linux/net/ceph
Xiang Mei 9f00f9cf2b libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE
__decode_pg_temp() decodes an user-controlled length but only rejects
values large enough to overflow the allocation; it does not bound it to
CEPH_PG_MAX_SIZE. The helper backs both pg_temp and pg_upmap decoding, and
apply_upmap()/get_temp_osds() later copy the decoded list into the fixed-size
on-stack array struct ceph_osds.osds[CEPH_PG_MAX_SIZE]. A monitor that sends
an OSDMap with a pg_temp/pg_upmap entry longer than 32 thus causes a stack
out-of-bounds write.

An OSD set for a single PG can never exceed CEPH_PG_MAX_SIZE, so reject longer
entries at decode time. The bound is well below the old overflow threshold, so
it also covers the allocation-size overflow the previous check guarded against.

  BUG: KASAN: stack-out-of-bounds in ceph_pg_to_up_acting_osds
  Write of size 4 ... by task exploit
   kasan_report (mm/kasan/report.c:595)
   ceph_pg_to_up_acting_osds (net/ceph/osdmap.c:2617 net/ceph/osdmap.c:2833)
   calc_target (net/ceph/osd_client.c:1638)
   __submit_request (net/ceph/osd_client.c:2394)
   ceph_osdc_start_request (net/ceph/osd_client.c:2490)
   ceph_osdc_call (net/ceph/osd_client.c:5164)
   rbd_dev_image_probe (drivers/block/rbd.c:6899)
   do_rbd_add (drivers/block/rbd.c:7138)
   ...
  kernel BUG at net/ceph/osdmap.c:2670!

[ idryomov: do the same in __decode_pg_upmap_items() ]

Cc: stable@vger.kernel.org
Fixes: a303bb0e58 ("libceph: introduce and switch to decode_pg_mapping()")
Reported-by: Weiming Shi <bestswngs@gmail.com>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Reviewed-by: Alex Markuze <amarkuze@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2026-07-23 20:29:42 +02:00
..
crush libceph: Fix potential out-of-bounds access in crush_decode() 2026-05-11 10:39:21 +02:00
armor.c
auth_none.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
auth_none.h
auth_x_protocol.h libceph: add support for CEPH_CRYPTO_AES256KRB5 2026-02-09 12:29:22 +01:00
auth_x.c libceph: refresh auth->authorizer_buf{,_len} after authorizer update 2026-07-23 20:29:41 +02:00
auth_x.h
auth.c libceph: Fix slab-out-of-bounds access in auth message processing 2026-04-22 01:40:23 +02:00
buffer.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
ceph_common.c libceph: remove debugfs files before client teardown 2026-07-23 20:29:41 +02:00
ceph_hash.c
ceph_strings.c
cls_lock_client.c libceph: fix two unsafe bare decodes in decode_lockers() 2026-07-23 20:29:41 +02:00
crypto.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
crypto.h libceph: adapt ceph_x_challenge_blob hashing and msgr1 message signing 2026-02-09 12:29:22 +01:00
debugfs.c libceph: fix potential use-after-free in have_mon_and_osd_map() 2025-11-26 23:29:10 +01:00
decode.c
Kconfig libceph: add support for CEPH_CRYPTO_AES256KRB5 2026-02-09 12:29:22 +01:00
Makefile
messenger_v1.c libceph: add empty check to ceph_con_get_out_msg() 2025-10-08 23:30:47 +02:00
messenger_v2.c libceph: Remove obsolete session key alignment logic 2026-04-22 01:40:22 +02:00
messenger.c libceph: update outdated comment in ceph_sock_write_space() 2026-04-22 01:40:22 +02:00
mon_client.c libceph: bound get_version reply decode to front len 2026-07-23 20:29:41 +02:00
msgpool.c
osd_client.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
osdmap.c libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE 2026-07-23 20:29:42 +02:00
pagelist.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
pagevec.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
snapshot.c
string_table.c
striper.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00