Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: rose: Fix NULL pointer dereference in rose_send_frame() The syzkaller reported an issue: KASAN: null-ptr-deref in range [0x0000000000000380-0x0000000000000387] CPU: 0 PID: 4069 Comm: kworker/0:15 Not tainted 6.0.0-syzkaller-02734-g0326074ff465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Workqueue: rcu_gp srcu_invoke_callbacks RIP: 0010:rose_send_frame+0x1dd/0x2f0 net/rose/rose_link.c:101 Call Trace: <IRQ> rose_transmit_clear_request+0x1d5/0x290 net/rose/rose_link.c:255 rose_rx_call_request+0x4c0/0x1bc0 net/rose/af_rose.c:1009 rose_loopback_timer+0x19e/0x590 net/rose/rose_loopback.c:111 call_timer_fn+0x1a0/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1519 [inline] __run_timers.part.0+0x674/0xa80 kernel/time/timer.c:1790 __run_timers kernel/time/timer.c:1768 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1803 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 [...] </IRQ> It triggers NULL pointer dereference when 'neigh->dev->dev_addr' is called in the rose_send_frame(). It's the first occurrence of the `neigh` is in rose_loopback_timer() as `rose_loopback_neigh', and the 'dev' in 'rose_loopback_neigh' is initialized sa nullptr. It had been fixed by commit 3b3fd068c56e3fbea30090859216a368398e39bf ("rose: Fix Null pointer dereference in rose_send_frame()") ever. But it's introduced by commit 3c53cd65dece47dd1f9d3a809f32e59d1d87b2b8 ("rose: check NULL rose_loopback_neigh->loopback") again. We fix it by add NULL check in rose_transmit_clear_request(). When the 'dev' in 'neigh' is NULL, we don't reply the request and just clear it. syzkaller don't provide repro, and I provide a syz repro like: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) ioctl$sock_inet_SIOCSIFFLAGS(r0, 0x8914, &(0x7f0000000180)={'rose0\x00', 0x201}) r1 = syz_init_net_socket$rose(0xb, 0x5, 0x0) bind$rose(r1, &(0x7f00000000c0)=@full={0xb, @dev, @null, 0x0, [@null, @null, @netrom, @netrom, @default, @null]}, 0x40) connect$rose(r1, &(0x7f0000000240)=@short={0xb, @dev={0xbb, 0xbb, 0xbb, 0x1, 0x0}, @remote={0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0x1}, 0x1, @netrom={0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0x0, 0x0}}, 0x1c)Show less

In the Linux kernel, the following vulnerability has been resolved: mISDN: fix possible memory leak in mISDN_register_device() Afer commit 1fa5ae857bb1 ("driver core: get rid of struct device's bus_id string array"), the name of device is allocated dynamically, add put_device() to give up the reference, so that the name can be freed in kobject_cleanup() when the refcount is 0. Set device class before put_device() to avoid null release() function WARN message in device_release().Show less

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix inode list leak during backref walking at resolve_indirect_refs() During backref walking, at resolve_indirect_refs(), if we get an error we jump to the 'out' label and call ulist_free() on the 'parents' ulist, which frees all the elements in the ulist - however that does not free any inode lists that may be attached to elements, through the 'aux' field of a ulist node, so we end up leaking lists if we have any attached to the unodes. Fix this by calling free_leaf_list() instead of ulist_free() when we exit from resolve_indirect_refs(). The static function free_leaf_list() is moved up for this to be possible and it's slightly simplified by removing unnecessary code.Show less

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix inode list leak during backref walking at find_parent_nodes() During backref walking, at find_parent_nodes(), if we are dealing with a data extent and we get an error while resolving the indirect backrefs, at resolve_indirect_refs(), or in the while loop that iterates over the refs in the direct refs rbtree, we end up leaking the inode lists attached to the direct refs we have in the direct refs rbtree that were not yet added to the refs ulist passed as argument to find_parent_nodes(). Since they were not yet added to the refs ulist and prelim_release() does not free the lists, on error the caller can only free the lists attached to the refs that were added to the refs ulist, all the remaining refs get their inode lists never freed, therefore leaking their memory. Fix this by having prelim_release() always free any attached inode list to each ref found in the rbtree, and have find_parent_nodes() set the ref's inode list to NULL once it transfers ownership of the inode list to a ref added to the refs ulist passed to find_parent_nodes().Show less

