NULL Pointer Dereference

A vulnerability was found in HTACG tidy-html5 5.8.0. It has been declared as problematic. This vulnerability affects the function InsertNodeAsParent of the file src/parser.c. The manipulation leads to null pointer dereference. Local access is required to approach this attack. The exploit has been disclosed to the public and may be used.Show less

A vulnerability was found in poco up to 1.14.1. It has been rated as problematic. Affected by this issue is the function MultipartInputStream of the file Net/src/MultipartReader.cpp. The manipulation leads to null pointer dereference. The attack needs to be approached locally. The exploit has been disclosed to the public and may be used. Upgrading to version 1.14.2 is able to address this issue. The patch is identified as 6f2f85913c191ab9ddfb8fae781f5d66afccf3bf. It is recommended to upgrade the affected component.Show less

brplot v420.69.1 contains a Null Pointer Dereference (NPD) vulnerability in the br_dagens_handle_once function of its data processing module, leading to unpredictable program behavior, causing segmentation faults, and program crashes.Show less

In the Linux kernel, the following vulnerability has been resolved: iio: light: isl29028: Fix the warning in isl29028_remove() The driver use the non-managed form of the register function in isl29028_remove(). To keep the release order as mirroring the ordering in probe, the driver should use non-managed form in probe, too. The following log reveals it: [ 32.374955] isl29028 0-0010: remove [ 32.376861] general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN PTI [ 32.377676] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] [ 32.379432] RIP: 0010:kernfs_find_and_get_ns+0x28/0xe0 [ 32.385461] Call Trace: [ 32.385807] sysfs_unmerge_group+0x59/0x110 [ 32.386110] dpm_sysfs_remove+0x58/0xc0 [ 32.386391] device_del+0x296/0xe50 [ 32.386959] cdev_device_del+0x1d/0xd0 [ 32.387231] devm_iio_device_unreg+0x27/0xb0 [ 32.387542] devres_release_group+0x319/0x3d0 [ 32.388162] i2c_device_remove+0x93/0x1f0Show less

In the Linux kernel, the following vulnerability has been resolved: arm64: fix oops in concurrently setting insn_emulation sysctls emulation_proc_handler() changes table->data for proc_dointvec_minmax and can generate the following Oops if called concurrently with itself: | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010 | Internal error: Oops: 96000006 [#1] SMP | Call trace: | update_insn_emulation_mode+0xc0/0x148 | emulation_proc_handler+0x64/0xb8 | proc_sys_call_handler+0x9c/0xf8 | proc_sys_write+0x18/0x20 | __vfs_write+0x20/0x48 | vfs_write+0xe4/0x1d0 | ksys_write+0x70/0xf8 | __arm64_sys_write+0x20/0x28 | el0_svc_common.constprop.0+0x7c/0x1c0 | el0_svc_handler+0x2c/0xa0 | el0_svc+0x8/0x200 To fix this issue, keep the table->data as &insn->current_mode and use container_of() to retrieve the insn pointer. Another mutex is used to protect against the current_mode update but not for retrieving insn_emulation as table->data is no longer changing.Show less

In the Linux kernel, the following vulnerability has been resolved: virtio-gpu: fix a missing check to avoid NULL dereference 'cache_ent' could be set NULL inside virtio_gpu_cmd_get_capset() and it will lead to a NULL dereference by a lately use of it (i.e., ptr = cache_ent->caps_cache). Fix it with a NULL check. [ kraxel: minor codestyle fixup ]Show less

In the Linux kernel, the following vulnerability has been resolved: kernfs: fix potential NULL dereference in __kernfs_remove When lockdep is enabled, lockdep_assert_held_write would cause potential NULL pointer dereference. Fix the following smatch warnings: fs/kernfs/dir.c:1353 __kernfs_remove() warn: variable dereferenced before check 'kn' (see line 1346)Show less

