crush: fix a bug in tree bucket decode
struct crush_bucket_tree::num_nodes is u8, so ceph_decode_8_safe()
should be used. -Wconversion catches this, but I guess it went
unnoticed in all the noise it spews. The actual problem (at least for
common crushmaps) isn't the u32 -> u8 truncation though - it's the
advancement by 4 bytes instead of 1 in the crushmap buffer.
Fixes: http://tracker.ceph.com/issues/2759
Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Josh Durgin <jdurgin@redhat.com>
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 1579669..4a31258 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -89,7 +89,7 @@
{
int j;
dout("crush_decode_tree_bucket %p to %p\n", *p, end);
- ceph_decode_32_safe(p, end, b->num_nodes, bad);
+ ceph_decode_8_safe(p, end, b->num_nodes, bad);
b->node_weights = kcalloc(b->num_nodes, sizeof(u32), GFP_NOFS);
if (b->node_weights == NULL)
return -ENOMEM;