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| author | Juergen Gross <jgross@suse.com> | 2020-03-26 09:03:58 +0100 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2020-04-14 15:09:37 +0200 |
| commit | 6b51fd3f65a22e3d1471b18a1d56247e246edd46 (patch) | |
| tree | 5f476d8320603421bcdde379b3c60f35171a5957 | |
| parent | d6f34f4c6b4a962eb7a86c923fea206f866a40be (diff) | |
| download | linux-6b51fd3f65a22e3d1471b18a1d56247e246edd46.tar.gz linux-6b51fd3f65a22e3d1471b18a1d56247e246edd46.tar.bz2 linux-6b51fd3f65a22e3d1471b18a1d56247e246edd46.zip | |
xen/xenbus: ensure xenbus_map_ring_valloc() returns proper grant status
xenbus_map_ring_valloc() maps a ring page and returns the status of the
used grant (0 meaning success).
There are Xen hypervisors which might return the value 1 for the status
of a failed grant mapping due to a bug. Some callers of
xenbus_map_ring_valloc() test for errors by testing the returned status
to be less than zero, resulting in no error detected and crashing later
due to a not available ring page.
Set the return value of xenbus_map_ring_valloc() to GNTST_general_error
in case the grant status reported by Xen is greater than zero.
This is part of XSA-316.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Link: https://lore.kernel.org/r/20200326080358.1018-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
| -rw-r--r-- | drivers/xen/xenbus/xenbus_client.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c index 385843256865..040d2a43e8e3 100644 --- a/drivers/xen/xenbus/xenbus_client.c +++ b/drivers/xen/xenbus/xenbus_client.c @@ -448,7 +448,14 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn); int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs, unsigned int nr_grefs, void **vaddr) { - return ring_ops->map(dev, gnt_refs, nr_grefs, vaddr); + int err; + + err = ring_ops->map(dev, gnt_refs, nr_grefs, vaddr); + /* Some hypervisors are buggy and can return 1. */ + if (err > 0) + err = GNTST_general_error; + + return err; } EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc); |