CVE-2022-50873
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: vdpa/vp_vdpa: fix kfree a wrong pointer in vp_vdpa_remove In vp_vdpa_remove(), the code kfree(&vp_vdpa_mgtdev->mgtdev.id_table) uses a reference of pointer as the argument of kfree, which is the wrong pointer and then may hit crash like this: Unable to handle kernel paging request at virtual address 00ffff003363e30c Internal error: Oops: 96000004 [#1] SMP Call trace: rb_next+0x20/0x5c ext4_readdir+0x494/0x5c4 [ext4] iterate_dir+0x168/0x1b4 __se_sys_getdents64+0x68/0x170 __arm64_sys_getdents64+0x24/0x30 el0_svc_common.constprop.0+0x7c/0x1bc do_el0_svc+0x2c/0x94 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb4 el0_sync+0x160/0x180 Code: 54000220 f9400441 b4000161 aa0103e0 (f9400821) SMP: stopping secondary CPUs Starting crashdump kernel...
Statement
An invalid free occurs in vp_vdpa_remove because the driver calls kfree on the address of the id_table pointer field instead of the pointer value. This effectively passes a non heap address to kfree. The result is memory corruption or an immediate kernel crash during device removal. The crash can be triggered when unloading the vp_vdpa module or removing the associated PCI vDPA device. For the CVSS the PR is L in the paranoid scenario because removal actions typically require elevated capabilities such as device management permissions.
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 | 6.2 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands; Modify Memory
There is the potential for arbitrary code execution with privileges of the vulnerable program via a "write, what where" primitive. If pointers to memory which hold user information are freed, a malicious user will be able to write 4 bytes anywhere in memory.
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