In the Linux kernel, the following vulnerability has been resolved: dmaengine: sf-pdma: Add multithread support for a DMA channel When we get a DMA channel and try to use it in multiple threads it will cause oops and hanging the system. % echo 64 > /sys/module/dmatest/parameters/threads_per_chan % echo 10000 > /sys/module/dmatest/parameters/iterations % echo 1 > /sys/module/dmatest/parameters/run [ 89.480664] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a0 [ 89.488725] Oops [#1] [ 89.494708] CPU: 2 PID: 1008 Comm: dma0chan0-copy0 Not tainted 5.17.0-rc5 [ 89.509385] epc : vchan_find_desc+0x32/0x46 [ 89.513553] ra : sf_pdma_tx_status+0xca/0xd6 This happens because of data race. Each thread rewrite channels's descriptor as soon as device_prep_dma_memcpy() is called. It leads to the situation when the driver thinks that it uses right descriptor that actually is freed or substituted for other one. With current fixes a descriptor changes its value only when it has been used. A new descriptor is acquired from vc->desc_issued queue that is already filled with descriptors that are ready to be sent. Threads have no direct access to DMA channel descriptor. Now it is just possible to queue a descriptor for further processing.Show less

In the Linux kernel, the following vulnerability has been resolved: soundwire: revisit driver bind/unbind and callbacks In the SoundWire probe, we store a pointer from the driver ops into the 'slave' structure. This can lead to kernel oopses when unbinding codec drivers, e.g. with the following sequence to remove machine driver and codec driver. /sbin/modprobe -r snd_soc_sof_sdw /sbin/modprobe -r snd_soc_rt711 The full details can be found in the BugLink below, for reference the two following examples show different cases of driver ops/callbacks being invoked after the driver .remove(). kernel: BUG: kernel NULL pointer dereference, address: 0000000000000150 kernel: Workqueue: events cdns_update_slave_status_work [soundwire_cadence] kernel: RIP: 0010:mutex_lock+0x19/0x30 kernel: Call Trace: kernel: ? sdw_handle_slave_status+0x426/0xe00 [soundwire_bus 94ff184bf398570c3f8ff7efe9e32529f532e4ae] kernel: ? newidle_balance+0x26a/0x400 kernel: ? cdns_update_slave_status_work+0x1e9/0x200 [soundwire_cadence 1bcf98eebe5ba9833cd433323769ac923c9c6f82] kernel: BUG: unable to handle page fault for address: ffffffffc07654c8 kernel: Workqueue: pm pm_runtime_work kernel: RIP: 0010:sdw_bus_prep_clk_stop+0x6f/0x160 [soundwire_bus] kernel: Call Trace: kernel: <TASK> kernel: sdw_cdns_clock_stop+0xb5/0x1b0 [soundwire_cadence 1bcf98eebe5ba9833cd433323769ac923c9c6f82] kernel: intel_suspend_runtime+0x5f/0x120 [soundwire_intel aca858f7c87048d3152a4a41bb68abb9b663a1dd] kernel: ? dpm_sysfs_remove+0x60/0x60 This was not detected earlier in Intel tests since the tests first remove the parent PCI device and shut down the bus. The sequence above is a corner case which keeps the bus operational but without a driver bound. While trying to solve this kernel oopses, it became clear that the existing SoundWire bus does not deal well with the unbind case. Commit 528be501b7d4a ("soundwire: sdw_slave: add probe_complete structure and new fields") added a 'probed' status variable and a 'probe_complete' struct completion. This status is however not reset on remove and likewise the 'probe complete' is not re-initialized, so the bind/unbind/bind test cases would fail. The timeout used before the 'update_status' callback was also a bad idea in hindsight, there should really be no timing assumption as to if and when a driver is bound to a device. An initial draft was based on device_lock() and device_unlock() was tested. This proved too complicated, with deadlocks created during the suspend-resume sequences, which also use the same device_lock/unlock() as the bind/unbind sequences. On a CometLake device, a bad DSDT/BIOS caused spurious resumes and the use of device_lock() caused hangs during suspend. After multiple weeks or testing and painful reverse-engineering of deadlocks on different devices, we looked for alternatives that did not interfere with the device core. A bus notifier was used successfully to keep track of DRIVER_BOUND and DRIVER_UNBIND events. This solved the bind-unbind-bind case in tests, but it can still be defeated with a theoretical corner case where the memory is freed by a .remove while the callback is in use. The notifier only helps make sure the driver callbacks are valid, but not that the memory allocated in probe remains valid while the callbacks are invoked. This patch suggests the introduction of a new 'sdw_dev_lock' mutex protecting probe/remove and all driver callbacks. Since this mutex is 'local' to SoundWire only, it does not interfere with existing locks and does not create deadlocks. In addition, this patch removes the 'probe_complete' completion, instead we directly invoke the 'update_status' from the probe routine. That removes any sort of timing dependency and a much better support for the device/driver model, the driver could be bound before the bus started, or eons after the bus started and the hardware would be properly initialized in all cases. BugLink: https://github.com/thesofproject/linux/is ---truncated---Show less

