In the Linux kernel, the following vulnerability has been resolved: comedi: ni_usb6501: fix NULL-deref in command paths The driver uses endpoint-sized USB transfer buffers but had no sanity checks on the sizes. This can lead to zero-size-pointer dereferences or overflowed transfer buffers in ni6501_port_command() and ni6501_counter_command() if a (malicious) device has smaller max-packet sizes than expected (or when doing descriptor fuzz testing). Add the missing sanity checks to probe().

An issue was discovered in the Linux kernel before 5.2.3. There is a NULL pointer dereference caused by a malicious USB device in the drivers/media/usb/zr364xx/zr364xx.c driver.

An issue was discovered in the Linux kernel before 5.1.8. There is a NULL pointer dereference caused by a malicious USB device in the drivers/media/usb/siano/smsusb.c driver.

An issue was discovered in the Linux kernel before 5.0.14. There is a NULL pointer dereference caused by a malicious USB device in the drivers/usb/misc/yurex.c driver.

An issue was discovered in the Linux kernel before 5.1.8. There is a NULL pointer dereference caused by a malicious USB device in the sound/usb/line6/driver.c driver.

An issue was discovered in the Linux kernel before 5.1.8. There is a NULL pointer dereference caused by a malicious USB device in the drivers/usb/misc/sisusbvga/sisusb.c driver.

The treo_attach function in drivers/usb/serial/visor.c in the Linux kernel before 4.5 allows physically proximate attackers to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact by inserting a USB device that lacks a (1) bulk-in or (2) interrupt-in endpoint.

The aiptek_probe function in drivers/input/tablet/aiptek.c in the Linux kernel before 4.4 allows physically proximate attackers to cause a denial of service (NULL pointer dereference and system crash) via a crafted USB device that lacks endpoints.

An issue was discovered in drivers/usb/gadget/composite.c in the Linux kernel before 5.16.10. The USB Gadget subsystem lacks certain validation of interface OS descriptor requests (ones with a large array index and ones associated with NULL function pointer retrieval). Memory corruption might occur.

An issue was discovered in the Linux kernel before 5.2.8. There is a NULL pointer dereference caused by a malicious USB device in the sound/usb/helper.c (motu_microbookii) driver.

An issue was discovered in the Linux kernel before 5.1.17. There is a NULL pointer dereference caused by a malicious USB device in the sound/usb/line6/pcm.c driver.

drivers/net/wireless/ath/ath6kl/usb.c in the Linux kernel through 5.2.9 has a NULL pointer dereference via an incomplete address in an endpoint descriptor.

In the Linux kernel through 5.15.2, mwifiex_usb_recv in drivers/net/wireless/marvell/mwifiex/usb.c allows an attacker (who can connect a crafted USB device) to cause a denial of service (skb_over_panic).

A memory leak in the rtl8xxxu_submit_int_urb() function in drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c in the Linux kernel through 5.3.11 allows attackers to cause a denial of service (memory consumption) by triggering usb_submit_urb() failures, aka CID-a2cdd07488e6.

In the Linux kernel before 5.2.10, there is a use-after-free bug that can be caused by a malicious USB device in the drivers/usb/class/cdc-acm.c driver, aka CID-c52873e5a1ef.

In the Linux kernel before 5.3.7, there is a use-after-free bug that can be caused by a malicious USB device in the drivers/usb/misc/adutux.c driver, aka CID-44efc269db79.

An issue was discovered in OpenSC through 0.19.0 and 0.20.x through 0.20.0-rc3. libopensc/pkcs15-prkey.c has an incorrect free operation in sc_pkcs15_decode_prkdf_entry.

A memory leak in the af9005_identify_state() function in drivers/media/usb/dvb-usb/af9005.c in the Linux kernel through 5.3.9 allows attackers to cause a denial of service (memory consumption), aka CID-2289adbfa559.

Two memory leaks in the rtl_usb_probe() function in drivers/net/wireless/realtek/rtlwifi/usb.c in the Linux kernel through 5.3.11 allow attackers to cause a denial of service (memory consumption), aka CID-3f9361695113.

An issue was discovered in the Linux kernel before 5.2.6. There is a use-after-free caused by a malicious USB device in the drivers/media/usb/cpia2/cpia2_usb.c driver.

