| Message ID | 20250305194437.59309-1-slava@dubeyko.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v4] ceph: fix slab-use-after-free in have_mon_and_osd_map() | expand |
Viacheslav Dubeyko <slava@dubeyko.com> wrote: > The generic/395 and generic/397 is capable of generating > the oops is on line net/ceph/ceph_common.c:794 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 > ... > This patch fixes the issue by means of locking > client->osdc.lock and client->monc.mutex before > the checking client->osdc.osdmap and > client->monc.monmap in have_mon_and_osd_map() function. > Patch adds locking in the ceph_osdc_stop() > method during the destructruction of osdc->osdmap and > assigning of NULL to the pointer. The lock is used > in the ceph_monc_stop() during the freeing of monc->monmap > and assigning NULL to the pointer too. The monmap_show() > and osdmap_show() methods were reworked to prevent > the potential race condition during the methods call. > > Reported-by: David Howells <dhowells@redhat.com> > Signed-off-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com> Reviewed-by: David Howells <dhowells@redhat.com>
On Wed, Mar 5, 2025 at 8:44 PM Viacheslav Dubeyko <slava@dubeyko.com> wrote: > > From: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com> > > The generic/395 and generic/397 is capable of generating > the oops is on line net/ceph/ceph_common.c:794 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 > Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014 > Call Trace: > <TASK> > dump_stack_lvl+0x57/0x80 > ? have_mon_and_osd_map+0x56/0x70 > print_address_description.constprop.0+0x84/0x330 > ? have_mon_and_osd_map+0x56/0x70 > print_report+0xe2/0x1e0 > ? rcu_read_unlock_sched+0x60/0x80 > ? kmem_cache_debug_flags+0xc/0x20 > ? fixup_red_left+0x17/0x30 > ? have_mon_and_osd_map+0x56/0x70 > kasan_report+0x8d/0xc0 > ? have_mon_and_osd_map+0x56/0x70 > have_mon_and_osd_map+0x56/0x70 > ceph_open_session+0x182/0x290 > ? __pfx_ceph_open_session+0x10/0x10 > ? __init_swait_queue_head+0x8d/0xa0 > ? __pfx_autoremove_wake_function+0x10/0x10 > ? shrinker_register+0xdd/0xf0 > ceph_get_tree+0x333/0x680 > vfs_get_tree+0x49/0x180 > do_new_mount+0x1a3/0x2d0 > ? __pfx_do_new_mount+0x10/0x10 > ? security_capable+0x39/0x70 > path_mount+0x6dd/0x730 > ? __pfx_path_mount+0x10/0x10 > ? kmem_cache_free+0x1e5/0x270 > ? user_path_at+0x48/0x60 > do_mount+0x99/0xe0 > ? __pfx_do_mount+0x10/0x10 > ? lock_release+0x155/0x190 > __do_sys_mount+0x141/0x180 > do_syscall_64+0x9f/0x100 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > RIP: 0033:0x7f01b1b14f3e > Code: 48 8b 0d d5 3e 0f 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a2 3e 0f 00 f7 d8 64 89 01 48 > RSP: 002b:00007fffd129fa08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 > RAX: ffffffffffffffda RBX: 0000564ec01a7850 RCX: 00007f01b1b14f3e > RDX: 0000564ec00f2225 RSI: 00007fffd12a1964 RDI: 0000564ec0147a20 > RBP: 00007fffd129fbd0 R08: 0000564ec014da90 R09: 0000000000000080 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffd12a194e > R13: 0000000000000000 R14: 00007fffd129fa50 R15: 00007fffd129fa40 > </TASK> > > Allocated by task 13305: > stack_trace_save+0x8c/0xc0 > kasan_save_stack+0x1e/0x40 > kasan_save_track+0x10/0x30 > __kasan_kmalloc+0x3a/0x50 > __kmalloc_noprof+0x247/0x290 > 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: > stack_trace_save+0x8c/0xc0 > kasan_save_stack+0x1e/0x40 > kasan_save_track+0x10/0x30 > kasan_save_free_info+0x3b/0x50 > __kasan_slab_free+0x18/0x30 > 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 > > The buggy address belongs to the object at ffff88811012d800 > which belongs to the cache kmalloc-512 of size 512 > The buggy address is located 16 bytes inside of > freed 512-byte