In the Linux kernel, the following vulnerability has been resolved: vfs: fix race between evice_inodes() and find_inode()&iput() Hi, all Recently I noticed a bug[1] in btrfs, after digged it into and I believe it'a race in vfs. Let's assume there's a inode (ie ino 261) with i_count 1 is called by iput(), and there's a concurrent thread calling generic_shutdown_super(). cpu0: cpu1: iput() // i_count is 1 ->spin_lock(inode) ->dec i_count to 0 ->iput_final() generic_shutdown_super() ->__inode_add_lru() ->evict_inodes() // cause some reason[2] ->if (atomic_read(inode->i_count)) continue; // return before // inode 261 passed the above check // list_lru_add_obj() // and then schedule out ->spin_unlock() // note here: the inode 261 // was still at sb list and hash list, // and I_FREEING|I_WILL_FREE was not been set btrfs_iget() // after some function calls ->find_inode() // found the above inode 261 ->spin_lock(inode) // check I_FREEING|I_WILL_FREE // and passed ->__iget() ->spin_unlock(inode) // schedule back ->spin_lock(inode) // check (I_NEW|I_FREEING|I_WILL_FREE) flags, // passed and set I_FREEING iput() ->spin_unlock(inode) ->spin_lock(inode) ->evict() // dec i_count to 0 ->iput_final() ->spin_unlock() ->evict() Now, we have two threads simultaneously evicting the same inode, which may trigger the BUG(inode->i_state & I_CLEAR) statement both within clear_inode() and iput(). To fix the bug, recheck the inode->i_count after holding i_lock. Because in the most scenarios, the first check is valid, and the overhead of spin_lock() can be reduced. If there is any misunderstanding, please let me know, thanks. [1]: https://lore.kernel.org/linux-btrfs/000000000000eabe1d0619c48986@google.com/ [2]: The reason might be 1. SB_ACTIVE was removed or 2. mapping_shrinkable() return false when I reproduced the bug.

In the Linux kernel, the following vulnerability has been resolved: icmp: change the order of rate limits ICMP messages are ratelimited : After the blamed commits, the two rate limiters are applied in this order: 1) host wide ratelimit (icmp_global_allow()) 2) Per destination ratelimit (inetpeer based) In order to avoid side-channels attacks, we need to apply the per destination check first. This patch makes the following change : 1) icmp_global_allow() checks if the host wide limit is reached. But credits are not yet consumed. This is deferred to 3) 2) The per destination limit is checked/updated. This might add a new node in inetpeer tree. 3) icmp_global_consume() consumes tokens if prior operations succeeded. This means that host wide ratelimit is still effective in keeping inetpeer tree small even under DDOS. As a bonus, I removed icmp_global.lock as the fast path can use a lock-free operation.

In the Linux kernel, the following vulnerability has been resolved: mm: avoid leaving partial pfn mappings around in error case As Jann points out, PFN mappings are special, because unlike normal memory mappings, there is no lifetime information associated with the mapping - it is just a raw mapping of PFNs with no reference counting of a 'struct page'. That's all very much intentional, but it does mean that it's easy to mess up the cleanup in case of errors. Yes, a failed mmap() will always eventually clean up any partial mappings, but without any explicit lifetime in the page table mapping itself, it's very easy to do the error handling in the wrong order. In particular, it's easy to mistakenly free the physical backing store before the page tables are actually cleaned up and (temporarily) have stale dangling PTE entries. To make this situation less error-prone, just make sure that any partial pfn mapping is torn down early, before any other error handling.

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mvm: pause TCM when the firmware is stopped Not doing so will make us send a host command to the transport while the firmware is not alive, which will trigger a WARNING. bad state = 0 WARNING: CPU: 2 PID: 17434 at drivers/net/wireless/intel/iwlwifi/iwl-trans.c:115 iwl_trans_send_cmd+0x1cb/0x1e0 [iwlwifi] RIP: 0010:iwl_trans_send_cmd+0x1cb/0x1e0 [iwlwifi] Call Trace: <TASK> iwl_mvm_send_cmd+0x40/0xc0 [iwlmvm] iwl_mvm_config_scan+0x198/0x260 [iwlmvm] iwl_mvm_recalc_tcm+0x730/0x11d0 [iwlmvm] iwl_mvm_tcm_work+0x1d/0x30 [iwlmvm] process_one_work+0x29e/0x640 worker_thread+0x2df/0x690 ? rescuer_thread+0x540/0x540 kthread+0x192/0x1e0 ? set_kthread_struct+0x90/0x90 ret_from_fork+0x22/0x30

