aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/xen
diff options
context:
space:
mode:
authorWen Yang <wen.yang99@zte.com.cn>2019-01-15 02:31:27 (GMT)
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2019-01-15 21:13:47 (GMT)
commitb4711098066f1cf808d4dc11a1a842860a3292fe (patch)
tree4c628a969f0ba0333be86b28307815ba91e21d60 /drivers/xen
parent5268c8f39e0efef81af2aaed160272d9eb507beb (diff)
pvcalls-front: fix potential null dereference
static checker warning: drivers/xen/pvcalls-front.c:373 alloc_active_ring() error: we previously assumed 'map->active.ring' could be null (see line 357) drivers/xen/pvcalls-front.c 351 static int alloc_active_ring(struct sock_mapping *map) 352 { 353 void *bytes; 354 355 map->active.ring = (struct pvcalls_data_intf *) 356 get_zeroed_page(GFP_KERNEL); 357 if (!map->active.ring) ^^^^^^^^^^^^^^^^^ Check 358 goto out; 359 360 map->active.ring->ring_order = PVCALLS_RING_ORDER; 361 bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 362 PVCALLS_RING_ORDER); 363 if (!bytes) 364 goto out; 365 366 map->active.data.in = bytes; 367 map->active.data.out = bytes + 368 XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); 369 370 return 0; 371 372 out: --> 373 free_active_ring(map); ^^^ Add null check on map->active.ring before dereferencing it to avoid any NULL pointer dereferences. Fixes: 9f51c05dc41a ("pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Juergen Gross <jgross@suse.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: Dan Carpenter <dan.carpenter@oracle.com> CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/pvcalls-front.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 307861f..8a249c9 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -343,6 +343,9 @@ int pvcalls_front_socket(struct socket *sock)
static void free_active_ring(struct sock_mapping *map)
{
+ if (!map->active.ring)
+ return;
+
free_pages((unsigned long)map->active.data.in,
map->active.ring->ring_order);
free_page((unsigned long)map->active.ring);

Privacy Policy