In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix BUG: KASAN: null-ptr-deref in rxe_qp_do_cleanup The function rxe_create_qp calls rxe_qp_from_init. If some error occurs, the error handler of function rxe_qp_from_init will set both scq and rcq to NULL. Then rxe_create_qp calls rxe_put to handle qp. In the end, rxe_qp_do_cleanup is called by rxe_put. rxe_qp_do_cleanup directly accesses scq and rcq before checking them. This will cause null-ptr-deref error. The call graph is as below: rxe_create_qp { ... rxe_qp_from_init { ... err1: ... qp->rcq = NULL; <---rcq is set to NULL qp->scq = NULL; <---scq is set to NULL ... } qp_init: rxe_put{ ... rxe_qp_do_cleanup { ... atomic_dec(&qp->scq->num_wq); <--- scq is accessed ... atomic_dec(&qp->rcq->num_wq); <--- rcq is accessed } }Show less

In the Linux kernel, the following vulnerability has been resolved: usb: xhci_plat_remove: avoid NULL dereference Since commit 4736ebd7fcaff1eb8481c140ba494962847d6e0a ("usb: host: xhci-plat: omit shared hcd if either root hub has no ports") xhci->shared_hcd can be NULL, which causes the following Oops on reboot: [ 710.124450] systemd-shutdown[1]: Rebooting. [ 710.298861] xhci-hcd xhci-hcd.2.auto: remove, state 4 [ 710.304217] usb usb3: USB disconnect, device number 1 [ 710.317441] xhci-hcd xhci-hcd.2.auto: USB bus 3 deregistered [ 710.323280] xhci-hcd xhci-hcd.2.auto: remove, state 1 [ 710.328401] usb usb2: USB disconnect, device number 1 [ 710.333515] usb 2-3: USB disconnect, device number 2 [ 710.467649] xhci-hcd xhci-hcd.2.auto: USB bus 2 deregistered [ 710.475450] Unable to handle kernel NULL pointer dereference at virtual address 00000000000003b8 [ 710.484425] Mem abort info: [ 710.487265] ESR = 0x0000000096000004 [ 710.491060] EC = 0x25: DABT (current EL), IL = 32 bits [ 710.496427] SET = 0, FnV = 0 [ 710.499525] EA = 0, S1PTW = 0 [ 710.502716] FSC = 0x04: level 0 translation fault [ 710.507648] Data abort info: [ 710.510577] ISV = 0, ISS = 0x00000004 [ 710.514462] CM = 0, WnR = 0 [ 710.517480] user pgtable: 4k pages, 48-bit VAs, pgdp=00000008b0050000 [ 710.523976] [00000000000003b8] pgd=0000000000000000, p4d=0000000000000000 [ 710.530961] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 710.536551] Modules linked in: rfkill input_leds snd_soc_simple_card snd_soc_simple_card_utils snd_soc_nau8822 designware_i2s snd_soc_core dw_hdmi_ahb_audio snd_pcm_dmaengine arm_ccn panfrost ac97_bus gpu_sched snd_pcm at24 fuse configfs sdhci_of_dwcmshc sdhci_pltfm sdhci nvme led_class mmc_core nvme_core bt1_pvt polynomial tp_serio snd_seq_midi snd_seq_midi_event snd_seq snd_timer snd_rawmidi snd_seq_device snd soundcore efivarfs ipv6 [ 710.575286] CPU: 7 PID: 1 Comm: systemd-shutdow Not tainted 5.19.0-rc7-00043-gfd8619f4fd54 #1 [ 710.583822] Hardware name: T-Platforms TF307-MB/BM1BM1-A, BIOS 5.6 07/06/2022 [ 710.590972] pstate: 40000005 (nZcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 710.597949] pc : usb_remove_hcd+0x34/0x1e4 [ 710.602067] lr : xhci_plat_remove+0x74/0x140 [ 710.606351] sp : ffff800009f3b7c0 [ 710.609674] x29: ffff800009f3b7c0 x28: ffff000800960040 x27: 0000000000000000 [ 710.616833] x26: ffff800008dc22a0 x25: 0000000000000000 x24: 0000000000000000 [ 710.623992] x23: 0000000000000000 x22: ffff000805465810 x21: ffff000805465800 [ 710.631149] x20: ffff000800f80000 x19: 0000000000000000 x18: ffffffffffffffff [ 710.638307] x17: ffff000805096000 x16: ffff00080633b800 x15: ffff000806537a1c [ 710.645465] x14: 0000000000000001 x13: 0000000000000000 x12: ffff00080378d6f0 [ 710.652621] x11: ffff00080041a900 x10: ffff800009b204e8 x9 : ffff8000088abaa4 [ 710.659779] x8 : ffff000800960040 x7 : ffff800009409000 x6 : 0000000000000001 [ 710.666936] x5 : ffff800009241000 x4 : ffff800009241440 x3 : 0000000000000000 [ 710.674094] x2 : ffff000800960040 x1 : ffff000800960040 x0 : 0000000000000000 [ 710.681251] Call trace: [ 710.683704] usb_remove_hcd+0x34/0x1e4 [ 710.687467] xhci_plat_remove+0x74/0x140 [ 710.691400] platform_remove+0x34/0x70 [ 710.695165] device_remove+0x54/0x90 [ 710.698753] device_release_driver_internal+0x200/0x270 [ 710.703992] device_release_driver+0x24/0x30 [ 710.708273] bus_remove_device+0xe0/0x16c [ 710.712293] device_del+0x178/0x390 [ 710.715797] platform_device_del.part.0+0x24/0x90 [ 710.720514] platform_device_unregister+0x30/0x50 [ 710.725232] dwc3_host_exit+0x20/0x30 [ 710.728907] dwc3_remove+0x174/0x1b0 [ 710.732494] platform_remove+0x34/0x70 [ 710.736254] device_remove+0x54/0x90 [ 710.739840] device_release_driver_internal+0x200/0x270 [ 710.745078] device_release_driver+0x24/0x30 [ 710.749359] bus_remove_device+0xe0/0x16c [ 710.753380] device_del+0x178/0x390 [ 710.756881] platform_device_del.part ---truncated---Show less

In the Linux kernel, the following vulnerability has been resolved: usb: cdns3: change place of 'priv_ep' assignment in cdns3_gadget_ep_dequeue(), cdns3_gadget_ep_enable() If 'ep' is NULL, result of ep_to_cdns3_ep(ep) is invalid pointer and its dereference with priv_ep->cdns3_dev may cause panic. Found by Linux Verification Center (linuxtesting.org) with SVACE.Show less

In the Linux kernel, the following vulnerability has been resolved: locking/csd_lock: Change csdlock_debug from early_param to __setup The csdlock_debug kernel-boot parameter is parsed by the early_param() function csdlock_debug(). If set, csdlock_debug() invokes static_branch_enable() to enable csd_lock_wait feature, which triggers a panic on arm64 for kernels built with CONFIG_SPARSEMEM=y and CONFIG_SPARSEMEM_VMEMMAP=n. With CONFIG_SPARSEMEM_VMEMMAP=n, __nr_to_section is called in static_key_enable() and returns NULL, resulting in a NULL dereference because mem_section is initialized only later in sparse_init(). This is also a problem for powerpc because early_param() functions are invoked earlier than jump_label_init(), also resulting in static_key_enable() failures. These failures cause the warning "static key 'xxx' used before call to jump_label_init()". Thus, early_param is too early for csd_lock_wait to run static_branch_enable(), so changes it to __setup to fix these.Show less

