CVE-2022-48897: In the Linux kernel, the following vulnerability has been resolved: arm64/mm: fix incorrect file_map_count for invalid pmd The page table check trigger…

PriorityP419medium5.5CVSS 3.1

AVLACLPRLUINSUCNINAH

EPSS

0.21%

10.6th percentile

In the Linux kernel, the following vulnerability has been resolved: arm64/mm: fix incorrect file_map_count for invalid pmd The page table check trigger BUG_ON() unexpectedly when split hugepage: ------------[ cut here ]------------ kernel BUG at mm/page_table_check.c:119! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 7 PID: 210 Comm: transhuge-stres Not tainted 6.1.0-rc3+ #748 Hardware name: linux,dummy-virt (DT) pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : page_table_check_set.isra.0+0x398/0x468 lr : page_table_check_set.isra.0+0x1c0/0x468 [...] Call trace: page_table_check_set.isra.0+0x398/0x468 __page_table_check_pte_set+0x160/0x1c0 __split_huge_pmd_locked+0x900/0x1648 __split_huge_pmd+0x28c/0x3b8 unmap_page_range+0x428/0x858 unmap_single_vma+0xf4/0x1c8 zap_page_range+0x2b0/0x410 madvise_vma_behavior+0xc44/0xe78 do_madvise+0x280/0x698 __arm64_sys_madvise+0x90/0xe8 invoke_syscall.constprop.0+0xdc/0x1d8 do_el0_svc+0xf4/0x3f8 el0_svc+0x58/0x120 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x19c/0x1a0 [...] On arm64, pmd_leaf() will return true even if the pmd is invalid due to pmd_present_invalid() check. So in pmdp_invalidate() the file_map_count will not only decrease once but also increase once. Then in set_pte_at(), the file_map_count increase again, and so trigger BUG_ON() unexpectedly. Add !pmd_present_invalid() check in pmd_user_accessible_page() to fix the problem.

Affected

9 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 6.1.7-1 (bookworm)	linux 6.1.7-1 (bookworm)
linux	linux	—	—
linux	linux	>= 42b2547137f5c974bb1bfd657c869fe96b96d86f < 21e5eca0ac9046da9918a919bc92b7b5a78d27e7	21e5eca0ac9046da9918a919bc92b7b5a78d27e7
linux	linux	>= 42b2547137f5c974bb1bfd657c869fe96b96d86f < 74c2f81054510d45b813548cb0a1c4ebf87cdd5f	74c2f81054510d45b813548cb0a1c4ebf87cdd5f
linux	linux_kernel	—	—
linux	linux_kernel	>= 0 < 6.1.7-1	6.1.7-1
linux	linux_kernel	>= 0 < 6.1.7-1	6.1.7-1
linux	linux_kernel	>= 0 < 6.1.7-1	6.1.7-1
linux	linux_kernel	>= 5.19 < 6.1.7	6.1.7

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv5.5MEDIUM

vendor_debian5.5MEDIUM

vendor_redhat5.5MEDIUM

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