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ubuntucveUbuntu.comUB:CVE-2022-48762
HistoryJun 20, 2024 - 12:00 a.m.

CVE-2022-48762

2024-06-2000:00:00
ubuntu.com
ubuntu.com
linux kernel
arm64
vulnerability fix
load_unaligned_zeropad
address register
data register
null pointer
dereference
crash

6.8 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

9.1%

In the Linux kernel, the following vulnerability has been resolved:
arm64: extable: fix load_unaligned_zeropad() reg indices
In ex_handler_load_unaligned_zeropad() we erroneously extract the data and
addr register indices from ex->type rather than ex->data. As ex->type will
contain EX_TYPE_LOAD_UNALIGNED_ZEROPAD (i.e. 4):

  • We’ll always treat X0 as the address register, since EX_DATA_REG_ADDR is
    extracted from bits [9:5]. Thus, we may attempt to dereference an
    arbitrary address as X0 may hold an arbitrary value.
  • We’ll always treat X4 as the data register, since EX_DATA_REG_DATA is
    extracted from bits [4:0]. Thus we will corrupt X4 and cause arbitrary
    behaviour within load_unaligned_zeropad() and its caller.
    Fix this by extracting both values from ex->data as originally intended.
    On an MTE-enabled QEMU image we are hitting the following crash:
    Unable to handle kernel NULL pointer dereference at virtual address
    0000000000000000
    Call trace:
    fixup_exception+0xc4/0x108
    __do_kernel_fault+0x3c/0x268
    do_tag_check_fault+0x3c/0x104
    do_mem_abort+0x44/0xf4
    el1_abort+0x40/0x64
    el1h_64_sync_handler+0x60/0xa0
    el1h_64_sync+0x7c/0x80
    link_path_walk+0x150/0x344
    path_openat+0xa0/0x7dc
    do_filp_open+0xb8/0x168
    do_sys_openat2+0x88/0x17c
    __arm64_sys_openat+0x74/0xa0
    invoke_syscall+0x48/0x148
    el0_svc_common+0xb8/0xf8
    do_el0_svc+0x28/0x88
    el0_svc+0x24/0x84
    el0t_64_sync_handler+0x88/0xec
    el0t_64_sync+0x1b4/0x1b8
    Code: f8695a69 71007d1f 540000e0 927df12a (f940014a)

6.8 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

9.1%