* [PATCH v7] ceph: fix slab-use-after-free in have_mon_and_osd_map()
@ 2025-07-03 17:41 Viacheslav Dubeyko
2025-08-20 20:04 ` Ilya Dryomov
0 siblings, 1 reply; 3+ messages in thread
From: Viacheslav Dubeyko @ 2025-07-03 17:41 UTC (permalink / raw)
To: ceph-devel, idryomov
Cc: dhowells, linux-fsdevel, pdonnell, amarkuze, Slava.Dubeyko, slava
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.
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 | 43 +++++++++++++++++++++++++++++++++++-------
net/ceph/debugfs.c | 17 +++++++++++++----
net/ceph/mon_client.c | 2 ++
net/ceph/osd_client.c | 2 ++
4 files changed, 53 insertions(+), 11 deletions(-)
diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 4c6441536d55..bf2be6e43ff7 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;
}
/*
@@ -800,6 +810,7 @@ static bool have_mon_and_osd_map(struct ceph_client *client)
int __ceph_open_session(struct ceph_client *client, unsigned long started)
{
unsigned long timeout = client->options->mount_timeout;
+ int auth_err = 0;
long err;
/* open session, and wait for mon and osd maps */
@@ -808,18 +819,36 @@ int __ceph_open_session(struct ceph_client *client, unsigned long started)
return err;
while (!have_mon_and_osd_map(client)) {
+ mutex_lock(&client->monc.mutex);
+ auth_err = client->auth_err;
+ mutex_unlock(&client->monc.mutex);
+
+ if (auth_err < 0)
+ return auth_err;
+
if (timeout && time_after_eq(jiffies, started + timeout))
return -ETIMEDOUT;
/* wait */
dout("mount waiting for mon_map\n");
- err = wait_event_interruptible_timeout(client->auth_wq,
- have_mon_and_osd_map(client) || (client->auth_err < 0),
- ceph_timeout_jiffies(timeout));
+
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
+
+ add_wait_queue(&client->auth_wq, &wait);
+
+ while (!have_mon_and_osd_map(client)) {
+ if (signal_pending(current)) {
+ err = -ERESTARTSYS;
+ break;
+ }
+ wait_woken(&wait, TASK_INTERRUPTIBLE,
+ ceph_timeout_jiffies(timeout));
+ }
+
+ remove_wait_queue(&client->auth_wq, &wait);
+
if (err < 0)
return err;
- if (client->auth_err < 0)
- return client->auth_err;
}
pr_info("client%llu fsid %pU\n", ceph_client_gid(client),
diff --git a/net/ceph/debugfs.c b/net/ceph/debugfs.c
index 2110439f8a24..7b45c169a859 100644
--- a/net/ceph/debugfs.c
+++ b/net/ceph/debugfs.c
@@ -36,8 +36,10 @@ static int monmap_show(struct seq_file *s, void *p)
int i;
struct ceph_client *client = s->private;
+ mutex_lock(&client->monc.mutex);
+
if (client->monc.monmap == NULL)
- return 0;
+ goto out_unlock;
seq_printf(s, "epoch %d\n", client->monc.monmap->epoch);
for (i = 0; i < client->monc.monmap->num_mon; i++) {
@@ -48,6 +50,10 @@ static int monmap_show(struct seq_file *s, void *p)
ENTITY_NAME(inst->name),
ceph_pr_addr(&inst->addr));
}
+
+out_unlock:
+ mutex_unlock(&client->monc.mutex);
+
return 0;
}
@@ -56,13 +62,15 @@ 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 out_unlock;
- down_read(&osdc->lock);
seq_printf(s, "epoch %u barrier %u flags 0x%x\n", map->epoch,
osdc->epoch_barrier, map->flags);
@@ -131,6 +139,7 @@ static int osdmap_show(struct seq_file *s, void *p)
seq_printf(s, "]\n");
}
+out_unlock:
up_read(&osdc->lock);
return 0;
}
diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c
index ab66b599ac47..2d67ed4aec8b 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;
}
@@ -1267,6 +1268,7 @@ void ceph_monc_stop(struct ceph_mon_client *monc)
ceph_msg_put(monc->m_subscribe_ack);
kfree(monc->monmap);
+ monc->monmap = NULL;
}
EXPORT_SYMBOL(ceph_monc_stop);
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 6664ea73ccf8..5f1e358bdfff 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -5255,6 +5255,7 @@ 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;
}
@@ -5284,6 +5285,7 @@ void ceph_osdc_stop(struct ceph_osd_client *osdc)
WARN_ON(atomic_read(&osdc->num_homeless));
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);
--
2.49.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v7] ceph: fix slab-use-after-free in have_mon_and_osd_map()
2025-07-03 17:41 [PATCH v7] ceph: fix slab-use-after-free in have_mon_and_osd_map() Viacheslav Dubeyko
@ 2025-08-20 20:04 ` Ilya Dryomov
2025-08-20 23:40 ` Viacheslav Dubeyko
0 siblings, 1 reply; 3+ messages in thread
From: Ilya Dryomov @ 2025-08-20 20:04 UTC (permalink / raw)
To: Viacheslav Dubeyko
Cc: ceph-devel, dhowells, linux-fsdevel, pdonnell, amarkuze,
Slava.Dubeyko
On Thu, Jul 3, 2025 at 7:41 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.