The Linux kernel through 6.1.9 has a Use-After-Free in bigben_remove in drivers/hid/hid-bigbenff.c via a crafted USB device because the LED controllers remain registered for too long.

A denial of service vulnerability was reported in some ThinkPad models that could cause a system to crash when the Enhanced Biometrics setting is enabled in BIOS.

NVIDIA GPU Display Driver for Windows and Linux contains a vulnerability in the kernel mode layer driver, where an invalid display configuration may lead to denial of service.

An issue was discovered in the Linux kernel before 5.1.8. There is a double-free caused by a malicious USB device in the drivers/usb/misc/rio500.c driver.

An issue was discovered in the Linux kernel before 5.2.1. There is a use-after-free caused by a malicious USB device in the drivers/net/wireless/intersil/p54/p54usb.c driver.

In the Linux kernel, the following vulnerability has been resolved: usb: typec: ucsi: glink: fix off-by-one in connector_status UCSI connector's indices start from 1 up to 3, PMIC_GLINK_MAX_PORTS. Correct the condition in the pmic_glink_ucsi_connector_status() callback, fixing Type-C orientation reporting for the third USB-C connector.

In the Linux kernel, the following vulnerability has been resolved: fs/inode: Prevent dump_mapping() accessing invalid dentry.d_name.name It's observed that a crash occurs during hot-remove a memory device, in which user is accessing the hugetlb. See calltrace as following: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 14045 at arch/x86/mm/fault.c:1278 do_user_addr_fault+0x2a0/0x790 Modules linked in: kmem device_dax cxl_mem cxl_pmem cxl_port cxl_pci dax_hmem dax_pmem nd_pmem cxl_acpi nd_btt cxl_core crc32c_intel nvme virtiofs fuse nvme_core nfit libnvdimm dm_multipath scsi_dh_rdac scsi_dh_emc s mirror dm_region_hash dm_log dm_mod CPU: 1 PID: 14045 Comm: daxctl Not tainted 6.10.0-rc2-lizhijian+ #492 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:do_user_addr_fault+0x2a0/0x790 Code: 48 8b 00 a8 04 0f 84 b5 fe ff ff e9 1c ff ff ff 4c 89 e9 4c 89 e2 be 01 00 00 00 bf 02 00 00 00 e8 b5 ef 24 00 e9 42 fe ff ff <0f> 0b 48 83 c4 08 4c 89 ea 48 89 ee 4c 89 e7 5b 5d 41 5c 41 5d 41 RSP: 0000:ffffc90000a575f0 EFLAGS: 00010046 RAX: ffff88800c303600 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000001000 RSI: ffffffff82504162 RDI: ffffffff824b2c36 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90000a57658 R13: 0000000000001000 R14: ffff88800bc2e040 R15: 0000000000000000 FS: 00007f51cb57d880(0000) GS:ffff88807fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000001000 CR3: 00000000072e2004 CR4: 00000000001706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? __warn+0x8d/0x190 ? do_user_addr_fault+0x2a0/0x790 ? report_bug+0x1c3/0x1d0 ? handle_bug+0x3c/0x70 ? exc_invalid_op+0x14/0x70 ? asm_exc_invalid_op+0x16/0x20 ? do_user_addr_fault+0x2a0/0x790 ? exc_page_fault+0x31/0x200 exc_page_fault+0x68/0x200 <...snip...> BUG: unable to handle page fault for address: 0000000000001000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 800000000ad92067 P4D 800000000ad92067 PUD 7677067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI ---[ end trace 0000000000000000 ]--- BUG: unable to handle page fault for address: 0000000000001000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 800000000ad92067 P4D 800000000ad92067 PUD 7677067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 14045 Comm: daxctl Kdump: loaded Tainted: G W 6.10.0-rc2-lizhijian+ #492 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:dentry_name+0x1f4/0x440 <...snip...> ? dentry_name+0x2fa/0x440 vsnprintf+0x1f3/0x4f0 vprintk_store+0x23a/0x540 vprintk_emit+0x6d/0x330 _printk+0x58/0x80 dump_mapping+0x10b/0x1a0 ? __pfx_free_object_rcu+0x10/0x10 __dump_page+0x26b/0x3e0 ? vprintk_emit+0xe0/0x330 ? _printk+0x58/0x80 ? dump_page+0x17/0x50 dump_page+0x17/0x50 do_migrate_range+0x2f7/0x7f0 ? do_migrate_range+0x42/0x7f0 ? offline_pages+0x2f4/0x8c0 offline_pages+0x60a/0x8c0 memory_subsys_offline+0x9f/0x1c0 ? lockdep_hardirqs_on+0x77/0x100 ? _raw_spin_unlock_irqrestore+0x38/0x60 device_offline+0xe3/0x110 state_store+0x6e/0xc0 kernfs_fop_write_iter+0x143/0x200 vfs_write+0x39f/0x560 ksys_write+0x65/0xf0 do_syscall_64+0x62/0x130 Previously, some sanity check have been done in dump_mapping() before the print facility parsing '%pd' though, it's still possible to run into an invalid dentry.d_name.name. Since dump_mapping() only needs to dump the filename only, retrieve it by itself in a safer way to prevent an unnecessary crash. Note that either retrieving the filename with '%pd' or strncpy_from_kernel_nofault(), the filename could be unreliable.

