CVE-2021-47641

The Linux Kernel, the operating system core itself.

Security Fix(es):

In the Linux kernel, the following vulnerability has been resolved:

can: dev: can_get_echo_skb(): prevent call to kfree_skb() in hard IRQ context

If a driver calls can_get_echo_skb() during a hardware IRQ (which is often, but not always, the case), the 'WARN_ON(in_irq)' in net/core/skbuff.c#skb_release_head_state() might be triggered, under network congestion circumstances, together with the potential risk of a NULL pointer dereference.

The root cause of this issue is the call to kfree_skb() instead of dev_kfree_skb_irq() in net/core/dev.c#enqueue_to_backlog().

This patch prevents the skb to be freed within the call to netif_rx() by incrementing its reference count with skb_get(). The skb is finally freed by one of the in-irq-context safe functions: dev_consume_skb_any() or dev_kfree_skb_any(). The "any" version is used because some drivers might call can_get_echo_skb() in a normal context.

The reason for this issue to occur is that initially, in the core network stack, loopback skb were not supposed to be received in hardware IRQ context. The CAN stack is an exeption.

This bug was previously reported back in 2017 in [1] but the proposed patch never got accepted.

While [1] directly modifies net/core/dev.c, we try to propose here a smoother modification local to CAN network stack (the assumption behind is that only CAN devices are affected by this issue).

[1] http://lore.kernel.org/r/57a3ffb6-3309-3ad5-5a34-e93c3fe3614d@cetitec.com(CVE-2020-36789)

In the Linux kernel, the following vulnerability has been resolved:

video: fbdev: cirrusfb: check pixclock to avoid divide by zero

Do a sanity check on pixclock value to avoid divide by zero.

If the pixclock value is zero, the cirrusfb driver will round up pixclock to get the derived frequency as close to maxclock as possible.

Syzkaller reported a divide error in cirrusfb_check_pixclock.

divide error: 0000 [#1] SMP KASAN PTI CPU: 0 PID: 14938 Comm: cirrusfb_test Not tainted 5.15.0-rc6 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2 RIP: 0010:cirrusfb_check_var+0x6f1/0x1260

Call Trace: fb_set_var+0x398/0xf90 do_fb_ioctl+0x4b8/0x6f0 fb_ioctl+0xeb/0x130 __x64_sys_ioctl+0x19d/0x220 do_syscall_64+0x3a/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae(CVE-2021-47641)

In the Linux kernel, the following vulnerability has been resolved:

can: dev: can_restart: fix use after free bug

After calling netif_rx_ni(skb), dereferencing skb is unsafe. Especially, the can_frame cf which aliases skb memory is accessed after the netif_rx_ni() in: stats->rx_bytes += cf->len;

Reordering the lines solves the issue.(CVE-2021-47668)

In the Linux kernel, the following vulnerability has been resolved:

can: peak_usb: fix use after free bugs

After calling peak_usb_netif_rx_ni(skb), dereferencing skb is unsafe. Especially, the can_frame cf which aliases skb memory is accessed after the peak_usb_netif_rx_ni().

Reordering the lines solves the issue.(CVE-2021-47670)

In the Linux kernel, the following vulnerability has been resolved:

qede: confirm skb is allocated before using

qede_build_skb() assumes build_skb() always works and goes straight to skb_reserve(). However, build_skb() can fail under memory pressure. This results in a kernel panic because the skb to reserve is NULL.

Add a check in case build_skb() failed to allocate and return NULL.

The NULL return is handled correctly in callers to qede_build_skb().(CVE-2022-49084)

In the Linux kernel, the following vulnerability has been resolved:

net: openvswitch: fix leak of nested actions

While parsing user-provided actions, openvswitch module may dynamically allocate memory and store pointers in the internal copy of the actions. So this memory has to be freed while destroying the actions.

