CVE Database

In the Linux kernel, the following vulnerability has been resolved: ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE The FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the destination file's data via vfs_clone_file_range() with neither the share-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle fp->daccess check that the other write-bearing arms carry. A client can overwrite destination data on a read-only share, or from a handle opened with only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp). FILE_WRITE_ATTRIBUTES-only destination handle overwrote the file's data via the clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix; require FILE_WRITE_DATA since this writes data.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: add a permission check for FSCTL_SET_ZERO_DATA FSCTL_SET_ZERO_DATA in smb2_ioctl() destroys file data via ksmbd_vfs_zero_data() -> vfs_fallocate(PUNCH_HOLE/ZERO_RANGE) after checking only the share-level KSMBD_TREE_CONN_FLAG_WRITABLE, with no per-handle access check. A handle opened with only FILE_WRITE_ATTRIBUTES still yields an FMODE_WRITE filp (FILE_WRITE_ATTRIBUTES is part of FILE_WRITE_DESIRE_ACCESS_LE, so smb2_create_open_flags() opens it O_WRONLY), so the vfs_fallocate FMODE_WRITE check does not stop it; only the missing fp->daccess gate would. Reproduced on mainline 7.1-rc7 with KASAN by an authenticated SMB client: a FILE_WRITE_ATTRIBUTES-only handle zeroed 4096 bytes of file data it had no FILE_WRITE_DATA right to (6/6; a FILE_READ_DATA-only handle was correctly denied). This is the unfixed sibling of commit cc57232cae23 ("ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE"). Because SET_ZERO_DATA writes data (not an attribute), require FILE_WRITE_DATA.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: serialize QUERY_DIRECTORY requests per file smb2_query_dir() stores a pointer to its stack-allocated private data in the ksmbd_file readdir_data. Concurrent QUERY_DIRECTORY requests using the same file handle can overwrite this pointer while an iterate_dir() callback is still using it, resulting in a stack use-after-free. Add a per-file mutex and hold it while accessing the shared directory enumeration state. The lock covers scan restart, dot entry state, readdir_data setup and iteration, and response construction. This prevents another request from replacing readdir_data.private before the current request has finished using it and also serializes the shared file position.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix UAF of struct file_lock in SMB2_LOCK deferred-lock cancellation When a blocking byte-range lock request is deferred in the FILE_LOCK_DEFERRED path, ksmbd registers the asynchronous work into the connection's async_requests list via setup_async_work(). The cancel callback smb2_remove_blocked_lock() holds a reference to the flock. If the lock waiter is subsequently woken up but the work state is no longer KSMBD_WORK_ACTIVE (e.g., due to a concurrent cancellation), the cleanup path calls locks_free_lock(flock) without dequeuing the work from the async_requests list. Concurrently, smb2_cancel() walks the list under conn->request_lock and invokes the cancel callback, which then dereferences the already freed 'flock'. This leads to a slab-use-after-free inside __wake_up_common. Fix this by restructuring the cleanup logic after the worker returns from ksmbd_vfs_posix_lock_wait(). Move list_del(&smb_lock->llist) and release_async_work(work) to the top of the cleanup block. This guarantees that the async work is completely dequeued and serialized under conn->request_lock before locks_free_lock(flock) is called, rendering the flock unreachable for any concurrent smb2_cancel().