> 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 | 43 +++++++++++++++++++++++++++++++++++-------
> net/ceph/debugfs.c | 17 +++++++++++++----
> net/ceph/mon_client.c | 2 ++
> net/ceph/osd_client.c | 2 ++
> 4 files changed, 53 insertions(+), 11 deletions(-)
>
> diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
> index 4c6441536d55..bf2be6e43ff7 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;
> }
>
> /*
> @@ -800,6 +810,7 @@ static bool have_mon_and_osd_map(struct ceph_client *client)
> int __ceph_open_session(struct ceph_client *client, unsigned long started)
> {
> unsigned long timeout = client->options->mount_timeout;
> + int auth_err = 0;
> long err;
>
> /* open session, and wait for mon and osd maps */
> @@ -808,18 +819,36 @@ int __ceph_open_session(struct ceph_client *client, unsigned long started)
> return err;
>
> while (!have_mon_and_osd_map(client)) {
> + mutex_lock(&client->monc.mutex);
> + auth_err = client->auth_err;
> + mutex_unlock(&client->monc.mutex);
> +
> + if (auth_err < 0)
> + return auth_err;
> +
> if (timeout && time_after_eq(jiffies, started + timeout))
> return -ETIMEDOUT;
>
> /* wait */
> dout("mount waiting for mon_map\n");
> - err = wait_event_interruptible_timeout(client->auth_wq,
> - have_mon_and_osd_map(client) || (client->auth_err < 0),
> - ceph_timeout_jiffies(timeout));
> +
> + DEFINE_WAIT_FUNC(wait, woken_wake_function);
> +
> + add_wait_queue(&client->auth_wq, &wait);
> +
> + while (!have_mon_and_osd_map(client)) {
Hi Slava,
This still doesn't seem right to me.
There is a nested while loop with the same !have_mon_and_osd_map(client)
condition which suggests that one of those is redundant -- once the
nested loop is entered there is no way for the outer loop to be entered
again (i.e. continued) because upon exit from the nested loop either
have_mon_and_osd_map() would no longer be false or err would be set to
ERESTARTSYS.
An important detail also got lost in the change: client->auth_err < 0
was previously part of wait_event_interruptible_timeout() condition
which meant that it was checked repeatedly on every wakeup whereas now
it's checked just once at the beginning. This would lead to a hang on
any authentication-related error raised by the monitor client.
Thanks,
Ilya
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v7] ceph: fix slab-use-after-free in have_mon_and_osd_map()
2025-08-20 20:04 ` Ilya Dryomov
@ 2025-08-20 23:40 ` Viacheslav Dubeyko
0 siblings, 0 replies; 3+ messages in thread
From: Viacheslav Dubeyko @ 2025-08-20 23:40 UTC (permalink / raw)
To: Ilya Dryomov
Cc: ceph-devel, dhowells, linux-fsdevel, pdonnell, amarkuze,
Slava.Dubeyko
On Wed, 2025-08-20 at 22:04 +0200, Ilya Dryomov wrote:
> On Thu, Jul 3, 2025 at 7:41 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.
> > 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 | 43 +++++++++++++++++++++++++++++++++++---
> > ----
> > net/ceph/debugfs.c | 17 +++++++++++++----
> > net/ceph/mon_client.c | 2 ++
> > net/ceph/osd_client.c | 2 ++
> > 4 files changed, 53 insertions(+), 11 deletions(-)
> >
> > diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
> > index 4c6441536d55..bf2be6e43ff7 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;
> > }
> >
> > /*
> > @@ -800,6 +810,7 @@ static bool have_mon_and_osd_map(struct
> > ceph_client *client)
> > int __ceph_open_session(struct ceph_client *client, unsigned long
> > started)
> > {
> > unsigned long timeout = client->options->mount_timeout;
> > + int auth_err = 0;
> > long err;
> >
> > /* open session, and wait for mon and osd maps */
> > @@ -808,18 +819,36 @@ int __ceph_open_session(struct ceph_client
> > *client, unsigned long started)
> > return err;
> >
> > while (!have_mon_and_osd_map(client)) {
> > + mutex_lock(&client->monc.mutex);
> > + auth_err = client->auth_err;
> > + mutex_unlock(&client->monc.mutex);
> > +
> > + if (auth_err < 0)
> > + return auth_err;
> > +
> > if (timeout && time_after_eq(jiffies, started +
> > timeout))
> > return -ETIMEDOUT;
> >
> > /* wait */
> > dout("mount waiting for mon_map\n");
> > - err = wait_event_interruptible_timeout(client-
> > >auth_wq,
> > - have_mon_and_osd_map(client) || (client-
> > >auth_err < 0),
> > - ceph_timeout_jiffies(timeout));
> > +
> > + DEFINE_WAIT_FUNC(wait, woken_wake_function);
> > +
> > + add_wait_queue(&client->auth_wq, &wait);
> > +
> > + while (!have_mon_and_osd_map(client)) {
>
> Hi Slava,
>
> This still doesn't seem right to me.
>
> There is a nested while loop with the same
> !have_mon_and_osd_map(client)
> condition which suggests that one of those is redundant -- once the
> nested loop is entered there is no way for the outer loop to be
> entered
> again (i.e. continued) because upon exit from the nested loop either
> have_mon_and_osd_map() would no longer be false or err would be set
> to
> ERESTARTSYS.
>
> An important detail also got lost in the change: client->auth_err < 0
> was previously part of wait_event_interruptible_timeout() condition
> which meant that it was checked repeatedly on every wakeup whereas
> now
> it's checked just once at the beginning. This would lead to a hang
> on
> any authentication-related error raised by the monitor client.
>
>
OK. Makes sense. Let me double check the logic.
Thanks,
Slava.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-08-20 23:40 UTC | newest]
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2025-07-03 17:41 [PATCH v7] ceph: fix slab-use-after-free in have_mon_and_osd_map() Viacheslav Dubeyko
2025-08-20 20:04 ` Ilya Dryomov
2025-08-20 23:40 ` Viacheslav Dubeyko
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