Linux

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: Prevent NULL deref when RX memory exhausted The CPU receives frames from the MAC through conventional DMA: the CPU allocates buffers for the MAC, then the MAC fills them and returns ownership to the CPU. For each hardware RX queue, the CPU and MAC coordinate through a shared ring array of DMA descriptors: one descriptor per DMA buffer. Each descriptor includes the buffer's physical address and a status flag ("OWN") indicating which side owns the buffer: OWN=0 for CPU, OWN=1 for MAC. The CPU is only allowed to set the flag and the MAC is only allowed to clear it, and both must move through the ring in sequence: thus the ring is used for both "submissions" and "completions." In the stmmac driver, stmmac_rx() bookmarks its position in the ring with the `cur_rx` index. The main receive loop in that function checks for rx_descs[cur_rx].own=0, gives the corresponding buffer to the network stack (NULLing the pointer), and increments `cur_rx` modulo the ring size. After the loop exits, stmmac_rx_refill(), which bookmarks its position with `dirty_rx`, allocates fresh buffers and rearms the descriptors (setting OWN=1). If it fails any allocation, it simply stops early (leaving OWN=0) and will retry where it left off when next called. This means descriptors have a three-stage lifecycle (terms my own): - `empty` (OWN=1, buffer valid) - `full` (OWN=0, buffer valid and populated) - `dirty` (OWN=0, buffer NULL) But because stmmac_rx() only checks OWN, it confuses `full`/`dirty`. In the past (see 'Fixes:'), there was a bug where the loop could cycle `cur_rx` all the way back to the first descriptor it dirtied, resulting in a NULL dereference when mistaken for `full`. The aforementioned commit resolved that *specific* failure by capping the loop's iteration limit at `dma_rx_size - 1`, but this is only a partial fix: if the previous stmmac_rx_refill() didn't complete, then there are leftover `dirty` descriptors that the loop might encounter without needing to cycle fully around. The current code therefore panics (see 'Closes:') when stmmac_rx_refill() is memory-starved long enough for `cur_rx` to catch up to `dirty_rx`. Fix this by explicitly checking, before advancing `cur_rx`, if the next entry is dirty; exit the loop if so. This prevents processing of the final, used descriptor until stmmac_rx_refill() succeeds, but fully prevents the `cur_rx == dirty_rx` ambiguity as the previous bugfix intended: so remove the clamp as well. Since stmmac_rx_zc() is a copy-paste-and-tweak of stmmac_rx() and the code structure is identical, any fix to stmmac_rx() will also need a corresponding fix for stmmac_rx_zc(). Therefore, apply the same check there. In stmmac_rx() (not stmmac_rx_zc()), a related bug remains: after the MAC sets OWN=0 on the final descriptor, it will be unable to send any further DMA-complete IRQs until it's given more `empty` descriptors. Currently, the driver simply *hopes* that the next stmmac_rx_refill() succeeds, risking an indefinite stall of the receive process if not. But this is not a regression, so it can be addressed in a future change.Show less

In the Linux kernel, the following vulnerability has been resolved: usb: ulpi: fix memory leak on ulpi_register() error paths Commit 01af542392b5 ("usb: ulpi: fix double free in ulpi_register_interface() error path") removed kfree(ulpi) from ulpi_register_interface() to fix a double-free when device_register() fails. But when ulpi_of_register() or ulpi_read_id() fail before device_register() is called, the ulpi allocation is leaked. Add kfree(ulpi) on both error paths to properly clean up the allocation.Show less

In the Linux kernel, the following vulnerability has been resolved: ipmi:si: Return state to normal if message allocation fails There were places where nothing would get started if a message allocation failed, so the driver needs to return to normal state.Show less

In the Linux kernel, the following vulnerability has been resolved: dm-thin: fix metadata refcount underflow There's a bug in dm-thin in the function rebalance_children. If the internal btree node has one entry, the code tries to copy all btree entries from the node's child to the node itself and then decrement the child's reference count. If the child node is shared (it has reference count > 1), we won't free it, so there would be two pointers to each of the grandchildren nodes. But the reference counts of the grandchildren is not increased, thus the reference count doesn't match the number of pointers that point to the grandchildren. This results in "device mapper: space map common: unable to decrement block" errors. Fix this bug by incrementing reference counts on the grandchildren if the btree node is shared.Show less

In the Linux kernel, the following vulnerability has been resolved: eventfs: Hold eventfs_mutex and SRCU when remount walks events Commit 340f0c7067a9 ("eventfs: Update all the eventfs_inodes from the events descriptor") had eventfs_set_attrs() recurse through ei->children on remount. The walk only holds the rcu_read_lock() taken by tracefs_apply_options() over tracefs_inodes, which is wrong: - list_for_each_entry over ei->children races with the list_del_rcu() in eventfs_remove_rec() -- LIST_POISON1 deref, same shape as d2603279c7d6. - eventfs_inodes are freed via call_srcu(&eventfs_srcu, ...). rcu_read_lock() does not extend an SRCU grace period, so ti->private can be reclaimed under the walk. - The writes to ei->attr race with eventfs_set_attr(), which holds eventfs_mutex. Reproducer: while :; do mount -o remount,uid=$((RANDOM%1000)) /sys/kernel/tracing; done & while :; do echo "p:kp submit_bio" > /sys/kernel/tracing/kprobe_events echo > /sys/kernel/tracing/kprobe_events done Wrap the events portion of tracefs_apply_options() in eventfs_remount_lock()/_unlock() that take eventfs_mutex and srcu_read_lock(&eventfs_srcu). eventfs_set_attrs() doesn't sleep so the nested rcu_read_lock() is fine; lockdep_assert_held() pins the contract. Comment in tracefs_drop_inode() said "RCU cycle" -- it is SRCU.Show less