Currently there are only two such actions: ct() and set(). However, there are many actions that can hold nested lists…

In the Linux kernel, the following vulnerability has been resolved: video: fbdev: cirrusfb: check pixclock to avoid divide by zero Do a sanity check on pixclock value to avoid divide by zero. If the pixclock value is zero, the cirrusfb driver will round up pixclock to get the derived frequency as close to maxclock as possible. Syzkaller reported a divide error in cirrusfb_check_pixclock. divide error: 0000 [#1] SMP KASAN PTI CPU: 0 PID: 14938 Comm: cirrusfb_test Not tainted 5.15.0-rc6 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2 RIP: 0010:cirrusfb_check_var+0x6f1/0x1260 Call Trace: fb_set_var+0x398/0xf90 do_fb_ioctl+0x4b8/0x6f0 fb_ioctl+0xeb/0x130 __x64_sys_ioctl+0x19d/0x220 do_syscall_64+0x3a/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae

The SUSE Linux Enterprise 15 SP4 kernel was updated to receive various security bugfixes.

The following security bugs were fixed:

• CVE-2024-2201: Fixed information leak in x86/BHI (bsc#1217339).
• CVE-2024-41092: drm/i915/gt: Fix potential UAF by revoke of fence registers (bsc#1228483).
• CVE-2024-42098: crypto: ecdh - explicitly zeroize private_key (bsc#1228779).
• CVE-2024-42229: crypto: aead,cipher - zeroize key buffer after use (bsc#1228708).
• CVE-2024-57996: net_sched: sch_sfq: do not allow 1 packet limit (bsc#1239076).
• CVE-2024-58014: wifi: brcmsmac: add gain range check to wlc_phy_iqcal_gainparams_nphy() (bsc#1239109).
• CVE-2025-21718: net: rose: fix timer races against user threads (bsc#1239073).
• CVE-2025-21780: drm/amdgpu: avoid buffer overflow attach in smu_sys_set_pp_table() (bsc#1239115).

The following non-security bugs were fixed:

• initcall_blacklist: Does not allow kernel_lockdown be blacklisted (bsc#1237521).
• x86/bhi: Avoid warning in #DB handler due to BHI mitigation (git-fixes).
• x86/bugs: Cache the value of MSR_IA32_ARCH_CAPABILITIES (git-fixes).
• x86/bugs: Fix BHI documentation (git-fixes).
• x86/bugs: Fix BHI handling of RRSBA (git-fixes).
• x86/bugs: Fix BHI retpoline check (git-fixes).
• x86/bugs: Fix return type of spectre_bhi_state() (git-fixes).
• x86/bugs: Remove CONFIG_BHI_MITIGATION_AUTO and spectre_bhi=auto (git-fixes).

The SUSE Linux Enterprise 15 SP5 RT kernel was updated to receive various security bugfixes.

The following security bugs were fixed:

• CVE-2022-49053: scsi: target: tcmu: Fix possible page UAF (bsc#1237918).
• CVE-2022-49465: blk-throttle: Set BIO_THROTTLED when bio has been throttled (bsc#1238919).
• CVE-2022-49739: gfs2: Always check inode size of inline inodes (bsc#1240207).
• CVE-2023-52935: mm/khugepaged: fix ->anon_vma race (bsc#1240276).
• CVE-2024-53124: net: fix data-races around sk->sk_forward_alloc (bsc#1234074).
• CVE-2024-53176: smb: During unmount, ensure all cached dir instances drop their dentry (bsc#1234894).
• CVE-2024-53178: smb: Do not leak cfid when reconnect races with open_cached_dir (bsc#1234895).
• CVE-2024-56651: can: hi311x: hi3110_can_ist(): fix potential use-after-free (bsc#1235528).
• CVE-2024-57996: net_sched: sch_sfq: do not allow 1 packet limit (bsc#1239076).
• CVE-2024-58013: Bluetooth: MGMT: Fix slab-use-after-free Read in mgmt_remove_adv_monitor_sync (bsc#1239095).
• CVE-2024-58014: wifi: brcmsmac: add gain range check to wlc_phy_iqcal_gainparams_nphy() (bsc#1239109).
• CVE-2025-21693: mm: zswap: properly synchronize freeing resources during CPU hotunplug (bsc#1237029).
• CVE-2025-21718: net: rose: fix timer races against user threads (bsc#1239073).
• CVE-2025-21772: partitions: mac: fix handling of bogus partition table (bsc#1238911).
• CVE-2025-21780: drm/amdgpu: avoid buffer overflow attach in smu_sys_set_pp_table() (bsc#1239115).

