3fb2b68..cb63b13 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1766,7 +1766,8 @@
static int x509_crt_verify_top(
x509_crt *child, x509_crt *trust_ca,
- x509_crl *ca_crl, int path_cnt, int *flags,
+ x509_crl *ca_crl,
+ int path_cnt, int self_cnt, int *flags,
int (*f_vrfy)(void *, x509_crt *, int, int *),
void *p_vrfy )
{
@@ -1815,8 +1816,9 @@
check_path_cnt--;
}
+ /* Self signed certificates do not count towards the limit */
if( trust_ca->max_pathlen > 0 &&
- trust_ca->max_pathlen < check_path_cnt )
+ trust_ca->max_pathlen < check_path_cnt - self_cnt )
{
continue;
}
@@ -1881,8 +1883,9 @@
}
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,
+ x509_crt *child, x509_crt *parent,
+ x509_crt *trust_ca, x509_crl *ca_crl,
+ int path_cnt, int self_cnt, int *flags,
int (*f_vrfy)(void *, x509_crt *, int, int *),
void *p_vrfy )
{
@@ -1892,6 +1895,10 @@
x509_crt *grandparent;
const md_info_t *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 > POLARSSL_X509_MAX_INTERMEDIATE_CA )
{
@@ -1943,7 +1950,7 @@
if( grandparent != NULL )
{
ret = x509_crt_verify_top( parent, grandparent, ca_crl,
- path_cnt + 1, &parent_flags, f_vrfy, p_vrfy );
+ path_cnt + 1, self_cnt, &parent_flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
@@ -1954,6 +1961,15 @@
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;
@@ -1963,7 +1979,7 @@
if( grandparent != NULL )
{
ret = x509_crt_verify_child( parent, grandparent, trust_ca, ca_crl,
- path_cnt + 1, &parent_flags,
+ path_cnt + 1, self_cnt, &parent_flags,
f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
@@ -1971,7 +1987,7 @@
else
{
ret = x509_crt_verify_top( parent, trust_ca, ca_crl,
- path_cnt + 1, &parent_flags,
+ path_cnt + 1, self_cnt, &parent_flags,
f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
@@ -2001,6 +2017,7 @@
size_t cn_len;
int ret;
int pathlen = 0;
+ int selfsigned = 0;
x509_crt *parent;
x509_name *name;
x509_sequence *cur = NULL;
@@ -2067,7 +2084,7 @@
if( parent != NULL )
{
ret = x509_crt_verify_top( crt, parent, ca_crl,
- pathlen, flags, f_vrfy, p_vrfy );
+ pathlen, selfsigned, flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
@@ -2076,6 +2093,14 @@
/* Look for a parent upwards the chain */
for( parent = crt->next; parent != NULL; parent = parent->next )
{
+ /* +2 because the current step is not yet accounted for
+ * and because max_pathlen is one higher than it should be */
+ if( parent->max_pathlen > 0 &&
+ parent->max_pathlen < 2 + pathlen )
+ {
+ continue;
+ }
+
if( x509_crt_check_parent( crt, parent, 0, pathlen == 0 ) == 0 )
break;
}
@@ -2084,14 +2109,14 @@
if( parent != NULL )
{
ret = x509_crt_verify_child( crt, parent, trust_ca, ca_crl,
- pathlen, flags, f_vrfy, p_vrfy );
+ pathlen, selfsigned, 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 );
+ pathlen, selfsigned, flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}