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix ulist leaks in error paths of qgroup self tests In the test_no_shared_qgroup() and test_multiple_refs() qgroup self tests, if we fail to add the tree ref, remove the extent item or remove the extent ref, we are returning from the test function without freeing the "old_roots" ulist that was allocated by the previous calls to btrfs_find_all_roots(). Fix that by calling ulist_free() before returning.Show less

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: enforce documented limit to prevent allocating huge memory Daniel Xu reported that the hash:net,iface type of the ipset subsystem does not limit adding the same network with different interfaces to a set, which can lead to huge memory usage or allocation failure. The quick reproducer is $ ipset create ACL.IN.ALL_PERMIT hash:net,iface hashsize 1048576 timeout 0 $ for i in $(seq 0 100); do /sbin/ipset add ACL.IN.ALL_PERMIT 0.0.0.0/0,kaf_$i timeout 0 -exist; done The backtrace when vmalloc fails: [Tue Oct 25 00:13:08 2022] ipset: vmalloc error: size 1073741848, exceeds total pages <...> [Tue Oct 25 00:13:08 2022] Call Trace: [Tue Oct 25 00:13:08 2022] <TASK> [Tue Oct 25 00:13:08 2022] dump_stack_lvl+0x48/0x60 [Tue Oct 25 00:13:08 2022] warn_alloc+0x155/0x180 [Tue Oct 25 00:13:08 2022] __vmalloc_node_range+0x72a/0x760 [Tue Oct 25 00:13:08 2022] ? hash_netiface4_add+0x7c0/0xb20 [Tue Oct 25 00:13:08 2022] ? __kmalloc_large_node+0x4a/0x90 [Tue Oct 25 00:13:08 2022] kvmalloc_node+0xa6/0xd0 [Tue Oct 25 00:13:08 2022] ? hash_netiface4_resize+0x99/0x710 <...> The fix is to enforce the limit documented in the ipset(8) manpage: > The internal restriction of the hash:net,iface set type is that the same > network prefix cannot be stored with more than 64 different interfaces > in a single set.Show less

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu Fix the race condition between the following two flows that run in parallel: 1. l2cap_reassemble_sdu -> chan->ops->recv (l2cap_sock_recv_cb) -> __sock_queue_rcv_skb. 2. bt_sock_recvmsg -> skb_recv_datagram, skb_free_datagram. An SKB can be queued by the first flow and immediately dequeued and freed by the second flow, therefore the callers of l2cap_reassemble_sdu can't use the SKB after that function returns. However, some places continue accessing struct l2cap_ctrl that resides in the SKB's CB for a short time after l2cap_reassemble_sdu returns, leading to a use-after-free condition (the stack trace is below, line numbers for kernel 5.19.8). Fix it by keeping a local copy of struct l2cap_ctrl. BUG: KASAN: use-after-free in l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth Read of size 1 at addr ffff88812025f2f0 by task kworker/u17:3/43169 Workqueue: hci0 hci_rx_work [bluetooth] Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4)) print_report.cold (mm/kasan/report.c:314 mm/kasan/report.c:429) ? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth kasan_report (mm/kasan/report.c:162 mm/kasan/report.c:493) ? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth l2cap_rx (net/bluetooth/l2cap_core.c:7236 net/bluetooth/l2cap_core.c:7271) bluetooth ret_from_fork (arch/x86/entry/entry_64.S:306) </TASK> Allocated by task 43169: kasan_save_stack (mm/kasan/common.c:39) __kasan_slab_alloc (mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469) kmem_cache_alloc_node (mm/slab.h:750 mm/slub.c:3243 mm/slub.c:3293) __alloc_skb (net/core/skbuff.c:414) l2cap_recv_frag (./include/net/bluetooth/bluetooth.h:425 net/bluetooth/l2cap_core.c:8329) bluetooth l2cap_recv_acldata (net/bluetooth/l2cap_core.c:8442) bluetooth hci_rx_work (net/bluetooth/hci_core.c:3642 net/bluetooth/hci_core.c:3832) bluetooth process_one_work (kernel/workqueue.c:2289) worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2437) kthread (kernel/kthread.c:376) ret_from_fork (arch/x86/entry/entry_64.S:306) Freed by task 27920: kasan_save_stack (mm/kasan/common.c:39) kasan_set_track (mm/kasan/common.c:45) kasan_set_free_info (mm/kasan/generic.c:372) ____kasan_slab_free (mm/kasan/common.c:368 mm/kasan/common.c:328) slab_free_freelist_hook (mm/slub.c:1780) kmem_cache_free (mm/slub.c:3536 mm/slub.c:3553) skb_free_datagram (./include/net/sock.h:1578 ./include/net/sock.h:1639 net/core/datagram.c:323) bt_sock_recvmsg (net/bluetooth/af_bluetooth.c:295) bluetooth l2cap_sock_recvmsg (net/bluetooth/l2cap_sock.c:1212) bluetooth sock_read_iter (net/socket.c:1087) new_sync_read (./include/linux/fs.h:2052 fs/read_write.c:401) vfs_read (fs/read_write.c:482) ksys_read (fs/read_write.c:620) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)Show less