An incorrect read request flaw was found in the Infrared Transceiver USB driver in the Linux kernel. This issue occurs when a user attaches a malicious USB device. A local user could use this flaw to starve the resources, causing denial of service or potentially crashing the system.

An issue was discovered in the USB subsystem in the Linux kernel through 6.4.2. There is an out-of-bounds and crash in read_descriptors in drivers/usb/core/sysfs.c.

In the Linux kernel before 5.1.6, there is a use-after-free in cpia2_exit() in drivers/media/usb/cpia2/cpia2_v4l.c that will cause denial of service, aka CID-dea37a972655.

In the Linux kernel before 5.3.6, there is a use-after-free bug that can be caused by a malicious USB device in the drivers/net/ieee802154/atusb.c driver, aka CID-7fd25e6fc035.

In the Linux kernel before 5.3.9, there is a use-after-free bug that can be caused by a malicious USB device in the drivers/nfc/pn533/usb.c driver, aka CID-6af3aa57a098.

An issue was discovered in the Linux kernel before 5.2.6. There is a use-after-free caused by a malicious USB device in the drivers/media/v4l2-core/v4l2-dev.c driver because drivers/media/radio/radio-raremono.c does not properly allocate memory.

An issue was discovered in the Linux kernel before 5.2.3. There is a use-after-free caused by a malicious USB device in the drivers/media/usb/dvb-usb/dvb-usb-init.c driver.

A flaw was found in the USB Host Controller Driver framework in the Linux kernel. The usb_giveback_urb function has a logic loophole in its implementation. Due to the inappropriate judgment condition of the goto statement, the function cannot return under the input of a specific malformed descriptor file, so it falls into an endless loop, resulting in a denial of service.

In the Linux kernel before 5.3.12, there is a use-after-free bug that can be caused by a malicious USB device in the drivers/input/ff-memless.c driver, aka CID-fa3a5a1880c9.

A null pointer dereference was found in the Linux kernel's Integrated Sensor Hub (ISH) driver. This issue could allow a local user to crash the system.

A null pointer dereference flaw was found in the Linux kernel's DECnet networking protocol. This issue could allow a remote user to crash the system.

In the Linux kernel, the following vulnerability has been resolved: tee: amdtee: fix an IS_ERR() vs NULL bug The __get_free_pages() function does not return error pointers it returns NULL so fix this condition to avoid a NULL dereference.

In the Linux kernel, the following vulnerability has been resolved: mptcp: clear 'kern' flag from fallback sockets The mptcp ULP extension relies on sk->sk_sock_kern being set correctly: It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); from working for plain tcp sockets (any userspace-exposed socket). But in case of fallback, accept() can return a plain tcp sk. In such case, sk is still tagged as 'kernel' and setsockopt will work. This will crash the kernel, The subflow extension has a NULL ctx->conn mptcp socket: BUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0 Call Trace: tcp_data_ready+0xf8/0x370 [..]

