[PATCH ceph 1/1] libceph: osdmap: guard missing CRUSH type name lookup

From: Zhao Zhang <[email protected]>

Localized read selection can walk a parent bucket whose name exists in
the CRUSH map while its type has no matching entry in type_names.
get_immediate_parent() then dereferences a NULL type_cn and passes an
invalid pointer into strcmp(), causing a null-ptr-deref.

Skip such malformed parent buckets unless both the bucket name and type
name metadata are present. This keeps malformed hierarchy data from
crashing locality lookup and safely falls back to "not local".

Fixes: 117d96a04f00 ("libceph: support for balanced and localized reads")
Cc: [email protected]
Reported-by: Yuan Tan <[email protected]>
Reported-by: Zhengchuan Liang <[email protected]>
Reported-by: Xin Liu <[email protected]>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Zhao Zhang <[email protected]>
Signed-off-by: Ren Wei <[email protected]>
---
 net/ceph/osdmap.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 8b5b0587a0cf..5eb50d9c1361 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -3055,8 +3055,11 @@ static int get_immediate_parent(struct crush_map *c, int id,
 			if (b->items[j] != id)
 				continue;
 
-			*parent_type_id = b->type;
 			type_cn = lookup_crush_name(&c->type_names, b->type);
+			if (!type_cn)
+				continue;
+
+			*parent_type_id = b->type;
 			parent_loc->cl_type_name = type_cn->cn_name;
 			parent_loc->cl_name = cn->cn_name;
 			return b->id;
-- 
2.47.3