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix memory leak in vhci_write Syzkaller reports a memory leak as follows: ==================================== BUG: memory leak unreferenced object 0xffff88810d81ac00 (size 240): [...] hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff838733d9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:418 [<ffffffff833f742f>] alloc_skb include/linux/skbuff.h:1257 [inline] [<ffffffff833f742f>] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline] [<ffffffff833f742f>] vhci_get_user drivers/bluetooth/hci_vhci.c:391 [inline] [<ffffffff833f742f>] vhci_write+0x5f/0x230 drivers/bluetooth/hci_vhci.c:511 [<ffffffff815e398d>] call_write_iter include/linux/fs.h:2192 [inline] [<ffffffff815e398d>] new_sync_write fs/read_write.c:491 [inline] [<ffffffff815e398d>] vfs_write+0x42d/0x540 fs/read_write.c:578 [<ffffffff815e3cdd>] ksys_write+0x9d/0x160 fs/read_write.c:631 [<ffffffff845e0645>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff845e0645>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd ==================================== HCI core will uses hci_rx_work() to process frame, which is queued to the hdev->rx_q tail in hci_recv_frame() by HCI driver. Yet the problem is that, HCI core may not free the skb after handling ACL data packets. To be more specific, when start fragment does not contain the L2CAP length, HCI core just copies skb into conn->rx_skb and finishes frame process in l2cap_recv_acldata(), without freeing the skb, which triggers the above memory leak. This patch solves it by releasing the relative skb, after processing the above case in l2cap_recv_acldata().Show less

In the Linux kernel, the following vulnerability has been resolved: net: mdio: fix undefined behavior in bit shift for __mdiobus_register Shifting signed 32-bit value by 31 bits is undefined, so changing significant bit to unsigned. The UBSAN warning calltrace like below: UBSAN: shift-out-of-bounds in drivers/net/phy/mdio_bus.c:586:27 left shift of 1 by 31 places cannot be represented in type 'int' Call Trace: <TASK> dump_stack_lvl+0x7d/0xa5 dump_stack+0x15/0x1b ubsan_epilogue+0xe/0x4e __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c __mdiobus_register+0x49d/0x4e0 fixed_mdio_bus_init+0xd8/0x12d do_one_initcall+0x76/0x430 kernel_init_freeable+0x3b3/0x422 kernel_init+0x24/0x1e0 ret_from_fork+0x1f/0x30 </TASK>Show less

In the Linux kernel, the following vulnerability has been resolved: ibmvnic: Free rwi on reset success Free the rwi structure in the event that the last rwi in the list processed successfully. The logic in commit 4f408e1fa6e1 ("ibmvnic: retry reset if there are no other resets") introduces an issue that results in a 32 byte memory leak whenever the last rwi in the list gets processed.Show less

In the Linux kernel, the following vulnerability has been resolved: net/smc: Fix possible leaked pernet namespace in smc_init() In smc_init(), register_pernet_subsys(&smc_net_stat_ops) is called without any error handling. If it fails, registering of &smc_net_ops won't be reverted. And if smc_nl_init() fails, &smc_net_stat_ops itself won't be reverted. This leaves wild ops in subsystem linkedlist and when another module tries to call register_pernet_operations() it triggers page fault: BUG: unable to handle page fault for address: fffffbfff81b964c RIP: 0010:register_pernet_operations+0x1b9/0x5f0 Call Trace: <TASK> register_pernet_subsys+0x29/0x40 ebtables_init+0x58/0x1000 [ebtables] ...Show less

