Use After Free

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix slab-use-after-free in l2cap_connect() Extend a critical section to prevent chan from early freeing. Also make the l2cap_connect() return type void. Nothing is using the returned value but it is ugly to return a potentially freed pointer. Making it void will help with backports because earlier kernels did use the return value. Now the compile will break for kernels where this patch is not a complete fix. Call stack summary: [use] l2cap_bredr_sig_cmd l2cap_connect ┌ mutex_lock(&conn->chan_lock); │ chan = pchan->ops->new_connection(pchan); <- alloc chan │ __l2cap_chan_add(conn, chan); │ l2cap_chan_hold(chan); │ list_add(&chan->list, &conn->chan_l); ... (1) └ mutex_unlock(&conn->chan_lock); chan->conf_state ... (4) <- use after free [free] l2cap_conn_del ┌ mutex_lock(&conn->chan_lock); │ foreach chan in conn->chan_l: ... (2) │ l2cap_chan_put(chan); │ l2cap_chan_destroy │ kfree(chan) ... (3) <- chan freed └ mutex_unlock(&conn->chan_lock); ================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline] BUG: KASAN: slab-use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] BUG: KASAN: slab-use-after-free in l2cap_connect+0xa67/0x11a0 net/bluetooth/l2cap_core.c:4260 Read of size 8 at addr ffff88810bf040a0 by task kworker/u3:1/311Show less

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: msft: fix slab-use-after-free in msft_do_close() Tying the msft->data lifetime to hdev by freeing it in hci_release_dev() to fix the following case: [use] msft_do_close() msft = hdev->msft_data; if (!msft) ...(1) <- passed. return; mutex_lock(&msft->filter_lock); ...(4) <- used after freed. [free] msft_unregister() msft = hdev->msft_data; hdev->msft_data = NULL; ...(2) kfree(msft); ...(3) <- msft is freed. ================================================================== BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:587 [inline] BUG: KASAN: slab-use-after-free in __mutex_lock+0x8f/0xc30 kernel/locking/mutex.c:752 Read of size 8 at addr ffff888106cbbca8 by task kworker/u5:2/309Show less

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8712: fix use-after-free in rtl8712_dl_fw Syzbot reported use-after-free in rtl8712_dl_fw(). The problem was in race condition between r871xu_dev_remove() ->ndo_open() callback. It's easy to see from crash log, that driver accesses released firmware in ->ndo_open() callback. It may happen, since driver was releasing firmware _before_ unregistering netdev. Fix it by moving unregister_netdev() before cleaning up resources. Call Trace: ... rtl871x_open_fw drivers/staging/rtl8712/hal_init.c:83 [inline] rtl8712_dl_fw+0xd95/0xe10 drivers/staging/rtl8712/hal_init.c:170 rtl8712_hal_init drivers/staging/rtl8712/hal_init.c:330 [inline] rtl871x_hal_init+0xae/0x180 drivers/staging/rtl8712/hal_init.c:394 netdev_open+0xe6/0x6c0 drivers/staging/rtl8712/os_intfs.c:380 __dev_open+0x2bc/0x4d0 net/core/dev.c:1484 Freed by task 1306: ... release_firmware+0x1b/0x30 drivers/base/firmware_loader/main.c:1053 r871xu_dev_remove+0xcc/0x2c0 drivers/staging/rtl8712/usb_intf.c:599 usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458Show less

In the Linux kernel, the following vulnerability has been resolved: mm, slub: fix potential use-after-free in slab_debugfs_fops When sysfs_slab_add failed, we shouldn't call debugfs_slab_add() for s because s will be freed soon. And slab_debugfs_fops will use s later leading to a use-after-free.Show less

In the Linux kernel, the following vulnerability has been resolved: can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv It will trigger UAF for rx_kref of j1939_priv as following. cpu0 cpu1 j1939_sk_bind(socket0, ndev0, ...) j1939_netdev_start j1939_sk_bind(socket1, ndev0, ...) j1939_netdev_start j1939_priv_set j1939_priv_get_by_ndev_locked j1939_jsk_add ..... j1939_netdev_stop kref_put_lock(&priv->rx_kref, ...) kref_get(&priv->rx_kref, ...) REFCOUNT_WARN("addition on 0;...") ==================================================== refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 RIP: 0010:refcount_warn_saturate+0x169/0x1e0 Call Trace: j1939_netdev_start+0x68b/0x920 j1939_sk_bind+0x426/0xeb0 ? security_socket_bind+0x83/0xb0 The rx_kref's kref_get() and kref_put() should use j1939_netdev_lock to protect.Show less

