In the Linux kernel, the following vulnerability has been resolved: nfc: st-nci: Fix use after free bug in ndlc_remove due to race condition This bug influences both st_nci_i2c_remove and st_nci_spi_remove. Take st_nci_i2c_remove as an example. In st_nci_i2c_probe, it called ndlc_probe and bound &ndlc->sm_work with llt_ndlc_sm_work. When it calls ndlc_recv or timeout handler, it will finally call schedule_work to start the work. When we call st_nci_i2c_remove to remove the driver, there may be a sequence as follows: Fix it by finishing the work before cleanup in ndlc_remove CPU0 CPU1 |llt_ndlc_sm_work st_nci_i2c_remove | ndlc_remove | st_nci_remove | nci_free_device| kfree(ndev) | //free ndlc->ndev | |llt_ndlc_rcv_queue |nci_recv_frame |//use ndlc->ndev

In the Linux kernel, the following vulnerability has been resolved: lib: cpu_rmap: Avoid use after free on rmap->obj array entries When calling irq_set_affinity_notifier() with NULL at the notify argument, it will cause freeing of the glue pointer in the corresponding array entry but will leave the pointer in the array. A subsequent call to free_irq_cpu_rmap() will try to free this entry again leading to possible use after free. Fix that by setting NULL to the array entry and checking that we have non-zero at the array entry when iterating over the array in free_irq_cpu_rmap(). The current code does not suffer from this since there are no cases where irq_set_affinity_notifier(irq, NULL) (note the NULL passed for the notify arg) is called, followed by a call to free_irq_cpu_rmap() so we don't hit and issue. Subsequent patches in this series excersize this flow, hence the required fix.

In the Linux kernel, the following vulnerability has been resolved: media: aspeed: Fix memory overwrite if timing is 1600x900 When capturing 1600x900, system could crash when system memory usage is tight. The way to reproduce this issue: 1. Use 1600x900 to display on host 2. Mount ISO through 'Virtual media' on OpenBMC's web 3. Run script as below on host to do sha continuously #!/bin/bash while [ [1] ]; do find /media -type f -printf '"%h/%f"\n' | xargs sha256sum done 4. Open KVM on OpenBMC's web The size of macro block captured is 8x8. Therefore, we should make sure the height of src-buf is 8 aligned to fix this issue.

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: Fix shift out-of-bounds issue [ 567.613292] shift exponent 255 is too large for 64-bit type 'long unsigned int' [ 567.614498] CPU: 5 PID: 238 Comm: kworker/5:1 Tainted: G OE 6.2.0-34-generic #34~22.04.1-Ubuntu [ 567.614502] Hardware name: AMD Splinter/Splinter-RPL, BIOS WS43927N_871 09/25/2023 [ 567.614504] Workqueue: events send_exception_work_handler [amdgpu] [ 567.614748] Call Trace: [ 567.614750] <TASK> [ 567.614753] dump_stack_lvl+0x48/0x70 [ 567.614761] dump_stack+0x10/0x20 [ 567.614763] __ubsan_handle_shift_out_of_bounds+0x156/0x310 [ 567.614769] ? srso_alias_return_thunk+0x5/0x7f [ 567.614773] ? update_sd_lb_stats.constprop.0+0xf2/0x3c0 [ 567.614780] svm_range_split_by_granularity.cold+0x2b/0x34 [amdgpu] [ 567.615047] ? srso_alias_return_thunk+0x5/0x7f [ 567.615052] svm_migrate_to_ram+0x185/0x4d0 [amdgpu] [ 567.615286] do_swap_page+0x7b6/0xa30 [ 567.615291] ? srso_alias_return_thunk+0x5/0x7f [ 567.615294] ? __free_pages+0x119/0x130 [ 567.615299] handle_pte_fault+0x227/0x280 [ 567.615303] __handle_mm_fault+0x3c0/0x720 [ 567.615311] handle_mm_fault+0x119/0x330 [ 567.615314] ? lock_mm_and_find_vma+0x44/0x250 [ 567.615318] do_user_addr_fault+0x1a9/0x640 [ 567.615323] exc_page_fault+0x81/0x1b0 [ 567.615328] asm_exc_page_fault+0x27/0x30 [ 567.615332] RIP: 0010:__get_user_8+0x1c/0x30

In the Linux kernel, the following vulnerability has been resolved: drm/nouveau/disp: fix use-after-free in error handling of nouveau_connector_create We can't simply free the connector after calling drm_connector_init on it. We need to clean up the drm side first. It might not fix all regressions from commit 2b5d1c29f6c4 ("drm/nouveau/disp: PIOR DP uses GPIO for HPD, not PMGR AUX interrupts"), but at least it fixes a memory corruption in error handling related to that commit.

In the Linux kernel, the following vulnerability has been resolved: sctp: fix a potential overflow in sctp_ifwdtsn_skip Currently, when traversing ifwdtsn skips with _sctp_walk_ifwdtsn, it only checks the pos against the end of the chunk. However, the data left for the last pos may be < sizeof(struct sctp_ifwdtsn_skip), and dereference it as struct sctp_ifwdtsn_skip may cause coverflow. This patch fixes it by checking the pos against "the end of the chunk - sizeof(struct sctp_ifwdtsn_skip)" in sctp_ifwdtsn_skip, similar to sctp_fwdtsn_skip.