In the Linux kernel, the following vulnerability has been resolved: net, neigh: Fix null-ptr-deref in neigh_table_clear() When IPv6 module gets initialized but hits an error in the middle, kenel panic with: KASAN: null-ptr-deref in range [0x0000000000000598-0x000000000000059f] CPU: 1 PID: 361 Comm: insmod Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:__neigh_ifdown.isra.0+0x24b/0x370 RSP: 0018:ffff888012677908 EFLAGS: 00000202 ... Call Trace: <TASK> neigh_table_clear+0x94/0x2d0 ndisc_cleanup+0x27/0x40 [ipv6] inet6_init+0x21c/0x2cb [ipv6] do_one_initcall+0xd3/0x4d0 do_init_module+0x1ae/0x670 ... Kernel panic - not syncing: Fatal exception When ipv6 initialization fails, it will try to cleanup and calls: neigh_table_clear() neigh_ifdown(tbl, NULL) pneigh_queue_purge(&tbl->proxy_queue, dev_net(dev == NULL)) # dev_net(NULL) triggers null-ptr-deref. Fix it by passing NULL to pneigh_queue_purge() in neigh_ifdown() if dev is NULL, to make kernel not panic immediately.Show less

In the Linux kernel, the following vulnerability has been resolved: ipv6: fix WARNING in ip6_route_net_exit_late() During the initialization of ip6_route_net_init_late(), if file ipv6_route or rt6_stats fails to be created, the initialization is successful by default. Therefore, the ipv6_route or rt6_stats file doesn't be found during the remove in ip6_route_net_exit_late(). It will cause WRNING. The following is the stack information: name 'rt6_stats' WARNING: CPU: 0 PID: 9 at fs/proc/generic.c:712 remove_proc_entry+0x389/0x460 Modules linked in: Workqueue: netns cleanup_net RIP: 0010:remove_proc_entry+0x389/0x460 PKRU: 55555554 Call Trace: <TASK> ops_exit_list+0xb0/0x170 cleanup_net+0x4ea/0xb00 process_one_work+0x9bf/0x1710 worker_thread+0x665/0x1080 kthread+0x2e4/0x3a0 ret_from_fork+0x1f/0x30 </TASK>Show less

In the Linux kernel, the following vulnerability has been resolved: block: Fix possible memory leak for rq_wb on add_disk failure kmemleak reported memory leaks in device_add_disk(): kmemleak: 3 new suspected memory leaks unreferenced object 0xffff88800f420800 (size 512): comm "modprobe", pid 4275, jiffies 4295639067 (age 223.512s) hex dump (first 32 bytes): 04 00 00 00 08 00 00 00 01 00 00 00 00 00 00 00 ................ 00 e1 f5 05 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000d3662699>] kmalloc_trace+0x26/0x60 [<00000000edc7aadc>] wbt_init+0x50/0x6f0 [<0000000069601d16>] wbt_enable_default+0x157/0x1c0 [<0000000028fc393f>] blk_register_queue+0x2a4/0x420 [<000000007345a042>] device_add_disk+0x6fd/0xe40 [<0000000060e6aab0>] nbd_dev_add+0x828/0xbf0 [nbd] ... It is because the memory allocated in wbt_enable_default() is not released in device_add_disk() error path. Normally, these memory are freed in: del_gendisk() rq_qos_exit() rqos->ops->exit(rqos); wbt_exit() So rq_qos_exit() is called to free the rq_wb memory for wbt_init(). However in the error path of device_add_disk(), only blk_unregister_queue() is called and make rq_wb memory leaked. Add rq_qos_exit() to the error path to fix it.Show less

