crush: pass weight vector size to map function

Pass the size of the weight vector into crush_do_rule() to ensure that we
don't access values past the end.  This can happen if the caller misbehaves
and passes a weight vector that is smaller than max_devices.

Currently the monitor tries to prevent that from happening, but this will
gracefully tolerate previous bad osdmaps that got into this state.  It's
also a bit more defensive.

Reflects ceph.git commit 5922e2c2b8335b5e46c9504349c3a55b7434c01a.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

2 files changed, 13 insertions, 6 deletions

diff --git a/net/ceph/crush/mapper.c b/net/ceph/crush/mapper.c
index cbd06a91941c..18d2cf66f102 100644
--- a/net/ceph/crush/mapper.c
+++ b/net/ceph/crush/mapper.c
@@ -264,8 +264,12 @@ static int crush_bucket_choose(struct crush_bucket *in, int x, int r)
  * true if device is marked "out" (failed, fully offloaded)
  * of the cluster
  */
-static int is_out(const struct crush_map *map, const __u32 *weight, int item, int x)
+static int is_out(const struct crush_map *map,
+                  const __u32 *weight, int weight_max,
+                  int item, int x)
 {
+        if (item >= weight_max)
+                return 1;
         if (weight[item] >= 0x10000)
                 return 0;
         if (weight[item] == 0)
@@ -292,7 +296,7 @@ static int is_out(const struct crush_map *map, const __u32 *weight, int item, in
  */
 static int crush_choose(const struct crush_map *map,
                         struct crush_bucket *bucket,
-                        const __u32 *weight,
+                        const __u32 *weight, int weight_max,
                         int x, int numrep, int type,
                         int *out, int outpos,
                         int firstn, int recurse_to_leaf,
@@ -396,7 +400,7 @@ static int crush_choose(const struct crush_map *map,
                                         if (item < 0) {
                                                 if (crush_choose(map,
                                                          map->buckets[-1-item],
-                                                         weight,
+                                                         weight, weight_max,
                                                          x, outpos+1, 0,
                                                          out2, outpos,
                                                          firstn, 0,
@@ -414,6 +418,7 @@ static int crush_choose(const struct crush_map *map,
                                         /* out? */
                                         if (itemtype == 0)
                                                 reject = is_out(map, weight,
+                                                                weight_max,
                                                                 item, x);
                                         else
                                                 reject = 0;
@@ -470,10 +475,12 @@ reject:
  * @x: hash input
  * @result: pointer to result vector
  * @result_max: maximum result size
+ * @weight: weight vector (for map leaves)
+ * @weight_max: size of weight vector
  */
 int crush_do_rule(const struct crush_map *map,
                   int ruleno, int x, int *result, int result_max,
-                  const __u32 *weight)
+                  const __u32 *weight, int weight_max)
 {
         int result_len;
         int a[CRUSH_MAX_SET];
@@ -545,7 +552,7 @@ int crush_do_rule(const struct crush_map *map,
                                 j = 0;
                                 osize += crush_choose(map,
                                                       map->buckets[-1-w[i]],
-                                                      weight,
+                                                      weight, weight_max,
                                                       x, numrep,
                                                       curstep->arg2,
                                                       o+osize, j,
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index dbd9a4792427..6477a68ddecb 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -1165,7 +1165,7 @@ static int *calc_pg_raw(struct ceph_osdmap *osdmap, struct ceph_pg pgid,
         }
         r = crush_do_rule(osdmap->crush, ruleno, pps, osds,
                           min_t(int, pool->size, *num),
-                          osdmap->osd_weight);
+                          osdmap->osd_weight, osdmap->max_osd);
         if (r < 0) {
                 pr_err("error %d from crush rule: pool %lld ruleset %d type %d"
                        " size %d\n", r, pgid.pool, pool->crush_ruleset,