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mvm: don't wait for tx queues if firmware is dead There is a WARNING in iwl_trans_wait_tx_queues_empty() (that was recently converted from just a message), that can be hit if we wait for TX queues to become empty after firmware died. Clearly, we can't expect anything from the firmware after it's declared dead. Don't call iwl_trans_wait_tx_queues_empty() in this case. While it could be a good idea to stop the flow earlier, the flush functions do some maintenance work that is not related to the firmware, so keep that part of the code running even when the firmware is not running. [edit commit message]

In the Linux kernel, the following vulnerability has been resolved: USB: usbtmc: prevent kernel-usb-infoleak The syzbot reported a kernel-usb-infoleak in usbtmc_write, we need to clear the structure before filling fields.

In the Linux kernel, the following vulnerability has been resolved: ocfs2: add bounds checking to ocfs2_xattr_find_entry() Add a paranoia check to make sure it doesn't stray beyond valid memory region containing ocfs2 xattr entries when scanning for a match. It will prevent out-of-bound access in case of crafted images.

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix state management in error path of log writing function After commit a694291a6211 ("nilfs2: separate wait function from nilfs_segctor_write") was applied, the log writing function nilfs_segctor_do_construct() was able to issue I/O requests continuously even if user data blocks were split into multiple logs across segments, but two potential flaws were introduced in its error handling. First, if nilfs_segctor_begin_construction() fails while creating the second or subsequent logs, the log writing function returns without calling nilfs_segctor_abort_construction(), so the writeback flag set on pages/folios will remain uncleared. This causes page cache operations to hang waiting for the writeback flag. For example, truncate_inode_pages_final(), which is called via nilfs_evict_inode() when an inode is evicted from memory, will hang. Second, the NILFS_I_COLLECTED flag set on normal inodes remain uncleared. As a result, if the next log write involves checkpoint creation, that's fine, but if a partial log write is performed that does not, inodes with NILFS_I_COLLECTED set are erroneously removed from the "sc_dirty_files" list, and their data and b-tree blocks may not be written to the device, corrupting the block mapping. Fix these issues by uniformly calling nilfs_segctor_abort_construction() on failure of each step in the loop in nilfs_segctor_do_construct(), having it clean up logs and segment usages according to progress, and correcting the conditions for calling nilfs_redirty_inodes() to ensure that the NILFS_I_COLLECTED flag is cleared.

In the Linux kernel, the following vulnerability has been resolved: lib/generic-radix-tree.c: Fix rare race in __genradix_ptr_alloc() If we need to increase the tree depth, allocate a new node, and then race with another thread that increased the tree depth before us, we'll still have a preallocated node that might be used later. If we then use that node for a new non-root node, it'll still have a pointer to the old root instead of being zeroed - fix this by zeroing it in the cmpxchg failure path.

In the Linux kernel, the following vulnerability has been resolved: PCI: keystone: Add workaround for Errata #i2037 (AM65x SR 1.0) Errata #i2037 in AM65x/DRA80xM Processors Silicon Revision 1.0 (SPRZ452D_July 2018_Revised December 2019 [1]) mentions when an inbound PCIe TLP spans more than two internal AXI 128-byte bursts, the bus may corrupt the packet payload and the corrupt data may cause associated applications or the processor to hang. The workaround for Errata #i2037 is to limit the maximum read request size and maximum payload size to 128 bytes. Add workaround for Errata #i2037 here. The errata and workaround is applicable only to AM65x SR 1.0 and later versions of the silicon will have this fixed. [1] -> https://www.ti.com/lit/er/sprz452i/sprz452i.pdf

In the Linux kernel, the following vulnerability has been resolved: scsi: pm80xx: Set phy->enable_completion only when we wait for it pm8001_phy_control() populates the enable_completion pointer with a stack address, sends a PHY_LINK_RESET / PHY_HARD_RESET, waits 300 ms, and returns. The problem arises when a phy control response comes late. After 300 ms the pm8001_phy_control() function returns and the passed enable_completion stack address is no longer valid. Late phy control response invokes complete() on a dangling enable_completion pointer which leads to a kernel crash.

