Vulnerabilidades do Linux Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: Hold module reference while requesting a module User space may unload ip_set.ko while it is itself requesting a set type backend module, leading to a kernel crash. The race condition may be provoked by inserting an mdelay() right after the nfnl_unlock() call.

In the Linux kernel, the following vulnerability has been resolved: iommufd: Fix out_fput in iommufd_fault_alloc() As fput() calls the file->f_op->release op, where fault obj and ictx are getting released, there is no need to release these two after fput() one more time, which would result in imbalanced refcounts: refcount_t: decrement hit 0; leaking memory. WARNING: CPU: 48 PID: 2369 at lib/refcount.c:31 refcount_warn_saturate+0x60/0x230 Call trace: refcount_warn_saturate+0x60/0x230 (P) refcount_warn_saturate+0x60/0x230 (L) iommufd_fault_fops_release+0x9c/0xe0 [iommufd] ... VFS: Close: file count is 0 (f_op=iommufd_fops [iommufd]) WARNING: CPU: 48 PID: 2369 at fs/open.c:1507 filp_flush+0x3c/0xf0 Call trace: filp_flush+0x3c/0xf0 (P) filp_flush+0x3c/0xf0 (L) __arm64_sys_close+0x34/0x98 ... imbalanced put on file reference count WARNING: CPU: 48 PID: 2369 at fs/file.c:74 __file_ref_put+0x100/0x138 Call trace: __file_ref_put+0x100/0x138 (P) __file_ref_put+0x100/0x138 (L) __fput_sync+0x4c/0xd0 Drop those two lines to fix the warnings above.

In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix regression with module command in stack_trace_filter When executing the following command: # echo "write*:mod:ext3" > /sys/kernel/tracing/stack_trace_filter The current mod command causes a null pointer dereference. While commit 0f17976568b3f ("ftrace: Fix regression with module command in stack_trace_filter") has addressed part of the issue, it left a corner case unhandled, which still results in a kernel crash.

In the Linux kernel, the following vulnerability has been resolved: udmabuf: change folios array from kmalloc to kvmalloc When PAGE_SIZE 4096, MAX_PAGE_ORDER 10, 64bit machine, page_alloc only support 4MB. If above this, trigger this warn and return NULL. udmabuf can change size limit, if change it to 3072(3GB), and then alloc 3GB udmabuf, will fail create. [ 4080.876581] ------------[ cut here ]------------ [ 4080.876843] WARNING: CPU: 3 PID: 2015 at mm/page_alloc.c:4556 __alloc_pages+0x2c8/0x350 [ 4080.878839] RIP: 0010:__alloc_pages+0x2c8/0x350 [ 4080.879470] Call Trace: [ 4080.879473] <TASK> [ 4080.879473] ? __alloc_pages+0x2c8/0x350 [ 4080.879475] ? __warn.cold+0x8e/0xe8 [ 4080.880647] ? __alloc_pages+0x2c8/0x350 [ 4080.880909] ? report_bug+0xff/0x140 [ 4080.881175] ? handle_bug+0x3c/0x80 [ 4080.881556] ? exc_invalid_op+0x17/0x70 [ 4080.881559] ? asm_exc_invalid_op+0x1a/0x20 [ 4080.882077] ? udmabuf_create+0x131/0x400 Because MAX_PAGE_ORDER, kmalloc can max alloc 4096 * (1 << 10), 4MB memory, each array entry is pointer(8byte), so can save 524288 pages(2GB). Further more, costly order(order 3) may not be guaranteed that it can be applied for, due to fragmentation. This patch change udmabuf array use kvmalloc_array, this can fallback alloc into vmalloc, which can guarantee allocation for any size and does not affect the performance of kmalloc allocations.

In the Linux kernel, the following vulnerability has been resolved: cachefiles: Fix NULL pointer dereference in object->file At present, the object->file has the NULL pointer dereference problem in ondemand-mode. The root cause is that the allocated fd and object->file lifetime are inconsistent, and the user-space invocation to anon_fd uses object->file. Following is the process that triggers the issue: [write fd] [umount] cachefiles_ondemand_fd_write_iter fscache_cookie_state_machine cachefiles_withdraw_cookie if (!file) return -ENOBUFS cachefiles_clean_up_object cachefiles_unmark_inode_in_use fput(object->file) object->file = NULL // file NULL pointer dereference! __cachefiles_write(..., file, ...) Fix this issue by add an additional reference count to the object->file before write/llseek, and decrement after it finished.

