crush: ensure bucket id is valid before indexing buckets array
We were indexing the buckets array without verifying the index was
within the [0,max_buckets) range. This could happen because
a multistep rule does not have enough buckets and has CRUSH_ITEM_NONE
for an intermediate result, which would feed in CRUSH_ITEM_NONE and
make us crash.
Reflects ceph.git commit 976a24a326da8931e689ee22fce35feab5b67b76.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Sage Weil <sage@redhat.com>
diff --git a/net/ceph/crush/mapper.c b/net/ceph/crush/mapper.c
index 393bfb2..97ecf6f 100644
--- a/net/ceph/crush/mapper.c
+++ b/net/ceph/crush/mapper.c
@@ -888,6 +888,7 @@
osize = 0;
for (i = 0; i < wsize; i++) {
+ int bno;
/*
* see CRUSH_N, CRUSH_N_MINUS macros.
* basically, numrep <= 0 means relative to
@@ -900,6 +901,13 @@
continue;
}
j = 0;
+ /* make sure bucket id is valid */
+ bno = -1 - w[i];
+ if (bno < 0 || bno >= map->max_buckets) {
+ /* w[i] is probably CRUSH_ITEM_NONE */
+ dprintk(" bad w[i] %d\n", w[i]);
+ continue;
+ }
if (firstn) {
int recurse_tries;
if (choose_leaf_tries)
@@ -911,7 +919,7 @@
recurse_tries = choose_tries;
osize += crush_choose_firstn(
map,
- map->buckets[-1-w[i]],
+ map->buckets[bno],
weight, weight_max,
x, numrep,
curstep->arg2,
@@ -930,7 +938,7 @@
numrep : (result_max-osize));
crush_choose_indep(
map,
- map->buckets[-1-w[i]],
+ map->buckets[bno],
weight, weight_max,
x, out_size, numrep,
curstep->arg2,