The following non-security bugs were fixed:

• ACPI: processor: idle: Return an error if both P_LVL{2,3} idle states are invalid (bsc#1237530).
• RDMA/mana_ib: Prefer struct_size over open coded arithmetic (bsc#1239016).
• RDMA/mana_ib: Use v2 version of cfg_rx_steer_req to enable RX coalescing (bsc#1239016).
• Revert 'gfs2: Fix inode height consistency check (git-fixes).
• btrfs: defrag: do not use merged extent map for their generation check (bsc#1239968).
• btrfs: fix defrag not merging contiguous extents due to merged extent maps (bsc#1239968).
• btrfs: fix extent map merging not happening for adjacent extents (bsc#1239968).
• btrfs: send: allow cloning non-aligned extent if it ends at i_size (bsc#1239969).
• btrfs: send: fix invalid clone operation for file that got its size decreased (bsc#1239969).
• cifs: Add a laundromat thread for cached directories (git-fixes).
• cifs: fix potential null pointer use in destroy_workqueue in init_cifs error path (git-fixes).
• gfs2: Fix inode height consistency check (git-fixes).
• mm/mmu_notifier.c: fix race in mmu_interval_notifier_remove() (bsc#1239126).
• mm: zswap: move allocations during CPU init outside the lock (git-fixes).
• net: mana: Add flex array to struct mana_cfg_rx_steer_req_v2 (bsc#1239016).
• net: mana: Allow variable size indirection table (bsc#1239016).
• net: mana: Avoid open coded arithmetic (bsc#1239016).
• net: mana: Support holes in device list reply msg (bsc#1240133).
• sched/membarrier: Fix redundant load of membarrier_state (bsc#1232743).
• smb3: allow controlling length of time directory entries are cached with dir leases (git-fixes).
• smb3: do not start laundromat thread when dir leases disabled (git-fixes).
• smb3: retrying on failed server close (git-fixes).
• smb: client: destroy cfid_put_wq on module exit (git-fixes).
• smb: client: disable directory caching when dir_cache_timeout is zero (git-fixes).
• smb: client: do not start laundromat thread on nohandlecache (git-fixes).
• smb: client: make laundromat a delayed worker (git-fixes).
• smb: client: properly close cfids on umount (bsc#1231432, bsc#1232299, bsc#1235599, bsc#1234896).
• tpm: send_data: Wait longer for the TPM to become ready (bsc#1235870).

The SUSE Linux Enterprise 15 SP4 RT kernel was updated to receive various security bugfixes.

The following security bugs were fixed:

• CVE-2022-49053: scsi: target: tcmu: Fix possible page UAF (bsc#1237918).
• CVE-2022-49465: blk-throttle: Set BIO_THROTTLED when bio has been throttled (bsc#1238919).
• CVE-2022-49739: gfs2: Always check inode size of inline inodes (bsc#1240207).
• CVE-2023-52935: mm/khugepaged: fix ->anon_vma race (bsc#1240276).
• CVE-2024-2201: Fixed information leak in x86/BHI (bsc#1217339).
• CVE-2024-41092: drm/i915/gt: Fix potential UAF by revoke of fence registers (bsc#1228483).
• CVE-2024-42098: crypto: ecdh - explicitly zeroize private_key (bsc#1228779).
• CVE-2024-42229: crypto: aead,cipher - zeroize key buffer after use (bsc#1228708).
• CVE-2024-53064: idpf: fix idpf_vc_core_init error path (bsc#1233558 bsc#1234464).
• CVE-2024-56651: can: hi311x: hi3110_can_ist(): fix potential use-after-free (bsc#1235528).
• CVE-2024-57996: net_sched: sch_sfq: do not allow 1 packet limit (bsc#1239076).
• CVE-2024-58014: wifi: brcmsmac: add gain range check to wlc_phy_iqcal_gainparams_nphy() (bsc#1239109).
• CVE-2024-58083: KVM: Explicitly verify target vCPU is online in kvm_get_vcpu() (bsc#1239036).
• CVE-2025-21693: mm: zswap: properly synchronize freeing resources during CPU hotunplug (bsc#1237029).
• CVE-2025-21714: RDMA/mlx5: Fix implicit ODP use after free (bsc#1237890).
• CVE-2025-21718: net: rose: fix timer races against user threads (bsc#1239073).
• CVE-2025-21732: RDMA/mlx5: Fix a race for an ODP MR which leads to CQE with error (bsc#1237877).
• CVE-2025-21753: btrfs: fix use-after-free when attempting to join an aborted transaction (bsc#1237875).
• CVE-2025-21772: partitions: mac: fix handling of bogus partition table (bsc#1238911).
• CVE-2025-21780: drm/amdgpu: avoid buffer overflow attach in smu_sys_set_pp_table() (bsc#1239115).
• CVE-2025-21839: kABI: Fix kABI after backport od CVE-2025-21839 (bsc#1239061).