region [ffff88811012d800, ffff88811012da00) > > The buggy address belongs to the physical page: > page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11012c > head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 > flags: 0x200000000000040(head|node=0|zone=2) > page_type: f5(slab) > raw: 0200000000000040 ffff888100042c80 dead000000000100 dead000000000122 > raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000 > head: 0200000000000040 ffff888100042c80 dead000000000100 dead000000000122 > head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000 > head: 0200000000000002 ffffea0004404b01 ffffffffffffffff 0000000000000000 > head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff88811012d700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff88811012d780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > ffff88811012d800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ^ > ffff88811012d880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88811012d900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== > Disabling lock debugging due to kernel taint > libceph: client274326 fsid 8598140e-35c2-11ee-b97c-001517c545cc > libceph: mon0 (1)90.155.74.19:6789 session established > libceph: client274327 fsid 8598140e-35c2-11ee-b97c-001517c545cc > > We have such scenario: > > Thread 1: > void ceph_osdmap_destroy(...) { > <skipped> > kfree(map); > } > Thread 1 sleep... > > Thread 2: > static bool have_mon_and_osd_map(struct ceph_client *client) { > return client->monc.monmap && client->monc.monmap->epoch && > client->osdc.osdmap && client->osdc.osdmap->epoch; > } > Thread 2 has oops... > > Thread 1 wake up: > static int handle_one_map(...) { > <skipped> > osdc->osdmap = newmap; > <skipped> > } > > This patch fixes the issue by means of locking > client->osdc.lock and client->monc.mutex before > the checking client->osdc.osdmap and > client->monc.monmap in have_mon_and_osd_map() function. > Patch adds locking in the ceph_osdc_stop() > method during the destructruction of osdc->osdmap and > assigning of NULL to the pointer. The lock is used > in the ceph_monc_stop() during the freeing of monc->monmap > and assigning NULL to the pointer too. The monmap_show() > and osdmap_show() methods were reworked to prevent > the potential race condition during the methods call. > > Reported-by: David Howells <dhowells@redhat.com> > Signed-off-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com> > --- > net/ceph/ceph_common.c | 14 ++++++++++++-- > net/ceph/debugfs.c | 33 +++++++++++++++++++-------------- > net/ceph/mon_client.c | 9 ++++++++- > net/ceph/osd_client.c | 4 ++++ > 4 files changed, 43 insertions(+), 17 deletions(-) > > diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c > index 4c6441536d55..5c8fd78d6bd5 100644 > --- a/net/ceph/ceph_common.c > +++ b/net/ceph/ceph_common.c > @@ -790,8 +790,18 @@ EXPORT_SYMBOL(ceph_reset_client_addr); > */ > static bool have_mon_and_osd_map(struct ceph_client *client) > { > - return client->monc.monmap && client->monc.monmap->epoch && > - client->osdc.osdmap && client->osdc.osdmap->epoch; > + bool have_mon_map = false; > + bool have_osd_map = false; > + > + mutex_lock(&client->monc.mutex); Hi Slava, This introduces a potential sleep into a function that is used as a wait_event condition in __ceph_open_session() which could result in a nested sleep. This is frowned up by the scheduler because the task state may get reset to TASK_RUNNING when not desired: do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff819c19fc>] prepare_to_wait_event+0x3ac/0x460 kernel/sched/wait.c:298 You would probably need to open-code waiting in __ceph_open_session() per [1]. > + have_mon_map = client->monc.monmap && client->monc.monmap->epoch; > + mutex_unlock(&client->monc.mutex); > + > + down_read(&client->osdc.lock); > + have_osd_map = client->osdc.osdmap && client->osdc.osdmap->epoch; > + up_read(&client->osdc.lock); > + > + return have_mon_map && have_osd_map; > } > > /* > diff --git a/net/ceph/debugfs.c b/net/ceph/debugfs.c > index 2110439f8a24..6e2014c813ca 100644 > --- a/net/ceph/debugfs.c > +++ b/net/ceph/debugfs.c > @@ -36,18 +36,20 @@ static int monmap_show(struct seq_file *s, void *p) > int i; > struct ceph_client *client = s->private; > > - if (client->monc.monmap == NULL) > - return 0; > - > - seq_printf(s, "epoch %d\n", client->monc.monmap->epoch); > - for (i = 0; i < client->monc.monmap->num_mon; i++) { > - struct ceph_entity_inst *inst = > - &client->monc.monmap->mon_inst[i]; > - > - seq_printf(s, "\t%s%lld\t%s\n", > - ENTITY_NAME(inst->name), > - ceph_pr_addr(&inst->addr)); > + mutex_lock(&client->monc.mutex); > + if (client->monc.monmap) { > + seq_printf(s, "epoch %d\n", client->monc.monmap->epoch); > + for (i = 0; i < client->monc.monmap->num_mon; i++) { > + struct ceph_entity_inst *inst = > + &client->monc.monmap->mon_inst[i]; > + > + seq_printf(s, "\t%s%lld\t%s\n", > + ENTITY_NAME(inst->name), > + ceph_pr_addr(&inst->addr)); > + } > } > + mutex_unlock(&client->monc.mutex); Nit: I'd prefer mutex_lock(&client->monc.mutex); if (client->monc.monmap == NULL) goto out_unlock; ... out_unlock: mutex_unlock(&client->monc.mutex); return 0; to an additional level of indentation here. > + > return 0; > } > > @@ -56,13 +58,15 @@ static int osdmap_show(struct seq_file *s, void *p) > int i; > struct ceph_client *client = s->private; > struct ceph_osd_client *osdc = &client->osdc; > - struct ceph_osdmap *map = osdc->osdmap; > + struct ceph_osdmap *map = NULL; > struct rb_node *n; > > + down_read(&osdc->lock); > + > + map = osdc->osdmap; > if (map == NULL) > - return 0; > + goto finish_osdmap_show; > > - down_read(&osdc->lock); > seq_printf(s, "epoch %u barrier %u flags 0x%x\n", map->epoch, > osdc->epoch_barrier, map->flags); > > @@ -131,6 +135,7 @@ static int osdmap_show(struct seq_file *s, void *p) > seq_printf(s, "]\n"); > } > > +finish_osdmap_show: Nit: I'd rename this label to out_unlock so that name communicates what the label is for. > up_read(&osdc->lock); > return 0; > } > diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c > index ab66b599ac47..b299e5bbddb1 100644 > --- a/net/ceph/mon_client.c > +++ b/net/ceph/mon_client.c > @@ -1232,6 +1232,7 @@ int ceph_monc_init(struct ceph_mon_client *monc, struct ceph_client *cl) > ceph_auth_destroy(monc->auth); > out_monmap: > kfree(monc->monmap); > + monc->monmap = NULL; > out: > return err; > } > @@ -1239,6 +1240,8 @@ EXPORT_SYMBOL(ceph_monc_init); > > void ceph_monc_stop(struct ceph_mon_client *monc) > { > + struct ceph_monmap *old_monmap; > + > dout("stop\n"); > > mutex_lock(&monc->mutex); > @@ -1266,7 +1269,11 @@ void ceph_monc_stop(struct ceph_mon_client *monc) > ceph_msg_put(monc->m_subscribe); > ceph_msg_put(monc->m_subscribe_ack); > > - kfree(monc->monmap); > + mutex_lock(&monc->mutex); Did you have a specific reason for adding locking here and in ceph_osdc_stop()? I see that David inquired about this in a comment on v2 and I think the answer to his question is no. By this point we are long past the point of no return and no new messages can arrive for e.g. handle_one_map() to be called. [1] https://lwn.net/Articles/628628/ Thanks, Ilya
diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c index 4c6441536d55..5c8fd78d6bd5 100644 --- a/net/ceph/ceph_common.c +++ b/net/ceph/ceph_common.c @@ -790,8 +790,18 @@ EXPORT_SYMBOL(ceph_reset_client_addr); */ static bool have_mon_and_osd_map(struct ceph_client *client) { - return client->monc.monmap && client->monc.monmap->epoch && - client->osdc.osdmap && client->osdc.osdmap->epoch; + bool have_mon_map = false; + bool have_osd_map = false; + + mutex_lock(&client->monc.mutex); + have_mon_map = client->monc.monmap && client->monc.monmap->epoch; + mutex_unlock(&client->monc.mutex); + + down_read(&client->osdc.lock); + have_osd_map = client->osdc.osdmap && client->osdc.osdmap->epoch; + up_read(&client->osdc.lock); + + return have_mon_map && have_osd_map; } /* diff --git a/net/ceph/debugfs.c b/net/ceph/debugfs.c index 2110439f8a24..6e2014c813ca 100644 --- a/net/ceph/debugfs.c +++ b/net/ceph/debugfs.c @@ -36,18 +36,20 @@ static int monmap_show(struct seq_file *s, void *p) int i; struct ceph_client *client = s->private; - if (client->monc.monmap == NULL) - return 0; - - seq_printf(s, "epoch %d\n", client->monc.monmap->epoch); - for (i = 0; i < client->monc.monmap->num_mon; i++) { - struct ceph_entity_inst *inst = - &client->monc.monmap->mon_inst[i]; - - seq_printf(s, "\t%s%lld\t%s\n", - ENTITY_NAME(inst->name), - ceph_pr_addr(&inst->addr)); + mutex_lock(&client->monc.mutex); + if (client->monc.monmap) { + seq_printf(s, "epoch %d\n", client->monc.monmap->epoch); + for (i = 0; i < client->monc.monmap->num_mon; i++) { + struct ceph_entity_inst *inst = + &client->monc.monmap->mon_inst[i]; + + seq_printf(s, "\t%s%lld\t%s\n", + ENTITY_NAME(inst->name), + ceph_pr_addr(&inst->addr)); + } } + mutex_unlock(&client->monc.mutex); + return 0; } @@ -56,13 +58,15 @@ static int osdmap_show(struct seq_file *s, void *p) int i; struct ceph_client *client = s->private; struct ceph_osd_client *osdc = &client->osdc; - struct ceph_osdmap *map = osdc->osdmap; + struct ceph_osdmap *map = NULL; struct rb_node *n; + down_read(&osdc->lock); + + map = osdc->osdmap; if (map == NULL) - return 0; + goto finish_osdmap_show; - down_read(&osdc->lock); seq_printf(s, "epoch %u barrier %u flags 0x%x\n", map->epoch, osdc->epoch_barrier, map->flags); @@ -131,6 +135,7 @@ static int osdmap_show(struct seq_file *s, void *p) seq_printf(s, "]\n"); } +finish_osdmap_show: up_read(&osdc->lock); return 0; } diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c index ab66b599ac47..b299e5bbddb1 100644 --- a/net/ceph/mon_client.c +++ b/net/ceph/mon_client.c @@ -1232,6 +1232,7 @@ int ceph_monc_init(struct ceph_mon_client *monc, struct ceph_client *cl) ceph_auth_destroy(monc->auth); out_monmap: kfree(monc->monmap); + monc->monmap = NULL; out: return err; } @@ -1239,6 +1240,8 @@ EXPORT_SYMBOL(ceph_monc_init); void ceph_monc_stop(struct ceph_mon_client *monc) { + struct ceph_monmap *old_monmap; + dout("stop\n"); mutex_lock(&monc->mutex); @@ -1266,7 +1269,11 @@ void ceph_monc_stop(struct ceph_mon_client *monc) ceph_msg_put(monc->m_subscribe); ceph_msg_put(monc->m_subscribe_ack); - kfree(monc->monmap); + mutex_lock(&monc->mutex); + old_monmap = monc->monmap; + monc->monmap = NULL; + mutex_unlock(&monc->mutex); + kfree(old_monmap); } EXPORT_SYMBOL(ceph_monc_stop); diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c index b24afec24138..762f4df5763b 100644 --- a/net/ceph/osd_client.c +++ b/net/ceph/osd_client.c @@ -5278,6 +5278,7 @@ int ceph_osdc_init(struct ceph_osd_client *osdc, struct ceph_client *client) mempool_destroy(osdc->req_mempool); out_map: ceph_osdmap_destroy(osdc->osdmap); + osdc->osdmap = NULL; out: return err; } @@ -5306,10 +5307,13 @@ void ceph_osdc_stop(struct ceph_osd_client *osdc) WARN_ON(atomic_read(&osdc->num_requests)); WARN_ON(atomic_read(&osdc->num_homeless)); + down_write(&osdc->lock); ceph_osdmap_destroy(osdc->osdmap); + osdc->osdmap = NULL; mempool_destroy(osdc->req_mempool); ceph_msgpool_destroy(&osdc->msgpool_op); ceph_msgpool_destroy(&osdc->msgpool_op_reply); + up_write(&osdc->lock); } int osd_req_op_copy_from_init(struct ceph_osd_request *req,