In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: af_bluetooth: Fix deadlock
Attemting to do sock_lock on .recvmsg may cause a deadlock as shown
bellow, so instead of using sock_sock this u...Show moreIn the Linux kernel, the following vulnerability has been resolved:
Bluetooth: af_bluetooth: Fix deadlock
Attemting to do sock_lock on .recvmsg may cause a deadlock as shown
bellow, so instead of using sock_sock this uses sk_receive_queue.lock
on bt_sock_ioctl to avoid the UAF:
INFO: task kworker/u9:1:121 blocked for more than 30 seconds.
Not tainted 6.7.6-lemon #183
Workqueue: hci0 hci_rx_work
Call Trace:
<TASK>
__schedule+0x37d/0xa00
schedule+0x32/0xe0
__lock_sock+0x68/0xa0
? __pfx_autoremove_wake_function+0x10/0x10
lock_sock_nested+0x43/0x50
l2cap_sock_recv_cb+0x21/0xa0
l2cap_recv_frame+0x55b/0x30a0
? psi_task_switch+0xeb/0x270
? finish_task_switch.isra.0+0x93/0x2a0
hci_rx_work+0x33a/0x3f0
process_one_work+0x13a/0x2f0
worker_thread+0x2f0/0x410
? __pfx_worker_thread+0x10/0x10
kthread+0xe0/0x110
? __pfx_kthread+0x10/0x10
ret_from_fork+0x2c/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1b/0x30
</TASK>Show less |
In the Linux kernel, the following vulnerability has been resolved:
media: pvrusb2: fix uaf in pvr2_context_set_notify
[Syzbot reported]
BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2c4/0x310 drivers/me...Show moreIn the Linux kernel, the following vulnerability has been resolved:
media: pvrusb2: fix uaf in pvr2_context_set_notify
[Syzbot reported]
BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
Read of size 4 at addr ffff888113aeb0d8 by task kworker/1:1/26
CPU: 1 PID: 26 Comm: kworker/1:1 Not tainted 6.8.0-rc1-syzkaller-00046-gf1a27f081c1f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc4/0x620 mm/kasan/report.c:488
kasan_report+0xda/0x110 mm/kasan/report.c:601
pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
pvr2_context_notify drivers/media/usb/pvrusb2/pvrusb2-context.c:95 [inline]
pvr2_context_disconnect+0x94/0xb0 drivers/media/usb/pvrusb2/pvrusb2-context.c:272
Freed by task 906:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:640
poison_slab_object mm/kasan/common.c:241 [inline]
__kasan_slab_free+0x106/0x1b0 mm/kasan/common.c:257
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2121 [inline]
slab_free mm/slub.c:4299 [inline]
kfree+0x105/0x340 mm/slub.c:4409
pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:137 [inline]
pvr2_context_thread_func+0x69d/0x960 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
[Analyze]
Task A set disconnect_flag = !0, which resulted in Task B's condition being met
and releasing mp, leading to this issue.
[Fix]
Place the disconnect_flag assignment operation after all code in pvr2_context_disconnect()
to avoid this issue.Show less |
In the Linux kernel, the following vulnerability has been resolved:
RDMA/srpt: Do not register event handler until srpt device is fully setup
Upon rare occasions, KASAN reports a use-after-free Write
in srpt_refresh_po...Show moreIn the Linux kernel, the following vulnerability has been resolved:
RDMA/srpt: Do not register event handler until srpt device is fully setup
Upon rare occasions, KASAN reports a use-after-free Write
in srpt_refresh_port().
This seems to be because an event handler is registered before the
srpt device is fully setup and a race condition upon error may leave a
partially setup event handler in place.
