[PATCH 6.1 252/609] libceph: guard missing CRUSH type name lookup

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Zhao Zhang <[email protected]>

commit bbeae12fda3384a90fbebc8a19ba9d33f85b5361 upstream.

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".

[ idryomov: add WARN_ON_ONCE ]

Cc: [email protected]
Fixes: 117d96a04f00 ("libceph: support for balanced and localized reads")
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]>
Reviewed-by: Viacheslav Dubeyko <[email protected]>
Signed-off-by: Ilya Dryomov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 net/ceph/osdmap.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -3060,8 +3060,11 @@ static int get_immediate_parent(struct c
 			if (b->items[j] != id)
 				continue;
 
-			*parent_type_id = b->type;
 			type_cn = lookup_crush_name(&c->type_names, b->type);
+			if (WARN_ON_ONCE(!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;