In the Linux kernel, the following vulnerability has been resolved: scsi: mpt3sas: Limit NVMe request size to 2 MiB The HBA firmware reports NVMe MDTS values based on the underlying drive capability. However, because the driver allocates a fixed 4K buffer for the PRP list, accommodating at most 512 entries, the driver supports a maximum I/O transfer size of 2 MiB. Limit max_hw_sectors to the smaller of the reported MDTS and the 2 MiB driver limit to prevent issuing oversized I/O that may lead to a kernel oops.Show less

In the Linux kernel, the following vulnerability has been resolved: selinux: use sk blob accessor in socket permission helpers SELinux socket state lives in the composite LSM socket blob. sock_has_perm() and nlmsg_sock_has_extended_perms() currently dereference sk->sk_security directly, which assumes the SELinux socket blob is at offset zero. In stacked configurations that assumption does not hold. If another LSM allocates socket blob storage before SELinux, these helpers may read the wrong blob and feed invalid SID and class values into AVC checks. Use selinux_sock() instead of accessing sk->sk_security directly.Show less

In the Linux kernel, the following vulnerability has been resolved: can: ucan: fix devres lifetime USB drivers bind to USB interfaces and any device managed resources should have their lifetime tied to the interface rather than parent USB device. This avoids issues like memory leaks when drivers are unbound without their devices being physically disconnected (e.g. on probe deferral or configuration changes). Fix the control message buffer lifetime so that it is released on driver unbind.Show less

In the Linux kernel, the following vulnerability has been resolved: net: strparser: fix skb_head leak in strp_abort_strp() When the stream parser is aborted, for example after a message assembly timeout, it can still hold a reference to a partially assembled message in strp->skb_head. That skb is not released in strp_abort_strp(), which leaks the partially assembled message and can be triggered repeatedly to exhaust memory. Fix this by freeing strp->skb_head and resetting the parser state in the abort path. Leave strp_stop() unchanged so final cleanup still happens in strp_done() after the work and timer have been synchronized.Show less

In the Linux kernel, the following vulnerability has been resolved: netfilter: reject zero shift in nft_bitwise Reject zero shift operands for nft_bitwise left and right shift expressions during initialization. The carry propagation logic computes the carry from the adjacent 32-bit word using BITS_PER_TYPE(u32) - shift. A zero shift operand turns this into a 32-bit shift, which is undefined behaviour. Reject zero shift operands in the control plane, alongside the existing check for values greater than or equal to 32, so malformed rules never reach the packet path.Show less

In the Linux kernel, the following vulnerability has been resolved: fs: afs: revert mmap_prepare() change Partially reverts commit 9d5403b1036c ("fs: convert most other generic_file_*mmap() users to .mmap_prepare()"). This is because the .mmap invocation establishes a refcount, but .mmap_prepare is called at a point where a merge or an allocation failure might happen after the call, which would leak the refcount increment. Functionality is being added to permit the use of .mmap_prepare in this case, but in the interim, we need to fix this.Show less

In the Linux kernel, the following vulnerability has been resolved: net: ipv6: fix NOREF dst use in seg6 and rpl lwtunnels seg6_input_core() and rpl_input() call ip6_route_input() which sets a NOREF dst on the skb, then pass it to dst_cache_set_ip6() invoking dst_hold() unconditionally. On PREEMPT_RT, ksoftirqd is preemptible and a higher-priority task can release the underlying pcpu_rt between the lookup and the caching through a concurrent FIB lookup on a shared nexthop. Simplified race sequence: ksoftirqd/X higher-prio task (same CPU X) ----------- -------------------------------- seg6_input_core(,skb)/rpl_input(skb) dst_cache_get() -> miss ip6_route_input(skb) -> ip6_pol_route(,skb,flags) [RT6_LOOKUP_F_DST_NOREF in flags] -> FIB lookup resolves fib6_nh [nhid=N route] -> rt6_make_pcpu_route() [creates pcpu_rt, refcount=1] pcpu_rt->sernum = fib6_sernum [fib6_sernum=W] -> cmpxchg(fib6_nh.rt6i_pcpu, NULL, pcpu_rt) [slot was empty, store succeeds] -> skb_dst_set_noref(skb, dst) [dst is pcpu_rt, refcount still 1] rt_genid_bump_ipv6() -> bumps fib6_sernum [fib6_sernum from W to Z] ip6_route_output() -> ip6_pol_route() -> FIB lookup resolves fib6_nh [nhid=N] -> rt6_get_pcpu_route() pcpu_rt->sernum != fib6_sernum [W <> Z, stale] -> prev = xchg(rt6i_pcpu, NULL) -> dst_release(prev) [prev is pcpu_rt, refcount 1->0, dead] dst = skb_dst(skb) [dst is the dead pcpu_rt] dst_cache_set_ip6(dst) -> dst_hold() on dead dst -> WARN / use-after-free For the race to occur, ksoftirqd must be preemptible (PREEMPT_RT without PREEMPT_RT_NEEDS_BH_LOCK) and a concurrent task must be able to release the pcpu_rt. Shared nexthop objects provide such a path, as two routes pointing to the same nhid share the same fib6_nh and its rt6i_pcpu entry. Fix seg6_input_core() and rpl_input() by calling skb_dst_force() after ip6_route_input() to force the NOREF dst into a refcounted one before caching. The output path is not affected as ip6_route_output() already returns a refcounted dst.Show less