In the Linux kernel, the following vulnerability has been resolved: nvme: host: fix double-free of struct nvme_id_ns in ns_update_nuse() When nvme_identify_ns() fails, it frees the pointer to the struct nvme_id_ns before it returns. However, ns_update_nuse() calls kfree() for the pointer even when nvme_identify_ns() fails. This results in KASAN double-free, which was observed with blktests nvme/045 with proposed patches [1] on the kernel v6.8-rc7. Fix the double-free by skipping kfree() when nvme_identify_ns() fails.

In the Linux kernel, the following vulnerability has been resolved: blk-crypto: make blk_crypto_evict_key() more robust If blk_crypto_evict_key() sees that the key is still in-use (due to a bug) or that ->keyslot_evict failed, it currently just returns while leaving the key linked into the keyslot management structures. However, blk_crypto_evict_key() is only called in contexts such as inode eviction where failure is not an option. So actually the caller proceeds with freeing the blk_crypto_key regardless of the return value of blk_crypto_evict_key(). These two assumptions don't match, and the result is that there can be a use-after-free in blk_crypto_reprogram_all_keys() after one of these errors occurs. (Note, these errors *shouldn't* happen; we're just talking about what happens if they do anyway.) Fix this by making blk_crypto_evict_key() unlink the key from the keyslot management structures even on failure. Also improve some comments.

In the Linux kernel, the following vulnerability has been resolved: scsi: target: iscsi: Fix buffer overflow in lio_target_nacl_info_show() The function lio_target_nacl_info_show() uses sprintf() in a loop to print details for every iSCSI connection in a session without checking for the buffer length. With enough iSCSI connections it's possible to overflow the buffer provided by configfs and corrupt the memory. This patch replaces sprintf() with sysfs_emit_at() that checks for buffer boundries.

A out-of-bounds write flaw was found in the xorg-x11-server. This issue occurs due to an incorrect calculation of a buffer offset when copying data stored in the heap in the XIChangeDeviceProperty function in Xi/xiproperty.c and in RRChangeOutputProperty function in randr/rrproperty.c, allowing for possible escalation of privileges or denial of service.

In the Linux kernel, the following vulnerability has been resolved: net: hns3: fix out-of-bounds access may occur when coalesce info is read via debugfs The hns3 driver define an array of string to show the coalesce info, but if the kernel adds a new mode or a new state, out-of-bounds access may occur when coalesce info is read via debugfs, this patch fix the problem.

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.

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix potential UAF of struct nilfs_sc_info in nilfs_segctor_thread() The finalization of nilfs_segctor_thread() can race with nilfs_segctor_kill_thread() which terminates that thread, potentially causing a use-after-free BUG as KASAN detected. At the end of nilfs_segctor_thread(), it assigns NULL to "sc_task" member of "struct nilfs_sc_info" to indicate the thread has finished, and then notifies nilfs_segctor_kill_thread() of this using waitqueue "sc_wait_task" on the struct nilfs_sc_info. However, here, immediately after the NULL assignment to "sc_task", it is possible that nilfs_segctor_kill_thread() will detect it and return to continue the deallocation, freeing the nilfs_sc_info structure before the thread does the notification. This fixes the issue by protecting the NULL assignment to "sc_task" and its notification, with spinlock "sc_state_lock" of the struct nilfs_sc_info. Since nilfs_segctor_kill_thread() does a final check to see if "sc_task" is NULL with "sc_state_lock" locked, this can eliminate the race.

In the Linux kernel, the following vulnerability has been resolved: net: ethernet: mvpp2_main: fix possible OOB write in mvpp2_ethtool_get_rxnfc() rules is allocated in ethtool_get_rxnfc and the size is determined by rule_cnt from user space. So rule_cnt needs to be check before using rules to avoid OOB writing or NULL pointer dereference.

In the Linux kernel, the following vulnerability has been resolved: crypto: xts - Handle EBUSY correctly As it is xts only handles the special return value of EINPROGRESS, which means that in all other cases it will free data related to the request. However, as the caller of xts may specify MAY_BACKLOG, we also need to expect EBUSY and treat it in the same way. Otherwise backlogged requests will trigger a use-after-free.

In the Linux kernel, the following vulnerability has been resolved: scsi: iscsi_tcp: Fix UAF during login when accessing the shost ipaddress If during iscsi_sw_tcp_session_create() iscsi_tcp_r2tpool_alloc() fails, userspace could be accessing the host's ipaddress attr. If we then free the session via iscsi_session_teardown() while userspace is still accessing the session we will hit a use after free bug. Set the tcp_sw_host->session after we have completed session creation and can no longer fail.

In the Linux kernel, the following vulnerability has been resolved: net: fec: Better handle pm_runtime_get() failing in .remove() In the (unlikely) event that pm_runtime_get() (disguised as pm_runtime_resume_and_get()) fails, the remove callback returned an error early. The problem with this is that the driver core ignores the error value and continues removing the device. This results in a resource leak. Worse the devm allocated resources are freed and so if a callback of the driver is called later the register mapping is already gone which probably results in a crash.