In the Linux kernel, the following vulnerability has been resolved: tee: add overflow check in register_shm_helper() With special lengths supplied by user space, register_shm_helper() has an integer overflow when calculating the number of pages covered by a supplied user space memory region. This causes internal_get_user_pages_fast() a helper function of pin_user_pages_fast() to do a NULL pointer dereference: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010 Modules linked in: CPU: 1 PID: 173 Comm: optee_example_a Not tainted 5.19.0 #11 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 pc : internal_get_user_pages_fast+0x474/0xa80 Call trace: internal_get_user_pages_fast+0x474/0xa80 pin_user_pages_fast+0x24/0x4c register_shm_helper+0x194/0x330 tee_shm_register_user_buf+0x78/0x120 tee_ioctl+0xd0/0x11a0 __arm64_sys_ioctl+0xa8/0xec invoke_syscall+0x48/0x114 Fix this by adding an an explicit call to access_ok() in tee_shm_register_user_buf() to catch an invalid user space address early.Show less

In the Linux kernel, the following vulnerability has been resolved: tracing/eprobes: Do not allow eprobes to use $stack, or % for regs While playing with event probes (eprobes), I tried to see what would happen if I attempted to retrieve the instruction pointer (%rip) knowing that event probes do not use pt_regs. The result was: BUG: kernel NULL pointer dereference, address: 0000000000000024 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 1847 Comm: trace-cmd Not tainted 5.19.0-rc5-test+ #309 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016 RIP: 0010:get_event_field.isra.0+0x0/0x50 Code: ff 48 c7 c7 c0 8f 74 a1 e8 3d 8b f5 ff e8 88 09 f6 ff 4c 89 e7 e8 50 6a 13 00 48 89 ef 5b 5d 41 5c 41 5d e9 42 6a 13 00 66 90 <48> 63 47 24 8b 57 2c 48 01 c6 8b 47 28 83 f8 02 74 0e 83 f8 04 74 RSP: 0018:ffff916c394bbaf0 EFLAGS: 00010086 RAX: ffff916c854041d8 RBX: ffff916c8d9fbf50 RCX: ffff916c255d2000 RDX: 0000000000000000 RSI: ffff916c255d2008 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffff916c3a2a0c08 R09: ffff916c394bbda8 R10: 0000000000000000 R11: 0000000000000000 R12: ffff916c854041d8 R13: ffff916c854041b0 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff916c9ea40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000024 CR3: 000000011b60a002 CR4: 00000000001706e0 Call Trace: <TASK> get_eprobe_size+0xb4/0x640 ? __mod_node_page_state+0x72/0xc0 __eprobe_trace_func+0x59/0x1a0 ? __mod_lruvec_page_state+0xaa/0x1b0 ? page_remove_file_rmap+0x14/0x230 ? page_remove_rmap+0xda/0x170 event_triggers_call+0x52/0xe0 trace_event_buffer_commit+0x18f/0x240 trace_event_raw_event_sched_wakeup_template+0x7a/0xb0 try_to_wake_up+0x260/0x4c0 __wake_up_common+0x80/0x180 __wake_up_common_lock+0x7c/0xc0 do_notify_parent+0x1c9/0x2a0 exit_notify+0x1a9/0x220 do_exit+0x2ba/0x450 do_group_exit+0x2d/0x90 __x64_sys_exit_group+0x14/0x20 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Obviously this is not the desired result. Move the testing for TPARG_FL_TPOINT which is only used for event probes to the top of the "$" variable check, as all the other variables are not used for event probes. Also add a check in the register parsing "%" to fail if an event probe is used.Show less

In the Linux kernel, the following vulnerability has been resolved: tracing/eprobes: Have event probes be consistent with kprobes and uprobes Currently, if a symbol "@" is attempted to be used with an event probe (eprobes), it will cause a NULL pointer dereference crash. Both kprobes and uprobes can reference data other than the main registers. Such as immediate address, symbols and the current task name. Have eprobes do the same thing. For "comm", if "comm" is used and the event being attached to does not have the "comm" field, then make it the "$comm" that kprobes has. This is consistent to the way histograms and filters work.Show less