In the Linux kernel, the following vulnerability has been resolved: net: caif: clear client service pointer on teardown `caif_connect()` can tear down an existing client after remote shutdown by calling `caif_disconnect_client()` followed by `caif_free_client()`. `caif_free_client()` releases the service layer referenced by `adap_layer->dn`, but leaves that pointer stale. When the socket is later destroyed, `caif_sock_destructor()` calls `caif_free_client()` again and dereferences the freed service pointer. Clear the client/service links before releasing the service object so repeated teardown becomes harmless.Show less

In the Linux kernel, the following vulnerability has been resolved: Input: edt-ft5x06 - fix use-after-free in debugfs teardown The commit 68743c500c6e ("Input: edt-ft5x06 - use per-client debugfs directory") removed the manual debugfs teardown, relying on the I2C core to handle it. However, this creates a window where debugfs files are still accessible after edt_ft5x06_ts_teardown_debugfs() frees tsdata->raw_buffer. To prevent a use-after-free, protect the freeing of raw_buffer with the device mutex and set raw_buffer to NULL. The debugfs read function already checks if raw_buffer is NULL under the same mutex, so this safely avoids the use-after-free.Show less

In the Linux kernel, the following vulnerability has been resolved: tpm2-sessions: Fix missing tpm_buf_destroy() in tpm2_read_public() tpm2_read_public() calls tpm_buf_init() but fails to call tpm_buf_destroy() on two exit paths, leaking a page allocation: 1. When name_size() returns an error (unrecognized hash algorithm), the function returns directly without destroying the buffer. 2. On the success path, the buffer is never destroyed before returning. All other error paths in the function correctly call tpm_buf_destroy() before returning. Fix both by adding the missing tpm_buf_destroy() calls.Show less

In the Linux kernel, the following vulnerability has been resolved: md/md-llbitmap: raise barrier before state machine transition Move the barrier raise operation before calling llbitmap_state_machine() in both llbitmap_start_write() and llbitmap_start_discard(). This ensures the barrier is in place before any state transitions occur, preventing potential race conditions where the state machine could complete before the barrier is properly raised.Show less

In the Linux kernel, the following vulnerability has been resolved: ext4: fix bounds check in check_xattrs() to prevent out-of-bounds access The bounds check for the next xattr entry in check_xattrs() uses (void *)next >= end, which allows next to point within sizeof(u32) bytes of end. On the next loop iteration, IS_LAST_ENTRY() reads 4 bytes via *(__u32 *)(entry), which can overrun the valid xattr region. For example, if next lands at end - 1, the check passes since next < end, but IS_LAST_ENTRY() reads 4 bytes starting at end - 1, accessing 3 bytes beyond the valid region. Fix this by changing the check to (void *)next + sizeof(u32) > end, ensuring there is always enough space for the IS_LAST_ENTRY() read on the subsequent iteration.Show less

In the Linux kernel, the following vulnerability has been resolved: mm/vmalloc: take vmap_purge_lock in shrinker decay_va_pool_node() can be invoked concurrently from two paths: __purge_vmap_area_lazy() when pools are being purged, and the shrinker via vmap_node_shrink_scan(). However, decay_va_pool_node() is not safe to run concurrently, and the shrinker path currently lacks serialization, leading to races and possible leaks. Protect decay_va_pool_node() by taking vmap_purge_lock in the shrinker path to ensure serialization with purge users.Show less

In the Linux kernel, the following vulnerability has been resolved: wifi: rtw88: check for PCI upstream bridge existence pci_upstream_bridge() returns NULL if the device is on a root bus. If 8821CE is installed in the system with such a PCI topology, the probing routine will crash. This has probably been unnoticed as 8821CE is mostly supplied in laptops where there is a PCI-to-PCI bridge located upstream from the device. However the card might be installed on a system with different configuration. Check if the bridge does exist for the specific workaround to be applied. Found by Linux Verification Center (linuxtesting.org) with Svace static analysis tool.Show less

In the Linux kernel, the following vulnerability has been resolved: media: rc: igorplugusb: heed coherency rules In a control request, the USB request structure can be subject to DMA on some HCs. Hence it must obey the rules for DMA coherency. Allocate it separately.Show less