A NULL pointer dereference flaw was found in the Linux kernel's BPF subsystem in the way a user triggers the map_get_next_key function of the BPF bloom filter. This flaw allows a local user to crash the system. This flaw affects Linux kernel versions prior to 5.17-rc1.

do_tls_getsockopt in net/tls/tls_main.c in the Linux kernel through 6.2.6 lacks a lock_sock call, leading to a race condition (with a resultant use-after-free or NULL pointer dereference).

In the Linux kernel, the following vulnerability has been resolved: usbnet:fix NPE during rx_complete Missing usbnet_going_away Check in Critical Path. The usb_submit_urb function lacks a usbnet_going_away validation, whereas __usbnet_queue_skb includes this check. This inconsistency creates a race condition where: A URB request may succeed, but the corresponding SKB data fails to be queued. Subsequent processes: (e.g., rx_complete → defer_bh → __skb_unlink(skb, list)) attempt to access skb->next, triggering a NULL pointer dereference (Kernel Panic).

In the Linux kernel, the following vulnerability has been resolved: blk-mq: cancel blk-mq dispatch work in both blk_cleanup_queue and disk_release() For avoiding to slow down queue destroy, we don't call blk_mq_quiesce_queue() in blk_cleanup_queue(), instead of delaying to cancel dispatch work in blk_release_queue(). However, this way has caused kernel oops[1], reported by Changhui. The log shows that scsi_device can be freed before running blk_release_queue(), which is expected too since scsi_device is released after the scsi disk is closed and the scsi_device is removed. Fixes the issue by canceling blk-mq dispatch work in both blk_cleanup_queue() and disk_release(): 1) when disk_release() is run, the disk has been closed, and any sync dispatch activities have been done, so canceling dispatch work is enough to quiesce filesystem I/O dispatch activity. 2) in blk_cleanup_queue(), we only focus on passthrough request, and passthrough request is always explicitly allocated & freed by its caller, so once queue is frozen, all sync dispatch activity for passthrough request has been done, then it is enough to just cancel dispatch work for avoiding any dispatch activity. [1] kernel panic log [12622.769416] BUG: kernel NULL pointer dereference, address: 0000000000000300 [12622.777186] #PF: supervisor read access in kernel mode [12622.782918] #PF: error_code(0x0000) - not-present page [12622.788649] PGD 0 P4D 0 [12622.791474] Oops: 0000 [#1] PREEMPT SMP PTI [12622.796138] CPU: 10 PID: 744 Comm: kworker/10:1H Kdump: loaded Not tainted 5.15.0+ #1 [12622.804877] Hardware name: Dell Inc. PowerEdge R730/0H21J3, BIOS 1.5.4 10/002/2015 [12622.813321] Workqueue: kblockd blk_mq_run_work_fn [12622.818572] RIP: 0010:sbitmap_get+0x75/0x190 [12622.823336] Code: 85 80 00 00 00 41 8b 57 08 85 d2 0f 84 b1 00 00 00 45 31 e4 48 63 cd 48 8d 1c 49 48 c1 e3 06 49 03 5f 10 4c 8d 6b 40 83 f0 01 <48> 8b 33 44 89 f2 4c 89 ef 0f b6 c8 e8 fa f3 ff ff 83 f8 ff 75 58 [12622.844290] RSP: 0018:ffffb00a446dbd40 EFLAGS: 00010202 [12622.850120] RAX: 0000000000000001 RBX: 0000000000000300 RCX: 0000000000000004 [12622.858082] RDX: 0000000000000006 RSI: 0000000000000082 RDI: ffffa0b7a2dfe030 [12622.866042] RBP: 0000000000000004 R08: 0000000000000001 R09: ffffa0b742721334 [12622.874003] R10: 0000000000000008 R11: 0000000000000008 R12: 0000000000000000 [12622.881964] R13: 0000000000000340 R14: 0000000000000000 R15: ffffa0b7a2dfe030 [12622.889926] FS: 0000000000000000(0000) GS:ffffa0baafb40000(0000) knlGS:0000000000000000 [12622.898956] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [12622.905367] CR2: 0000000000000300 CR3: 0000000641210001 CR4: 00000000001706e0 [12622.913328] Call Trace: [12622.916055] <TASK> [12622.918394] scsi_mq_get_budget+0x1a/0x110 [12622.922969] __blk_mq_do_dispatch_sched+0x1d4/0x320 [12622.928404] ? pick_next_task_fair+0x39/0x390 [12622.933268] __blk_mq_sched_dispatch_requests+0xf4/0x140 [12622.939194] blk_mq_sched_dispatch_requests+0x30/0x60 [12622.944829] __blk_mq_run_hw_queue+0x30/0xa0 [12622.949593] process_one_work+0x1e8/0x3c0 [12622.954059] worker_thread+0x50/0x3b0 [12622.958144] ? rescuer_thread+0x370/0x370 [12622.962616] kthread+0x158/0x180 [12622.966218] ? set_kthread_struct+0x40/0x40 [12622.970884] ret_from_fork+0x22/0x30 [12622.974875] </TASK> [12622.977309] Modules linked in: scsi_debug rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs sunrpc dm_multipath intel_rapl_msr intel_rapl_common dell_wmi_descriptor sb_edac rfkill video x86_pkg_temp_thermal intel_powerclamp dcdbas coretemp kvm_intel kvm mgag200 irqbypass i2c_algo_bit rapl drm_kms_helper ipmi_ssif intel_cstate intel_uncore syscopyarea sysfillrect sysimgblt fb_sys_fops pcspkr cec mei_me lpc_ich mei ipmi_si ipmi_devintf ipmi_msghandler acpi_power_meter drm fuse xfs libcrc32c sr_mod cdrom sd_mod t10_pi sg ixgbe ahci libahci crct10dif_pclmul crc32_pclmul crc32c_intel libata megaraid_sas ghash_clmulni_intel tg3 wdat_w ---truncated---