In the Linux kernel, the following vulnerability has been resolved: net: tap: NULL pointer derefence in dev_parse_header_protocol when skb->dev is null Fixes a NULL pointer derefence bug triggered from tap driver. When tap_get_user calls virtio_net_hdr_to_skb the skb->dev is null (in tap.c skb->dev is set after the call to virtio_net_hdr_to_skb) virtio_net_hdr_to_skb calls dev_parse_header_protocol which needs skb->dev field to be valid. The line that trigers the bug is in dev_parse_header_protocol (dev is at offset 0x10 from skb and is stored in RAX register) if (!dev->header_ops || !dev->header_ops->parse_protocol) 22e1: mov 0x10(%rbx),%rax 22e5: mov 0x230(%rax),%rax Setting skb->dev before the call in tap.c fixes the issue. BUG: kernel NULL pointer dereference, address: 0000000000000230 RIP: 0010:virtio_net_hdr_to_skb.constprop.0+0x335/0x410 [tap] Code: c0 0f 85 b7 fd ff ff eb d4 41 39 c6 77 cf 29 c6 48 89 df 44 01 f6 e8 7a 79 83 c1 48 85 c0 0f 85 d9 fd ff ff eb b7 48 8b 43 10 <48> 8b 80 30 02 00 00 48 85 c0 74 55 48 8b 40 28 48 85 c0 74 4c 48 RSP: 0018:ffffc90005c27c38 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888298f25300 RCX: 0000000000000010 RDX: 0000000000000005 RSI: ffffc90005c27cb6 RDI: ffff888298f25300 RBP: ffffc90005c27c80 R08: 00000000ffffffea R09: 00000000000007e8 R10: ffff88858ec77458 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000014 R14: ffffc90005c27e08 R15: ffffc90005c27cb6 FS: 0000000000000000(0000) GS:ffff88858ec40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000230 CR3: 0000000281408006 CR4: 00000000003706e0 Call Trace: tap_get_user+0x3f1/0x540 [tap] tap_sendmsg+0x56/0x362 [tap] ? get_tx_bufs+0xc2/0x1e0 [vhost_net] handle_tx_copy+0x114/0x670 [vhost_net] handle_tx+0xb0/0xe0 [vhost_net] handle_tx_kick+0x15/0x20 [vhost_net] vhost_worker+0x7b/0xc0 [vhost] ? vhost_vring_call_reset+0x40/0x40 [vhost] kthread+0xfa/0x120 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30Show less