In the Linux kernel, the following vulnerability has been resolved: udf: Do not bother merging very long extents When merging very long extents we try to push as much length as possible to the first extent. However this is unnecessarily complicated and not really worth the trouble. Furthermore there was a bug in the logic resulting in corrupting extents in the file as syzbot reproducer shows. So just don't bother with the merging of extents that are too long together.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: fix shift-out-of-bounds in CalculateVMAndRowBytes [WHY] When PTEBufferSizeInRequests is zero, UBSAN reports the following warning because dml_log2 returns an unexpected negative value: shift exponent 4294966273 is too large for 32-bit type 'int' [HOW] In the case PTEBufferSizeInRequests is zero, skip the dml_log2() and assign the result directly.

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`.

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: add the missing IP_SET_HASH_WITH_NET0 macro for ip_set_hash_netportnet.c The missing IP_SET_HASH_WITH_NET0 macro in ip_set_hash_netportnet can lead to the use of wrong `CIDR_POS(c)` for calculating array offsets, which can lead to integer underflow. As a result, it leads to slab out-of-bound access. This patch adds back the IP_SET_HASH_WITH_NET0 macro to ip_set_hash_netportnet to address the issue.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: Fix potential use-after-free when clear keys Similar to commit c5d2b6fa26b5 ("Bluetooth: Fix use-after-free in hci_remove_ltk/hci_remove_irk"). We can not access k after kfree_rcu() call.

In the Linux kernel, the following vulnerability has been resolved: fs/jfs: Add validity check for db_maxag and db_agpref Both db_maxag and db_agpref are used as the index of the db_agfree array, but there is currently no validity check for db_maxag and db_agpref, which can lead to errors. The following is related bug reported by Syzbot: UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dmap.c:639:20 index 7936 is out of range for type 'atomic_t[128]' Add checking that the values of db_maxag and db_agpref are valid indexes for the db_agfree array.

In the Linux kernel, the following vulnerability has been resolved: loop: Fix use-after-free issues do_req_filebacked() calls blk_mq_complete_request() synchronously or asynchronously when using asynchronous I/O unless memory allocation fails. Hence, modify loop_handle_cmd() such that it does not dereference 'cmd' nor 'rq' after do_req_filebacked() finished unless we are sure that the request has not yet been completed. This patch fixes the following kernel crash: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000054 Call trace: css_put.42938+0x1c/0x1ac loop_process_work+0xc8c/0xfd4 loop_rootcg_workfn+0x24/0x34 process_one_work+0x244/0x558 worker_thread+0x400/0x8fc kthread+0x16c/0x1e0 ret_from_fork+0x10/0x20

In the Linux kernel, the following vulnerability has been resolved: RDMA/bnxt_re: Properly order ib_device_unalloc() to avoid UAF ib_dealloc_device() should be called only after device cleanup. Fix the dealloc sequence.

In the Linux kernel, the following vulnerability has been resolved: xsk: Fix xsk_diag use-after-free error during socket cleanup Fix a use-after-free error that is possible if the xsk_diag interface is used after the socket has been unbound from the device. This can happen either due to the socket being closed or the device disappearing. In the early days of AF_XDP, the way we tested that a socket was not bound to a device was to simply check if the netdevice pointer in the xsk socket structure was NULL. Later, a better system was introduced by having an explicit state variable in the xsk socket struct. For example, the state of a socket that is on the way to being closed and has been unbound from the device is XSK_UNBOUND. The commit in the Fixes tag below deleted the old way of signalling that a socket is unbound, setting dev to NULL. This in the belief that all code using the old way had been exterminated. That was unfortunately not true as the xsk diagnostics code was still using the old way and thus does not work as intended when a socket is going down. Fix this by introducing a test against the state variable. If the socket is in the state XSK_UNBOUND, simply abort the diagnostic's netlink operation.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: btsdio: fix use after free bug in btsdio_remove due to race condition In btsdio_probe, the data->work is bound with btsdio_work. It will be started in btsdio_send_frame. If the btsdio_remove runs with a unfinished work, there may be a race condition that hdev is freed but used in btsdio_work. Fix it by canceling the work before do cleanup in btsdio_remove.

In the Linux kernel, the following vulnerability has been resolved: cifs: prevent use-after-free by freeing the cfile later In smb2_compound_op we have a possible use-after-free which can cause hard to debug problems later on. This was revealed during stress testing with KASAN enabled kernel. Fixing it by moving the cfile free call to a few lines below, after the usage.

