diff --git a/library/x509.c b/library/x509.c index f1d988aa75..cdc87e53eb 100644 --- a/library/x509.c +++ b/library/x509.c @@ -468,6 +468,11 @@ static int x509_get_attr_type_value( unsigned char **p, * For the general case we still use a flat list, but we mark elements of the * same set so that they are "merged" together in the functions that consume * this list, eg mbedtls_x509_dn_gets(). + * + * On success, this function allocates a linked list starting at cur->next + * that must later be free'd by the caller using mbedtls_free(). In error + * cases, this function frees all allocated memory internally and the caller + * has no freeing responsibilities. */ int mbedtls_x509_get_name( unsigned char **p, const unsigned char *end, mbedtls_x509_name *cur ) @@ -475,6 +480,8 @@ int mbedtls_x509_get_name( unsigned char **p, const unsigned char *end, int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t set_len; const unsigned char *end_set; + mbedtls_x509_name *head = cur; + mbedtls_x509_name *prev, *allocated; /* don't use recursion, we'd risk stack overflow if not optimized */ while( 1 ) @@ -484,14 +491,17 @@ int mbedtls_x509_get_name( unsigned char **p, const unsigned char *end, */ if( ( ret = mbedtls_asn1_get_tag( p, end, &set_len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SET ) ) != 0 ) - return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_X509_INVALID_NAME, ret ) ); + { + ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_X509_INVALID_NAME, ret ); + goto error; + } end_set = *p + set_len; while( 1 ) { if( ( ret = x509_get_attr_type_value( p, end_set, cur ) ) != 0 ) - return( ret ); + goto error; if( *p == end_set ) break; @@ -502,7 +512,10 @@ int mbedtls_x509_get_name( unsigned char **p, const unsigned char *end, cur->next = mbedtls_calloc( 1, sizeof( mbedtls_x509_name ) ); if( cur->next == NULL ) - return( MBEDTLS_ERR_X509_ALLOC_FAILED ); + { + ret = MBEDTLS_ERR_X509_ALLOC_FAILED; + goto error; + } cur = cur->next; } @@ -516,10 +529,35 @@ int mbedtls_x509_get_name( unsigned char **p, const unsigned char *end, cur->next = mbedtls_calloc( 1, sizeof( mbedtls_x509_name ) ); if( cur->next == NULL ) - return( MBEDTLS_ERR_X509_ALLOC_FAILED ); + { + ret = MBEDTLS_ERR_X509_ALLOC_FAILED; + goto error; + } cur = cur->next; } + +error: + prev = NULL; + + /* Skip the first element as we did not allocate it */ + allocated = head->next; + + /* Make sure we cannot be followed along this list */ + head->next = NULL; + + while( allocated != NULL ) + { + prev = allocated; + allocated = allocated->next; + + mbedtls_platform_zeroize( prev, sizeof( *prev ) ); + mbedtls_free( prev ); + } + + mbedtls_platform_zeroize( head, sizeof( *head ) ); + + return ret; } static int x509_parse_int( unsigned char **p, size_t n, int *res )