CVE-2024-26783

Published Apr 4, 2024

Last updated 13 days ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: mm/vmscan: fix a bug calling wakeup_kswapd() with a wrong zone index With numa balancing on, when a numa system is running where a numa node doesn't have its local memory so it has no managed zones, the following oops has been observed. It's because wakeup_kswapd() is called with a wrong zone index, -1. Fixed it by checking the index before calling wakeup_kswapd(). > BUG: unable to handle page fault for address: 00000000000033f3 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 0 P4D 0 > Oops: 0000 [#1] PREEMPT SMP NOPTI > CPU: 2 PID: 895 Comm: masim Not tainted 6.6.0-dirty #255 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 > RIP: 0010:wakeup_kswapd (./linux/mm/vmscan.c:7812) > Code: (omitted) > RSP: 0000:ffffc90004257d58 EFLAGS: 00010286 > RAX: ffffffffffffffff RBX: ffff88883fff0480 RCX: 0000000000000003 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88883fff0480 > RBP: ffffffffffffffff R08: ff0003ffffffffff R09: ffffffffffffffff > R10: ffff888106c95540 R11: 0000000055555554 R12: 0000000000000003 > R13: 0000000000000000 R14: 0000000000000000 R15: ffff88883fff0940 > FS: 00007fc4b8124740(0000) GS:ffff888827c00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000000033f3 CR3: 000000026cc08004 CR4: 0000000000770ee0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > PKRU: 55555554 > Call Trace: > <TASK> > ? __die > ? page_fault_oops > ? __pte_offset_map_lock > ? exc_page_fault > ? asm_exc_page_fault > ? wakeup_kswapd > migrate_misplaced_page > __handle_mm_fault > handle_mm_fault > do_user_addr_fault > exc_page_fault > asm_exc_page_fault > RIP: 0033:0x55b897ba0808 > Code: (omitted) > RSP: 002b:00007ffeefa821a0 EFLAGS: 00010287 > RAX: 000055b89983acd0 RBX: 00007ffeefa823f8 RCX: 000055b89983acd0 > RDX: 00007fc2f8122010 RSI: 0000000000020000 RDI: 000055b89983acd0 > RBP: 00007ffeefa821a0 R08: 0000000000000037 R09: 0000000000000075 > R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 > R13: 00007ffeefa82410 R14: 000055b897ba5dd8 R15: 00007fc4b8340000 > </TASK>
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
NVD-CWE-noinfo

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.CVE-2026-53362