In the Linux kernel, the following vulnerability has been resolved: virtiofs: use pages instead of pointer for kernel direct IO When trying to insert a 10MB kernel module kept in a virtio-fs with cache disabled, the following warning was reported: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 404 at mm/page_alloc.c:4551 ...... Modules linked in: CPU: 1 PID: 404 Comm: insmod Not tainted 6.9.0-rc5+ #123 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ...... RIP: 0010:__alloc_pages+0x2bf/0x380 ...... Call Trace: <TASK> ? __warn+0x8e/0x150 ? __alloc_pages+0x2bf/0x380 __kmalloc_large_node+0x86/0x160 __kmalloc+0x33c/0x480 virtio_fs_enqueue_req+0x240/0x6d0 virtio_fs_wake_pending_and_unlock+0x7f/0x190 queue_request_and_unlock+0x55/0x60 fuse_simple_request+0x152/0x2b0 fuse_direct_io+0x5d2/0x8c0 fuse_file_read_iter+0x121/0x160 __kernel_read+0x151/0x2d0 kernel_read+0x45/0x50 kernel_read_file+0x1a9/0x2a0 init_module_from_file+0x6a/0xe0 idempotent_init_module+0x175/0x230 __x64_sys_finit_module+0x5d/0xb0 x64_sys_call+0x1c3/0x9e0 do_syscall_64+0x3d/0xc0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 ...... </TASK> ---[ end trace 0000000000000000 ]--- The warning is triggered as follows: 1) syscall finit_module() handles the module insertion and it invokes kernel_read_file() to read the content of the module first. 2) kernel_read_file() allocates a 10MB buffer by using vmalloc() and passes it to kernel_read(). kernel_read() constructs a kvec iter by using iov_iter_kvec() and passes it to fuse_file_read_iter(). 3) virtio-fs disables the cache, so fuse_file_read_iter() invokes fuse_direct_io(). As for now, the maximal read size for kvec iter is only limited by fc->max_read. For virtio-fs, max_read is UINT_MAX, so fuse_direct_io() doesn't split the 10MB buffer. It saves the address and the size of the 10MB-sized buffer in out_args[0] of a fuse request and passes the fuse request to virtio_fs_wake_pending_and_unlock(). 4) virtio_fs_wake_pending_and_unlock() uses virtio_fs_enqueue_req() to queue the request. Because virtiofs need DMA-able address, so virtio_fs_enqueue_req() uses kmalloc() to allocate a bounce buffer for all fuse args, copies these args into the bounce buffer and passed the physical address of the bounce buffer to virtiofsd. The total length of these fuse args for the passed fuse request is about 10MB, so copy_args_to_argbuf() invokes kmalloc() with a 10MB size parameter and it triggers the warning in __alloc_pages(): if (WARN_ON_ONCE_GFP(order > MAX_PAGE_ORDER, gfp)) return NULL; 5) virtio_fs_enqueue_req() will retry the memory allocation in a kworker, but it won't help, because kmalloc() will always return NULL due to the abnormal size and finit_module() will hang forever. A feasible solution is to limit the value of max_read for virtio-fs, so the length passed to kmalloc() will be limited. However it will affect the maximal read size for normal read. And for virtio-fs write initiated from kernel, it has the similar problem but now there is no way to limit fc->max_write in kernel. So instead of limiting both the values of max_read and max_write in kernel, introducing use_pages_for_kvec_io in fuse_conn and setting it as true in virtiofs. When use_pages_for_kvec_io is enabled, fuse will use pages instead of pointer to pass the KVEC_IO data. After switching to pages for KVEC_IO data, these pages will be used for DMA through virtio-fs. If these pages are backed by vmalloc(), {flush|invalidate}_kernel_vmap_range() are necessary to flush or invalidate the cache before the DMA operation. So add two new fields in fuse_args_pages to record the base address of vmalloc area and the condition indicating whether invalidation is needed. Perform the flush in fuse_get_user_pages() for write operations and the invalidation in fuse_release_user_pages() for read operations. It may seem necessary to introduce another fie ---truncated---

In the Linux kernel, the following vulnerability has been resolved: NFSD: Prevent NULL dereference in nfsd4_process_cb_update() @ses is initialized to NULL. If __nfsd4_find_backchannel() finds no available backchannel session, setup_callback_client() will try to dereference @ses and segfault.

