Set type identifier on BIO

danielgustafsson · danielgustafsson · commit e15f32f0edf6 · 2021-08-17T14:31:00.000+02:00
In OpenSSL there are two types of BIO's (I/O abstractions): source/sink and filters. A source/sink BIO is a source and/or sink of data, ie one acting on a socket or a file. A filter BIO takes a stream of input from another BIO and transforms it. In order for BIO_find_type() to be able to traverse the chain of BIO's and correctly find all BIO's of a certain type they shall have the type bit set accordingly, source/sink BIO's (what PostgreSQL implements) use BIO_TYPE_SOURCE_SINK and filter BIO's use BIO_TYPE_FILTER. In addition to these, file descriptor based BIO's should have the descriptor bit set, BIO_TYPE_DESCRIPTOR. The PostgreSQL implementation didn't set the type bits, which went unnoticed for a long time as it's only really relevant for code auditing the OpenSSL installation, or doing similar tasks. It is required by the API though, so this fixes it. Backpatch through 9.6 as this has been wrong for a long time. Author: Itamar Gafni Discussion: https://postgr.es/m/SN6PR06MB39665EC10C34BB20956AE4578AF39@SN6PR06MB3966.namprd06.prod.outlook.com Backpatch-through: 9.6
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
@@ -808,6 +808,7 @@ my_BIO_s_socket(void)
 		my_bio_index = BIO_get_new_index();
 		if (my_bio_index == -1)
 			return NULL;
+		my_bio_index |= (BIO_TYPE_DESCRIPTOR | BIO_TYPE_SOURCE_SINK);
 		my_bio_methods = BIO_meth_new(my_bio_index, "PostgreSQL backend socket");
 		if (!my_bio_methods)
 			return NULL;
diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c
@@ -1642,6 +1642,7 @@ my_BIO_s_socket(void)
 		my_bio_index = BIO_get_new_index();
 		if (my_bio_index == -1)
 			return NULL;
+		my_bio_index |= (BIO_TYPE_DESCRIPTOR | BIO_TYPE_SOURCE_SINK);
 		my_bio_methods = BIO_meth_new(my_bio_index, "libpq socket");
 		if (!my_bio_methods)
 			return NULL;