In the Linux kernel, the following vulnerability has been resolved: ksmbd: require source read access for duplicate extents FSCTL_DUPLICATE_EXTENTS_TO_FILE passes the source file directly to vfs_clone_file_range() or vfs_copy_file_range() without checking the SMB access mask granted to the source handle. A handle opened with attribute access can consequently be used to copy file contents into an attacker-readable destination. Require FILE_READ_DATA on the source handle before either VFS operation, matching other ksmbd data-copy paths.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: add a WRITE_DAC/WRITE_OWNER check to SMB2 SET_INFO SECURITY commit cc57232cae23 ("ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE") added a fp->daccess gate to fsctl_set_sparse and noted that "similar handle-level checks exist in other functions but are missing here." The SMB2 SET_INFO SECURITY arm is one of the missing ones, and the most security-relevant: smb2_set_info_sec() calls set_info_sec() with no per-handle access check. set_info_sec() (fs/smb/server/smbacl.c) re-permissions the file: it rewrites owner/group/mode via notify_change(), rewrites the POSIX ACL via set_posix_acl(), and on KSMBD_SHARE_FLAG_ACL_XATTR shares removes and rewrites the Windows security descriptor via ksmbd_vfs_set_sd_xattr(). Every other persistent-mutation arm of the sibling handler smb2_set_info_file() checks fp->daccess first (FILE_WRITE_DATA / FILE_DELETE / FILE_WRITE_EA / FILE_WRITE_ATTRIBUTES); the SECURITY arm — which mutates the access control itself — is the only one with no gate. A client can therefore open a handle with FILE_WRITE_ATTRIBUTES only (no FILE_WRITE_DAC / FILE_WRITE_OWNER) and use SMB2_SET_INFO with InfoType SMB2_O_INFO_SECURITY to rewrite the file's DACL and owner, granting itself access the handle's daccess never carried. Unlike the FSCTL data arms this is a metadata/xattr operation, so there is no FMODE_WRITE VFS backstop — the missing fp->daccess check is the entire gate. Setting a security descriptor is the WRITE_DAC / WRITE_OWNER operation, so require at least one of those on the handle before re-permissioning the file. -EACCES is mapped to STATUS_ACCESS_DENIED by smb2_set_info().

In the Linux kernel, the following vulnerability has been resolved: ksmbd: run set info with opener credentials SMB2 SET_INFO handlers call path-based VFS helpers after checking the access mask granted to the SMB handle. Those helpers perform their owner, inode permission and LSM checks using the current ksmbd worker credentials. Run the complete SET_INFO dispatch with the credentials captured when the handle was opened. This also removes the separate security information credential setup and keeps all SET_INFO classes under one credential scope. Direct override_creds() is used because it can nest with the request credential overrides already used by rename and link helpers.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: use opener credentials for delete-on-close Delete-on-close can be completed by deferred or durable handle teardown, where no request work is available. Both the base-file unlink and the ADS xattr removal consequently run with the ksmbd worker credentials and can bypass filesystem permission checks. Run both operations with the credentials captured in struct file when the handle was opened. This preserves the authenticated user's fsuid, fsgid, supplementary groups and capability restrictions at final close.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: use opener credentials for ADS I/O Alternate data streams are stored as xattrs. Unlike regular file I/O, their read and write paths therefore call VFS xattr helpers which recheck inode permissions and LSM policy using the current task credentials. Run ADS I/O with the credentials captured when the SMB handle was opened.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: track the connection owning a byte-range lock SMB2_LOCK adds each granted byte-range lock to both the file lock list and the lock list of the connection which handled the request. The final close and durable handle paths, however, remove the connection list entry while holding fp->conn->llist_lock. With SMB3 multichannel, the connection handling the LOCK request can be different from the connection which opened the file. The entry can therefore be removed under a different spinlock from the one protecting the list it belongs to. A concurrent traversal can then access freed struct ksmbd_lock and struct file_lock objects. Record the connection owning each lock's clist entry and hold a reference to it while the entry is linked. Use that connection and its llist_lock for unlock, rollback, close, and durable preserve. Durable reconnect assigns the new connection as the owner when publishing the locks again.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate NTLMv2 response before updating session key ksmbd_auth_ntlmv2() derives the NTLMv2 session key into sess->sess_key before it verifies the NTLMv2 response. ksmbd_decode_ntlmssp_auth_blob() then continues into KEY_XCH even when ksmbd_auth_ntlmv2() failed. With SMB3 multichannel binding, the failed authentication operates on an existing session and the session setup error path does not expire binding sessions. A client can send a binding session setup with a bad NT proof and KEY_XCH and still modify sess->sess_key before STATUS_LOGON_FAILURE is returned. Relevant path: smb2_sess_setup() -> conn->binding = true -> ntlm_authenticate() -> session_user() -> ksmbd_decode_ntlmssp_auth_blob() -> ksmbd_auth_ntlmv2() -> calc_ntlmv2_hash() -> hmac_md5_usingrawkey(..., sess->sess_key) -> crypto_memneq() returns mismatch -> KEY_XCH arc4_crypt(..., sess->sess_key, ...) -> out_err without expiring the binding session Derive the base session key into a local buffer and copy it to sess->sess_key only after the proof matches. Return immediately on authentication failure so KEY_XCH is only processed after successful authentication.

