CVE-2024-56544
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: udmabuf: change folios array from kmalloc to kvmalloc When PAGE_SIZE 4096, MAX_PAGE_ORDER 10, 64bit machine, page_alloc only support 4MB. If above this, trigger this warn and return NULL. udmabuf can change size limit, if change it to 3072(3GB), and then alloc 3GB udmabuf, will fail create. [ 4080.876581] ------------[ cut here ]------------ [ 4080.876843] WARNING: CPU: 3 PID: 2015 at mm/page_alloc.c:4556 __alloc_pages+0x2c8/0x350 [ 4080.878839] RIP: 0010:__alloc_pages+0x2c8/0x350 [ 4080.879470] Call Trace: [ 4080.879473] <TASK> [ 4080.879473] ? __alloc_pages+0x2c8/0x350 [ 4080.879475] ? __warn.cold+0x8e/0xe8 [ 4080.880647] ? __alloc_pages+0x2c8/0x350 [ 4080.880909] ? report_bug+0xff/0x140 [ 4080.881175] ? handle_bug+0x3c/0x80 [ 4080.881556] ? exc_invalid_op+0x17/0x70 [ 4080.881559] ? asm_exc_invalid_op+0x1a/0x20 [ 4080.882077] ? udmabuf_create+0x131/0x400 Because MAX_PAGE_ORDER, kmalloc can max alloc 4096 * (1 << 10), 4MB memory, each array entry is pointer(8byte), so can save 524288 pages(2GB). Further more, costly order(order 3) may not be guaranteed that it can be applied for, due to fragmentation. This patch change udmabuf array use kvmalloc_array, this can fallback alloc into vmalloc, which can guarantee allocation for any size and does not affect the performance of kmalloc allocations.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.4 | 5.5 | 5.5 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | High | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/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
cve.org: 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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