In the Linux kernel, the following vulnerability has been resolved: ice: copy last block omitted in ice_get_module_eeprom() ice_get_module_eeprom() is broken since commit e9c9692c8a81 ("ice: Reimplement module reads used by ethtool") In this refactor, ice_get_module_eeprom() reads the eeprom in blocks of size 8. But the condition that should protect the buffer overflow ignores the last block. The last block always contains zeros. Bug uncovered by ethtool upstream commit 9538f384b535 ("netlink: eeprom: Defer page requests to individual parsers") After this commit, ethtool reads a block with length = 1; to read the SFF-8024 identifier value. unpatched driver: $ ethtool -m enp65s0f0np0 offset 0x90 length 8 Offset Values ------ ------ 0x0090: 00 00 00 00 00 00 00 00 $ ethtool -m enp65s0f0np0 offset 0x90 length 12 Offset Values ------ ------ 0x0090: 00 00 01 a0 4d 65 6c 6c 00 00 00 00 $ $ ethtool -m enp65s0f0np0 Offset Values ------ ------ 0x0000: 11 06 06 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 01 08 00 0x0070: 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 patched driver: $ ethtool -m enp65s0f0np0 offset 0x90 length 8 Offset Values ------ ------ 0x0090: 00 00 01 a0 4d 65 6c 6c $ ethtool -m enp65s0f0np0 offset 0x90 length 12 Offset Values ------ ------ 0x0090: 00 00 01 a0 4d 65 6c 6c 61 6e 6f 78 $ ethtool -m enp65s0f0np0 Identifier : 0x11 (QSFP28) Extended identifier : 0x00 Extended identifier description : 1.5W max. Power consumption Extended identifier description : No CDR in TX, No CDR in RX Extended identifier description : High Power Class (> 3.5 W) not enabled Connector : 0x23 (No separable connector) Transceiver codes : 0x88 0x00 0x00 0x00 0x00 0x00 0x00 0x00 Transceiver type : 40G Ethernet: 40G Base-CR4 Transceiver type : 25G Ethernet: 25G Base-CR CA-N Encoding : 0x05 (64B/66B) BR, Nominal : 25500Mbps Rate identifier : 0x00 Length (SMF,km) : 0km Length (OM3 50um) : 0m Length (OM2 50um) : 0m Length (OM1 62.5um) : 0m Length (Copper or Active cable) : 1m Transmitter technology : 0xa0 (Copper cable unequalized) Attenuation at 2.5GHz : 4db Attenuation at 5.0GHz : 5db Attenuation at 7.0GHz : 7db Attenuation at 12.9GHz : 10db ........ ....

In the Linux kernel, the following vulnerability has been resolved: drm/mediatek: Clean dangling pointer on bind error path mtk_drm_bind() can fail, in which case drm_dev_put() is called, destroying the drm_device object. However a pointer to it was still being held in the private object, and that pointer would be passed along to DRM in mtk_drm_sys_prepare() if a suspend were triggered at that point, resulting in a panic. Clean the pointer when destroying the object in the error path to prevent this from happening.

In the Linux kernel, the following vulnerability has been resolved: KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler We do check for target CPU == -1, but this might change at the time we are going to use it. Hold the physical target CPU in a local variable to avoid out-of-bound accesses to the cpu arrays.

In the Linux kernel, the following vulnerability has been resolved: jfs: fix array-index-out-of-bounds in dbFindLeaf Currently while searching for dmtree_t for sufficient free blocks there is an array out of bounds while getting element in tp->dm_stree. To add the required check for out of bound we first need to determine the type of dmtree. Thus added an extra parameter to dbFindLeaf so that the type of tree can be determined and the required check can be applied.

In the Linux kernel, the following vulnerability has been resolved: NFSD: Avoid calling OPDESC() with ops->opnum == OP_ILLEGAL OPDESC() simply indexes into nfsd4_ops[] by the op's operation number, without range checking that value. It assumes callers are careful to avoid calling it with an out-of-bounds opnum value. nfsd4_decode_compound() is not so careful, and can invoke OPDESC() with opnum set to OP_ILLEGAL, which is 10044 -- well beyond the end of nfsd4_ops[].

In the Linux kernel, the following vulnerability has been resolved: wifi: nl80211: fix integer overflow in nl80211_parse_mbssid_elems() nl80211_parse_mbssid_elems() uses a u8 variable num_elems to count the number of MBSSID elements in the nested netlink attribute attrs, which can lead to an integer overflow if a user of the nl80211 interface specifies 256 or more elements in the corresponding attribute in userspace. The integer overflow can lead to a heap buffer overflow as num_elems determines the size of the trailing array in elems, and this array is thereafter written to for each element in attrs. Note that this vulnerability only affects devices with the wiphy->mbssid_max_interfaces member set for the wireless physical device struct in the device driver, and can only be triggered by a process with CAP_NET_ADMIN capabilities. Fix this by checking for a maximum of 255 elements in attrs.

In the Linux kernel, the following vulnerability has been resolved: drivers: base: Free devm resources when unregistering a device In the current code, devres_release_all() only gets called if the device has a bus and has been probed. This leads to issues when using bus-less or driver-less devices where the device might never get freed if a managed resource holds a reference to the device. This is happening in the DRM framework for example. We should thus call devres_release_all() in the device_del() function to make sure that the device-managed actions are properly executed when the device is unregistered, even if it has neither a bus nor a driver. This is effectively the same change than commit 2f8d16a996da ("devres: release resources on device_del()") that got reverted by commit a525a3ddeaca ("driver core: free devres in device_release") over memory leaks concerns. This patch effectively combines the two commits mentioned above to release the resources both on device_del() and device_release() and get the best of both worlds.

In the Linux kernel, the following vulnerability has been resolved: thermal: core: prevent potential string overflow The dev->id value comes from ida_alloc() so it's a number between zero and INT_MAX. If it's too high then these sprintf()s will overflow.