In the Linux kernel, the following vulnerability has been resolved: blk-mq: Fix kmemleak in blk_mq_init_allocated_queue There is a kmemleak caused by modprobe null_blk.ko unreferenced object 0xffff8881acb1f000 (size 1024): comm "modprobe", pid 836, jiffies 4294971190 (age 27.068s) hex dump (first 32 bytes): 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... ff ff ff ff ff ff ff ff 00 53 99 9e ff ff ff ff .........S...... backtrace: [<000000004a10c249>] kmalloc_node_trace+0x22/0x60 [<00000000648f7950>] blk_mq_alloc_and_init_hctx+0x289/0x350 [<00000000af06de0e>] blk_mq_realloc_hw_ctxs+0x2fe/0x3d0 [<00000000e00c1872>] blk_mq_init_allocated_queue+0x48c/0x1440 [<00000000d16b4e68>] __blk_mq_alloc_disk+0xc8/0x1c0 [<00000000d10c98c3>] 0xffffffffc450d69d [<00000000b9299f48>] 0xffffffffc4538392 [<0000000061c39ed6>] do_one_initcall+0xd0/0x4f0 [<00000000b389383b>] do_init_module+0x1a4/0x680 [<0000000087cf3542>] load_module+0x6249/0x7110 [<00000000beba61b8>] __do_sys_finit_module+0x140/0x200 [<00000000fdcfff51>] do_syscall_64+0x35/0x80 [<000000003c0f1f71>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 That is because q->ma_ops is set to NULL before blk_release_queue is called. blk_mq_init_queue_data blk_mq_init_allocated_queue blk_mq_realloc_hw_ctxs for (i = 0; i < set->nr_hw_queues; i++) { old_hctx = xa_load(&q->hctx_table, i); if (!blk_mq_alloc_and_init_hctx(.., i, ..)) [1] if (!old_hctx) break; xa_for_each_start(&q->hctx_table, j, hctx, j) blk_mq_exit_hctx(q, set, hctx, j); [2] if (!q->nr_hw_queues) [3] goto err_hctxs; err_exit: q->mq_ops = NULL; [4] blk_put_queue blk_release_queue if (queue_is_mq(q)) [5] blk_mq_release(q); [1]: blk_mq_alloc_and_init_hctx failed at i != 0. [2]: The hctxs allocated by [1] are moved to q->unused_hctx_list and will be cleaned up in blk_mq_release. [3]: q->nr_hw_queues is 0. [4]: Set q->mq_ops to NULL. [5]: queue_is_mq returns false due to [4]. And blk_mq_release will not be called. The hctxs in q->unused_hctx_list are leaked. To fix it, call blk_release_queue in exception path.Show less

In the Linux kernel, the following vulnerability has been resolved: i2c: piix4: Fix adapter not be removed in piix4_remove() In piix4_probe(), the piix4 adapter will be registered in: piix4_probe() piix4_add_adapters_sb800() / piix4_add_adapter() i2c_add_adapter() Based on the probed device type, piix4_add_adapters_sb800() or single piix4_add_adapter() will be called. For the former case, piix4_adapter_count is set as the number of adapters, while for antoher case it is not set and kept default *zero*. When piix4 is removed, piix4_remove() removes the adapters added in piix4_probe(), basing on the piix4_adapter_count value. Because the count is zero for the single adapter case, the adapter won't be removed and makes the sources allocated for adapter leaked, such as the i2c client and device. These sources can still be accessed by i2c or bus and cause problems. An easily reproduced case is that if a new adapter is registered, i2c will get the leaked adapter and try to call smbus_algorithm, which was already freed: Triggered by: rmmod i2c_piix4 && modprobe max31730 BUG: unable to handle page fault for address: ffffffffc053d860 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3752 Comm: modprobe Tainted: G Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:i2c_default_probe (drivers/i2c/i2c-core-base.c:2259) i2c_core RSP: 0018:ffff888107477710 EFLAGS: 00000246 ... <TASK> i2c_detect (drivers/i2c/i2c-core-base.c:2302) i2c_core __process_new_driver (drivers/i2c/i2c-core-base.c:1336) i2c_core bus_for_each_dev (drivers/base/bus.c:301) i2c_for_each_dev (drivers/i2c/i2c-core-base.c:1823) i2c_core i2c_register_driver (drivers/i2c/i2c-core-base.c:1861) i2c_core do_one_initcall (init/main.c:1296) do_init_module (kernel/module/main.c:2455) ... </TASK> ---[ end trace 0000000000000000 ]--- Fix this problem by correctly set piix4_adapter_count as 1 for the single adapter so it can be normally removed.Show less

