CVE-2024-43837

Published Aug 17, 2024

Last updated 7 months ago

CVSS medium 5.5

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix null pointer dereference in resolve_prog_type() for BPF_PROG_TYPE_EXT When loading a EXT program without specifying `attr->attach_prog_fd`, the `prog->aux->dst_prog` will be null. At this time, calling resolve_prog_type() anywhere will result in a null pointer dereference. Example stack trace: [ 8.107863] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004 [ 8.108262] Mem abort info: [ 8.108384] ESR = 0x0000000096000004 [ 8.108547] EC = 0x25: DABT (current EL), IL = 32 bits [ 8.108722] SET = 0, FnV = 0 [ 8.108827] EA = 0, S1PTW = 0 [ 8.108939] FSC = 0x04: level 0 translation fault [ 8.109102] Data abort info: [ 8.109203] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 8.109399] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 8.109614] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 8.109836] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000101354000 [ 8.110011] [0000000000000004] pgd=0000000000000000, p4d=0000000000000000 [ 8.112624] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 8.112783] Modules linked in: [ 8.113120] CPU: 0 PID: 99 Comm: may_access_dire Not tainted 6.10.0-rc3-next-20240613-dirty #1 [ 8.113230] Hardware name: linux,dummy-virt (DT) [ 8.113390] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 8.113429] pc : may_access_direct_pkt_data+0x24/0xa0 [ 8.113746] lr : add_subprog_and_kfunc+0x634/0x8e8 [ 8.113798] sp : ffff80008283b9f0 [ 8.113813] x29: ffff80008283b9f0 x28: ffff800082795048 x27: 0000000000000001 [ 8.113881] x26: ffff0000c0bb2600 x25: 0000000000000000 x24: 0000000000000000 [ 8.113897] x23: ffff0000c1134000 x22: 000000000001864f x21: ffff0000c1138000 [ 8.113912] x20: 0000000000000001 x19: ffff0000c12b8000 x18: ffffffffffffffff [ 8.113929] x17: 0000000000000000 x16: 0000000000000000 x15: 0720072007200720 [ 8.113944] x14: 0720072007200720 x13: 0720072007200720 x12: 0720072007200720 [ 8.113958] x11: 0720072007200720 x10: 0000000000f9fca4 x9 : ffff80008021f4e4 [ 8.113991] x8 : 0101010101010101 x7 : 746f72705f6d656d x6 : 000000001e0e0f5f [ 8.114006] x5 : 000000000001864f x4 : ffff0000c12b8000 x3 : 000000000000001c [ 8.114020] x2 : 0000000000000002 x1 : 0000000000000000 x0 : 0000000000000000 [ 8.114126] Call trace: [ 8.114159] may_access_direct_pkt_data+0x24/0xa0 [ 8.114202] bpf_check+0x3bc/0x28c0 [ 8.114214] bpf_prog_load+0x658/0xa58 [ 8.114227] __sys_bpf+0xc50/0x2250 [ 8.114240] __arm64_sys_bpf+0x28/0x40 [ 8.114254] invoke_syscall.constprop.0+0x54/0xf0 [ 8.114273] do_el0_svc+0x4c/0xd8 [ 8.114289] el0_svc+0x3c/0x140 [ 8.114305] el0t_64_sync_handler+0x134/0x150 [ 8.114331] el0t_64_sync+0x168/0x170 [ 8.114477] Code: 7100707f 54000081 f9401c00 f9403800 (b9400403) [ 8.118672] ---[ end trace 0000000000000000 ]--- One way to fix it is by forcing `attach_prog_fd` non-empty when bpf_prog_load(). But this will lead to `libbpf_probe_bpf_prog_type` API broken which use verifier log to probe prog type and will log nothing if we reject invalid EXT prog before bpf_check(). Another way is by adding null check in resolve_prog_type(). The issue was introduced by commit 4a9c7bbe2ed4 ("bpf: Resolve to prog->aux->dst_prog->type only for BPF_PROG_TYPE_EXT") which wanted to correct type resolution for BPF_PROG_TYPE_TRACING programs. Before that, the type resolution of BPF_PROG_TYPE_EXT prog actually follows the logic below: prog->aux->dst_prog ? prog->aux->dst_prog->type : prog->type; It implies that when EXT program is not yet attached to `dst_prog`, the prog type should be EXT itself. This code worked fine in the past. So just keep using it. Fix this by returning `prog->type` for BPF_PROG_TYPE_EXT if `dst_prog` is not present in resolve_prog_type().
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-476

