Linux vulnerabilities

In the Linux kernel, the following vulnerability has been resolved: ext4: fix ABBA deadlock in ext4_xattr_inode_cache_find() Syzbot/stress-ng reported an ABBA deadlock in ext4 when exercising concurrent xattr workloads (using the ea_inode mount/format option). The deadlock occurs between the running transaction and the eviction thread: - Task 1 (stress-ng): Holds a reference to a shared mbcache_entry (ce) and calls ext4_xattr_inode_cache_find() -> ext4_iget() to retrieve the corresponding EA inode. Since the EA inode is currently being evicted, ext4_iget() blocks in __wait_on_freeing_inode() waiting for eviction to complete. - Task 2 (eviction thread): Currently evicting the same EA inode in ext4_evict_ea_inode(). It calls mb_cache_entry_wait_unused(oe) which blocks waiting for Task 1 to release the reference to the mbcache_entry. To break this deadlock, implement a new ext4_iget() configuration flag named EXT4_IGET_NOWAIT. When set, perform a non-blocking lookup of the inode via VFS's find_inode_nowait() API. If the inode is currently being evicted (marked with I_FREEING or I_WILL_FREE) or created (I_CREATING), or if it is not present in the VFS inode cache (cache miss), simply skip it (returning -ENOENT) rather than waiting for eviction/creation to complete, breaking the ABBA cycle. Since we return -ENOENT immediately on a cache miss, we never attempt to allocate a new inode or call iget_locked(), completely eliminating any TOCTOU race window. If the returned inode is I_NEW, wait for its initialization to clear via wait_on_new_inode(). If initialization fails and the inode is unhashed during wait_on_new_inode() waking up (e.g., due to an I/O read error in another thread), safely drop the reference and return -ENOENT. This unhashed check is executed unconditionally on all cache-hit pathways to properly handle concurrent initialization failures. Finally, standard validation checks (including is_bad_inode, EXT4_EA_INODE_FL, file_acl, and xattr flags) are executed as normal inside check_igot_inode() to fully guarantee VFS-layer safety. In ext4_xattr_inode_cache_find(), invoke ext4_iget() with the new EXT4_IGET_NOWAIT flag to perform the non-blocking cache search.

In the Linux kernel, the following vulnerability has been resolved: wifi: ath11k: Avoid buffer overread in ath11k_wmi_tlv_op_rx() Currently, in ath11k_wmi_tlv_op_rx(), the firmware buffer is read without first verifying that the buffer has enough data to hold a header. This could result in a buffer overread. Add an upfront length check before dereferencing skb->data as a wmi_cmd_hdr. The check is placed before the trace_ath11k_wmi_event() call to preserve the existing trace semantics (tracing the full raw WMI event including the header), unlike the analogous ath12k fix which could use skb_pull_data() directly. Compile tested only.

In the Linux kernel, the following vulnerability has been resolved: RDMA/bnxt_re: Clear VM_MAYWRITE on DBR/toggle page mmap bnxt_re_mmap() rejects VM_WRITE for the DBR_PAGE and TOGGLE_PAGE mmap flags, but a read-only mapping can still retain VM_MAYWRITE. nd later be upgraded with mprotect(PROT_WRITE). This can bypass the write check that only runs at mmap time. Clear VM_MAYWRITE before vm_insert_page() in the shared DBR/toggle-page branch, matching the existing policy that userspace writes are not expected for these pages.

In the Linux kernel, the following vulnerability has been resolved: ext4: fix buffer_head leak in ext4_init_orphan_info ext4_init_orphan_info() reads orphan file blocks with ext4_bread() and stores the returned buffer_head in oi->of_binfo[i].ob_bh. If ext4_bread() succeeds but the orphan block magic or checksum validation fails, the function jumps to out_free. However, the old out_free loop starts releasing buffers from i - 1, so the current buffer_head at index i is skipped. This leaks the buffer_head reference obtained by ext4_bread() on the bad magic and bad checksum error paths. Fix this by tracking the number of successfully read buffer_heads and releasing exactly those buffer_heads on the error path.

In the Linux kernel, the following vulnerability has been resolved: cpufreq: amd-pstate-ut: Skip tests when amd-pstate driver is not active The crash issue may occur when modprobe amd_pstate_ut on intel platform. amd_pstate_ut: 1 amd_pstate_ut_acpi_cpc_valid success! amd_pstate_ut: 2 amd_pstate_ut_check_enabled success! BUG: kernel NULL pointer dereference, address: 0000000000000080 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 PID: 20300 Comm: modprobe Kdump: loaded Tainted: G O 6.6.0-0010.rc1.ctl4.x86_64 #1 Hardware name: FiberHome R2200 V5/Xeon Boards, BIOS 3.1a 02/24/2020 RIP: 0010:amd_pstate_ut_check_perf+0x141/0x280 [amd_pstate_ut] Call Trace: <TASK> amd_pstate_ut_init+0x1b/0xff0 [amd_pstate_ut] ? __pfx_amd_pstate_ut_init+0x10/0x10 [amd_pstate_ut] do_one_initcall+0x42/0x2e0 ? kmalloc_trace+0x26/0x90 do_init_module+0x60/0x240 __se_sys_init_module+0x185/0x1c0 do_syscall_64+0x62/0x190 entry_SYSCALL_64_after_hwframe+0x76/0x7e </TASK> Add state detection to amd pstate driver to prevent amd_pstate_ut driver from testing on non-AMD platforms. (ML: adjust title)

