The error exit of privcmd_ioctl_dm_op() is calling unlock_pages()
potentially with pages being NULL, leading to a NULL dereference.
Fix that by calling unlock_pages only if lock_pages() was at least
partially successful.
Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: ab520be8cd5d ("xen/privcmd: Add IOCTL_PRIVCMD_DM_OP")
Reported-by: Rustam Subkhankulov <subkhankulov@xxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
drivers/xen/privcmd.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 3369734108af..ec87968b4459 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -679,7 +679,7 @@ static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
rc = lock_pages(kbufs, kdata.num, pages, nr_pages, &pinned);
if (rc < 0) {
nr_pages = pinned;
- goto out;
+ goto unlock;
}
for (i = 0; i < kdata.num; i++) {
@@ -691,8 +691,9 @@ static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
rc = HYPERVISOR_dm_op(kdata.dom, kdata.num, xbufs);
xen_preemptible_hcall_end();
-out:
+ unlock:
unlock_pages(pages, nr_pages);
+ out:
kfree(xbufs);
kfree(pages);
kfree(kbufs);
--
2.35.3