In the Linux kernel, the following vulnerability has been resolved: smb/client: fix chown/chgrp with SMB3 POSIX Extensions Ownership (chown) and group (chgrp) modifications were being ignored when mounting with SMB3 POSIX Extensions unless CIFS_MOUNT_CIFS_ACL or CIFS_MOUNT_MODE_FROM_SID were also explicitly set. Fix this by checking for posix_extensions in cifs_setattr_nounix() when updating UID and GID, ensuring that id_mode_to_cifs_acl() is called to map and set the ownership/group information on the server.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix query directory replay double-free A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_query_directory_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix query_info() replay double-free A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_query_info_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_ioctl() replay A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_ioctl_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix change notify replay double-free A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_notify_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_flush() replay SMB2_flush() keeps its response buffer bookkeeping across replay attempts. If a replayable flush response is received and the retry then fails before cifs_send_recv() stores a replacement response, flush_exit will free the stale response pointer a second time. Reinitialize resp_buftype and rsp_iov at the top of the replay loop so cleanup only acts on response state produced by the current attempt. This fixes a double-free without changing replay handling for successful requests.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_open() replay A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_open_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.

In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix next buffer leak in receive_encrypted_standard() receive_encrypted_standard() allocates next_buffer before checking whether the number of compound PDUs already reached MAX_COMPOUND. If the limit check fails, the function returns immediately and the newly allocated next_buffer is not assigned to server->smallbuf/server->bigbuf, making it leaked. Move the MAX_COMPOUND check before allocating next_buffer.

In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.

In the Linux kernel, the following vulnerability has been resolved: smb: client: mask server-provided mode to 07777 in modefromsid When modefromsid is active, parse_dacl() applies the server-provided sub_auth[2] value from the NFS mode SID to cf_mode without masking to 07777. Apply the correct masking, same as in the read path.

In the Linux kernel, the following vulnerability has been resolved: writeback: fix race between cgroup_writeback_umount() and inode_switch_wbs() When a container exits, the following BUG_ON() is occasionally triggered: ================================================================== VFS: Busy inodes after unmount of sdb (ext4) ------------[ cut here ]------------ kernel BUG at fs/super.c:695! CPU: 3 PID: 6 Comm: containerd-shim Tainted: G OE K 6.6 #1 pstate: 63400009 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) pc : generic_shutdown_super+0xf0/0x100 lr : generic_shutdown_super+0xf0/0x100 Call trace: generic_shutdown_super+0xf0/0x100 kill_block_super+0x20/0x48 ext4_kill_sb+0x28/0x60 deactivate_locked_super+0x54/0x130 deactivate_super+0x84/0xa0 cleanup_mnt+0xa4/0x140 __cleanup_mnt+0x18/0x28 task_work_run+0x78/0xe0 do_notify_resume+0x204/0x240 ================================================================== The root cause is a race between cgroup_writeback_umount() and inode_switch_wbs()/cleanup_offline_cgwb(). There is a window between inode_prepare_wbs_switch() returning true and the subsequent wb_queue_isw() call. Following is the process that triggers the issue: CPU A (umount) | CPU B (writeback) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ inode_switch_wbs/cleanup_offline_cgwb atomic_inc(&isw_nr_in_flight) inode_prepare_wbs_switch -> passes SB_ACTIVE check __iget(inode) generic_shutdown_super sb->s_flags &= ~SB_ACTIVE cgroup_writeback_umount(sb) smp_mb() atomic_read(&isw_nr_in_flight) rcu_barrier() -> no pending RCU callbacks flush_workqueue(isw_wq) -> nothing queued, returns evict_inodes(sb) -> Inode skipped as isw still holds a ref. sop->put_super(sb) /* destroys percpu counters */ -> VFS: Busy inodes after unmount! wb_queue_isw() queue_work(isw_wq, ...) /* later in work function */ inode_switch_wbs_work_fn process_inode_switch_wbs iput() -> evict percpu_counter_dec() // UAF! Fix this by extending the RCU read-side critical section in inode_switch_wbs() and cleanup_offline_cgwb() to cover from inode_prepare_wbs_switch() through wb_queue_isw(). Since there is no sleep in this window, rcu_read_lock() can be used. Then add a synchronize_rcu() in cgroup_writeback_umount() before the existing rcu_barrier(), so that all in-flight switchers that have passed the SB_ACTIVE check have completed queue_work() before flush_workqueue() is called. The existing rcu_barrier() is intentionally retained so this fix can be backported unchanged to stable kernels (5.10.y, 6.6.y, ...) that still queue switches via queue_rcu_work(). It is a no-op on current mainline (since commit e1b849cfa6b6 ("writeback: Avoid contention on wb->list_lock when switching inodes")) and is removed in a follow-up patch.