In the Linux kernel, the following vulnerability has been resolved: can: peak_pci: peak_pci_remove(): fix UAF When remove the module peek_pci, referencing 'chan' again after releasing 'dev' will cause UAF. Fix this by releasing 'dev' later. The following log reveals it: [ 35.961814 ] BUG: KASAN: use-after-free in peak_pci_remove+0x16f/0x270 [peak_pci] [ 35.963414 ] Read of size 8 at addr ffff888136998ee8 by task modprobe/5537 [ 35.965513 ] Call Trace: [ 35.965718 ] dump_stack_lvl+0xa8/0xd1 [ 35.966028 ] print_address_description+0x87/0x3b0 [ 35.966420 ] kasan_report+0x172/0x1c0 [ 35.966725 ] ? peak_pci_remove+0x16f/0x270 [peak_pci] [ 35.967137 ] ? trace_irq_enable_rcuidle+0x10/0x170 [ 35.967529 ] ? peak_pci_remove+0x16f/0x270 [peak_pci] [ 35.967945 ] __asan_report_load8_noabort+0x14/0x20 [ 35.968346 ] peak_pci_remove+0x16f/0x270 [peak_pci] [ 35.968752 ] pci_device_remove+0xa9/0x250Show less

In the Linux kernel, the following vulnerability has been resolved: perf: hisi: Fix use-after-free when register pmu fails When we fail to register the uncore pmu, the pmu context may not been allocated. The error handing will call cpuhp_state_remove_instance() to call uncore pmu offline callback, which migrate the pmu context. Since that's liable to lead to some kind of use-after-free. Use cpuhp_state_remove_instance_nocalls() instead of cpuhp_state_remove_instance() so that the notifiers don't execute after the PMU device has been failed to register.Show less

In the Linux kernel, the following vulnerability has been resolved: padata: Fix refcnt handling in padata_free_shell() In a high-load arm64 environment, the pcrypt_aead01 test in LTP can lead to system UAF (Use-After-Free) issues. Due to the lengthy analysis of the pcrypt_aead01 function call, I'll describe the problem scenario using a simplified model: Suppose there's a user of padata named `user_function` that adheres to the padata requirement of calling `padata_free_shell` after `serial()` has been invoked, as demonstrated in the following code: ```c struct request { struct padata_priv padata; struct completion *done; }; void parallel(struct padata_priv *padata) { do_something(); } void serial(struct padata_priv *padata) { struct request *request = container_of(padata, struct request, padata); complete(request->done); } void user_function() { DECLARE_COMPLETION(done) padata->parallel = parallel; padata->serial = serial; padata_do_parallel(); wait_for_completion(&done); padata_free_shell(); } ``` In the corresponding padata.c file, there's the following code: ```c static void padata_serial_worker(struct work_struct *serial_work) { ... cnt = 0; while (!list_empty(&local_list)) { ... padata->serial(padata); cnt++; } local_bh_enable(); if (refcount_sub_and_test(cnt, &pd->refcnt)) padata_free_pd(pd); } ``` Because of the high system load and the accumulation of unexecuted softirq at this moment, `local_bh_enable()` in padata takes longer to execute than usual. Subsequently, when accessing `pd->refcnt`, `pd` has already been released by `padata_free_shell()`, resulting in a UAF issue with `pd->refcnt`. The fix is straightforward: add `refcount_dec_and_test` before calling `padata_free_pd` in `padata_free_shell`.Show less

In the Linux kernel, the following vulnerability has been resolved: f2fs: compress: fix to avoid use-after-free on dic Call trace: __memcpy+0x128/0x250 f2fs_read_multi_pages+0x940/0xf7c f2fs_mpage_readpages+0x5a8/0x624 f2fs_readahead+0x5c/0x110 page_cache_ra_unbounded+0x1b8/0x590 do_sync_mmap_readahead+0x1dc/0x2e4 filemap_fault+0x254/0xa8c f2fs_filemap_fault+0x2c/0x104 __do_fault+0x7c/0x238 do_handle_mm_fault+0x11bc/0x2d14 do_mem_abort+0x3a8/0x1004 el0_da+0x3c/0xa0 el0t_64_sync_handler+0xc4/0xec el0t_64_sync+0x1b4/0x1b8 In f2fs_read_multi_pages(), once f2fs_decompress_cluster() was called if we hit cached page in compress_inode's cache, dic may be released, it needs break the loop rather than continuing it, in order to avoid accessing invalid dic pointer.Show less