In the Linux kernel, the following vulnerability has been resolved: media: staging: media: zoran: calculate the right buffer number for zoran_reap_stat_com On the case tmp_dcim=1, the index of buffer is miscalculated. This generate a NULL pointer dereference later. So let's fix the calcul and add a check to prevent this to reappear.

In the Linux kernel, the following vulnerability has been resolved: mptcp: remove tcp ulp setsockopt support TCP_ULP setsockopt cannot be used for mptcp because its already used internally to plumb subflow (tcp) sockets to the mptcp layer. syzbot managed to trigger a crash for mptcp connections that are in fallback mode: KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] CPU: 1 PID: 1083 Comm: syz-executor.3 Not tainted 5.16.0-rc2-syzkaller #0 RIP: 0010:tls_build_proto net/tls/tls_main.c:776 [inline] [..] __tcp_set_ulp net/ipv4/tcp_ulp.c:139 [inline] tcp_set_ulp+0x428/0x4c0 net/ipv4/tcp_ulp.c:160 do_tcp_setsockopt+0x455/0x37c0 net/ipv4/tcp.c:3391 mptcp_setsockopt+0x1b47/0x2400 net/mptcp/sockopt.c:638 Remove support for TCP_ULP setsockopt.

A NULL pointer dereference flaw was found in the Linux kernel AMD Sensor Fusion Hub driver. This flaw allows a local user to crash the system.

A NULL pointer dereference flaw was found in the Linux kernel's drivers/gpu/drm/msm/msm_gem_submit.c code in the submit_lookup_cmds function, which fails because it lacks a check of the return value of kmalloc(). This issue allows a local user to crash the system.

