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MEDIUM · 5.5

CVE-2021-46927

In the Linux kernel, the following vulnerability has been resolved: nitro_enclaves: Use get_user_pages_unlocked() call to handle mmap assert After commit 5b78ed24e8ec ("mm/pagemap: add mmap_assert_l...

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: nitro_enclaves: Use get_user_pages_unlocked() call to handle mmap assert After commit 5b78ed24e8ec ("mm/pagemap: add mmap_assert_locked() annotations to find_vma*()"), the call to get_user_pages() will trigger the mmap assert. static inline void mmap_assert_locked(struct mm_struct *mm) { lockdep_assert_held(&mm->mmap_lock); VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm); } [ 62.521410] kernel BUG at include/linux/mmap_lock.h:156! ........................................................... [ 62.538938] RIP: 0010:find_vma+0x32/0x80 ........................................................... [ 62.605889] Call Trace: [ 62.608502] <TASK> [ 62.610956] ? lock_timer_base+0x61/0x80 [ 62.614106] find_extend_vma+0x19/0x80 [ 62.617195] __get_user_pages+0x9b/0x6a0 [ 62.620356] __gup_longterm_locked+0x42d/0x450 [ 62.623721] ? finish_wait+0x41/0x80 [ 62.626748] ? __kmalloc+0x178/0x2f0 [ 62.629768] ne_set_user_memory_region_ioctl.isra.0+0x225/0x6a0 [nitro_enclaves] [ 62.635776] ne_enclave_ioctl+0x1cf/0x6d7 [nitro_enclaves] [ 62.639541] __x64_sys_ioctl+0x82/0xb0 [ 62.642620] do_syscall_64+0x3b/0x90 [ 62.645642] entry_SYSCALL_64_after_hwframe+0x44/0xae Use get_user_pages_unlocked() when setting the enclave memory regions. That's a similar pattern as mmap_read_lock() used together with get_user_pages().

CVSS Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Affected Products

VendorProductVersions
LinuxLinux Kernel>= 5.15.0, < 5.15.13

Related Weaknesses (CWE)

CWE-667

References

FAQ

What is CVE-2021-46927?

CVE-2021-46927 is a vulnerability with a CVSS score of 5.5 (MEDIUM). In the Linux kernel, the following vulnerability has been resolved: nitro_enclaves: Use get_user_pages_unlocked() call to handle mmap assert After commit 5b78ed24e8ec ("mm/pagemap: add mmap_assert_l...

How severe is CVE-2021-46927?

CVE-2021-46927 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2021-46927?

Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.