From: John Hubbard <jhubb...@nvidia.com>
KASAN reports a use-after-free during startup, in mei_cl_write:
BUG: KASAN: use-after-free in mei_cl_write+0x601/0x870 [mei]
(drivers/misc/mei/client.c:1770)
This is caused by commit 98e70866aacb ("mei: add support for variable
length mei headers."), which changed the return value from len, to
buf->size. That ends up using a stale buf pointer, because blocking
call, the cb (callback) is deleted in me_cl_complete() function.
However, fortunately, len remains unchanged throughout the function
(and I don't see anything else that would require re-reading buf->size
either), so the fix is to simply revert the change, and return len, as
before.
Fixes: 98e70866aacb ("mei: add support for variable length mei headers.")
CC: Arnd Bergmann <a...@arndb.de>
CC: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: John Hubbard <jhubb...@nvidia.com>
Signed-off-by: Tomas Winkler <tomas.wink...@intel.com>
---
V2: 1. Add better explaination in the commit message.
2. Add Fixes: marker
BTW: The usage len is changed in furhter patches that were not
yet merged.
drivers/misc/mei/client.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 4ab6251d418e..ebdcf0b450e2 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -1767,7 +1767,7 @@ ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb
*cb)
}
}
- rets = buf->size;
+ rets = len;
err:
cl_dbg(dev, cl, "rpm: autosuspend\n");
pm_runtime_mark_last_busy(dev->dev);
--
2.14.4