In the Linux kernel, the following vulnerability has been resolved: BPF: Fix potential bad pointer dereference in bpf_sys_bpf() The bpf_sys_bpf() helper function allows an eBPF program to load another eBPF program from within the kernel. In this case the argument union bpf_attr pointer (as well as the insns and license pointers inside) is a kernel address instead of a userspace address (which is the case of a usual bpf() syscall). To make the memory copying process in the syscall work in both cases, bpfptr_t was introduced to wrap around the pointer and distinguish its origin. Specifically, when copying memory contents from a bpfptr_t, a copy_from_user() is performed in case of a userspace address and a memcpy() is performed for a kernel address. This can lead to problems because the in-kernel pointer is never checked for validity. The problem happens when an eBPF syscall program tries to call bpf_sys_bpf() to load a program but provides a bad insns pointer -- say 0xdeadbeef -- in the bpf_attr union. The helper calls __sys_bpf() which would then call bpf_prog_load() to load the program. bpf_prog_load() is responsible for copying the eBPF instructions to the newly allocated memory for the program; it creates a kernel bpfptr_t for insns and invokes copy_from_bpfptr(). Internally, all bpfptr_t operations are backed by the corresponding sockptr_t operations, which performs direct memcpy() on kernel pointers for copy_from/strncpy_from operations. Therefore, the code is always happy to dereference the bad pointer to trigger a un-handle-able page fault and in turn an oops. However, this is not supposed to happen because at that point the eBPF program is already verified and should not cause a memory error. Sample KASAN trace: [ 25.685056][ T228] ================================================================== [ 25.685680][ T228] BUG: KASAN: user-memory-access in copy_from_bpfptr+0x21/0x30 [ 25.686210][ T228] Read of size 80 at addr 00000000deadbeef by task poc/228 [ 25.686732][ T228] [ 25.686893][ T228] CPU: 3 PID: 228 Comm: poc Not tainted 5.19.0-rc7 #7 [ 25.687375][ T228] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS d55cb5a 04/01/2014 [ 25.687991][ T228] Call Trace: [ 25.688223][ T228] <TASK> [ 25.688429][ T228] dump_stack_lvl+0x73/0x9e [ 25.688747][ T228] print_report+0xea/0x200 [ 25.689061][ T228] ? copy_from_bpfptr+0x21/0x30 [ 25.689401][ T228] ? _printk+0x54/0x6e [ 25.689693][ T228] ? _raw_spin_lock_irqsave+0x70/0xd0 [ 25.690071][ T228] ? copy_from_bpfptr+0x21/0x30 [ 25.690412][ T228] kasan_report+0xb5/0xe0 [ 25.690716][ T228] ? copy_from_bpfptr+0x21/0x30 [ 25.691059][ T228] kasan_check_range+0x2bd/0x2e0 [ 25.691405][ T228] ? copy_from_bpfptr+0x21/0x30 [ 25.691734][ T228] memcpy+0x25/0x60 [ 25.692000][ T228] copy_from_bpfptr+0x21/0x30 [ 25.692328][ T228] bpf_prog_load+0x604/0x9e0 [ 25.692653][ T228] ? cap_capable+0xb4/0xe0 [ 25.692956][ T228] ? security_capable+0x4f/0x70 [ 25.693324][ T228] __sys_bpf+0x3af/0x580 [ 25.693635][ T228] bpf_sys_bpf+0x45/0x240 [ 25.693937][ T228] bpf_prog_f0ec79a5a3caca46_bpf_func1+0xa2/0xbd [ 25.694394][ T228] bpf_prog_run_pin_on_cpu+0x2f/0xb0 [ 25.694756][ T228] bpf_prog_test_run_syscall+0x146/0x1c0 [ 25.695144][ T228] bpf_prog_test_run+0x172/0x190 [ 25.695487][ T228] __sys_bpf+0x2c5/0x580 [ 25.695776][ T228] __x64_sys_bpf+0x3a/0x50 [ 25.696084][ T228] do_syscall_64+0x60/0x90 [ 25.696393][ T228] ? fpregs_assert_state_consistent+0x50/0x60 [ 25.696815][ T228] ? exit_to_user_mode_prepare+0x36/0xa0 [ 25.697202][ T228] ? syscall_exit_to_user_mode+0x20/0x40 [ 25.697586][ T228] ? do_syscall_64+0x6e/0x90 [ 25.697899][ T228] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 25.698312][ T228] RIP: 0033:0x7f6d543fb759 [ 25.698624][ T228] Code: 08 5b 89 e8 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d ---truncated---Show less

