[dm-devel] [PATCH 1/2] crash in multipath argument parsing

[Mikulas Patocka <mpatocka redhat com>]

Fin a parsing crash with this command:

dmsetup create mpath --table "0 `blockdev --getsize /dev/mapper/cr0` multipath 0 0 2 1 round-robin 1000 0 1 1 /dev/mapper/cr0 round-robin 0 1 1 /dev/mapper/cr1 1000"
kernel BUG at drivers/md/dm-mpath.c:530!

The parser reads argument count as a number but doesn't check that sufficient
number of arguments is supplied. This triggers the bug.

Signed-off-by: Mikulas Patocka <mpatocka redhat com>

---
 drivers/md/dm-mpath.c |    5 +++++
 1 file changed, 5 insertions(+)

Index: linux-2.6.30-rc1-devel/drivers/md/dm-mpath.c
===================================================================
--- linux-2.6.30-rc1-devel.orig/drivers/md/dm-mpath.c	2009-04-10 06:33:51.000000000 +0200
+++ linux-2.6.30-rc1-devel/drivers/md/dm-mpath.c	2009-04-10 06:33:57.000000000 +0200
@@ -553,6 +553,11 @@ static int parse_path_selector(struct ar
 		dm_put_path_selector(pst);
 		return -EINVAL;
 	}
+	if (ps_argc > as->argc) {
+		dm_put_path_selector(pst);
+		ti->error = "not enough arguments for path selector";
+		return -EINVAL;
+	}
 
 	r = pst->create(&pg->ps, ps_argc, as->argv);
 	if (r) {