In the Linux kernel, the following vulnerability has been resolved: cifs: Fix writeback data corruption cifs writeback doesn't correctly handle the case where cifs_extend_writeback() hits a point where it is considering an additional folio, but this would overrun the wsize - at which point it drops out of the xarray scanning loop and calls xas_pause(). The problem is that xas_pause() advances the loop counter - thereby skipping that page. What needs to happen is for xas_reset() to be called any time we decide we don't want to process the page we're looking at, but rather send the request we are building and start a new one. Fix this by copying and adapting the netfslib writepages code as a temporary measure, with cifs writeback intending to be offloaded to netfslib in the near future. This also fixes the issue with the use of filemap_get_folios_tag() causing retry of a bunch of pages which the extender already dealt with. This can be tested by creating, say, a 64K file somewhere not on cifs (otherwise copy-offload may get underfoot), mounting a cifs share with a wsize of 64000, copying the file to it and then comparing the original file and the copy: dd if=/dev/urandom of=/tmp/64K bs=64k count=1 mount //192.168.6.1/test /mnt -o user=...,pass=...,wsize=64000 cp /tmp/64K /mnt/64K cmp /tmp/64K /mnt/64K Without the fix, the cmp fails at position 64000 (or shortly thereafter).

In the Linux kernel, the following vulnerability has been resolved: bpf: Make bpf_refcount_acquire fallible for non-owning refs This patch fixes an incorrect assumption made in the original bpf_refcount series [0], specifically that the BPF program calling bpf_refcount_acquire on some node can always guarantee that the node is alive. In that series, the patch adding failure behavior to rbtree_add and list_push_{front, back} breaks this assumption for non-owning references. Consider the following program: n = bpf_kptr_xchg(&mapval, NULL); /* skip error checking */ bpf_spin_lock(&l); if(bpf_rbtree_add(&t, &n->rb, less)) { bpf_refcount_acquire(n); /* Failed to add, do something else with the node */ } bpf_spin_unlock(&l); It's incorrect to assume that bpf_refcount_acquire will always succeed in this scenario. bpf_refcount_acquire is being called in a critical section here, but the lock being held is associated with rbtree t, which isn't necessarily the lock associated with the tree that the node is already in. So after bpf_rbtree_add fails to add the node and calls bpf_obj_drop in it, the program has no ownership of the node's lifetime. Therefore the node's refcount can be decr'd to 0 at any time after the failing rbtree_add. If this happens before the refcount_acquire above, the node might be free'd, and regardless refcount_acquire will be incrementing a 0 refcount. Later patches in the series exercise this scenario, resulting in the expected complaint from the kernel (without this patch's changes): refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 207 at lib/refcount.c:25 refcount_warn_saturate+0xbc/0x110 Modules linked in: bpf_testmod(O) CPU: 1 PID: 207 Comm: test_progs Tainted: G O 6.3.0-rc7-02231-g723de1a718a2-dirty #371 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 RIP: 0010:refcount_warn_saturate+0xbc/0x110 Code: 6f 64 f6 02 01 e8 84 a3 5c ff 0f 0b eb 9d 80 3d 5e 64 f6 02 00 75 94 48 c7 c7 e0 13 d2 82 c6 05 4e 64 f6 02 01 e8 64 a3 5c ff <0f> 0b e9 7a ff ff ff 80 3d 38 64 f6 02 00 0f 85 6d ff ff ff 48 c7 RSP: 0018:ffff88810b9179b0 EFLAGS: 00010082 RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000 RDX: 0000000000000202 RSI: 0000000000000008 RDI: ffffffff857c3680 RBP: ffff88810027d3c0 R08: ffffffff8125f2a4 R09: ffff88810b9176e7 R10: ffffed1021722edc R11: 746e756f63666572 R12: ffff88810027d388 R13: ffff88810027d3c0 R14: ffffc900005fe030 R15: ffffc900005fe048 FS: 00007fee0584a700(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005634a96f6c58 CR3: 0000000108ce9002 CR4: 0000000000770ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> bpf_refcount_acquire_impl+0xb5/0xc0 (rest of output snipped) The patch addresses this by changing bpf_refcount_acquire_impl to use refcount_inc_not_zero instead of refcount_inc and marking bpf_refcount_acquire KF_RET_NULL. For owning references, though, we know the above scenario is not possible and thus that bpf_refcount_acquire will always succeed. Some verifier bookkeeping is added to track "is input owning ref?" for bpf_refcount_acquire calls and return false from is_kfunc_ret_null for bpf_refcount_acquire on owning refs despite it being marked KF_RET_NULL. Existing selftests using bpf_refcount_acquire are modified where necessary to NULL-check its return value. [0]: https://lore.kernel.org/bpf/20230415201811.343116-1-davemarchevsky@fb.com/