In the Linux kernel, the following vulnerability has been resolved: fscrypt: stop using keyrings subsystem for fscrypt_master_key The approach of fs/crypto/ internally managing the fscrypt_master_key structs as the payloads of "struct key" objects contained in a "struct key" keyring has outlived its usefulness. The original idea was to simplify the code by reusing code from the keyrings subsystem. However, several issues have arisen that can't easily be resolved: - When a master key struct is destroyed, blk_crypto_evict_key() must be called on any per-mode keys embedded in it. (This started being the case when inline encryption support was added.) Yet, the keyrings subsystem can arbitrarily delay the destruction of keys, even past the time the filesystem was unmounted. Therefore, currently there is no easy way to call blk_crypto_evict_key() when a master key is destroyed. Currently, this is worked around by holding an extra reference to the filesystem's request_queue(s). But it was overlooked that the request_queue reference is *not* guaranteed to pin the corresponding blk_crypto_profile too; for device-mapper devices that support inline crypto, it doesn't. This can cause a use-after-free. - When the last inode that was using an incompletely-removed master key is evicted, the master key removal is completed by removing the key struct from the keyring. Currently this is done via key_invalidate(). Yet, key_invalidate() takes the key semaphore. This can deadlock when called from the shrinker, since in fscrypt_ioctl_add_key(), memory is allocated with GFP_KERNEL under the same semaphore. - More generally, the fact that the keyrings subsystem can arbitrarily delay the destruction of keys (via garbage collection delay, or via random processes getting temporary key references) is undesirable, as it means we can't strictly guarantee that all secrets are ever wiped. - Doing the master key lookups via the keyrings subsystem results in the key_permission LSM hook being called. fscrypt doesn't want this, as all access control for encrypted files is designed to happen via the files themselves, like any other files. The workaround which SELinux users are using is to change their SELinux policy to grant key search access to all domains. This works, but it is an odd extra step that shouldn't really have to be done. The fix for all these issues is to change the implementation to what I should have done originally: don't use the keyrings subsystem to keep track of the filesystem's fscrypt_master_key structs. Instead, just store them in a regular kernel data structure, and rework the reference counting, locking, and lifetime accordingly. Retain support for RCU-mode key lookups by using a hash table. Replace fscrypt_sb_free() with fscrypt_sb_delete(), which releases the keys synchronously and runs a bit earlier during unmount, so that block devices are still available. A side effect of this patch is that neither the master keys themselves nor the filesystem keyrings will be listed in /proc/keys anymore. ("Master key users" and the master key users keyrings will still be listed.) However, this was mostly an implementation detail, and it was intended just for debugging purposes. I don't know of anyone using it. This patch does *not* change how "master key users" (->mk_users) works; that still uses the keyrings subsystem. That is still needed for key quotas, and changing that isn't necessary to solve the issues listed above. If we decide to change that too, it would be a separate patch. I've marked this as fixing the original commit that added the fscrypt keyring, but as noted above the most important issue that this patch fixes wasn't introduced until the addition of inline encryption support.Show less