Instead, only register the event handler after srpt device initialization
is complete.Show less |
In the Linux kernel, the following vulnerability has been resolved:
spi: lpspi: Avoid potential use-after-free in probe()
fsl_lpspi_probe() is allocating/disposing memory manually with
spi_alloc_host()/spi_alloc_target...Show moreIn the Linux kernel, the following vulnerability has been resolved:
spi: lpspi: Avoid potential use-after-free in probe()
fsl_lpspi_probe() is allocating/disposing memory manually with
spi_alloc_host()/spi_alloc_target(), but uses
devm_spi_register_controller(). In case of error after the latter call the
memory will be explicitly freed in the probe function by
spi_controller_put() call, but used afterwards by "devm" management outside
probe() (spi_unregister_controller() <- devm_spi_unregister() below).
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000070
...
Call trace:
kernfs_find_ns
kernfs_find_and_get_ns
sysfs_remove_group
sysfs_remove_groups
device_remove_attrs
device_del
spi_unregister_controller
devm_spi_unregister
release_nodes
devres_release_all
really_probe
driver_probe_device
__device_attach_driver
bus_for_each_drv
__device_attach
device_initial_probe
bus_probe_device
deferred_probe_work_func
process_one_work
worker_thread
kthread
ret_from_forkShow less |
In the Linux kernel, the following vulnerability has been resolved:
rds: tcp: Fix use-after-free of net in reqsk_timer_handler().
syzkaller reported a warning of netns tracker [0] followed by KASAN
splat [1] and anothe...Show moreIn the Linux kernel, the following vulnerability has been resolved:
rds: tcp: Fix use-after-free of net in reqsk_timer_handler().
syzkaller reported a warning of netns tracker [0] followed by KASAN
splat [1] and another ref tracker warning [1].
syzkaller could not find a repro, but in the log, the only suspicious
sequence was as follows:
18:26:22 executing program 1:
r0 = socket$inet6_mptcp(0xa, 0x1, 0x106)
...
connect$inet6(r0, &(0x7f0000000080)={0xa, 0x4001, 0x0, @loopback}, 0x1c) (async)
The notable thing here is 0x4001 in connect(), which is RDS_TCP_PORT.
So, the scenario would be:
1. unshare(CLONE_NEWNET) creates a per netns tcp listener in
rds_tcp_listen_init().
2. syz-executor connect()s to it and creates a reqsk.
3. syz-executor exit()s immediately.
4. netns is dismantled. [0]
5. reqsk timer is fired, and UAF happens while freeing reqsk. [1]
6. listener is freed after RCU grace period. [2]
Basically, reqsk assumes that the listener guarantees netns safety
until all reqsk timers are expired by holding the listener's refcount.
However, this was not the case for kernel sockets.
Commit 740ea3c4a0b2 ("tcp: Clean up kernel listener's reqsk in
inet_twsk_purge()") fixed this issue only for per-netns ehash.
Let's apply the same fix for the global ehash.
[0]:
ref_tracker: net notrefcnt@0000000065449cc3 has 1/1 users at
sk_alloc (./include/net/net_namespace.h:337 net/core/sock.c:2146)
inet6_create (net/ipv6/af_inet6.c:192 net/ipv6/af_inet6.c:119)
__sock_create (net/socket.c:1572)
rds_tcp_listen_init (net/rds/tcp_listen.c:279)
rds_tcp_init_net (net/rds/tcp.c:577)
ops_init (net/core/net_namespace.c:137)
setup_net (net/core/net_namespace.c:340)
copy_net_ns (net/core/net_namespace.c:497)
create_new_namespaces (kernel/nsproxy.c:110)
unshare_nsproxy_namespaces (kernel/nsproxy.c:228 (discriminator 4))
ksys_unshare (kernel/fork.c:3429)
__x64_sys_unshare (kernel/fork.c:3496)
do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:129)
...
