CVE-2024-41083

2024-07-2916:15:03

Google

osv.dev

linux kernel

netfs_page_mkwrite()

folio->mapping validity

null pointer dereference

CVSS3

5.5

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

AI Score

5.1

Confidence

High

JSON

In the Linux kernel, the following vulnerability has been resolved:

netfs: Fix netfs_page_mkwrite() to check folio->mapping is valid

Fix netfs_page_mkwrite() to check that folio->mapping is valid once it has
taken the folio lock (as filemap_page_mkwrite() does). Without this,
generic/247 occasionally oopses with something like the following:

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page

RIP: 0010:trace_event_raw_event_netfs_folio+0x61/0xc0
...
Call Trace:
 &lt;TASK&gt;
 ? __die_body+0x1a/0x60
 ? page_fault_oops+0x6e/0xa0
 ? exc_page_fault+0xc2/0xe0
 ? asm_exc_page_fault+0x22/0x30
 ? trace_event_raw_event_netfs_folio+0x61/0xc0
 trace_netfs_folio+0x39/0x40
 netfs_page_mkwrite+0x14c/0x1d0
 do_page_mkwrite+0x50/0x90
 do_pte_missing+0x184/0x200
 __handle_mm_fault+0x42d/0x500
 handle_mm_fault+0x121/0x1f0
 do_user_addr_fault+0x23e/0x3c0
 exc_page_fault+0xc2/0xe0
 asm_exc_page_fault+0x22/0x30

This is due to the invalidate_inode_pages2_range() issued at the end of the
DIO write interfering with the mmap’d writes.