From 7118d33f2758eebf9e0d35ce36a74abbcabea1b7 Mon Sep 17 00:00:00 2001
From: Paul Dagnelie <pcd@delphix.com>
Date: Wed, 15 Jun 2016 14:51:27 -0700
Subject: [PATCH] OpenZFS 6876 - Stack corruption after importing a pool with a
 too-long name

Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Yuri Pankov <yuri.pankov@nexenta.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

Calling dsl_dataset_name on a dataset with a 256 byte buffer is asking
for trouble. We should check every dataset on import, using a 1024 byte
buffer and checking each time to see if the dataset's new name is longer
than 256 bytes.

OpenZFS-issue: https://www.illumos.org/issues/6876
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/ca8674e
---
 lib/libzfs/libzfs_pool.c                       |  7 ++++++-
 module/zfs/spa.c                               | 18 ++++++++++++++++++
 .../zpool_import_rename_001_pos.ksh            | 13 ++++++++++++-
 3 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/lib/libzfs/libzfs_pool.c b/lib/libzfs/libzfs_pool.c
index 0a9780733fae..2484ddc12a58 100644
--- a/lib/libzfs/libzfs_pool.c
+++ b/lib/libzfs/libzfs_pool.c
@@ -1907,7 +1907,12 @@ zpool_import_props(libzfs_handle_t *hdl, nvlist_t *config, const char *newname,
 			    "one or more devices are already in use\n"));
 			(void) zfs_error(hdl, EZFS_BADDEV, desc);
 			break;
-
+		case ENAMETOOLONG:
+			zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
+			    "new name of at least one dataset is longer than "
+			    "the maximum allowable length"));
+			(void) zfs_error(hdl, EZFS_NAMETOOLONG, desc);
+			break;
 		default:
 			(void) zpool_standard_error(hdl, error, desc);
 			zpool_explain_recover(hdl,
diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index 88c4b5bb1b1e..6caeca6e5176 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -2001,6 +2001,16 @@ spa_load_verify_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 	return (0);
 }
 
+/* ARGSUSED */
+int
+verify_dataset_name_len(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
+{
+	if (dsl_dataset_namelen(ds) >= ZFS_MAX_DATASET_NAME_LEN)
+		return (SET_ERROR(ENAMETOOLONG));
+
+	return (0);
+}
+
 static int
 spa_load_verify(spa_t *spa)
 {
@@ -2015,6 +2025,14 @@ spa_load_verify(spa_t *spa)
 	if (policy.zrp_request & ZPOOL_NEVER_REWIND)
 		return (0);
 
+	dsl_pool_config_enter(spa->spa_dsl_pool, FTAG);
+	error = dmu_objset_find_dp(spa->spa_dsl_pool,
+	    spa->spa_dsl_pool->dp_root_dir_obj, verify_dataset_name_len, NULL,
+	    DS_FIND_CHILDREN);
+	dsl_pool_config_exit(spa->spa_dsl_pool, FTAG);
+	if (error != 0)
+		return (error);
+
 	rio = zio_root(spa, NULL, &sle,
 	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE);
 
diff --git a/tests/zfs-tests/tests/functional/cli_root/zpool_import/zpool_import_rename_001_pos.ksh b/tests/zfs-tests/tests/functional/cli_root/zpool_import/zpool_import_rename_001_pos.ksh
index 60ccc0dd6006..441f7a7ae036 100755
--- a/tests/zfs-tests/tests/functional/cli_root/zpool_import/zpool_import_rename_001_pos.ksh
+++ b/tests/zfs-tests/tests/functional/cli_root/zpool_import/zpool_import_rename_001_pos.ksh
@@ -26,7 +26,7 @@
 #
 
 #
-# Copyright (c) 2012 by Delphix. All rights reserved.
+# Copyright (c) 2012, 2015 by Delphix. All rights reserved.
 #
 
 . $STF_SUITE/include/libtest.shlib
@@ -92,6 +92,8 @@ function cleanup
 
 	[[ -d $ALTER_ROOT ]] && \
 		log_must $RM -rf $ALTER_ROOT
+	[[ -e $VDEV_FILE ]] && \
+		log_must $RM $VDEV_FILE
 }
 
 log_onexit cleanup
@@ -159,4 +161,13 @@ while (( i < ${#pools[*]} )); do
 	((i = i + 1))
 done
 
+VDEV_FILE=$(mktemp /tmp/tmp.XXXXXX)
+
+log_must $MKFILE -n 128M $VDEV_FILE
+log_must $ZPOOL create testpool $VDEV_FILE
+log_must $ZFS create testpool/testfs
+ID=$($ZPOOL get -Ho value guid testpool)
+log_must $ZPOOL export testpool
+log_mustnot $ZPOOL import $(echo $ID) $($PRINTF "%*s\n" 250 "" | $TR ' ' 'c')
+
 log_pass "Successfully imported and renamed a ZPOOL"