In the Linux kernel, the following vulnerability has been resolved: net: nfc: Fix use-after-free in local_cleanup() Fix a use-after-free that occurs in kfree_skb() called from local_cleanup(). This could happen when killing nfc daemon (e.g. neard) after detaching an nfc device. When detaching an nfc device, local_cleanup() called from nfc_llcp_unregister_device() frees local->rx_pending and decreases local->ref by kref_put() in nfc_llcp_local_put(). In the terminating process, nfc daemon releases all sockets and it leads to decreasing local->ref. After the last release of local->ref, local_cleanup() called from local_release() frees local->rx_pending again, which leads to the bug. Setting local->rx_pending to NULL in local_cleanup() could prevent use-after-free when local_cleanup() is called twice. Found by a modified version of syzkaller. BUG: KASAN: use-after-free in kfree_skb() Call Trace: dump_stack_lvl (lib/dump_stack.c:106) print_address_description.constprop.0.cold (mm/kasan/report.c:306) kasan_check_range (mm/kasan/generic.c:189) kfree_skb (net/core/skbuff.c:955) local_cleanup (net/nfc/llcp_core.c:159) nfc_llcp_local_put.part.0 (net/nfc/llcp_core.c:172) nfc_llcp_local_put (net/nfc/llcp_core.c:181) llcp_sock_destruct (net/nfc/llcp_sock.c:959) __sk_destruct (net/core/sock.c:2133) sk_destruct (net/core/sock.c:2181) __sk_free (net/core/sock.c:2192) sk_free (net/core/sock.c:2203) llcp_sock_release (net/nfc/llcp_sock.c:646) __sock_release (net/socket.c:650) sock_close (net/socket.c:1365) __fput (fs/file_table.c:306) task_work_run (kernel/task_work.c:179) ptrace_notify (kernel/signal.c:2354) syscall_exit_to_user_mode_prepare (kernel/entry/common.c:278) syscall_exit_to_user_mode (kernel/entry/common.c:296) do_syscall_64 (arch/x86/entry/common.c:86) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:106) Allocated by task 4719: kasan_save_stack (mm/kasan/common.c:45) __kasan_slab_alloc (mm/kasan/common.c:325) slab_post_alloc_hook (mm/slab.h:766) kmem_cache_alloc_node (mm/slub.c:3497) __alloc_skb (net/core/skbuff.c:552) pn533_recv_response (drivers/nfc/pn533/usb.c:65) __usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1671) usb_giveback_urb_bh (drivers/usb/core/hcd.c:1704) tasklet_action_common.isra.0 (kernel/softirq.c:797) __do_softirq (kernel/softirq.c:571) Freed by task 1901: kasan_save_stack (mm/kasan/common.c:45) kasan_set_track (mm/kasan/common.c:52) kasan_save_free_info (mm/kasan/genericdd.c:518) __kasan_slab_free (mm/kasan/common.c:236) kmem_cache_free (mm/slub.c:3809) kfree_skbmem (net/core/skbuff.c:874) kfree_skb (net/core/skbuff.c:931) local_cleanup (net/nfc/llcp_core.c:159) nfc_llcp_unregister_device (net/nfc/llcp_core.c:1617) nfc_unregister_device (net/nfc/core.c:1179) pn53x_unregister_nfc (drivers/nfc/pn533/pn533.c:2846) pn533_usb_disconnect (drivers/nfc/pn533/usb.c:579) usb_unbind_interface (drivers/usb/core/driver.c:458) device_release_driver_internal (drivers/base/dd.c:1279) bus_remove_device (drivers/base/bus.c:529) device_del (drivers/base/core.c:3665) usb_disable_device (drivers/usb/core/message.c:1420) usb_disconnect (drivers/usb/core.c:2261) hub_event (drivers/usb/core/hub.c:5833) process_one_work (arch/x86/include/asm/jump_label.h:27 include/linux/jump_label.h:212 include/trace/events/workqueue.h:108 kernel/workqueue.c:2281) worker_thread (include/linux/list.h:282 kernel/workqueue.c:2423) kthread (kernel/kthread.c:319) ret_from_fork (arch/x86/entry/entry_64.S:301)

In the Linux kernel, the following vulnerability has been resolved: PCI/ASPM: Disable ASPM on MFD function removal to avoid use-after-free Struct pcie_link_state->downstream is a pointer to the pci_dev of function 0. Previously we retained that pointer when removing function 0, and subsequent ASPM policy changes dereferenced it, resulting in a use-after-free warning from KASAN, e.g.: # echo 1 > /sys/bus/pci/devices/0000:03:00.0/remove # echo powersave > /sys/module/pcie_aspm/parameters/policy BUG: KASAN: slab-use-after-free in pcie_config_aspm_link+0x42d/0x500 Call Trace: kasan_report+0xae/0xe0 pcie_config_aspm_link+0x42d/0x500 pcie_aspm_set_policy+0x8e/0x1a0 param_attr_store+0x162/0x2c0 module_attr_store+0x3e/0x80 PCIe spec r6.0, sec 7.5.3.7, recommends that software program the same ASPM Control value in all functions of multi-function devices. Disable ASPM and free the pcie_link_state when any child function is removed so we can discard the dangling pcie_link_state->downstream pointer and maintain the same ASPM Control configuration for all functions. [bhelgaas: commit log and comment]

