postgres.git / summary / log / commit / refs
commit d724237551b2b43c9c6f217de44bf210b0f50fdd
Author: Magnus Hagander <magnus@hagander.net>
Date: Wed Dec 09 06:37:25 2009 +0000
First released in: 9.0.0, 7.4.27, 8.0.23, 8.1.19, 8.2.15, 8.3.9, 8.4.2
Reject certificates with embedded NULLs in the commonName field. This stops
attacks where an attacker would put <attack>\0<propername> in the field and
trick the validation code that the certificate was for <attack>.
This is a very low risk attack since it reuqires the attacker to trick the
CA into issuing a certificate with an incorrect field, and the common
PostgreSQL deployments are with private CAs, and not external ones. Also,
default mode in 8.4 does not do any name validation, and is thus also not
vulnerable - but the higher security modes are.
Backpatch all the way. Even though versions 8.3.x and before didn't have
certificate name validation support, they still exposed this field for
the user to perform the validation in the application code, and there
is no way to detect this problem through that API.
Security: CVE-2009-4034
src/backend/libpq/be-secure.c | 24 ++++++++++++++++++++++--
src/interfaces/libpq/fe-secure.c | 25 ++++++++++++++++++++++---
2 files changed, 44 insertions(+), 5 deletions(-)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index b3d00746eb9..e3a7abc205e 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.83.2.1 2009/01/28 15:06:57 mha Exp $
+ * $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.83.2.2 2009/12/09 06:37:25 mha Exp $
*
* Since the server static private key ($DataDir/server.key)
* will normally be stored unencrypted so that the database
@@ -938,9 +938,29 @@ aloop:
X509_NAME_oneline(X509_get_subject_name(port->peer),
port->peer_dn, sizeof(port->peer_dn));
port->peer_dn[sizeof(port->peer_dn) - 1] = '\0';
- X509_NAME_get_text_by_NID(X509_get_subject_name(port->peer),
+ r = X509_NAME_get_text_by_NID(X509_get_subject_name(port->peer),
NID_commonName, port->peer_cn, sizeof(port->peer_cn));
port->peer_cn[sizeof(port->peer_cn) - 1] = '\0';
+ if (r == -1)
+ {
+ /* Unable to get the CN, set it to blank so it can't be used */
+ port->peer_cn[0] = '\0';
+ }
+ else
+ {
+ /*
+ * Reject embedded NULLs in certificate common name to prevent attacks like
+ * CVE-2009-4034.
+ */
+ if (r != strlen(port->peer_cn))
+ {
+ ereport(COMMERROR,
+ (errcode(ERRCODE_PROTOCOL_VIOLATION),
+ errmsg("SSL certificate's common name contains embedded null")));
+ close_SSL(port);
+ return -1;
+ }
+ }
}
ereport(DEBUG2,
(errmsg("SSL connection from \"%s\"", port->peer_cn)));
diff --git a/src/interfaces/libpq/fe-secure.c b/src/interfaces/libpq/fe-secure.c
index af919a8333e..a1aa0463407 100644
--- a/src/interfaces/libpq/fe-secure.c
+++ b/src/interfaces/libpq/fe-secure.c
@@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/fe-secure.c,v 1.102.2.1 2009/01/28 15:06:57 mha Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-secure.c,v 1.102.2.2 2009/12/09 06:37:25 mha Exp $
*
* NOTES
* [ Most of these notes are wrong/obsolete, but perhaps not all ]
@@ -1087,9 +1087,28 @@ open_client_SSL(PGconn *conn)
conn->peer_dn, sizeof(conn->peer_dn));
conn->peer_dn[sizeof(conn->peer_dn) - 1] = '\0';
- X509_NAME_get_text_by_NID(X509_get_subject_name(conn->peer),
+ r = X509_NAME_get_text_by_NID(X509_get_subject_name(conn->peer),
NID_commonName, conn->peer_cn, SM_USER);
- conn->peer_cn[SM_USER] = '\0';
+ conn->peer_cn[SM_USER] = '\0'; /* buffer is SM_USER+1 chars! */
+ if (r == -1)
+ {
+ /* Unable to get the CN, set it to blank so it can't be used */
+ conn->peer_cn[0] = '\0';
+ }
+ else
+ {
+ /*
+ * Reject embedded NULLs in certificate common name to prevent attacks like
+ * CVE-2009-4034.
+ */
+ if (r != strlen(conn->peer_cn))
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("SSL certificate's common name contains embedded null\n"));
+ close_SSL(conn);
+ return PGRES_POLLING_FAILED;
+ }
+ }
/* verify that the common name resolves to peer */
[parent: d01b2e4e47e0]