Messages in this thread Patch in this message | | | Date | Thu, 10 Jun 2010 12:33:05 -0700 | Subject | [PATCH] Fix kernel NULL pointer dereference in dm-mpath.c | From | "Patrick J. LoPresti" <> |
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I discovered this when I accidentally put the following in my /etc/multipath.conf file:
path_selector least_pending
...instead of this:
path_selector "least_pending 0"
To my surprise, this resulted in a NULL pointer dereference in the kernel. The bug (and fix) is trivial:
--- linux/drivers/md/dm-mpath.c 2010-05-20 03:06:58.000000000 -0700 +++ linux-patl/drivers/md/dm-mpath.c 2010-06-10 12:22:49.000000000 -0700 @@ -736,12 +736,13 @@ for (i = 0; i < pg->nr_pgpaths; i++) { struct pgpath *pgpath; struct arg_set path_args;
if (as->argc < nr_params) { ti->error = "not enough path parameters"; + r = -EINVAL; goto bad; }
path_args.argc = nr_params; path_args.argv = as->argv;
Without this patch, the parse_priority_group function can return 0, which the caller (multipath_ctr()) immediately dereferences. Bang! I have confirmed that this bug still exists in 2.6.32.9 and 2.6.35-rc2.
- Pat
P.S. Are the Coverity folks still running the kernel through their tool? This seems like the sort of thing it would catch.
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