In the Linux kernel, the following vulnerability has been resolved: drm/ttm: Fix dummy res NULL ptr deref bug Check the bo->resource value before accessing the resource mem_type. v2: Fix commit description unwrapped warning <log snip> [ 40.191227][ T184] general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN PTI [ 40.192995][ T184] KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] [ 40.194411][ T184] CPU: 1 PID: 184 Comm: systemd-udevd Not tainted 5.19.0-rc4-00721-gb297c22b7070 #1 [ 40.196063][ T184] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014 [ 40.199605][ T184] RIP: 0010:ttm_bo_validate+0x1b3/0x240 [ttm] [ 40.200754][ T184] Code: e8 72 c5 ff ff 83 f8 b8 74 d4 85 c0 75 54 49 8b 9e 58 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 10 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 04 3c 03 7e 44 8b 53 10 31 c0 85 d2 0f 85 58 [ 40.203685][ T184] RSP: 0018:ffffc900006df0c8 EFLAGS: 00010202 [ 40.204630][ T184] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1102f4bb71b [ 40.205864][ T184] RDX: 0000000000000002 RSI: ffffc900006df208 RDI: 0000000000000010 [ 40.207102][ T184] RBP: 1ffff920000dbe1a R08: ffffc900006df208 R09: 0000000000000000 [ 40.208394][ T184] R10: ffff88817a5f0000 R11: 0000000000000001 R12: ffffc900006df110 [ 40.209692][ T184] R13: ffffc900006df0f0 R14: ffff88817a5db800 R15: ffffc900006df208 [ 40.210862][ T184] FS: 00007f6b1d16e8c0(0000) GS:ffff88839d700000(0000) knlGS:0000000000000000 [ 40.212250][ T184] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 40.213275][ T184] CR2: 000055a1001d4ff0 CR3: 00000001700f4000 CR4: 00000000000006e0 [ 40.214469][ T184] Call Trace: [ 40.214974][ T184] <TASK> [ 40.215438][ T184] ? ttm_bo_bounce_temp_buffer+0x140/0x140 [ttm] [ 40.216572][ T184] ? mutex_spin_on_owner+0x240/0x240 [ 40.217456][ T184] ? drm_vma_offset_add+0xaa/0x100 [drm] [ 40.218457][ T184] ttm_bo_init_reserved+0x3d6/0x540 [ttm] [ 40.219410][ T184] ? shmem_get_inode+0x744/0x980 [ 40.220231][ T184] ttm_bo_init_validate+0xb1/0x200 [ttm] [ 40.221172][ T184] ? bo_driver_evict_flags+0x340/0x340 [drm_vram_helper] [ 40.222530][ T184] ? ttm_bo_init_reserved+0x540/0x540 [ttm] [ 40.223643][ T184] ? __do_sys_finit_module+0x11a/0x1c0 [ 40.224654][ T184] ? __shmem_file_setup+0x102/0x280 [ 40.234764][ T184] drm_gem_vram_create+0x305/0x480 [drm_vram_helper] [ 40.235766][ T184] ? bo_driver_evict_flags+0x340/0x340 [drm_vram_helper] [ 40.236846][ T184] ? __kasan_slab_free+0x108/0x180 [ 40.237650][ T184] drm_gem_vram_fill_create_dumb+0x134/0x340 [drm_vram_helper] [ 40.238864][ T184] ? local_pci_probe+0xdf/0x180 [ 40.239674][ T184] ? drmm_vram_helper_init+0x400/0x400 [drm_vram_helper] [ 40.240826][ T184] drm_client_framebuffer_create+0x19c/0x400 [drm] [ 40.241955][ T184] ? drm_client_buffer_delete+0x200/0x200 [drm] [ 40.243001][ T184] ? drm_client_pick_crtcs+0x554/0xb80 [drm] [ 40.244030][ T184] drm_fb_helper_generic_probe+0x23f/0x940 [drm_kms_helper] [ 40.245226][ T184] ? __cond_resched+0x1c/0xc0 [ 40.245987][ T184] ? drm_fb_helper_memory_range_to_clip+0x180/0x180 [drm_kms_helper] [ 40.247316][ T184] ? mutex_unlock+0x80/0x100 [ 40.248005][ T184] ? __mutex_unlock_slowpath+0x2c0/0x2c0 [ 40.249083][ T184] drm_fb_helper_single_fb_probe+0x907/0xf00 [drm_kms_helper] [ 40.250314][ T184] ? drm_fb_helper_check_var+0x1180/0x1180 [drm_kms_helper] [ 40.251540][ T184] ? __cond_resched+0x1c/0xc0 [ 40.252321][ T184] ? mutex_lock+0x9f/0x100 [ 40.253062][ T184] __drm_fb_helper_initial_config_and_unlock+0xb9/0x2c0 [drm_kms_helper] [ 40.254394][ T184] drm_fbdev_client_hotplug+0x56f/0x840 [drm_kms_helper] [ 40.255477][ T184] drm_fbdev_generic_setup+0x165/0x3c0 [drm_kms_helper] [ 40.256607][ T184] bochs_pci_probe+0x6b7/0x900 [bochs] [ ---truncated---Show less