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput During unmount process of nilfs2, nothing holds nilfs_root structure after nilfs2 detaches its writer in nilfs_detach_log_writer(). Previously, nilfs_evict_inode() could cause use-after-free read for nilfs_root if inodes are left in "garbage_list" and released by nilfs_dispose_list at the end of nilfs_detach_log_writer(), and this bug was fixed by commit 9b5a04ac3ad9 ("nilfs2: fix use-after-free bug of nilfs_root in nilfs_evict_inode()"). However, it turned out that there is another possibility of UAF in the call path where mark_inode_dirty_sync() is called from iput(): nilfs_detach_log_writer() nilfs_dispose_list() iput() mark_inode_dirty_sync() __mark_inode_dirty() nilfs_dirty_inode() __nilfs_mark_inode_dirty() nilfs_load_inode_block() --> causes UAF of nilfs_root struct This can happen after commit 0ae45f63d4ef ("vfs: add support for a lazytime mount option"), which changed iput() to call mark_inode_dirty_sync() on its final reference if i_state has I_DIRTY_TIME flag and i_nlink is non-zero. This issue appears after commit 28a65b49eb53 ("nilfs2: do not write dirty data after degenerating to read-only") when using the syzbot reproducer, but the issue has potentially existed before. Fix this issue by adding a "purging flag" to the nilfs structure, setting that flag while disposing the "garbage_list" and checking it in __nilfs_mark_inode_dirty(). Unlike commit 9b5a04ac3ad9 ("nilfs2: fix use-after-free bug of nilfs_root in nilfs_evict_inode()"), this patch does not rely on ns_writer to determine whether to skip operations, so as not to break recovery on mount. The nilfs_salvage_orphan_logs routine dirties the buffer of salvaged data before attaching the log writer, so changing __nilfs_mark_inode_dirty() to skip the operation when ns_writer is NULL will cause recovery write to fail. The purpose of using the cleanup-only flag is to allow for narrowing of such conditions.

In the Linux kernel, the following vulnerability has been resolved: drm/i915: Avoid potential vm use-after-free Adding the vm to the vm_xa table makes it visible to userspace, which could try to race with us to close the vm. So we need to take our extra reference before putting it in the table. (cherry picked from commit 99343c46d4e2b34c285d3d5f68ff04274c2f9fb4)

A use-after-free vulnerability in the Linux kernel's fs/smb/client component can be exploited to achieve local privilege escalation. In case of an error in smb3_fs_context_parse_param, ctx->password was freed but the field was not set to NULL which could lead to double free. We recommend upgrading past commit e6e43b8aa7cd3c3af686caf0c2e11819a886d705.

In the Linux kernel, the following vulnerability has been resolved: media: netup_unidvb: fix use-after-free at del_timer() When Universal DVB card is detaching, netup_unidvb_dma_fini() uses del_timer() to stop dma->timeout timer. But when timer handler netup_unidvb_dma_timeout() is running, del_timer() could not stop it. As a result, the use-after-free bug could happen. The process is shown below: (cleanup routine) | (timer routine) | mod_timer(&dev->tx_sim_timer, ..) netup_unidvb_finidev() | (wait a time) netup_unidvb_dma_fini() | netup_unidvb_dma_timeout() del_timer(&dma->timeout); | | ndev->pci_dev->dev //USE Fix by changing del_timer() to del_timer_sync().

In the Linux kernel, the following vulnerability has been resolved: cifs: fix use-after-free bug in refresh_cache_worker() The UAF bug occurred because we were putting DFS root sessions in cifs_umount() while DFS cache refresher was being executed. Make DFS root sessions have same lifetime as DFS tcons so we can avoid the use-after-free bug is DFS cache refresher and other places that require IPCs to get new DFS referrals on. Also, get rid of mount group handling in DFS cache as we no longer need it. This fixes below use-after-free bug catched by KASAN [ 379.946955] BUG: KASAN: use-after-free in __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.947642] Read of size 8 at addr ffff888018f57030 by task kworker/u4:3/56 [ 379.948096] [ 379.948208] CPU: 0 PID: 56 Comm: kworker/u4:3 Not tainted 6.2.0-rc7-lku #23 [ 379.948661] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552-rebuilt.opensuse.org 04/01/2014 [ 379.949368] Workqueue: cifs-dfscache refresh_cache_worker [cifs] [ 379.949942] Call Trace: [ 379.950113] <TASK> [ 379.950260] dump_stack_lvl+0x50/0x67 [ 379.950510] print_report+0x16a/0x48e [ 379.950759] ? __virt_addr_valid+0xd8/0x160 [ 379.951040] ? __phys_addr+0x41/0x80 [ 379.951285] kasan_report+0xdb/0x110 [ 379.951533] ? __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.952056] ? __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.952585] __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.953096] ? __pfx___refresh_tcon.isra.0+0x10/0x10 [cifs] [ 379.953637] ? __pfx___mutex_lock+0x10/0x10 [ 379.953915] ? lock_release+0xb6/0x720 [ 379.954167] ? __pfx_lock_acquire+0x10/0x10 [ 379.954443] ? refresh_cache_worker+0x34e/0x6d0 [cifs] [ 379.954960] ? __pfx_wb_workfn+0x10/0x10 [ 379.955239] refresh_cache_worker+0x4ad/0x6d0 [cifs] [ 379.955755] ? __pfx_refresh_cache_worker+0x10/0x10 [cifs] [ 379.956323] ? __pfx_lock_acquired+0x10/0x10 [ 379.956615] ? read_word_at_a_time+0xe/0x20 [ 379.956898] ? lockdep_hardirqs_on_prepare+0x12/0x220 [ 379.957235] process_one_work+0x535/0x990 [ 379.957509] ? __pfx_process_one_work+0x10/0x10 [ 379.957812] ? lock_acquired+0xb7/0x5f0 [ 379.958069] ? __list_add_valid+0x37/0xd0 [ 379.958341] ? __list_add_valid+0x37/0xd0 [ 379.958611] worker_thread+0x8e/0x630 [ 379.958861] ? __pfx_worker_thread+0x10/0x10 [ 379.959148] kthread+0x17d/0x1b0 [ 379.959369] ? __pfx_kthread+0x10/0x10 [ 379.959630] ret_from_fork+0x2c/0x50 [ 379.959879] </TASK>

In the Linux kernel, the following vulnerability has been resolved: r8169: fix LED-related deadlock on module removal Binding devm_led_classdev_register() to the netdev is problematic because on module removal we get a RTNL-related deadlock. Fix this by avoiding the device-managed LED functions. Note: We can safely call led_classdev_unregister() for a LED even if registering it failed, because led_classdev_unregister() detects this and is a no-op in this case.