In the Linux kernel, the following vulnerability has been resolved: cpufreq/amd-pstate: handle missing policy in dynamic EPP callbacks cpufreq_cpu_get() returns NULL when no cpufreq policy is associated with the requested CPU, for example because the CPU is offline or the policy has already been torn down. Both amd_pstate_power_supply_notifier() and amd_pstate_profile_set() acquire a policy via cpufreq_cpu_get() and then pass that pointer to amd_pstate_get_balanced_epp() and amd_pstate_set_epp(), which dereference it unconditionally. A racing CPU hotplug or driver teardown can therefore lead to a NULL pointer dereference on either of these dynamic EPP paths. The third cpufreq_cpu_get() caller in this file, amd_pstate_verify(), already handles the NULL case. Bring the two new callers in line with that pattern: return NOTIFY_OK from the power-supply notifier (matching the other "nothing to do" exits) and -ENODEV from amd_pstate_profile_set() (the usual cpufreq error for a missing CPU policy). Found by code inspection; not tested on hardware.

In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Roll back partial protocol table registration scmi_protocol_table_register() can leave earlier requests registered when a later entry in the same ID table fails. Each request retains a pointer to the driver's ID table, so a failed module load can leave a dangling pointer after the module storage is released. Unrequest only the successfully registered prefix, in reverse order, before returning the failure. Leave the failed entry and the remaining entries untouched because matching requests can be owned by another driver.

In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Unrequest devices if driver registration fails scmi_driver_register() requests protocol devices before registering the driver. If driver_register() fails, those requests remain in the global IDR and retain pointers to the module's ID table. Once the failed module load releases that storage, later request matching or SCMI device creation can dereference the stale pointers. Unrequest the complete protocol table before returning the registration failure. At this point table registration succeeded, so every entry is owned by the current registration attempt.

In the Linux kernel, the following vulnerability has been resolved: exfat: fix valid_size extension over a shared writable mapping When a shared writable mapping has its valid_size extended by a buffered write or a page fault, exfat zeroes the page-cache gap below the new valid_size. A store through the mapping can race with this zeroing and be overwritten. Fix this by zeroing the gap lazily. Drop ->map_pages so that every first write fault goes through exfat_page_mkwrite(), which advances valid_size to cover the faulting page. With fault-around enabled, a store could install a writable PTE, skip ->page_mkwrite(), and land past valid_size without advancing it. Extending valid_size one faulting page at a time also leaves never-written pages in a large mapping alone. The gap is filled with block granularity, zeroing only the not-uptodate blocks and preserving blocks that may hold data stored through the mapping. On the buffered-write path the invalidate lock is held and the gap is unmapped before zeroing, so a racing store re-faults and, under the inode lock, completes only after the gap has been zeroed and valid_size covers it.

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix CFI mismatch in task work callback BPF subprograms use the bpf_callback_t ABI, but task work invokes the callback through a three-argument function pointer. This trips kCFI. Store and invoke the callback as bpf_callback_t.

In the Linux kernel, the following vulnerability has been resolved: cxl/region: Fix use-after-free in find_pos_and_ways() error path The error path releases its reference to a switch decoder before logging an error that includes the decoder name. If the released reference is the last one, the decoder can be freed before the error message accesses its name. Drop the reference after the error is reported.

In the Linux kernel, the following vulnerability has been resolved: liveupdate: Remember FLB retrieve() status LUO keeps track of successful retrieve attempts on an FLB. It does so to avoid multiple retrievals of the same FLB. Multiple retrievals cause problems because once the FLB is retrieved, the serialized data structures are likely freed and the FLB is likely in a very different state from what the code expects. All this works well when retrieve succeeds. When it fails, luo_flb_retrieve_one() returns the error immediately, without ever storing anywhere that a retrieve was attempted or what its error code was. If the user attempts to retrieve another file registered with the same FLB, LUO will attempt to call the FLB's retrieve() callback again. The retry is problematic for much of the same reasons listed above. The FLB is likely in a very different state than what the retrieve logic normally expects (e.g. some KHO pages may have already been restored and freed). There is no sane way of attempting the retrieve again. Remember the error retrieve returned and directly return it on a retry. This is done by changing the retrieved bool to a retrieve_status integer. A value of 0 means retrieve was never attempted, a positive value means it succeeded, and a negative value means it failed and the error code is the value. This is similar to commit f85b1c6af5bc ("liveupdate: luo_file: remember retrieve() status") which did the same for LUO files.

