From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: lixiaokeng <lixiaokeng@huawei.com>

Date: Mon, 21 Sep 2020 12:00:39 +0800

Subject: [PATCH] libmultipath: check udev_device_get_* return value to avoid

 segfault

The udev_device_get_* function may return NULL, and it will be

deregerenced in str* and sscanf func. We check the return value

to avoid segfault. Fix all.

Reviewed-by: Martin Wilck <mwilck@suse.com>

Signed-off-by:Lixiaokeng<lixiaokeng@huawei.com>

Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>

Signed-off-by: Linfeilong <linfeilong@huawei.com>

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>

---

 libmultipath/configure.c    |  4 +++-

 libmultipath/discovery.c    |  9 +++++++--

 libmultipath/foreign/nvme.c | 10 +++++++---

 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/libmultipath/configure.c b/libmultipath/configure.c

index 2e8f34f9..a6893d8d 100644

--- a/libmultipath/configure.c

+++ b/libmultipath/configure.c

@@ -511,6 +511,7 @@ static void trigger_partitions_udev_change(struct udev_device *dev,

 {

 	struct udev_enumerate *part_enum;

 	struct udev_list_entry *item;

+	const char *devtype;

 	part_enum = udev_enumerate_new(udev);

 	if (!part_enum)

@@ -531,7 +532,8 @@ static void trigger_partitions_udev_change(struct udev_device *dev,

 		if (!part)

 			continue;

-		if (!strcmp("partition", udev_device_get_devtype(part))) {

+		devtype = udev_device_get_devtype(part);

+		if (devtype && !strcmp("partition", devtype)) {

 			condlog(4, "%s: triggering %s event for %s", __func__,

 				action, syspath);

 			sysfs_attr_set_value(part, "uevent", action, len);

diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c

index a328aafa..74abf34d 100644

--- a/libmultipath/discovery.c

+++ b/libmultipath/discovery.c

@@ -353,7 +353,7 @@ sysfs_get_tgt_nodename(struct path *pp, char *node)

 		tgtdev = udev_device_get_parent(parent);

 		while (tgtdev) {

 			tgtname = udev_device_get_sysname(tgtdev);

-			if (sscanf(tgtname, "end_device-%d:%d",

+			if (tgtname && sscanf(tgtname, "end_device-%d:%d",

 				   &host, &tgtid) == 2)

 				break;

 			tgtdev = udev_device_get_parent(tgtdev);

@@ -386,7 +386,7 @@ sysfs_get_tgt_nodename(struct path *pp, char *node)

 	/* Check for FibreChannel */

 	tgtdev = udev_device_get_parent(parent);

 	value = udev_device_get_sysname(tgtdev);

-	if (sscanf(value, "rport-%d:%d-%d",

+	if (value && sscanf(value, "rport-%d:%d-%d",

 		   &host, &channel, &tgtid) == 3) {

 		tgtdev = udev_device_new_from_subsystem_sysname(udev,

 				"fc_remote_ports", value);

@@ -516,6 +516,9 @@ int sysfs_get_host_pci_name(const struct path *pp, char *pci_name)

 		 */

 		value = udev_device_get_sysname(parent);

+		if (!value)

+			return 1;

+

 		strncpy(pci_name, value, SLOT_NAME_SIZE);

 		udev_device_unref(hostdev);

 		return 0;

@@ -1518,6 +1521,8 @@ ccw_sysfs_pathinfo (struct path * pp, vector hwtable)

 	 * host / bus / target / lun

 	 */

 	attr_path = udev_device_get_sysname(parent);

+	if (!attr_path)

+		return PATHINFO_FAILED;

 	pp->sg_id.lun = 0;

 	if (sscanf(attr_path, "%i.%i.%x",

 		   &pp->sg_id.host_no,

diff --git a/libmultipath/foreign/nvme.c b/libmultipath/foreign/nvme.c

index 09cdddf0..5feb1e95 100644

--- a/libmultipath/foreign/nvme.c

+++ b/libmultipath/foreign/nvme.c

@@ -482,6 +482,7 @@ _find_path_by_syspath(struct nvme_map *map, const char *syspath)

 	struct nvme_pathgroup *pg;

 	char real[PATH_MAX];

 	const char *ppath;

+	const char *psyspath;

 	int i;

 	ppath = realpath(syspath, real);

@@ -493,8 +494,8 @@ _find_path_by_syspath(struct nvme_map *map, const char *syspath)

 	vector_foreach_slot(&map->pgvec, pg, i) {

 		struct nvme_path *path = nvme_pg_to_path(pg);

-		if (!strcmp(ppath,

-			    udev_device_get_syspath(path->udev)))

+		psyspath = udev_device_get_syspath(path->udev);

+		if (psyspath && !strcmp(ppath, psyspath))

 			return path;

 	}

 	condlog(4, "%s: %s: %s not found", __func__, THIS, ppath);

@@ -538,6 +539,7 @@ struct udev_device *get_ctrl_blkdev(const struct context *ctx,

 	struct udev_list_entry *item;

 	struct udev_device *blkdev = NULL;

 	struct udev_enumerate *enm = udev_enumerate_new(ctx->udev);

+	const char *devtype;

 	if (enm == NULL)

 		return NULL;

@@ -562,7 +564,9 @@ struct udev_device *get_ctrl_blkdev(const struct context *ctx,

 					   udev_list_entry_get_name(item));

 		if (tmp == NULL)

 			continue;

-		if (!strcmp(udev_device_get_devtype(tmp), "disk")) {

+

+		devtype = udev_device_get_devtype(tmp);

+		if (devtype && !strcmp(devtype, "disk")) {

 			blkdev = tmp;

 			break;

 		} else

-- 

2.17.2