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_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().