In the Linux kernel, the following vulnerability has been resolved: i3c: mipi-i3c-hci: Error out instead on BUG_ON() in IBI DMA setup Definitely condition dma_get_cache_alignment * defined value > 256 during driver initialization is not reason to BUG_ON(). Turn that to graceful error out with -EINVAL.

In the Linux kernel, the following vulnerability has been resolved: spi: hisi-kunpeng: Add verification for the max_frequency provided by the firmware If the value of max_speed_hz is 0, it may cause a division by zero error in hisi_calc_effective_speed(). The value of max_speed_hz is provided by firmware. Firmware is generally considered as a trusted domain. However, as division by zero errors can cause system failure, for defense measure, the value of max_speed is validated here. So 0 is regarded as invalid and an error code is returned.

In the Linux kernel, the following vulnerability has been resolved: staging: iio: frequency: ad9834: Validate frequency parameter value In ad9834_write_frequency() clk_get_rate() can return 0. In such case ad9834_calc_freqreg() call will lead to division by zero. Checking 'if (fout > (clk_freq / 2))' doesn't protect in case of 'fout' is 0. ad9834_write_frequency() is called from ad9834_write(), where fout is taken from text buffer, which can contain any value. Modify parameters checking. Found by Linux Verification Center (linuxtesting.org) with SVACE.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Remove register from DCN35 DMCUB diagnostic collection [Why] These registers should not be read from driver and triggering the security violation when DMCUB work times out and diagnostics are collected blocks Z8 entry. [How] Remove the register read from DCN35.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Avoid overflow from uint32_t to uint8_t [WHAT & HOW] dmub_rb_cmd's ramping_boundary has size of uint8_t and it is assigned 0xFFFF. Fix it by changing it to uint8_t with value of 0xFF. This fixes 2 INTEGER_OVERFLOW issues reported by Coverity.

In the Linux kernel, the following vulnerability has been resolved: fsnotify: clear PARENT_WATCHED flags lazily In some setups directories can have many (usually negative) dentries. Hence __fsnotify_update_child_dentry_flags() function can take a significant amount of time. Since the bulk of this function happens under inode->i_lock this causes a significant contention on the lock when we remove the watch from the directory as the __fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask() races with __fsnotify_update_child_dentry_flags() calls from __fsnotify_parent() happening on children. This can lead upto softlockup reports reported by users. Fix the problem by calling fsnotify_update_children_dentry_flags() to set PARENT_WATCHED flags only when parent starts watching children. When parent stops watching children, clear false positive PARENT_WATCHED flags lazily in __fsnotify_parent() for each accessed child.

In the Linux kernel, the following vulnerability has been resolved: smack: tcp: ipv4, fix incorrect labeling Currently, Smack mirrors the label of incoming tcp/ipv4 connections: when a label 'foo' connects to a label 'bar' with tcp/ipv4, 'foo' always gets 'foo' in returned ipv4 packets. So, 1) returned packets are incorrectly labeled ('foo' instead of 'bar') 2) 'bar' can write to 'foo' without being authorized to write. Here is a scenario how to see this: * Take two machines, let's call them C and S, with active Smack in the default state (no settings, no rules, no labeled hosts, only builtin labels) * At S, add Smack rule 'foo bar w' (labels 'foo' and 'bar' are instantiated at S at this moment) * At S, at label 'bar', launch a program that listens for incoming tcp/ipv4 connections * From C, at label 'foo', connect to the listener at S. (label 'foo' is instantiated at C at this moment) Connection succeedes and works. * Send some data in both directions. * Collect network traffic of this connection. All packets in both directions are labeled with the CIPSO of the label 'foo'. Hence, label 'bar' writes to 'foo' without being authorized, and even without ever being known at C. If anybody cares: exactly the same happens with DCCP. This behavior 1st manifested in release 2.6.29.4 (see Fixes below) and it looks unintentional. At least, no explanation was provided. I changed returned packes label into the 'bar', to bring it into line with the Smack documentation claims.

In the Linux kernel, the following vulnerability has been resolved: crypto: stm32/cryp - call finalize with bh disabled The finalize operation in interrupt mode produce a produces a spinlock recursion warning. The reason is the fact that BH must be disabled during this process.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Correct the defined value for AMDGPU_DMUB_NOTIFICATION_MAX [Why & How] It actually exposes '6' types in enum dmub_notification_type. Not 5. Using smaller number to create array dmub_callback & dmub_thread_offload has potential to access item out of array bound. Fix it.