In the Linux kernel, the following vulnerability has been resolved: IB/mlx5: Fix init stage error handling to avoid double free of same QP and UAF In the unlikely event that workqueue allocation fails and returns NULL in mlx5_mkey_cache_init(), delete the call to mlx5r_umr_resource_cleanup() (which frees the QP) in mlx5_ib_stage_post_ib_reg_umr_init(). This will avoid attempted double free of the same QP when __mlx5_ib_add() does its cleanup. Resolves a splat: Syzkaller reported a UAF in ib_destroy_qp_user workqueue: Failed to create a rescuer kthread for wq "mkey_cache": -EINTR infiniband mlx5_0: mlx5_mkey_cache_init:981:(pid 1642): failed to create work queue infiniband mlx5_0: mlx5_ib_stage_post_ib_reg_umr_init:4075:(pid 1642): mr cache init failed -12 ================================================================== BUG: KASAN: slab-use-after-free in ib_destroy_qp_user (drivers/infiniband/core/verbs.c:2073) Read of size 8 at addr ffff88810da310a8 by task repro_upstream/1642 Call Trace: <TASK> kasan_report (mm/kasan/report.c:590) ib_destroy_qp_user (drivers/infiniband/core/verbs.c:2073) mlx5r_umr_resource_cleanup (drivers/infiniband/hw/mlx5/umr.c:198) __mlx5_ib_add (drivers/infiniband/hw/mlx5/main.c:4178) mlx5r_probe (drivers/infiniband/hw/mlx5/main.c:4402) ... </TASK> Allocated by task 1642: __kmalloc (./include/linux/kasan.h:198 mm/slab_common.c:1026 mm/slab_common.c:1039) create_qp (./include/linux/slab.h:603 ./include/linux/slab.h:720 ./include/rdma/ib_verbs.h:2795 drivers/infiniband/core/verbs.c:1209) ib_create_qp_kernel (drivers/infiniband/core/verbs.c:1347) mlx5r_umr_resource_init (drivers/infiniband/hw/mlx5/umr.c:164) mlx5_ib_stage_post_ib_reg_umr_init (drivers/infiniband/hw/mlx5/main.c:4070) __mlx5_ib_add (drivers/infiniband/hw/mlx5/main.c:4168) mlx5r_probe (drivers/infiniband/hw/mlx5/main.c:4402) ... Freed by task 1642: __kmem_cache_free (mm/slub.c:1826 mm/slub.c:3809 mm/slub.c:3822) ib_destroy_qp_user (drivers/infiniband/core/verbs.c:2112) mlx5r_umr_resource_cleanup (drivers/infiniband/hw/mlx5/umr.c:198) mlx5_ib_stage_post_ib_reg_umr_init (drivers/infiniband/hw/mlx5/main.c:4076 drivers/infiniband/hw/mlx5/main.c:4065) __mlx5_ib_add (drivers/infiniband/hw/mlx5/main.c:4168) mlx5r_probe (drivers/infiniband/hw/mlx5/main.c:4402) ...Show less

In the Linux kernel, the following vulnerability has been resolved: media: bttv: fix use after free error due to btv->timeout timer There may be some a race condition between timer function bttv_irq_timeout and bttv_remove. The timer is setup in probe and there is no timer_delete operation in remove function. When it hit kfree btv, the function might still be invoked, which will cause use after free bug. This bug is found by static analysis, it may be false positive. Fix it by adding del_timer_sync invoking to the remove function. cpu0 cpu1 bttv_probe ->timer_setup ->bttv_set_dma ->mod_timer; bttv_remove ->kfree(btv); ->bttv_irq_timeout ->USE btvShow less

In the Linux kernel, the following vulnerability has been resolved: hsr: Prevent use after free in prp_create_tagged_frame() The prp_fill_rct() function can fail. In that situation, it frees the skb and returns NULL. Meanwhile on the success path, it returns the original skb. So it's straight forward to fix bug by using the returned value.Show less

In the Linux kernel, the following vulnerability has been resolved: Input: synaptics-rmi4 - fix use after free in rmi_unregister_function() The put_device() calls rmi_release_function() which frees "fn" so the dereference on the next line "fn->num_of_irqs" is a use after free. Move the put_device() to the end to fix this.Show less

In the Linux kernel, the following vulnerability has been resolved: fbdev: imsttfb: fix a resource leak in probe I've re-written the error handling but the bug is that if init_imstt() fails we need to call iounmap(par->cmap_regs).Show less

In the Linux kernel, the following vulnerability has been resolved: nbd: fix uaf in nbd_open Commit 4af5f2e03013 ("nbd: use blk_mq_alloc_disk and blk_cleanup_disk") cleans up disk by blk_cleanup_disk() and it won't set disk->private_data as NULL as before. UAF may be triggered in nbd_open() if someone tries to open nbd device right after nbd_put() since nbd has been free in nbd_dev_remove(). Fix this by implementing ->free_disk and free private data in it.Show less