In the Linux kernel, the following vulnerability has been resolved: cpufreq: qcom-cpufreq-hw: Fix possible double free qcom_cpufreq.data is allocated with devm_kzalloc() in probe() as an array of per-domain data. qcom_cpufreq_hw_cpu_init() stores a pointer to one element of this array in policy->driver_data. qcom_cpufreq_hw_cpu_exit() currently calls kfree() on policy->driver_data. This is not valid because the memory is devm-managed. For the first domain, this can free the devm-managed allocation while the devres entry is still active, leading to a possible double free when the platform device is later detached. For other domains, the pointer may refer to an element inside the array rather than the allocation base. Remove the kfree(data) call and let devres release qcom_cpufreq.data. This issue was found by a static analysis tool I am developing.

In the Linux kernel, the following vulnerability has been resolved: firmware_loader: fix device reference leak in firmware_upload_register() firmware_upload_register() -> fw_create_instance() -> device_initialize() After fw_create_instance() succeeds, the lifetime of the embedded struct device is expected to be managed through the device core reference counting, since fw_create_instance() has already called device_initialize(). In firmware_upload_register(), if alloc_lookup_fw_priv() fails after fw_create_instance() succeeds, the code reaches free_fw_sysfs and frees fw_sysfs directly instead of releasing the device reference with put_device(). This may leave the reference count of the embedded struct device unbalanced, resulting in a refcount leak. The issue was identified by a static analysis tool I developed and confirmed by manual review. Fix this by using put_device(fw_dev) in the failure path and letting fw_dev_release() handle the final cleanup, instead of freeing the instance directly from the error path.

In the Linux kernel, the following vulnerability has been resolved: proc: protect ptrace_may_access() with exec_update_lock (FD links) proc_pid_get_link() and proc_pid_readlink() currently look up the task from the pid once, then do the ptrace access check on that task, then look up the task from the pid a second time to do the actual access. That's racy in several ways. To fix it, pass the task to the ->proc_get_link() handler, and instead of proc_fd_access_allowed(), introduce a new helper call_proc_get_link() that looks up and locks the task, does the access check, and calls ->proc_get_link().

In the Linux kernel, the following vulnerability has been resolved: sched/rt: Have RT_PUSH_IPI be default off for non PREEMPT_RT RT migration is done aggressively. When a CPU schedules out a high priority RT task for a lower priority task, it will look to see if there's any RT tasks that are waiting to run on another CPU that is of higher priority than the task this CPU is about to run. If it finds one, it will pull that task over to the CPU and allow it to run there instead. Normally, this pulling is done by looking at the RT overloaded mask (rto) which contains all the CPUs in the scheduler domain with RT tasks that are waiting to run due to a higher priority RT task currently running on their CPU. The CPU that is about to schedule a lower priority task will grab the rq lock of the overloaded CPU and move the RT task from that CPU's runqueue to the local one and schedule the higher priority RT task. This caused issues when a lot of CPUs would schedule a lower priority task at the same time. They would all try to grab the same runqueue lock of the CPU with the overloaded RT tasks. Only the first CPU that got in will get that task. All the others would wait until they got the runqueue lock and see there's nothing to pull and do nothing. On systems with lots of CPUs, this caused a large latency (up to 500us) which is beyond what PREEMPT_RT is to allow. The solution to that was to create an RT_PUSH_IPI logic. When any CPU wanted to pull a task, instead of grabbing the runqueue lock of the overloaded CPU, it would start by sending an IPI to the overloaded CPU, and that IPI handler would have the CPU with the waiting RT task do a push instead. Then that handler would send an IPI to the next CPU with overloaded RT tasks, and so on. Note, after the first CPU starts this process, if another CPU wanted to do a pull, it would see that the process has already begun and would only increment a counter to have the IPIs continue again. The RT_PUSH_IPI solved the latency problem with PREEMPT_RT but could cause a new issue with non PREEMPT_RT. Namely, softirqs run in a threaded context on PREEMPT_RT but they can run in an interrupt context in non-RT. If an IPI lands on a CPU that has just woken up multiple RT tasks and the current CPU is running a non RT or a low priority RT task, instead of doing a push, it would simply do a schedule on that CPU. But if a softirq was also executing on this CPU, the schedule would need to wait until the softirq finished. Until then, the CPU would still be considered overloaded as there are RT tasks still waiting to run on it. A live lock occurred on a workload that was doing heavy networking traffic on a large machine where the softirqs would run 500us out of 750us. And it would also be waking up RT tasks, causing the RT pull logic to be constantly executed. When a softirq triggered on a CPU with RT tasks queued but not running yet, and the other CPUs would see this CPU as being overloaded, they would send an IPI over to it. The CPU would notice that the waiting RT tasks are of higher priority than the currently running task and simply schedule that CPU instead. But because the softirq was executing, before it could schedule, it would receive another IPI to do the same. The amount of IPIs would slow down the currently running softirq so much that before it could return back to task context, it would execute another softirq never allowing the CPU to schedule. This live locked that CPU. As RT_PUSH_IPI was created to help PREEMPT_RT, make it default off if PREEMPT_RT is not enabled.

