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Ilya Dryomov 076381c261 libceph: fix potential use-after-free in have_mon_and_osd_map()
The wait loop in __ceph_open_session() can race with the client
receiving a new monmap or osdmap shortly after the initial map is
received.  Both ceph_monc_handle_map() and handle_one_map() install
a new map immediately after freeing the old one

    kfree(monc->monmap);
    monc->monmap = monmap;

    ceph_osdmap_destroy(osdc->osdmap);
    osdc->osdmap = newmap;

under client->monc.mutex and client->osdc.lock respectively, but
because neither is taken in have_mon_and_osd_map() it's possible for
client->monc.monmap->epoch and client->osdc.osdmap->epoch arms in

    client->monc.monmap && client->monc.monmap->epoch &&
        client->osdc.osdmap && client->osdc.osdmap->epoch;

condition to dereference an already freed map.  This happens to be
reproducible with generic/395 and generic/397 with KASAN enabled:

    BUG: KASAN: slab-use-after-free in have_mon_and_osd_map+0x56/0x70
    Read of size 4 at addr ffff88811012d810 by task mount.ceph/13305
    CPU: 2 UID: 0 PID: 13305 Comm: mount.ceph Not tainted 6.14.0-rc2-build2+ #1266
    ...
    Call Trace:
    <TASK>
    have_mon_and_osd_map+0x56/0x70
    ceph_open_session+0x182/0x290
    ceph_get_tree+0x333/0x680
    vfs_get_tree+0x49/0x180
    do_new_mount+0x1a3/0x2d0
    path_mount+0x6dd/0x730
    do_mount+0x99/0xe0
    __do_sys_mount+0x141/0x180
    do_syscall_64+0x9f/0x100
    entry_SYSCALL_64_after_hwframe+0x76/0x7e
    </TASK>

    Allocated by task 13305:
    ceph_osdmap_alloc+0x16/0x130
    ceph_osdc_init+0x27a/0x4c0
    ceph_create_client+0x153/0x190
    create_fs_client+0x50/0x2a0
    ceph_get_tree+0xff/0x680
    vfs_get_tree+0x49/0x180
    do_new_mount+0x1a3/0x2d0
    path_mount+0x6dd/0x730
    do_mount+0x99/0xe0
    __do_sys_mount+0x141/0x180
    do_syscall_64+0x9f/0x100
    entry_SYSCALL_64_after_hwframe+0x76/0x7e

    Freed by task 9475:
    kfree+0x212/0x290
    handle_one_map+0x23c/0x3b0
    ceph_osdc_handle_map+0x3c9/0x590
    mon_dispatch+0x655/0x6f0
    ceph_con_process_message+0xc3/0xe0
    ceph_con_v1_try_read+0x614/0x760
    ceph_con_workfn+0x2de/0x650
    process_one_work+0x486/0x7c0
    process_scheduled_works+0x73/0x90
    worker_thread+0x1c8/0x2a0
    kthread+0x2ec/0x300
    ret_from_fork+0x24/0x40
    ret_from_fork_asm+0x1a/0x30

Rewrite the wait loop to check the above condition directly with
client->monc.mutex and client->osdc.lock taken as appropriate.  While
at it, improve the timeout handling (previously mount_timeout could be
exceeded in case wait_event_interruptible_timeout() slept more than
once) and access client->auth_err under client->monc.mutex to match
how it's set in finish_auth().

monmap_show() and osdmap_show() now take the respective lock before
accessing the map as well.

Cc: stable@vger.kernel.org
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
2025-11-26 23:29:10 +01:00
arch Fix perf CPU-clock counters, and address a static checker warning. 2025-11-23 08:20:15 -08:00
block vfs-6.18-rc7.fixes 2025-11-17 09:11:27 -08:00
certs
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
Documentation Input updates for v6.18-rc6 2025-11-22 09:58:41 -08:00
drivers Fixes for the Allwinner clk driver: 2025-11-23 12:03:28 -08:00
fs xfs: fixes for 6.18-rc7 2025-11-22 10:23:34 -08:00
include Input updates for v6.18-rc6 2025-11-22 09:58:41 -08:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/cmd_net: fix wrong argument types for skb_queue_splice() 2025-11-20 11:40:15 -07:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel Miscellaneous fixes: 2025-11-23 08:23:30 -08:00
lib Crypto library fix for v6.18-rc7 2025-11-22 11:53:53 -08:00
LICENSES
mm slab fix for 6.18-rc7 2025-11-20 10:49:12 -08:00
net libceph: fix potential use-after-free in have_mon_and_osd_map() 2025-11-26 23:29:10 +01:00
rust rust: Add -fno-isolate-erroneous-paths-dereference to bindgen_skip_c_flags 2025-11-10 08:37:06 +08:00
samples samples: work around glibc redefining some of our defines wrong 2025-11-21 09:29:02 -08:00
scripts Rust fixes for v6.18 (2nd) 2025-11-14 15:36:15 -08:00
security selinux/stable-6.18 PR 20251121 2025-11-22 09:24:36 -08:00
sound ALSA: usb-audio: Add native DSD quirks for PureAudio DAC series 2025-11-14 14:19:47 +01:00
tools RISC-V updates for v6.18-rc7 2025-11-22 09:44:50 -08:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying 2025-11-04 09:16:53 -08:00
.clang-format
.clippy.toml
.cocciconfig
.editorconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap soc: fixes for 6.18, part 3 2025-11-19 09:36:04 -08:00
.pylintrc
.rustfmt.toml
COPYING
CREDITS MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig
MAINTAINERS gpio fixes for v6.18-rc7 2025-11-21 10:43:58 -08:00
Makefile Linux 6.18-rc7 2025-11-23 14:53:16 -08:00
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