WARNING: CPU: 0 PID: 27 at lib/ref_tracker.c:179 ref_tracker_dir_exit (lib/ref_tracker.c:179)
[1]:
BUG: KASAN: slab-use-after-free in inet_csk_reqsk_queue_drop (./include/net/inet_hashtables.h:180 net/ipv4/inet_connection_sock.c:952 net/ipv4/inet_connection_sock.c:966)
Read of size 8 at addr ffff88801b370400 by task swapper/0/0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl (lib/dump_stack.c:107 (discriminator 1))
print_report (mm/kasan/report.c:378 mm/kasan/report.c:488)
kasan_report (mm/kasan/report.c:603)
inet_csk_reqsk_queue_drop (./include/net/inet_hashtables.h:180 net/ipv4/inet_connection_sock.c:952 net/ipv4/inet_connection_sock.c:966)
reqsk_timer_handler (net/ipv4/inet_connection_sock.c:979 net/ipv4/inet_connection_sock.c:1092)
call_timer_fn (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/timer.h:127 kernel/time/timer.c:1701)
__run_timers.part.0 (kernel/time/timer.c:1752 kernel/time/timer.c:2038)
run_timer_softirq (kernel/time/timer.c:2053)
__do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:554)
irq_exit_rcu (kernel/softirq.c:427 kernel/softirq.c:632 kernel/softirq.c:644)
sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1076 (discriminator 14))
</IRQ>
Allocated by task 258 on cpu 0 at 83.612050s:
kasan_save_stack (mm/kasan/common.c:48)
kasan_save_track (mm/kasan/common.c:68)
__kasan_slab_alloc (mm/kasan/common.c:343)
kmem_cache_alloc (mm/slub.c:3813 mm/slub.c:3860 mm/slub.c:3867)
copy_net_ns (./include/linux/slab.h:701 net/core/net_namespace.c:421 net/core/net_namespace.c:480)
create_new_namespaces (kernel/nsproxy.c:110)
unshare_nsproxy_name
---truncated---Show less |
In the Linux kernel, the following vulnerability has been resolved:
net: sparx5: Fix use after free inside sparx5_del_mact_entry
Based on the static analyzis of the code it looks like when an entry
from the MAC table w...Show moreIn the Linux kernel, the following vulnerability has been resolved:
net: sparx5: Fix use after free inside sparx5_del_mact_entry
Based on the static analyzis of the code it looks like when an entry
from the MAC table was removed, the entry was still used after being
freed. More precise the vid of the mac_entry was used after calling
devm_kfree on the mac_entry.
The fix consists in first using the vid of the mac_entry to delete the
entry from the HW and after that to free it.Show less |
In the Linux kernel, the following vulnerability has been resolved:
net/ipv6: avoid possible UAF in ip6_route_mpath_notify()
syzbot found another use-after-free in ip6_route_mpath_notify() [1]
Commit f7225172f25a ("ne...Show moreIn the Linux kernel, the following vulnerability has been resolved:
net/ipv6: avoid possible UAF in ip6_route_mpath_notify()
syzbot found another use-after-free in ip6_route_mpath_notify() [1]
Commit f7225172f25a ("net/ipv6: prevent use after free in
ip6_route_mpath_notify") was not able to fix the root cause.
We need to defer the fib6_info_release() calls after
ip6_route_mpath_notify(), in the cleanup phase.