In the Linux kernel, the following vulnerability has been resolved: bnxt_en: Fix receive ring space parameters when XDP is active The MTU setting at the time an XDP multi-buffer is attached determines whether the aggregation ring will be used and the rx_skb_func handler. This is done in bnxt_set_rx_skb_mode(). If the MTU is later changed, the aggregation ring setting may need to be changed and it may become out-of-sync with the settings initially done in bnxt_set_rx_skb_mode(). This may result in random memory corruption and crashes as the HW may DMA data larger than the allocated buffer size, such as: BUG: kernel NULL pointer dereference, address: 00000000000003c0 PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 17 PID: 0 Comm: swapper/17 Kdump: loaded Tainted: G S OE 6.1.0-226bf9805506 #1 Hardware name: Wiwynn Delta Lake PVT BZA.02601.0150/Delta Lake-Class1, BIOS F0E_3A12 08/26/2021 RIP: 0010:bnxt_rx_pkt+0xe97/0x1ae0 [bnxt_en] Code: 8b 95 70 ff ff ff 4c 8b 9d 48 ff ff ff 66 41 89 87 b4 00 00 00 e9 0b f7 ff ff 0f b7 43 0a 49 8b 95 a8 04 00 00 25 ff 0f 00 00 <0f> b7 14 42 48 c1 e2 06 49 03 95 a0 04 00 00 0f b6 42 33f RSP: 0018:ffffa19f40cc0d18 EFLAGS: 00010202 RAX: 00000000000001e0 RBX: ffff8e2c805c6100 RCX: 00000000000007ff RDX: 0000000000000000 RSI: ffff8e2c271ab990 RDI: ffff8e2c84f12380 RBP: ffffa19f40cc0e48 R08: 000000000001000d R09: 974ea2fcddfa4cbf R10: 0000000000000000 R11: ffffa19f40cc0ff8 R12: ffff8e2c94b58980 R13: ffff8e2c952d6600 R14: 0000000000000016 R15: ffff8e2c271ab990 FS: 0000000000000000(0000) GS:ffff8e3b3f840000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000003c0 CR3: 0000000e8580a004 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <IRQ> __bnxt_poll_work+0x1c2/0x3e0 [bnxt_en] To address the issue, we now call bnxt_set_rx_skb_mode() within bnxt_change_mtu() to properly set the AGG rings configuration and update rx_skb_func based on the new MTU value. Additionally, BNXT_FLAG_NO_AGG_RINGS is cleared at the beginning of bnxt_set_rx_skb_mode() to make sure it gets set or cleared based on the current MTU.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix null check for pipe_ctx->plane_state in dcn20_program_pipe This commit addresses a null pointer dereference issue in dcn20_program_pipe(). Previously, commit 8e4ed3cf1642 ("drm/amd/display: Add null check for pipe_ctx->plane_state in dcn20_program_pipe") partially fixed the null pointer dereference issue. However, in dcn20_update_dchubp_dpp(), the variable pipe_ctx is passed in, and plane_state is accessed again through pipe_ctx. Multiple if statements directly call attributes of plane_state, leading to potential null pointer dereference issues. This patch adds necessary null checks to ensure stability.

In the Linux kernel, the following vulnerability has been resolved: io_uring: check for overflows in io_pin_pages WARNING: CPU: 0 PID: 5834 at io_uring/memmap.c:144 io_pin_pages+0x149/0x180 io_uring/memmap.c:144 CPU: 0 UID: 0 PID: 5834 Comm: syz-executor825 Not tainted 6.12.0-next-20241118-syzkaller #0 Call Trace: <TASK> __io_uaddr_map+0xfb/0x2d0 io_uring/memmap.c:183 io_rings_map io_uring/io_uring.c:2611 [inline] io_allocate_scq_urings+0x1c0/0x650 io_uring/io_uring.c:3470 io_uring_create+0x5b5/0xc00 io_uring/io_uring.c:3692 io_uring_setup io_uring/io_uring.c:3781 [inline] ... </TASK> io_pin_pages()'s uaddr parameter came directly from the user and can be garbage. Don't just add size to it as it can overflow.

In the Linux kernel, the following vulnerability has been resolved: nfs/blocklayout: Don't attempt unregister for invalid block device Since commit d869da91cccb ("nfs/blocklayout: Fix premature PR key unregistration") an unmount of a pNFS SCSI layout-enabled NFS may dereference a NULL block_device in: bl_unregister_scsi+0x16/0xe0 [blocklayoutdriver] bl_free_device+0x70/0x80 [blocklayoutdriver] bl_free_deviceid_node+0x12/0x30 [blocklayoutdriver] nfs4_put_deviceid_node+0x60/0xc0 [nfsv4] nfs4_deviceid_purge_client+0x132/0x190 [nfsv4] unset_pnfs_layoutdriver+0x59/0x60 [nfsv4] nfs4_destroy_server+0x36/0x70 [nfsv4] nfs_free_server+0x23/0xe0 [nfs] deactivate_locked_super+0x30/0xb0 cleanup_mnt+0xba/0x150 task_work_run+0x59/0x90 syscall_exit_to_user_mode+0x217/0x220 do_syscall_64+0x8e/0x160 This happens because even though we were able to create the nfs4_deviceid_node, the lookup for the device was unable to attach the block device to the pnfs_block_dev. If we never found a block device to register, we can avoid this case with the PNFS_BDEV_REGISTERED flag. Move the deref behind the test for the flag.

In the Linux kernel, the following vulnerability has been resolved: net: sched: fix ordering of qlen adjustment Changes to sch->q.qlen around qdisc_tree_reduce_backlog() need to happen _before_ a call to said function because otherwise it may fail to notify parent qdiscs when the child is about to become empty.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: Align BR/EDR JUST_WORKS paring with LE This aligned BR/EDR JUST_WORKS method with LE which since 92516cd97fd4 ("Bluetooth: Always request for user confirmation for Just Works") always request user confirmation with confirm_hint set since the likes of bluetoothd have dedicated policy around JUST_WORKS method (e.g. main.conf:JustWorksRepairing). CVE: CVE-2024-8805