In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Fix mlx5_poll_one() cur_qp update flow When cur_qp isn't NULL, in order to avoid fetching the QP from the radix tree again we check if the next cqe QP is identical to the one we already have. The bug however is that we are checking if the QP is identical by checking the QP number inside the CQE against the QP number inside the mlx5_ib_qp, but that's wrong since the QP number from the CQE is from FW so it should be matched against mlx5_core_qp which is our FW QP number. Otherwise we could use the wrong QP when handling a CQE which could cause the kernel trace below. This issue is mainly noticeable over QPs 0 & 1, since for now they are the only QPs in our driver whereas the QP number inside mlx5_ib_qp doesn't match the QP number inside mlx5_core_qp. BUG: kernel NULL pointer dereference, address: 0000000000000012 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP CPU: 0 UID: 0 PID: 7927 Comm: kworker/u62:1 Not tainted 6.14.0-rc3+ #189 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 Workqueue: ib-comp-unb-wq ib_cq_poll_work [ib_core] RIP: 0010:mlx5_ib_poll_cq+0x4c7/0xd90 [mlx5_ib] Code: 03 00 00 8d 58 ff 21 cb 66 39 d3 74 39 48 c7 c7 3c 89 6e a0 0f b7 db e8 b7 d2 b3 e0 49 8b 86 60 03 00 00 48 c7 c7 4a 89 6e a0 <0f> b7 5c 98 02 e8 9f d2 b3 e0 41 0f b7 86 78 03 00 00 83 e8 01 21 RSP: 0018:ffff88810511bd60 EFLAGS: 00010046 RAX: 0000000000000010 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff88885fa1b3c0 RDI: ffffffffa06e894a RBP: 00000000000000b0 R08: 0000000000000000 R09: ffff88810511bc10 R10: 0000000000000001 R11: 0000000000000001 R12: ffff88810d593000 R13: ffff88810e579108 R14: ffff888105146000 R15: 00000000000000b0 FS: 0000000000000000(0000) GS:ffff88885fa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000012 CR3: 00000001077e6001 CR4: 0000000000370eb0 Call Trace: <TASK> ? __die+0x20/0x60 ? page_fault_oops+0x150/0x3e0 ? exc_page_fault+0x74/0x130 ? asm_exc_page_fault+0x22/0x30 ? mlx5_ib_poll_cq+0x4c7/0xd90 [mlx5_ib] __ib_process_cq+0x5a/0x150 [ib_core] ib_cq_poll_work+0x31/0x90 [ib_core] process_one_work+0x169/0x320 worker_thread+0x288/0x3a0 ? work_busy+0xb0/0xb0 kthread+0xd7/0x1f0 ? kthreads_online_cpu+0x130/0x130 ? kthreads_online_cpu+0x130/0x130 ret_from_fork+0x2d/0x50 ? kthreads_online_cpu+0x130/0x130 ret_from_fork_asm+0x11/0x20 </TASK>

In the Linux kernel, the following vulnerability has been resolved: btrfs: avoid NULL pointer dereference if no valid extent tree [BUG] Syzbot reported a crash with the following call trace: BTRFS info (device loop0): scrub: started on devid 1 BUG: kernel NULL pointer dereference, address: 0000000000000208 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 106e70067 P4D 106e70067 PUD 107143067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 UID: 0 PID: 689 Comm: repro Kdump: loaded Tainted: G O 6.13.0-rc4-custom+ #206 Tainted: [O]=OOT_MODULE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022 RIP: 0010:find_first_extent_item+0x26/0x1f0 [btrfs] Call Trace: <TASK> scrub_find_fill_first_stripe+0x13d/0x3b0 [btrfs] scrub_simple_mirror+0x175/0x260 [btrfs] scrub_stripe+0x5d4/0x6c0 [btrfs] scrub_chunk+0xbb/0x170 [btrfs] scrub_enumerate_chunks+0x2f4/0x5f0 [btrfs] btrfs_scrub_dev+0x240/0x600 [btrfs] btrfs_ioctl+0x1dc8/0x2fa0 [btrfs] ? do_sys_openat2+0xa5/0xf0 __x64_sys_ioctl+0x97/0xc0 do_syscall_64+0x4f/0x120 entry_SYSCALL_64_after_hwframe+0x76/0x7e </TASK> [CAUSE] The reproducer is using a corrupted image where extent tree root is corrupted, thus forcing to use "rescue=all,ro" mount option to mount the image. Then it triggered a scrub, but since scrub relies on extent tree to find where the data/metadata extents are, scrub_find_fill_first_stripe() relies on an non-empty extent root. But unfortunately scrub_find_fill_first_stripe() doesn't really expect an NULL pointer for extent root, it use extent_root to grab fs_info and triggered a NULL pointer dereference. [FIX] Add an extra check for a valid extent root at the beginning of scrub_find_fill_first_stripe(). The new error path is introduced by 42437a6386ff ("btrfs: introduce mount option rescue=ignorebadroots"), but that's pretty old, and later commit b979547513ff ("btrfs: scrub: introduce helper to find and fill sector info for a scrub_stripe") changed how we do scrub. So for kernels older than 6.6, the fix will need manual backport.