The following non-security bugs were fixed:

• ACPI: processor: idle: Return an error if both P_LVL{2,3} idle states are invalid (bsc#1237530).
• RDMA/mana_ib: Prefer struct_size over open coded arithmetic (bsc#1239016).
• RDMA/mana_ib: Use v2 version of cfg_rx_steer_req to enable RX coalescing (bsc#1239016).
• RDMA/mlx5: Fix implicit ODP hang on parent deregistration (git-fixes)
• btrfs: defrag: do not use merged extent map for their generation check (bsc#1239968).
• btrfs: fix defrag not merging contiguous extents due to merged extent maps (bsc#1239968).
• btrfs: fix extent map merging not happening for adjacent extents (bsc#1239968).
• btrfs: send: allow cloning non-aligned extent if it ends at i_size (bsc#1239969).
• btrfs: send: fix invalid clone operation for file that got its size decreased (bsc#1239969).
• gfs2: Fix inode height consistency check (git-fixes).
• mm/mmu_notifier.c: fix race in mmu_interval_notifier_remove() (bsc#1239126).
• mm: zswap: move allocations during CPU init outside the lock (git-fixes).
• net: mana: Add flex array to struct mana_cfg_rx_steer_req_v2 (bsc#1239016).
• net: mana: Allow variable size indirection table (bsc#1239016).
• net: mana: Avoid open coded arithmetic (bsc#1239016).
• net: mana: Fix error handling in mana_create_txq/rxq's NAPI cleanup (bsc#1240195).
• net: mana: Support holes in device list reply msg (bsc#1240133).
• x86/bhi: Avoid warning in #DB handler due to BHI mitigation (git-fixes).
• x86/bugs: Cache the value of MSR_IA32_ARCH_CAPABILITIES (git-fixes).
• x86/bugs: Fix BHI documentation (git-fixes).
• x86/bugs: Fix BHI handling of RRSBA (git-fixes).
• x86/bugs: Fix BHI retpoline check (git-fixes).
• x86/bugs: Fix return type of spectre_bhi_state() (git-fixes).
• x86/bugs: Remove CONFIG_BHI_MITIGATION_AUTO and spectre_bhi=auto (git-fixes).

The SUSE Linux Enterprise 15 SP3 RT kernel was updated to receive various security bugfixes.

The following security bugs were fixed:

• CVE-2021-47248: udp: fix race between close() and udp_abort() (bsc#1224867).
• CVE-2022-49051: net: usb: aqc111: Fix out-of-bounds accesses in RX fixup (bsc#1237903).
• CVE-2022-49053: scsi: target: tcmu: Fix possible page UAF (bsc#1237918).
• CVE-2022-49275: can: m_can: m_can_tx_handler(): fix use after free of skb (bsc#1238719).
• CVE-2022-49413: bfq: Update cgroup information before merging bio (bsc#1238710).
• CVE-2022-49465: blk-throttle: Set BIO_THROTTLED when bio has been throttled (bsc#1238919).
• CVE-2022-49545: ALSA: usb-audio: Cancel pending work at closing a MIDI substream (bsc#1238729).
• CVE-2022-49563: crypto: qat - add param check for RSA (bsc#1238787).
• CVE-2022-49564: crypto: qat - add param check for DH (bsc#1238789).
• CVE-2022-49739: gfs2: Always check inode size of inline inodes (bsc#1240207).
• CVE-2023-52935: mm/khugepaged: fix ->anon_vma race (bsc#1240276).
• CVE-2024-56642: tipc: Fix use-after-free of kernel socket in cleanup_bearer() (bsc#1235433).
• CVE-2024-56651: can: hi311x: hi3110_can_ist(): fix potential use-after-free (bsc#1235528).
• CVE-2024-57996: net_sched: sch_sfq: do not allow 1 packet limit (bsc#1239076).
• CVE-2024-58014: wifi: brcmsmac: add gain range check to wlc_phy_iqcal_gainparams_nphy() (bsc#1239109).
• CVE-2025-21772: partitions: mac: fix handling of bogus partition table (bsc#1238911).
• CVE-2025-21780: drm/amdgpu: avoid buffer overflow attach in smu_sys_set_pp_table() (bsc#1239115).

The following non-security bugs were fixed:

• ACPI: processor: idle: Return an error if both P_LVL{2,3} idle states are invalid (bsc#1237530).
• btrfs: send: allow cloning non-aligned extent if it ends at i_size (bsc#1239969).
• btrfs: send: fix invalid clone operation for file that got its size decreased (bsc#1239969).
• btrfs: send: use btrfs_file_extent_end() in send_write_or_clone() (bsc#1239969).

The SUSE Linux Enterprise 15 SP5 kernel was updated to receive various security bugfixes.

The following security bugs were fixed:

• CVE-2022-49053: scsi: target: tcmu: Fix possible page UAF (bsc#1237918).
• CVE-2022-49465: blk-throttle: Set BIO_THROTTLED when bio has been throttled (bsc#1238919).
• CVE-2022-49739: gfs2: Always check inode size of inline inodes (bsc#1240207).
• CVE-2023-52935: mm/khugepaged: fix ->anon_vma race (bsc#1240276).
• CVE-2024-53124: net: fix data-races around sk->sk_forward_alloc (bsc#1234074).
• CVE-2024-53176: smb: During unmount, ensure all cached dir instances drop their dentry (bsc#1234894).
• CVE-2024-53178: smb: Do not leak cfid when reconnect races with open_cached_dir (bsc#1234895).
• CVE-2024-56651: can: hi311x: hi3110_can_ist(): fix potential use-after-free (bsc#1235528).
• CVE-2024-57996: net_sched: sch_sfq: do not allow 1 packet limit (bsc#1239076).
• CVE-2024-58013: Bluetooth: MGMT: Fix slab-use-after-free Read in mgmt_remove_adv_monitor_sync (bsc#1239095).
• CVE-2024-58014: wifi: brcmsmac: add gain range check to wlc_phy_iqcal_gainparams_nphy() (bsc#1239109).
• CVE-2025-21693: mm: zswap: properly synchronize freeing resources during CPU hotunplug (bsc#1237029).
• CVE-2025-21718: net: rose: fix timer races against user threads (bsc#1239073).
• CVE-2025-21772: partitions: mac: fix handling of bogus partition table (bsc#1238911).
• CVE-2025-21780: drm/amdgpu: avoid buffer overflow attach in smu_sys_set_pp_table() (bsc#1239115).

The following non-security bugs were fixed:

• ACPI: processor: idle: Return an error if both P_LVL{2,3} idle states are invalid (bsc#1237530).
• btrfs: defrag: do not use merged extent map for their generation check (bsc#1239968).
• btrfs: fix defrag not merging contiguous extents due to merged extent maps (bsc#1239968).
• btrfs: fix extent map merging not happening for adjacent extents (bsc#1239968).
• btrfs: send: allow cloning non-aligned extent if it ends at i_size (bsc#1239969).
• btrfs: send: fix invalid clone operation for file that got its size decreased (bsc#1239969).
• cifs: Add a laundromat thread for cached directories (git-fixes).
• cifs: fix potential null pointer use in destroy_workqueue in init_cifs error path (git-fixes).
• gfs2: Fix inode height consistency check (git-fixes).
• mm: zswap: move allocations during CPU init outside the lock (git-fixes).
• mm/mmu_notifier.c: fix race in mmu_interval_notifier_remove() (bsc#1239126).
• net: mana: Add flex array to struct mana_cfg_rx_steer_req_v2 (bsc#1239016).
• net: mana: Allow variable size indirection table (bsc#1239016).
• net: mana: Avoid open coded arithmetic (bsc#1239016).
• net: mana: Support holes in device list reply msg (bsc#1240133).
• RDMA/mana_ib: Prefer struct_size over open coded arithmetic (bsc#1239016).
• RDMA/mana_ib: Use v2 version of cfg_rx_steer_req to enable RX coalescing (bsc#1239016).
• sched/membarrier: Fix redundant load of membarrier_state (bsc#1232743).
• smb: client: destroy cfid_put_wq on module exit (git-fixes).
• smb: client: disable directory caching when dir_cache_timeout is zero (git-fixes).
• smb: client: do not start laundromat thread on nohandlecache (git-fixes).
• smb: client: make laundromat a delayed worker (git-fixes).
• smb: client: properly close cfids on umount (bsc#1231432, bsc#1232299, bsc#1235599, bsc#1234896).
• smb3: allow controlling length of time directory entries are cached with dir leases (git-fixes).
• smb3: do not start laundromat thread when dir leases disabled (git-fixes).
• smb3: retrying on failed server close (git-fixes).
• tpm: send_data: Wait longer for the TPM to become ready (bsc#1235870).

The SUSE Linux Enterprise 15 SP3 kernel was updated to receive various security bugfixes.

The following security bugs were fixed:

• CVE-2021-47248: udp: fix race between close() and udp_abort() (bsc#1224867).
• CVE-2022-49051: net: usb: aqc111: Fix out-of-bounds accesses in RX fixup (bsc#1237903).
• CVE-2022-49053: scsi: target: tcmu: Fix possible page UAF (bsc#1237918).
• CVE-2022-49275: can: m_can: m_can_tx_handler(): fix use after free of skb (bsc#1238719).
• CVE-2022-49413: bfq: Update cgroup information before merging bio (bsc#1238710).
• CVE-2022-49465: blk-throttle: Set BIO_THROTTLED when bio has been throttled (bsc#1238919).
• CVE-2022-49545: ALSA: usb-audio: Cancel pending work at closing a MIDI substream (bsc#1238729).
• CVE-2022-49563: crypto: qat - add param check for RSA (bsc#1238787).
• CVE-2022-49564: crypto: qat - add param check for DH (bsc#1238789).
• CVE-2022-49739: gfs2: Always check inode size of inline inodes (bsc#1240207).
• CVE-2023-52935: mm/khugepaged: fix ->anon_vma race (bsc#1240276).
• CVE-2024-56642: tipc: Fix use-after-free of kernel socket in cleanup_bearer() (bsc#1235433).
• CVE-2024-56651: can: hi311x: hi3110_can_ist(): fix potential use-after-free (bsc#1235528).
• CVE-2024-57996: net_sched: sch_sfq: do not allow 1 packet limit (bsc#1239076).
• CVE-2024-58014: wifi: brcmsmac: add gain range check to wlc_phy_iqcal_gainparams_nphy() (bsc#1239109).
• CVE-2025-21772: partitions: mac: fix handling of bogus partition table (bsc#1238911).
• CVE-2025-21780: drm/amdgpu: avoid buffer overflow attach in smu_sys_set_pp_table() (bsc#1239115).

The following non-security bugs were fixed:

• ACPI: processor: idle: Return an error if both P_LVL{2,3} idle states are invalid (bsc#1237530).
• btrfs: send: allow cloning non-aligned extent if it ends at i_size (bsc#1239969).
• btrfs: send: fix invalid clone operation for file that got its size decreased (bsc#1239969).
• btrfs: send: use btrfs_file_extent_end() in send_write_or_clone() (bsc#1239969).