From: Greg Hudson <ghudson@mit.edu>
Date: Mon, 2 Nov 2015 03:46:56 +0000 (-0500)
Subject: Fix SPNEGO context import
X-Git-Tag: krb5-1.12.5-final~14
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=04d0faa8cf9548eddcf9e2d893fc52d57f7b7531;p=thirdparty%2Fkrb5.git

Fix SPNEGO context import

The patches for CVE-2015-2695 did not implement a SPNEGO
gss_import_sec_context() function, under the erroneous belief that an
exported SPNEGO context would be tagged with the underlying context
mechanism.  Implement it now to allow SPNEGO contexts to be
successfully exported and imported after establishment.

(cherry picked from commit 222b09f6e2f536354555f2a0dedfe29fc10c01d6)

ticket: 8316
version_fixed: 1.12.5
status: resolved
---

diff --git a/src/lib/gssapi/spnego/spnego_mech.c b/src/lib/gssapi/spnego/spnego_mech.c
index 35c1c250cc..75ae2d8749 100644
--- a/src/lib/gssapi/spnego/spnego_mech.c
+++ b/src/lib/gssapi/spnego/spnego_mech.c
@@ -2218,12 +2218,33 @@ spnego_gss_import_sec_context(
 	const gss_buffer_t	interprocess_token,
 	gss_ctx_id_t		*context_handle)
 {
-	/*
-	 * Until we implement partial context exports, there are no SPNEGO
-	 * exported context tokens, only tokens for underlying mechs.  So just
-	 * return an error for now.
-	 */
-	return GSS_S_UNAVAILABLE;
+	OM_uint32 ret, tmpmin;
+	gss_ctx_id_t mctx;
+	spnego_gss_ctx_id_t sc;
+	int initiate, opened;
+
+	ret = gss_import_sec_context(minor_status, interprocess_token, &mctx);
+	if (ret != GSS_S_COMPLETE)
+		return ret;
+
+	ret = gss_inquire_context(&tmpmin, mctx, NULL, NULL, NULL, NULL, NULL,
+				  &initiate, &opened);
+	if (ret != GSS_S_COMPLETE || !opened) {
+		/* We don't currently support importing partially established
+		 * contexts. */
+		(void) gss_delete_sec_context(&tmpmin, &mctx, GSS_C_NO_BUFFER);
+		return GSS_S_FAILURE;
+	}
+
+	sc = create_spnego_ctx(initiate);
+	if (sc == NULL) {
+		(void) gss_delete_sec_context(&tmpmin, &mctx, GSS_C_NO_BUFFER);
+		return GSS_S_FAILURE;
+	}
+	sc->ctx_handle = mctx;
+	sc->opened = 1;
+	*context_handle = (gss_ctx_id_t)sc;
+	return GSS_S_COMPLETE;
 }
 #endif /* LEAN_CLIENT */