CVE-2024-50296
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: net: hns3: fix kernel crash when uninstalling driver When the driver is uninstalled and the VF is disabled concurrently, a kernel crash occurs. The reason is that the two actions call function pci_disable_sriov(). The num_VFs is checked to determine whether to release the corresponding resources. During the second calling, num_VFs is not 0 and the resource release function is called. However, the corresponding resource has been released during the first invoking. Therefore, the problem occurs: [15277.839633][T50670] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 ... [15278.131557][T50670] Call trace: [15278.134686][T50670] klist_put+0x28/0x12c [15278.138682][T50670] klist_del+0x14/0x20 [15278.142592][T50670] device_del+0xbc/0x3c0 [15278.146676][T50670] pci_remove_bus_device+0x84/0x120 [15278.151714][T50670] pci_stop_and_remove_bus_device+0x6c/0x80 [15278.157447][T50670] pci_iov_remove_virtfn+0xb4/0x12c [15278.162485][T50670] sriov_disable+0x50/0x11c [15278.166829][T50670] pci_disable_sriov+0x24/0x30 [15278.171433][T50670] hnae3_unregister_ae_algo_prepare+0x60/0x90 [hnae3] [15278.178039][T50670] hclge_exit+0x28/0xd0 [hclge] [15278.182730][T50670] __se_sys_delete_module.isra.0+0x164/0x230 [15278.188550][T50670] __arm64_sys_delete_module+0x1c/0x30 [15278.193848][T50670] invoke_syscall+0x50/0x11c [15278.198278][T50670] el0_svc_common.constprop.0+0x158/0x164 [15278.203837][T50670] do_el0_svc+0x34/0xcc [15278.207834][T50670] el0_svc+0x20/0x30 For details, see the following figure. rmmod hclge disable VFs ---------------------------------------------------- hclge_exit() sriov_numvfs_store() ... device_lock() pci_disable_sriov() hns3_pci_sriov_configure() pci_disable_sriov() sriov_disable() sriov_disable() if !num_VFs : if !num_VFs : return; return; sriov_del_vfs() sriov_del_vfs() ... ... klist_put() klist_put() ... ... num_VFs = 0; num_VFs = 0; device_unlock(); In this patch, when driver is removing, we get the device_lock() to protect num_VFs, just like sriov_numvfs_store().
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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