Social media

Hype score
Not currently trending

Configurations

Related CVEs

  1. In the Linux kernel, the following vulnerability has been resolved: ibmveth: Disable GSO for packets with small MSS Some physical adapters on Power systems do not support segmentation offload when the MSS is less than 224 bytes. Attempting to send such packets causes the adapter to freeze, stopping all traffic until manually reset. Implement ndo_features_check to disable GSO for packets with small MSS values. The network stack will perform software segmentation instead. The 224-byte minimum matches ibmvnic commit <f10b09ef687f> ("ibmvnic: Enforce stronger sanity checks on GSO packets") which uses the same physical adapters in SEA configurations. The issue occurs specifically when the hardware attempts to perform segmentation (gso_segs > 1) with a small MSS. Single-segment GSO packets (gso_segs == 1) do not trigger the problematic LSO code path and are transmitted normally without segmentation. Add an ndo_features_check callback to disable GSO when MSS < 224 bytes. Also call vlan_features_check() to ensure proper handling of VLAN packets, particularly QinQ (802.1ad) configurations where the hardware parser may not support certain offload features. Validated using iptables to force small MSS values. Without the fix, the adapter freezes. With the fix, packets are segmented in software and transmission succeeds. Comprehensive regression testing completedd (MSS tests, performance, stability).•CVE-2026-46273
  2. In the Linux kernel, the following vulnerability has been resolved: coresight: tmc-etr: Fix race condition between sysfs and perf mode When trying to run perf and sysfs mode simultaneously, the WARN_ON() in tmc_etr_enable_hw() is triggered sometimes: WARNING: CPU: 42 PID: 3911571 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1060 tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] [..snip..] Call trace: tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] (P) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] (L) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] coresight_enable_path+0x1c8/0x218 [coresight] coresight_enable_sysfs+0xa4/0x228 [coresight] enable_source_store+0x58/0xa8 [coresight] dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 kernfs_fop_write_iter+0x120/0x1b8 vfs_write+0x2c8/0x388 ksys_write+0x74/0x108 __arm64_sys_write+0x24/0x38 el0_svc_common.constprop.0+0x64/0x148 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x130 el0t_64_sync_handler+0xc8/0xd0 el0t_64_sync+0x1ac/0x1b0 ---[ end trace 0000000000000000 ]--- Since the enablement of sysfs mode is separeted into two critical regions, one for sysfs buffer allocation and another for hardware enablement, it's possible to race with the perf mode. Fix this by double check whether the perf mode's been used before enabling the hardware in sysfs mode. mode: [sysfs mode] [perf mode] tmc_etr_get_sysfs_buffer() spin_lock(&drvdata->spinlock) [sysfs buffer allocation] spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() drvdata->etr_buf = etr_perf->etr_buf spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() WARN_ON(drvdata->etr_buf) // WARN sicne etr_buf initialized at the perf side spin_unlock(&drvdata->spinlock) With this fix, we retain the check for CS_MODE_PERF in get_etr_sysfs_buf. This ensures we verify whether the perf mode's already running before we actually allocate the buffer. Then we can save the time of allocating/freeing the sysfs buffer if race with the perf mode.•CVE-2026-46272
  3. In the Linux kernel, the following vulnerability has been resolved: wifi: ath12k: do WoW offloads only on primary link In case of multi-link connection, WCN7850 firmware crashes due to WoW offloads enabled on both primary and secondary links. Change to do it only on primary link to fix it. Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00284-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1•CVE-2026-46271
  4. In the Linux kernel, the following vulnerability has been resolved: power: supply: rt9455: Fix use-after-free in power_supply_changed() Using the `devm_` variant for requesting IRQ _before_ the `devm_` variant for allocating/registering the `power_supply` handle, means that the `power_supply` handle will be deallocated/unregistered _before_ the interrupt handler (since `devm_` naturally deallocates in reverse allocation order). This means that during removal, there is a race condition where an interrupt can fire just _after_ the `power_supply` handle has been freed, *but* just _before_ the corresponding unregistration of the IRQ handler has run. This will lead to the IRQ handler calling `power_supply_changed()` with a freed `power_supply` handle. Which usually crashes the system or otherwise silently corrupts the memory... Note that there is a similar situation which can also happen during `probe()`; the possibility of an interrupt firing _before_ registering the `power_supply` handle. This would then lead to the nasty situation of using the `power_supply` handle *uninitialized* in `power_supply_changed()`. Fix this racy use-after-free by making sure the IRQ is requested _after_ the registration of the `power_supply` handle.•CVE-2026-46270
  5. In the Linux kernel, the following vulnerability has been resolved: pinctrl: canaan: k230: Fix NULL pointer dereference when parsing devicetree When probing the k230 pinctrl driver, the kernel triggers a NULL pointer dereference. The crash trace showed: [ 0.732084] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000068 [ 0.740737] ... [ 0.776296] epc : k230_pinctrl_probe+0x1be/0x4fc In k230_pinctrl_parse_functions(), we attempt to retrieve the device pointer via info->pctl_dev->dev, but info->pctl_dev is only initialized after k230_pinctrl_parse_dt() completes. At the time of DT parsing, info->pctl_dev is still NULL, leading to the invalid dereference of info->pctl_dev->dev. Use the already available device pointer from platform_device instead of accessing through uninitialized pctl_dev.•CVE-2026-46269

References

Sources include official advisories and independent security research.