[1]
BUG: KASAN: slab-use-after-free in rt6_fill_node+0x1460/0x1ac0
Read of size 4 at addr ffff88809a07fc64 by task syz-executor.2/23037
CPU: 0 PID: 23037 Comm: syz-executor.2 Not tainted 6.8.0-rc4-syzkaller-01035-gea7f3cfaa588 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x167/0x540 mm/kasan/report.c:488
kasan_report+0x142/0x180 mm/kasan/report.c:601
rt6_fill_node+0x1460/0x1ac0
inet6_rt_notify+0x13b/0x290 net/ipv6/route.c:6184
ip6_route_mpath_notify net/ipv6/route.c:5198 [inline]
ip6_route_multipath_add net/ipv6/route.c:5404 [inline]
inet6_rtm_newroute+0x1d0f/0x2300 net/ipv6/route.c:5517
rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543
netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367
netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
do_syscall_64+0xf9/0x240
entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f73dd87dda9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f73de6550c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f73dd9ac050 RCX: 00007f73dd87dda9
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005
RBP: 00007f73dd8ca47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f73dd9ac050 R15: 00007ffdbdeb7858
</TASK>
Allocated by task 23037:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:372 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:389
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slub.c:3981 [inline]
__kmalloc+0x22e/0x490 mm/slub.c:3994
kmalloc include/linux/slab.h:594 [inline]
kzalloc include/linux/slab.h:711 [inline]
fib6_info_alloc+0x2e/0xf0 net/ipv6/ip6_fib.c:155
ip6_route_info_create+0x445/0x12b0 net/ipv6/route.c:3758
ip6_route_multipath_add net/ipv6/route.c:5298 [inline]
inet6_rtm_newroute+0x744/0x2300 net/ipv6/route.c:5517
rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543
netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367
netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
do_syscall_64+0xf9/0x240
entry_SYSCALL_64_after_hwframe+0x6f/0x77
Freed by task 16:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x4e/0x60 mm/kasan/generic.c:640
poison_slab_object+0xa6/0xe0 m
---truncated---Show less |
In the Linux kernel, the following vulnerability has been resolved:
RDMA/irdma: Fix KASAN issue with tasklet
KASAN testing revealed the following issue assocated with freeing an IRQ.
[50006.466686] Call Trace:
[50006....Show moreIn the Linux kernel, the following vulnerability has been resolved:
RDMA/irdma: Fix KASAN issue with tasklet
KASAN testing revealed the following issue assocated with freeing an IRQ.
[50006.466686] Call Trace:
[50006.466691] <IRQ>
[50006.489538] dump_stack+0x5c/0x80
[50006.493475] print_address_description.constprop.6+0x1a/0x150
[50006.499872] ? irdma_sc_process_ceq+0x483/0x790 [irdma]
[50006.505742] ? irdma_sc_process_ceq+0x483/0x790 [irdma]
[50006.511644] kasan_report.cold.11+0x7f/0x118
[50006.516572] ? irdma_sc_process_ceq+0x483/0x790 [irdma]
[50006.522473] irdma_sc_process_ceq+0x483/0x790 [irdma]
[50006.528232] irdma_process_ceq+0xb2/0x400 [irdma]
[50006.533601] ? irdma_hw_flush_wqes_callback+0x370/0x370 [irdma]
[50006.540298] irdma_ceq_dpc+0x44/0x100 [irdma]
[50006.545306] tasklet_action_common.isra.14+0x148/0x2c0
[50006.551096] __do_softirq+0x1d0/0xaf8
[50006.555396] irq_exit_rcu+0x219/0x260
[50006.559670] irq_exit+0xa/0x20
[50006.563320] smp_apic_timer_interrupt+0x1bf/0x690
[50006.568645] apic_timer_interrupt+0xf/0x20
[50006.573341] </IRQ>
The issue is that a tasklet could be pending on another core racing
the delete of the irq.
Fix by insuring any scheduled tasklet is killed after deleting the
irq.Show less |
Use after free in QUIC in Google Chrome prior to 124.0.6367.60 allowed a remote attacker who had compromised the renderer process to potentially exploit heap corruption via a crafted HTML page. (Chromium security severit...Show moreUse after free in QUIC in Google Chrome prior to 124.0.6367.60 allowed a remote attacker who had compromised the renderer process to potentially exploit heap corruption via a crafted HTML page. (Chromium security severity: Medium)Show less |
Use after free in Downloads in Google Chrome prior to 124.0.6367.60 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. (Chromium security severity: High) |
A Use After Free vulnerability in command processing of Juniper Networks Junos OS on MX Series allows a local, authenticated attacker to cause the broadband edge service manager daemon (bbe-smgd) to crash upon execution...Show moreA Use After Free vulnerability in command processing of Juniper Networks Junos OS on MX Series allows a local, authenticated attacker to cause the broadband edge service manager daemon (bbe-smgd) to crash upon execution of specific CLI commands, creating a Denial of Service (DoS) condition. The process crashes and restarts automatically.