In the Linux kernel, the following vulnerability has been resolved: cpufreq: Fix hotplug-suspend race during reboot During system reboot, cpufreq_suspend() is called via the kernel_restart() -> device_shutdown() path. Unlike the normal system suspend path, the reboot path does not call freeze_processes(), so userspace processes and kernel threads remain active. This allows CPU hotplug operations to run concurrently with cpufreq_suspend(). The original code has no synchronization with CPU hotplug, leading to a race condition where governor_data can be freed by the hotplug path while cpufreq_suspend() is still accessing it, resulting in a null pointer dereference: Unable to handle kernel NULL pointer dereference Call Trace: do_kernel_fault+0x28/0x3c cpufreq_suspend+0xdc/0x160 device_shutdown+0x18/0x200 kernel_restart+0x40/0x80 arm64_sys_reboot+0x1b0/0x200 Fix this by adding cpus_read_lock()/cpus_read_unlock() to cpufreq_suspend() to block CPU hotplug operations while suspend is in progress. [ rjw: Changelog edits ]

In the Linux kernel, the following vulnerability has been resolved: cpufreq: pcc: fix use-after-free and double free in _OSC evaluation pcc_cpufreq_do_osc() calls acpi_evaluate_object() twice for the two-phase _OSC negotiation. Between the two calls it freed output.pointer but left output.length unchanged. Since acpi_evaluate_object() treats a non-zero length with a non-NULL pointer as an existing buffer to write into, the second call wrote into freed memory (use-after-free). The subsequent kfree(output.pointer) at out_free then freed the same pointer a second time (double free). Reset output.pointer to NULL and output.length to ACPI_ALLOCATE_BUFFER after freeing the first result, so ACPICA allocates a fresh buffer for each phase independently.

In the Linux kernel, the following vulnerability has been resolved: proc: protect ptrace_may_access() with exec_update_lock (part 1) Fix the easy cases where procfs currently calls ptrace_may_access() without exec_update_lock protection, where the fix is to simply add the extra lock or use mm_access(): - do_task_stat(): grab exec_update_lock - proc_pid_wchan(): grab exec_update_lock - proc_map_files_lookup(): use mm_access() instead of get_task_mm() - proc_map_files_readdir(): use mm_access() instead of get_task_mm() - proc_ns_get_link(): grab exec_update_lock - proc_ns_readlink(): grab exec_update_lock

In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: Fix pid refcount leak in do_cpu_nanosleep() error path In do_cpu_nanosleep(), posix_cpu_timer_create() takes a pid reference via get_pid() and stores it in timer.it.cpu.pid. If the subsequent posix_cpu_timer_set() call fails, the function returns immediately without calling posix_cpu_timer_del() to release the pid reference, causing a leak. Fix it by calling posix_cpu_timer_del() before the unlock-and-return on the error path, consistent with the other exit paths in the same function.