libceph: fix a use after free issue in osdmap_set_max_osd

If the state variable is krealloced successfully, map->osd_state will be
freed, once following two reallocation failed, and exit the function
without resetting map->osd_state, map->osd_state become a wild pointer.

fix it by resetting them after krealloc successfully.

Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index c547e46..ec4d9e2 100644 (file)
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -671,26 +671,26 @@ static int osdmap_set_max_osd(struct ceph_osdmap *map, int max)
        int i;
 
        state = krealloc(map->osd_state, max*sizeof(*state), GFP_NOFS);
+       if (!state)
+               return -ENOMEM;
+       map->osd_state = state;
+
        weight = krealloc(map->osd_weight, max*sizeof(*weight), GFP_NOFS);
-       addr = krealloc(map->osd_addr, max*sizeof(*addr), GFP_NOFS);
-       if (!state || !weight || !addr) {
-               kfree(state);
-               kfree(weight);
-               kfree(addr);
+       if (!weight)
+               return -ENOMEM;
+       map->osd_weight = weight;
 
+       addr = krealloc(map->osd_addr, max*sizeof(*addr), GFP_NOFS);
+       if (!addr)
                return -ENOMEM;
-       }
+       map->osd_addr = addr;
 
        for (i = map->max_osd; i < max; i++) {
-               state[i] = 0;
-               weight[i] = CEPH_OSD_OUT;
-               memset(addr + i, 0, sizeof(*addr));
+               map->osd_state[i] = 0;
+               map->osd_weight[i] = CEPH_OSD_OUT;
+               memset(map->osd_addr + i, 0, sizeof(*map->osd_addr));
        }
 
-       map->osd_state = state;
-       map->osd_weight = weight;
-       map->osd_addr = addr;
-
        if (map->osd_primary_affinity) {
                u32 *affinity;
 
@@ -698,11 +698,11 @@ static int osdmap_set_max_osd(struct ceph_osdmap *map, int max)
                                    max*sizeof(*affinity), GFP_NOFS);
                if (!affinity)
                        return -ENOMEM;
+               map->osd_primary_affinity = affinity;
 
                for (i = map->max_osd; i < max; i++)
-                       affinity[i] = CEPH_OSD_DEFAULT_PRIMARY_AFFINITY;
-
-               map->osd_primary_affinity = affinity;
+                       map->osd_primary_affinity[i] =
+                           CEPH_OSD_DEFAULT_PRIMARY_AFFINITY;
        }
 
        map->max_osd = max;