In the Linux kernel, the following vulnerability has been resolved: SUNRPC: Fix RPC client cleaned up the freed pipefs dentries RPC client pipefs dentries cleanup is in separated rpc_remove_pipedir() workqueue,which takes care about pipefs superblock locking. In some special scenarios, when kernel frees the pipefs sb of the current client and immediately alloctes a new pipefs sb, rpc_remove_pipedir function would misjudge the existence of pipefs sb which is not the one it used to hold. As a result, the rpc_remove_pipedir would clean the released freed pipefs dentries. To fix this issue, rpc_remove_pipedir should check whether the current pipefs sb is consistent with the original pipefs sb. This error can be catched by KASAN: ========================================================= [ 250.497700] BUG: KASAN: slab-use-after-free in dget_parent+0x195/0x200 [ 250.498315] Read of size 4 at addr ffff88800a2ab804 by task kworker/0:18/106503 [ 250.500549] Workqueue: events rpc_free_client_work [ 250.501001] Call Trace: [ 250.502880] kasan_report+0xb6/0xf0 [ 250.503209] ? dget_parent+0x195/0x200 [ 250.503561] dget_parent+0x195/0x200 [ 250.503897] ? __pfx_rpc_clntdir_depopulate+0x10/0x10 [ 250.504384] rpc_rmdir_depopulate+0x1b/0x90 [ 250.504781] rpc_remove_client_dir+0xf5/0x150 [ 250.505195] rpc_free_client_work+0xe4/0x230 [ 250.505598] process_one_work+0x8ee/0x13b0 ... [ 22.039056] Allocated by task 244: [ 22.039390] kasan_save_stack+0x22/0x50 [ 22.039758] kasan_set_track+0x25/0x30 [ 22.040109] __kasan_slab_alloc+0x59/0x70 [ 22.040487] kmem_cache_alloc_lru+0xf0/0x240 [ 22.040889] __d_alloc+0x31/0x8e0 [ 22.041207] d_alloc+0x44/0x1f0 [ 22.041514] __rpc_lookup_create_exclusive+0x11c/0x140 [ 22.041987] rpc_mkdir_populate.constprop.0+0x5f/0x110 [ 22.042459] rpc_create_client_dir+0x34/0x150 [ 22.042874] rpc_setup_pipedir_sb+0x102/0x1c0 [ 22.043284] rpc_client_register+0x136/0x4e0 [ 22.043689] rpc_new_client+0x911/0x1020 [ 22.044057] rpc_create_xprt+0xcb/0x370 [ 22.044417] rpc_create+0x36b/0x6c0 ... [ 22.049524] Freed by task 0: [ 22.049803] kasan_save_stack+0x22/0x50 [ 22.050165] kasan_set_track+0x25/0x30 [ 22.050520] kasan_save_free_info+0x2b/0x50 [ 22.050921] __kasan_slab_free+0x10e/0x1a0 [ 22.051306] kmem_cache_free+0xa5/0x390 [ 22.051667] rcu_core+0x62c/0x1930 [ 22.051995] __do_softirq+0x165/0x52a [ 22.052347] [ 22.052503] Last potentially related work creation: [ 22.052952] kasan_save_stack+0x22/0x50 [ 22.053313] __kasan_record_aux_stack+0x8e/0xa0 [ 22.053739] __call_rcu_common.constprop.0+0x6b/0x8b0 [ 22.054209] dentry_free+0xb2/0x140 [ 22.054540] __dentry_kill+0x3be/0x540 [ 22.054900] shrink_dentry_list+0x199/0x510 [ 22.055293] shrink_dcache_parent+0x190/0x240 [ 22.055703] do_one_tree+0x11/0x40 [ 22.056028] shrink_dcache_for_umount+0x61/0x140 [ 22.056461] generic_shutdown_super+0x70/0x590 [ 22.056879] kill_anon_super+0x3a/0x60 [ 22.057234] rpc_kill_sb+0x121/0x200Show less

In the Linux kernel, the following vulnerability has been resolved: wifi: ath11k: fix htt pktlog locking The ath11k active pdevs are protected by RCU but the htt pktlog handling code calling ath11k_mac_get_ar_by_pdev_id() was not marked as a read-side critical section. Mark the code in question as an RCU read-side critical section to avoid any potential use-after-free issues. Compile tested only.Show less

In the Linux kernel, the following vulnerability has been resolved: wifi: ath11k: fix dfs radar event locking The ath11k active pdevs are protected by RCU but the DFS radar event handling code calling ath11k_mac_get_ar_by_pdev_id() was not marked as a read-side critical section. Mark the code in question as an RCU read-side critical section to avoid any potential use-after-free issues. Compile tested only.Show less

In the Linux kernel, the following vulnerability has been resolved: vhost-vdpa: fix use after free in vhost_vdpa_probe() The put_device() calls vhost_vdpa_release_dev() which calls ida_simple_remove() and frees "v". So this call to ida_simple_remove() is a use after free and a double free.Show less