libceph: reject zero bucket types in crush_decode

CRUSH bucket type 0 is reserved for devices.  The mapper relies on
that invariant and uses type 0 to identify leaf devices.

If crush_decode() accepts a bucket with type 0, a malformed CRUSH map
can make the mapper treat a negative bucket ID as a device and pass it
to is_out(), which then indexes the OSD weight array with a negative
value.

Reject zero bucket types while decoding the CRUSH map so the invalid
state never reaches the mapper.

Cc: stable@vger.kernel.org
Fixes: f24e9980eb ("ceph: OSD client")
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Douya Le <ldy3087146292@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Douya Le 2026-05-29 16:11:44 +08:00 committed by Ilya Dryomov
parent 98917a499e
commit 05f9028422

View File

@ -518,6 +518,8 @@ static struct crush_map *crush_decode(void *pbyval, void *end)
ceph_decode_need(p, end, 4*sizeof(u32), bad);
b->id = ceph_decode_32(p);
b->type = ceph_decode_16(p);
if (b->type == 0)
goto bad;
b->alg = ceph_decode_8(p);
if (b->alg != alg) {
b->alg = 0;