When specific CLI commands are executed, the bbe-smgd daemon attempts to write into an area of memory (mgd socket) that was already closed, causing the process to crash. This process manages and controls the configuration of broadband subscriber sessions and services. While the process is unavailable, additional subscribers will not be able to connect to the device, causing a temporary Denial of Service condition.
This issue only occurs if Graceful Routing Engine Switchover (GRES) and Subscriber Management are enabled.
This issue affects Junos OS:
* All versions before 20.4R3-S5,
* from 21.1 before 21.1R3-S4,
* from 21.2 before 21.2R3-S3,
* from 21.3 before 21.3R3-S5,
* from 21.4 before 21.4R3-S5,
* from 22.1 before 22.1R3,
* from 22.2 before 22.2R3,
* from 22.3 before 22.3R2;Show less |
If an AlignedBuffer were assigned to itself, the subsequent self-move could result in an incorrect reference count and later use-after-free. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird...Show moreIf an AlignedBuffer were assigned to itself, the subsequent self-move could result in an incorrect reference count and later use-after-free. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.Show less |
The JIT created incorrect code for arguments in certain cases. This led to potential use-after-free crashes during garbage collection. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115...Show moreThe JIT created incorrect code for arguments in certain cases. This led to potential use-after-free crashes during garbage collection. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.Show less |
A use-after-free could occur during WASM execution if garbage collection ran during the creation of an array. This vulnerability affects Firefox < 125. |
A use-after-free could result if a JavaScript realm was in the process of being initialized when a garbage collection started. This vulnerability affects Firefox < 125. |
A Use-After-Free vulnerability in the Layer 2 Address Learning Daemon (l2ald)
of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker to cause l2ald to crash leading to a Denial-o...Show moreA Use-After-Free vulnerability in the Layer 2 Address Learning Daemon (l2ald)
of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker to cause l2ald to crash leading to a Denial-of-Service (DoS).
In an EVPN-VXLAN scenario, when
state updates are received and processed by the affected system, the correct order of some processing steps is not ensured, which can lead to an l2ald crash and restart. Whether the crash occurs depends on system internal timing which is outside the attackers control.
This issue affects:
Junos OS:
* All versions before 20.4R3-S8,
* 21.2 versions before 21.2R3-S6,
* 21.3 versions before 21.3R3-S5,
* 21.4 versions before 21.4R3-S4,
* 22.1 versions before 22.1R3-S3,
* 22.2 versions before 22.2R3-S1,
* 22.3 versions before 22.3R3,,
* 22.4 versions before 22.4R2;
Junos OS Evolved:
* All versions before 20.4R3-S8-EVO,
* 21.2-EVO versions before 21.2R3-S6-EVO,
* 21.3-EVO
versions before 21.3R3-S5-EVO,
* 21.4-EVO
versions before 21.4R3-S4-EVO,
* 22.1-EVO
versions before 22.1R3-S3-EVO,
* 22.2-EVO
versions before 22.2R3-S1-EVO,
* 22.3-EVO
versions before 22.3R3-EVO,
* 22.4-EVO
versions before 22.4R2-EVO.Show less |
Use after free in Dawn in Google Chrome prior to 123.0.6312.122 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. (Chromium security severity: High) |
In the Linux kernel, the following vulnerability has been resolved:
sched/fair: Prevent dead task groups from regaining cfs_rq's
Kevin is reporting crashes which point to a use-after-free of a cfs_rq
in update_blocked_...Show moreIn the Linux kernel, the following vulnerability has been resolved:
sched/fair: Prevent dead task groups from regaining cfs_rq's
Kevin is reporting crashes which point to a use-after-free of a cfs_rq
in update_blocked_averages(). Initial debugging revealed that we've
live cfs_rq's (on_list=1) in an about to be kfree()'d task group in
free_fair_sched_group(). However, it was unclear how that can happen.
