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In the Linux kernel, the following vulnerability has been resolved: drm/panthor: validate userspace queue count against initialized firmware slot count In panthor_drv.c:panthor_ioctl_group_create(), the queue count is validated against the hardcoded maximum: if (!args->queues.count || args->queues.count > MAX_CS_PER_CSG) return -EINVAL; However, if the firmware reports fewer slots than MAX_CS_PER_CSG, panthor_fw_init_ifaces() will only initialize that smaller number of stream interfaces. If unprivileged use…

In the Linux kernel, the following vulnerability has been resolved: drm/vmwgfx: validate pitch coming from userspace Validate the pitch, alongside the box dimensions before trying to copy data from the underlying surface. Fixes possible out of bounds reads with cursor snooping.

In the Linux kernel, the following vulnerability has been resolved: drm/xe/i2c: cancel the client work on remove xe_i2c_notifier() stores the DesignWare adapter in i2c->adapter and schedules i2c->work when the adapter is registered under the xe I2C platform device, and xe_i2c_client_work() then instantiates the AMC client device on that adapter. xe_i2c_remove() tears down the AMC, unregisters the client devices, the bus notifier and the adapter platform device, but it never drains i2c->work. A work item that is …

In the Linux kernel, the following vulnerability has been resolved: drm/xe: Fix shrinker accounting double-subtraction on nested external pins xe_bo_pin_external() and xe_bo_unpin_external() support nested pins, since the underlying ttm_bo_pin()/ttm_bo_unpin() maintain a pin_count refcount rather than a boolean. However, the shrinker accounting calls xe_ttm_tt_account_subtract() and xe_ttm_tt_account_add() are invoked unconditionally on every pin_external()/unpin_external() call, instead of only on the transition…

In the Linux kernel, the following vulnerability has been resolved: drm/xe: Fix stale pinned_link entry when fb-pin performs the final unpin xe_bo_pin_external() and xe_bo_unpin_external() maintain the bo's pinned_link list membership in xe->pinned.late.external, based on whether the current call is the outermost pin or the final unpin. However, the same external bo's pin_count can also be raised and lowered directly by __xe_pin_fb_vma()/__xe_unpin_fb_vma(), which pin the bo as a display scanout buffer without go…

In the Linux kernel, the following vulnerability has been resolved: drm/bridge: th1520-dw-hdmi: Fix remove() callback This driver stores struct th1520_hdmi * in platform drvdata, but th1520_dw_hdmi_remove() was reading it back as struct dw_hdmi * and passing it to dw_hdmi_remove(), so teardown runs on the wrong pointer. Retrieve struct th1520_hdmi * from platform drvdata and pass hdmi->dw_hdmi to dw_hdmi_remove().

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/userq: only accept doorbell BOs as queue doorbell amdgpu_userq_get_doorbell_index() pins any BO passed as doorbell_handle into the doorbell domain. For a regular BO, TTM moves it with ttm_bo_move_null() and its contents are lost. Since an importer on the same device gets the exporter's GEM object, a client can do this to a buffer another client shared with it. Reject BOs that were not created in the doorbell domain. v2: drop the erro…

In the Linux kernel, the following vulnerability has been resolved: fs: don't silently unmount busy mounts The propagate_mount_busy() helper exists to decide whether a synchronous can suceed. It does that by looking at the copies of the victims in the mounts its parent propagates to. One of those functions from propagation hell. It skips a copy that has child mounts except for the case of a single child mount covering the copy's root. That algorithm used to be exact. It isn't anymore. Originally only childless …

In the Linux kernel, the following vulnerability has been resolved: namespace: reset the old parent's ->overmount in mnt_change_mountpoint() __umount_mnt() resets ->overmount of the parent when it unmounts the mount that overmounts it. mnt_change_mountpoint() doesn't. It moves the mount to its new parent and leaves the old one pointing at it. For a mount that is moved beneath in attach_recursive_mnt() that doesn't matter. The new mount has already reset ->overmount of the old parent by the time the old top mount…

In the Linux kernel, the following vulnerability has been resolved: statmount: read the parent of an unmounted mount under mount_lock statmount_mnt_basic() reads the ids of the parent through m->mnt_parent with namespace_sem held for reading. That's fine for a mount that is in a namespace. Everything above it is pinned by that namespace. STATMOUNT_BY_FD also accepts a file descriptor on a mount that has been unmounted on purpose and that only the file descriptor keeps alive. If that mount stayed attached to its …

In the Linux kernel, the following vulnerability has been resolved: namespace: don't inherit MNT_UMOUNT in clone_mnt() MNT_UMOUNT gets raised on a mount that umount_tree() or umount_one() has taken out of its namespace. It's never cleared. __detach_mounts() unhooks a mount that carries it instead of unmounting it. disconnect_mount() lets an unmounted child stay attached only if its parent carries it. propagate_umount() takes it as the sign that a mount is going to be unmounted when it decides what else can be un…

In the Linux kernel, the following vulnerability has been resolved: namespace: don't copy an unmounted mount tree may_copy_tree() accepts a mount whose root is an nsfs or pidfs file before it checks whether that mount is mounted. This exception exists for nsfs and pidfs mounts. They are part of no mount namespace so neither check_mnt() nor is_mounted() would let them through and bind-mounting a nsfsfd or a pidfd wouldn't work. Problem is that exception also admits a bind mount of such a file when it was lazily u…