In the Linux kernel, the following vulnerability has been resolved: cifs: Fix warning and UAF when destroy the MR list If the MR allocate failed, the MR recovery work not initialized and list not cleared. Then will be warning and UAF when release the MR: WARNING: CPU: 4 PID: 824 at kernel/workqueue.c:3066 __flush_work.isra.0+0xf7/0x110 CPU: 4 PID: 824 Comm: mount.cifs Not tainted 6.1.0-rc5+ #82 RIP: 0010:__flush_work.isra.0+0xf7/0x110 Call Trace: <TASK> __cancel_work_timer+0x2ba/0x2e0 smbd_destroy+0x4e1/0x990 _smbd_get_connection+0x1cbd/0x2110 smbd_get_connection+0x21/0x40 cifs_get_tcp_session+0x8ef/0xda0 mount_get_conns+0x60/0x750 cifs_mount+0x103/0xd00 cifs_smb3_do_mount+0x1dd/0xcb0 smb3_get_tree+0x1d5/0x300 vfs_get_tree+0x41/0xf0 path_mount+0x9b3/0xdd0 __x64_sys_mount+0x190/0x1d0 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 BUG: KASAN: use-after-free in smbd_destroy+0x4fc/0x990 Read of size 8 at addr ffff88810b156a08 by task mount.cifs/824 CPU: 4 PID: 824 Comm: mount.cifs Tainted: G W 6.1.0-rc5+ #82 Call Trace: dump_stack_lvl+0x34/0x44 print_report+0x171/0x472 kasan_report+0xad/0x130 smbd_destroy+0x4fc/0x990 _smbd_get_connection+0x1cbd/0x2110 smbd_get_connection+0x21/0x40 cifs_get_tcp_session+0x8ef/0xda0 mount_get_conns+0x60/0x750 cifs_mount+0x103/0xd00 cifs_smb3_do_mount+0x1dd/0xcb0 smb3_get_tree+0x1d5/0x300 vfs_get_tree+0x41/0xf0 path_mount+0x9b3/0xdd0 __x64_sys_mount+0x190/0x1d0 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Allocated by task 824: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_kmalloc+0x7a/0x90 _smbd_get_connection+0x1b6f/0x2110 smbd_get_connection+0x21/0x40 cifs_get_tcp_session+0x8ef/0xda0 mount_get_conns+0x60/0x750 cifs_mount+0x103/0xd00 cifs_smb3_do_mount+0x1dd/0xcb0 smb3_get_tree+0x1d5/0x300 vfs_get_tree+0x41/0xf0 path_mount+0x9b3/0xdd0 __x64_sys_mount+0x190/0x1d0 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Freed by task 824: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x2a/0x40 ____kasan_slab_free+0x143/0x1b0 __kmem_cache_free+0xc8/0x330 _smbd_get_connection+0x1c6a/0x2110 smbd_get_connection+0x21/0x40 cifs_get_tcp_session+0x8ef/0xda0 mount_get_conns+0x60/0x750 cifs_mount+0x103/0xd00 cifs_smb3_do_mount+0x1dd/0xcb0 smb3_get_tree+0x1d5/0x300 vfs_get_tree+0x41/0xf0 path_mount+0x9b3/0xdd0 __x64_sys_mount+0x190/0x1d0 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Let's initialize the MR recovery work before MR allocate to prevent the warning, remove the MRs from the list to prevent the UAF.

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.

In the Linux kernel, the following vulnerability has been resolved: locking/ww_mutex/test: Fix potential workqueue corruption In some cases running with the test-ww_mutex code, I was seeing odd behavior where sometimes it seemed flush_workqueue was returning before all the work threads were finished. Often this would cause strange crashes as the mutexes would be freed while they were being used. Looking at the code, there is a lifetime problem as the controlling thread that spawns the work allocates the "struct stress" structures that are passed to the workqueue threads. Then when the workqueue threads are finished, they free the stress struct that was passed to them. Unfortunately the workqueue work_struct node is in the stress struct. Which means the work_struct is freed before the work thread returns and while flush_workqueue is waiting. It seems like a better idea to have the controlling thread both allocate and free the stress structures, so that we can be sure we don't corrupt the workqueue by freeing the structure prematurely. So this patch reworks the test to do so, and with this change I no longer see the early flush_workqueue returns.

In the Linux kernel, the following vulnerability has been resolved: firewire: net: fix use after free in fwnet_finish_incoming_packet() The netif_rx() function frees the skb so we can't dereference it to save the skb->len.