[PATCH] dm: Add check for NULL dev_part_str

[Sean Anderson]

Some callers (e.g. cmd/fs.c) of fs_set_blk_dev may use a NULL dev_part_str.
While blk_get_device_part_str handles this fine,
part_get_info_by_dev_and_name does not. This fixes commands crashing when
implicitly using bootdevice.

Fixes: 7194527b6a ("cmd: fs: Use part_get_info_by_dev_and_name_or_num to parse partitions")
Reported-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
Signed-off-by: Sean Anderson <seanga2 at gmail.com>

---

 disk/part.c    | 6 +++++-
 test/dm/part.c | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/disk/part.c b/disk/part.c
index 5e7e59cf25..086da84b7f 100644
--- a/disk/part.c
+++ b/disk/part.c
@@ -714,7 +714,11 @@ static int part_get_info_by_dev_and_name(const char *dev_iface,
 	int ret;
 
 	/* Separate device and partition name specification */
-	part_str = strchr(dev_part_str, '#');
+	if (dev_part_str)
+		part_str = strchr(dev_part_str, '#');
+	else
+		part_str = NULL;
+
 	if (part_str) {
 		dup_str = strdup(dev_part_str);
 		dup_str[part_str - dev_part_str] = 0;
diff --git a/test/dm/part.c b/test/dm/part.c
index 051e9010b6..aff7cfe55f 100644
--- a/test/dm/part.c
+++ b/test/dm/part.c
@@ -46,8 +46,10 @@ static int dm_test_part(struct unit_test_state *uts)
 
 	test(-ENODEV, "", true);
 	env_set("bootdevice", "0");
+	test(0, NULL, true);
 	test(0, "", true);
 	env_set("bootdevice", "1");
+	test(1, NULL, false);
 	test(1, "", false);
 	test(1, "-", false);
 	env_set("bootdevice", "");
-- 
2.31.0