In the Linux kernel, the following vulnerability has been resolved: namespace: queue a mount only once for mount notifications mnt_notify_add() puts a mount on notify_list. It doesn't check whether the mount is on the list already. That's fine as long as every mount is queued at most once per namespace_sem hold. It isn't. propagate_umount() moves a surviving overmount off a stack of mounts that are going away and queues it as moved. shrink_submounts() and mark_mounts_for_expiry() call umount_tree() for several m…

In the Linux kernel, the following vulnerability has been resolved: namespace: check a submount for references right before unmounting it shrink_submounts() and mark_mounts_for_expiry() first collect all the mounts they are allowed to unmount and then unmount them. Whether a mount is busy is decided by propagate_mount_busy() on the tree. But unmounting the first mount changes the tree that the second one propagates into. propagate_umount() moves a surviving overmount off a copy it unmounts and mounts it where th…

In the Linux kernel, the following vulnerability has been resolved: namespace: check a recursive bind mount for mount namespace loops do_loopback() refuses to bind mount the file of a mount namespace that is as old as the caller's or older because a mount namespace that holds a mount of its own file, or of an ancestor's, would cause a cycle. But it only checks the dentry the bind mount starts from. With MS_REC everything below it is copied and do_loopback() passes CL_COPY_MNT_NS_FILE so mount namespace files belo…

In the Linux kernel, the following vulnerability has been resolved: namespace: keep covered mounts covered in OPEN_TREE_NAMESPACE open_tree(OPEN_TREE_NAMESPACE) creates a new mount namespace from a copy of the tree at the given path. The caller needs to be privileged over its current user namespace because the new mount namespace will be owned by it. It doesn't need to be privileged over the mount namespace the tree is copied from. An unprivileged user just needs to create a user namespace first. The copy follow…

In the Linux kernel, the following vulnerability has been resolved: namespace: look at the topmost mount for a mount namespace file attach_recursive_mnt() preallocates a mountpoint for the root of the topmost mount of the source so that a mount that already sits at the destination can be put on top of the source or on top of one of its propagated copies. The copies are made without CL_COPY_MNT_NS_FILE so their chain of overmounts is shorter than the source's. It ends below the first bind mount of a mount namespa…

In the Linux kernel, the following vulnerability has been resolved: namespace: remove the fsnotify marks of a mount namespace in process context mnt_ns_release() drops the last passive reference of a mount namespace and removes its fanotify marks via fsnotify_mntns_delete(). That takes the mutex of every group with a mark on the namespace and the spinlock of the connector. Fine from process context. But mnt_ns_tree_remove() hands the reference the namespace was allocated with to call_rcu() and so the marks are re…

In the Linux kernel, the following vulnerability has been resolved: namespace: check the mounts before reading their parents in pivot_root() path_pivot_root() reads the parents of new_root and of the caller's root and checks whether they are shared before it checks that either mount is in the caller's mount namespace. Only namespace_sem is held. That's fine for a mount that is in the caller's mount namespace. But new_root can be a file descriptor to a mount that has been unmounted and that only the file descript…

In the Linux kernel, the following vulnerability has been resolved: dcache: don't put a mountpoint on a dentry that's being removed rmdir(), unlink() and rename() call dont_mount() on the victim and then detach_mounts() with the victim's inode locked. do_lock_mount() takes the inode lock of the mountpoint and checks cant_mount() so a mount can't show up after detach_mounts(). But attach_recursive_mnt() makes a second mountpoint for the root of the source mount so that the mounts already located at the destinatio…

In the Linux kernel, the following vulnerability has been resolved: unshare: don't drop active namespace references that were never taken Active references on the namespaces of an nsproxy are taken when the nsproxy is installed into a task in switch_task_namespaces() and copy_namespaces() and dropped again by put_nsproxy() through deactivate_nsproxy(). But ksys_unshare() calls put_nsproxy() on an nsproxy that was never installed when set_cred_ucounts() fails. The new namespaces of that nsproxy go from zero to mi…

In the Linux kernel, the following vulnerability has been resolved: namespace: don't let a pseudo dentry become the root of a mount d_alloc_pseudo() hands out dentries for pipes, sockets and other files that are never anyone's child or parent. They carry DCACHE_NORCU and dentry_free() frees them right away because no lockless path walk can ever reach them. That holds as long as such a dentry isn't the root of a mount. But bind mounting /proc/self/fd/<fd> of such a file does exactly that. Most callers of alloc_fi…

In the Linux kernel, the following vulnerability has been resolved: namespace: unhash a dentry before detaching the mounts on it unlink(), rmdir() and rename() remove the entry from the filesystem, call detach_mounts() on the entry with the inode locked and then call d_delete() once the inode is unlocked. The thing is that between detach_mounts() and d_delete() the dentry is still hashed and positive. But after detach_mounts() nothing covers the dentry anymore. A lookup that finds this dentry in the dcache can u…

In the Linux kernel, the following vulnerability has been resolved: namei: don't reveal overmounted entries in refwalk In rcuwalk the dentry is validated before it is accepted. step_into() step_into() rechecks d_seq and __follow_mount_rcu() rechecks mount_lock. An entry that gets unlinked in between causes the lookup to retry and miss. A refwalk doesn't do this. lookup_fast() takes a reference on the hashed dentry and simply accepts it. So an unlink that happens after the reference was taken isn't seen by refwal…

In the Linux kernel, the following vulnerability has been resolved: namespace: refuse an automount below a mount that is in no namespace It's possible to add autmounts even when the parent mount isn't in the mount namespace of the caller. The only requirement we have is that the parent mount namespace must not be NULL, i.e., unmounted. Problem is that clone_private_mount() has MNT_NS_INTERNAL which makes that trivially true. So that passes the test and attach_recursive_mnt() accepts that as a mount point and fun…