krb5 commit [krb5-1.11]: Fix import_sec_context with interposers

[Tom Yu]

https://github.com/krb5/krb5/commit/db203a153fbe2b776210e966bf198c40f796d535
commit db203a153fbe2b776210e966bf198c40f796d535
Author: Simo Sorce <simo at redhat.com>
Date:   Sat Mar 16 15:23:03 2013 -0400

    Fix import_sec_context with interposers
    
    The code was correctly selecting the mechanism to execute, but it was
    improperly setting the mechanism type of the internal context when the
    selected mechanism was that of an interposer and vice versa.
    
    When an interposer is involved the internal context is that of the
    interposer, so the mechanism type of the context needs to be the
    interposer oid.  Conversely, when an interposer re-enters gssapi and
    presents a token with a special oid, the mechanism called is the real
    mechanism, and the context returned is a real mechanism context.  In
    this case the mechanism type of the context needs to be that of the
    real mechanism.
    
    (cherry picked from commit 36c76aa3c625afc9291b9e1df071db51ccf37dab)
    
    ticket: 7592
    version_fixed: 1.11.2
    status: resolved

 src/lib/gssapi/mechglue/g_imp_sec_context.c |   35 ++++++++++----------------
 1 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/src/lib/gssapi/mechglue/g_imp_sec_context.c b/src/lib/gssapi/mechglue/g_imp_sec_context.c
index 53310dd..a0e2d71 100644
--- a/src/lib/gssapi/mechglue/g_imp_sec_context.c
+++ b/src/lib/gssapi/mechglue/g_imp_sec_context.c
@@ -84,6 +84,7 @@ gss_ctx_id_t *		context_handle;
     gss_union_ctx_id_t	ctx;
     gss_ctx_id_t	mctx;
     gss_buffer_desc	token;
+    gss_OID_desc	token_mech;
     gss_OID		selected_mech = GSS_C_NO_OID;
     gss_OID		public_mech;
     gss_mechanism	mech;
@@ -100,12 +101,6 @@ gss_ctx_id_t *		context_handle;
     if (!ctx)
 	return (GSS_S_FAILURE);
 
-    ctx->mech_type = (gss_OID) malloc(sizeof(gss_OID_desc));
-    if (!ctx->mech_type) {
-	free(ctx);
-	return (GSS_S_FAILURE);
-    }
-
     if (interprocess_token->length >= sizeof (OM_uint32)) {
 	p = interprocess_token->value;
 	length = (OM_uint32)*p++;
@@ -120,12 +115,9 @@ gss_ctx_id_t *		context_handle;
 	return (GSS_S_CALL_BAD_STRUCTURE | GSS_S_DEFECTIVE_TOKEN);
     }
 
-    ctx->mech_type->length = length;
-    ctx->mech_type->elements = malloc(length);
-    if (!ctx->mech_type->elements) {
-	goto error_out;
-    }
-    memcpy(ctx->mech_type->elements, p, length);
+    token_mech.length = length;
+    token_mech.elements = p;
+
     p += length;
 
     token.length = interprocess_token->length - sizeof (OM_uint32) - length;
@@ -136,7 +128,7 @@ gss_ctx_id_t *		context_handle;
      * call it.
      */
 
-    status = gssint_select_mech_type(minor_status, ctx->mech_type,
+    status = gssint_select_mech_type(minor_status, &token_mech,
 				     &selected_mech);
     if (status != GSS_S_COMPLETE)
 	goto error_out;
@@ -152,6 +144,12 @@ gss_ctx_id_t *		context_handle;
 	goto error_out;
     }
 
+    if (generic_gss_copy_oid(minor_status, selected_mech,
+			     &ctx->mech_type) != GSS_S_COMPLETE) {
+	status = GSS_S_FAILURE;
+	goto error_out;
+    }
+
     if (mech->gssspi_import_sec_context_by_mech) {
 	public_mech = gssint_get_public_oid(selected_mech);
 	status = mech->gssspi_import_sec_context_by_mech(minor_status,
@@ -167,16 +165,11 @@ gss_ctx_id_t *		context_handle;
 	return (GSS_S_COMPLETE);
     }
     map_error(minor_status, mech);
+    free(ctx->mech_type->elements);
+    free(ctx->mech_type);
 
 error_out:
-    if (ctx) {
-	if (ctx->mech_type) {
-	    if (ctx->mech_type->elements)
-		free(ctx->mech_type->elements);
-	    free(ctx->mech_type);
-	}
-	free(ctx);
-    }
+    free(ctx);
     return status;
 }
 #endif /* LEAN_CLIENT */