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix tree mod log mishandling of reallocated nodes We have been seeing the following panic in production kernel BUG at fs/btrfs/tree-mod-log.c:677! invalid opcode: 0000 [#1] SMP RIP: 0010:tree_mod_log_rewind+0x1b4/0x200 RSP: 0000:ffffc9002c02f890 EFLAGS: 00010293 RAX: 0000000000000003 RBX: ffff8882b448c700 RCX: 0000000000000000 RDX: 0000000000008000 RSI: 00000000000000a7 RDI: ffff88877d831c00 RBP: 0000000000000002 R08: 000000000000009f R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000100c40 R12: 0000000000000001 R13: ffff8886c26d6a00 R14: ffff88829f5424f8 R15: ffff88877d831a00 FS: 00007fee1d80c780(0000) GS:ffff8890400c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fee1963a020 CR3: 0000000434f33002 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: btrfs_get_old_root+0x12b/0x420 btrfs_search_old_slot+0x64/0x2f0 ? tree_mod_log_oldest_root+0x3d/0xf0 resolve_indirect_ref+0xfd/0x660 ? ulist_alloc+0x31/0x60 ? kmem_cache_alloc_trace+0x114/0x2c0 find_parent_nodes+0x97a/0x17e0 ? ulist_alloc+0x30/0x60 btrfs_find_all_roots_safe+0x97/0x150 iterate_extent_inodes+0x154/0x370 ? btrfs_search_path_in_tree+0x240/0x240 iterate_inodes_from_logical+0x98/0xd0 ? btrfs_search_path_in_tree+0x240/0x240 btrfs_ioctl_logical_to_ino+0xd9/0x180 btrfs_ioctl+0xe2/0x2ec0 ? __mod_memcg_lruvec_state+0x3d/0x280 ? do_sys_openat2+0x6d/0x140 ? kretprobe_dispatcher+0x47/0x70 ? kretprobe_rethook_handler+0x38/0x50 ? rethook_trampoline_handler+0x82/0x140 ? arch_rethook_trampoline_callback+0x3b/0x50 ? kmem_cache_free+0xfb/0x270 ? do_sys_openat2+0xd5/0x140 __x64_sys_ioctl+0x71/0xb0 do_syscall_64+0x2d/0x40 Which is this code in tree_mod_log_rewind() switch (tm->op) { case BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING: BUG_ON(tm->slot < n); This occurs because we replay the nodes in order that they happened, and when we do a REPLACE we will log a REMOVE_WHILE_FREEING for every slot, starting at 0. 'n' here is the number of items in this block, which in this case was 1, but we had 2 REMOVE_WHILE_FREEING operations. The actual root cause of this was that we were replaying operations for a block that shouldn't have been replayed. Consider the following sequence of events 1. We have an already modified root, and we do a btrfs_get_tree_mod_seq(). 2. We begin removing items from this root, triggering KEY_REPLACE for it's child slots. 3. We remove one of the 2 children this root node points to, thus triggering the root node promotion of the remaining child, and freeing this node. 4. We modify a new root, and re-allocate the above node to the root node of this other root. The tree mod log looks something like this logical 0 op KEY_REPLACE (slot 1) seq 2 logical 0 op KEY_REMOVE (slot 1) seq 3 logical 0 op KEY_REMOVE_WHILE_FREEING (slot 0) seq 4 logical 4096 op LOG_ROOT_REPLACE (old logical 0) seq 5 logical 8192 op KEY_REMOVE_WHILE_FREEING (slot 1) seq 6 logical 8192 op KEY_REMOVE_WHILE_FREEING (slot 0) seq 7 logical 0 op LOG_ROOT_REPLACE (old logical 8192) seq 8 >From here the bug is triggered by the following steps 1. Call btrfs_get_old_root() on the new_root. 2. We call tree_mod_log_oldest_root(btrfs_root_node(new_root)), which is currently logical 0. 3. tree_mod_log_oldest_root() calls tree_mod_log_search_oldest(), which gives us the KEY_REPLACE seq 2, and since that's not a LOG_ROOT_REPLACE we incorrectly believe that we don't have an old root, because we expect that the most recent change should be a LOG_ROOT_REPLACE. 4. Back in tree_mod_log_oldest_root() we don't have a LOG_ROOT_REPLACE, so we don't set old_root, we simply use our e ---truncated---Show less

In the Linux kernel, the following vulnerability has been resolved: cxl/pmem: Fix cxl_pmem_region and cxl_memdev leak When a cxl_nvdimm object goes through a ->remove() event (device physically removed, nvdimm-bridge disabled, or nvdimm device disabled), then any associated regions must also be disabled. As highlighted by the cxl-create-region.sh test [1], a single device may host multiple regions, but the driver was only tracking one region at a time. This leads to a situation where only the last enabled region per nvdimm device is cleaned up properly. Other regions are leaked, and this also causes cxl_memdev reference leaks. Fix the tracking by allowing cxl_nvdimm objects to track multiple region associations.Show less

In the Linux kernel, the following vulnerability has been resolved: cxl/region: Fix decoder allocation crash When an intermediate port's decoders have been exhausted by existing regions, and creating a new region with the port in question in it's hierarchical path is attempted, cxl_port_attach_region() fails to find a port decoder (as would be expected), and drops into the failure / cleanup path. However, during cleanup of the region reference, a sanity check attempts to dereference the decoder, which in the above case didn't exist. This causes a NULL pointer dereference BUG. To fix this, refactor the decoder allocation and de-allocation into helper routines, and in this 'free' routine, check that the decoder, @cxld, is valid before attempting any operations on it.Show less