cbcvebase.
CVE-2024-47745
published 2024-10-21

CVE-2024-47745: In the Linux kernel, the following vulnerability has been resolved: mm: call the security_mmap_file() LSM hook in remap_file_pages() The remap_file_pages…

PriorityP340high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.29%
20.5th percentile
In the Linux kernel, the following vulnerability has been resolved: mm: call the security_mmap_file() LSM hook in remap_file_pages() The remap_file_pages syscall handler calls do_mmap() directly, which doesn't contain the LSM security check. And if the process has called personality(READ_IMPLIES_EXEC) before and remap_file_pages() is called for RW pages, this will actually result in remapping the pages to RWX, bypassing a W^X policy enforced by SELinux. So we should check prot by security_mmap_file LSM hook in the remap_file_pages syscall handler before do_mmap() is called. Otherwise, it potentially permits an attacker to bypass a W^X policy enforced by SELinux. The bypass is similar to CVE-2016-10044, which bypass the same thing via AIO and can be found in [1]. The PoC: $ cat > test.c int main(void) { size_t pagesz = sysconf(_SC_PAGE_SIZE); int mfd = syscall(SYS_memfd_create, "test", 0); const char *buf = mmap(NULL, 4 * pagesz, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0); unsigned int old = syscall(SYS_personality, 0xffffffff); syscall(SYS_personality, READ_IMPLIES_EXEC | old); syscall(SYS_remap_file_pages, buf, pagesz, 0, 2, 0); syscall(SYS_personality, old); // show the RWX page exists even if W^X policy is enforced int fd = open("/proc/self/maps", O_RDONLY); unsigned char buf2[1024]; while (1) { int ret = read(fd, buf2, 1024); if (ret <= 0) break; write(1, buf2, ret); } close(fd); } $ gcc test.c -o test $ ./test | grep rwx 7f1836c34000-7f1836c35000 rwxs 00002000 00:01 2050 /memfd:test (deleted) [PM: subject line tweaks]

Affected

19 ranges
VendorProductVersion rangeFixed in
debiandebian_linux——
debianlinux< linux 6.1.123-1 (bookworm)linux 6.1.123-1 (bookworm)
debianlinux-6.1< linux 6.1.123-1 (bookworm)linux 6.1.123-1 (bookworm)
linuxlinux_kernel< 6.1.1206.1.120
linuxlinux_kernel>= 0 < 6.1.123-16.1.123-1
linuxlinux_kernel>= 0 < 6.11.2-16.11.2-1
linuxlinux_kernel>= 0 < 6.11.2-16.11.2-1
linuxlinux_kernel>= 0 < 6.8.0-54.566.8.0-54.56
linuxlinux_kernel>= 0 < 6.11.0-18.186.11.0-18.18
linuxlinux_kernel>= 6.11 < 6.11.26.11.2
linuxlinux_kernel>= 6.2 < 6.6.546.6.54
linuxlinux_kernel>= 6.7 < 6.10.136.10.13
msrcazl3_kernel_6.6.51.1-5_on_azure_linux_3.0——
msrcazl3_kernel_6.6.56.1-5_on_azure_linux_3.0——
msrcazure_linux_3.0_arm——
msrcazure_linux_3.0_x64——
msrccbl2_kernel_5.15.186.1-1_on_cbl_mariner_2.0——
msrccbl2_kernel_5.15.200.1-1_on_cbl_mariner_2.0——
msrccbl2_kernel_5.15.202.1-1_on_cbl_mariner_2.0——

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian7.8HIGH
vendor_msrc7.8HIGH
vendor_redhat7.8HIGH
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