In the Linux kernel, the following vulnerability has been resolved: pinctrl: mediatek: free EINT resources on unbind mtk_eint_do_init() creates an IRQ domain, populates it with a mapping for every EINT line and installs a chained handler on the parent interrupt, but none of these are ever released. This was harmless while the drivers were built-in, but now that they can be built as modules and unbound/rmmod'd it leaves behind a dangling IRQ domain, interrupt mappings whose chip data points at freed memory, and a chained handler that keeps firing into that freed data. The plain allocations in mtk_eint_do_init() already use the device-managed devm_*() helpers, so tear the remaining resources down the same way: register a devm action that detaches the chained handler, waits for any in-flight handler to finish, disposes of the per-line mappings and removes the IRQ domain. This mirrors the device-managed lifecycle adopted for the GPIO chip and keeps the whole EINT setup self-cleaning on unbind.

In the Linux kernel, the following vulnerability has been resolved: pinctrl: mediatek: use devm_gpiochip_add_data() for GPIO chip The gpio_chip is allocated with device-managed memory but registered with the non-managed gpiochip_add_data(). This was harmless while the drivers were built-in, but once they can be built as modules and unbound/rmmod'd, devm frees the gpio_chip's memory while it is still registered, causing a use-after-free. Register it with devm_gpiochip_add_data() so it shares the same device-managed lifecycle, which also lets the manual gpiochip_remove() error paths go away.

In the Linux kernel, the following vulnerability has been resolved: scsi: ufs: core: Validate string descriptors The string descriptor length includes a two-byte header while the UTF-16 payload starts after it. utf16s_to_utf8s() expects a count of UTF-16 code units, not bytes. Passing the payload byte count can make it read beyond the descriptor buffer. Validate that the payload has an even byte count, pass a code-unit count to the converter, and allocate sufficient UTF-8 output space. The raw string buffer starts after the descriptor header but its size is bLength. Copying bLength bytes from that pointer can read beyond the response buffer. Allocate a zeroed bLength-sized buffer and copy only the UTF-16 payload. This preserves the raw buffer size consumed by the RPMB device-ID ABI while avoiding the overread.

In the Linux kernel, the following vulnerability has been resolved: scsi: ufs: Avoid NULL CQE dereference when reporting invalid tags The single-doorbell completion path can call ufshcd_compl_one_cqe() with a NULL CQE. If no command is associated with the completion tag, the warning message dereferences the CQE while reporting the error. Avoid that dereference and include the invalid tag in the warning.

In the Linux kernel, the following vulnerability has been resolved: scsi: ufs: core: Validate connected lane counts The connected lane count is used by TX equalization code to index arrays sized by UFS_MAX_LANES. Reject zero and out-of-range RX or TX lane counts before they can be propagated.

In the Linux kernel, the following vulnerability has been resolved: scsi: ufs: debugfs: Reserve space for a string terminator ufs_saved_err_write() copies user input into a zero-initialized stack buffer and passes it to kstrtoint(). A write that fills the entire buffer overwrites its only terminator. Reject an input whose length leaves no room for the trailing NUL.

In the Linux kernel, the following vulnerability has been resolved: crypto: keembay - Initialize completion before requesting IRQ kmb_ocs_aes_probe() requests the device IRQ before initializing irq_completion. Once the handler is registered it can run immediately, and ocs_aes_irq_handler() unconditionally calls complete(). An interrupt in this window would therefore use an uninitialized completion. Initialize the completion before requesting the IRQ, as the sibling OCS HCU and ECC drivers already do.

In the Linux kernel, the following vulnerability has been resolved: isofs: release zisofs block pointer buffer head zisofs_fill_pages() reads the compressed block pointer table. The error paths release the current buffer_head, the loop also releases the old buffer_head when it advances. However, the success path leaves the last buffer_head referenced. Release it before returning success.

In the Linux kernel, the following vulnerability has been resolved: spi: oc-tiny: switch to managed controller allocation The controller is allocated with the non-managed spi_alloc_host() while the interrupt is registered with devm_request_irq(). During removal, spi_bitbang_stop() only unregisters the controller; the subsequent spi_controller_put() then frees the controller together with its embedded driver-private devdata, which is the IRQ handler's dev_id. The devm_request_irq() release action (free_irq()), which drains the handler, does not run until after .remove() returns. A late or latched interrupt can therefore reach tiny_spi_irq() and dereference already-freed memory (e.g. hw->base). Switch to devm_spi_alloc_host() so that the devres LIFO order releases the controller only after free_irq() has drained the handler, and drop the now-redundant spi_controller_put() from .remove(). The probe error path is simplified to direct returns. This issue was found by an in-house static analysis tool.