His kernel config happened to lead to a layout of struct sched_entity
that put the 'my_q' member directly into the middle of the object
which makes it incidentally overlap with SLUB's freelist pointer.
That, in combination with SLAB_FREELIST_HARDENED's freelist pointer
mangling, leads to a reliable access violation in form of a #GP which
made the UAF fail fast.
Michal seems to have run into the same issue[1]. He already correctly
diagnosed that commit a7b359fc6a37 ("sched/fair: Correctly insert
cfs_rq's to list on unthrottle") is causing the preconditions for the
UAF to happen by re-adding cfs_rq's also to task groups that have no
more running tasks, i.e. also to dead ones. His analysis, however,
misses the real root cause and it cannot be seen from the crash
backtrace only, as the real offender is tg_unthrottle_up() getting
called via sched_cfs_period_timer() via the timer interrupt at an
inconvenient time.
When unregister_fair_sched_group() unlinks all cfs_rq's from the dying
task group, it doesn't protect itself from getting interrupted. If the
timer interrupt triggers while we iterate over all CPUs or after
unregister_fair_sched_group() has finished but prior to unlinking the
task group, sched_cfs_period_timer() will execute and walk the list of
task groups, trying to unthrottle cfs_rq's, i.e. re-add them to the
dying task group. These will later -- in free_fair_sched_group() -- be
kfree()'ed while still being linked, leading to the fireworks Kevin
and Michal are seeing.
To fix this race, ensure the dying task group gets unlinked first.
However, simply switching the order of unregistering and unlinking the
task group isn't sufficient, as concurrent RCU walkers might still see
it, as can be seen below:
CPU1: CPU2:
: timer IRQ:
: do_sched_cfs_period_timer():
: :
: distribute_cfs_runtime():
: rcu_read_lock();
: :
: unthrottle_cfs_rq():
sched_offline_group(): :
: walk_tg_tree_from(…,tg_unthrottle_up,…):
list_del_rcu(&tg->list); :
(1) : list_for_each_entry_rcu(child, &parent->children, siblings)
: :
(2) list_del_rcu(&tg->siblings); :
: tg_unthrottle_up():
unregister_fair_sched_group(): struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
: :
list_del_leaf_cfs_rq(tg->cfs_rq[cpu]); :
: :
: if (!cfs_rq_is_decayed(cfs_rq) || cfs_rq->nr_running)
(3) : list_add_leaf_cfs_rq(cfs_rq);
: :
: :
: :
: :
:
---truncated---Show less |
In the Linux kernel, the following vulnerability has been resolved:
net: dpaa2-eth: fix use-after-free in dpaa2_eth_remove
Access to netdev after free_netdev() will cause use-after-free bug.
Move debug log before free_...Show moreIn the Linux kernel, the following vulnerability has been resolved:
net: dpaa2-eth: fix use-after-free in dpaa2_eth_remove
Access to netdev after free_netdev() will cause use-after-free bug.
Move debug log before free_netdev() call to avoid it.Show less |
In the Linux kernel, the following vulnerability has been resolved:
drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap
drm_gem_ttm_mmap() drops a reference to the gem object on success. If
the gem object's ref...Show moreIn the Linux kernel, the following vulnerability has been resolved:
drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap
drm_gem_ttm_mmap() drops a reference to the gem object on success. If
the gem object's refcount == 1 on entry to drm_gem_prime_mmap(), that
drop will free the gem object, and the subsequent drm_gem_object_get()
will be a UAF. Fix by grabbing a reference before calling the mmap
helper.
This issue was forseen when the reference dropping was adding in
commit 9786b65bc61ac ("drm/ttm: fix mmap refcounting"):
"For that to work properly the drm_gem_object_get() call in
drm_gem_ttm_mmap() must be moved so it happens before calling
obj->funcs->mmap(), otherwise the gem refcount would go down
to zero."Show less |