In the Linux kernel, the following vulnerability has been resolved:

of/irq: Prevent device address out-of-bounds read in interrupt map walk

When of_irq_parse_raw() is invoked with a device address smaller than the interrupt parent node (from #address-cells property), KASAN detects the following out-of-bounds read when populating the initial match table (dyndbg=func of_irq_parse_* +p):

OF: of_irq_parse_one: dev=/soc@0/picasso/watchdog, index=0 OF: parent=/soc@0/pci@878000000000/gpio0@17,0, intsize=2 OF: intspec=4 OF: of_irq_parse_raw: ipar=/soc@0/pci@878000000000/gpio0@17,0, size=2 OF: -> addrsize=3

BUG: KASAN: slab-out-of-bounds in of_irq_parse_raw+0x2b8/0x8d0 Read of size 4 at addr ffffff81beca5608 by task bash/764

CPU: 1 PID: 764 Comm: bash Tainted: G O 6.1.67-484c613561-nokia_sm_arm64 #1 Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2023.01-12.24.03-dirty 01/01/2023 Call trace: dump_backtrace+0xdc/0x130 show_stack+0x1c/0x30 dump_stack_lvl+0x6c/0x84 print_report+0x150/0x448 kasan_report+0x98/0x140 __asan_load4+0x78/0xa0 of_irq_parse_raw+0x2b8/0x8d0 of_irq_parse_one+0x24c/0x270 parse_interrupts+0xc0/0x120 of_fwnode_add_links+0x100/0x2d0 fw_devlink_parse_fwtree+0x64/0xc0 device_add+0xb38/0xc30 of_device_add+0x64/0x90 of_platform_device_create_pdata+0xd0/0x170 of_platform_bus_create+0x244/0x600 of_platform_notify+0x1b0/0x254 blocking_notifier_call_chain+0x9c/0xd0 __of_changeset_entry_notify+0x1b8/0x230 __of_changeset_apply_notify+0x54/0xe4 of_overlay_fdt_apply+0xc04/0xd94 …

The buggy address belongs to the object at ffffff81beca5600 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 8 bytes inside of 128-byte region [ffffff81beca5600, ffffff81beca5680)

The buggy address belongs to the physical page: page:00000000230d3d03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1beca4 head:00000000230d3d03 order:1 compound_mapcount:0 compound_pincount:0 flags: 0x8000000000010200(slab|head|zone=2) raw: 8000000000010200 0000000000000000 dead000000000122 ffffff810000c300 raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected

Memory state around the buggy address: ffffff81beca5500: 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffffff81beca5580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

ffffff81beca5600: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffffff81beca5680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffffff81beca5700: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc ================================================================== OF: -> got it !

Prevent the out-of-bounds read by copying the device address into a buffer of sufficient size.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/7ead730af11ee7da107f16fc77995613c58d292d
• https://git.kernel.org/stable/c/8ff351ea12e918db1373b915c4c268815929cbe5
• https://git.kernel.org/stable/c/9d1e9f0876b03d74d44513a0ed3ed15ef8f2fed5
• https://git.kernel.org/stable/c/b739dffa5d570b411d4bdf4bb9b8dfd6b7d72305
• https://git.kernel.org/stable/c/baaf26723beab3a04da578d3008be3544f83758f
• https://git.kernel.org/stable/c/bf68acd840b6a5bfd3777e0d5aaa204db6b461a9
• https://git.kernel.org/stable/c/d2a79494d8a5262949736fb2c3ac44d20a51b0d8
• https://git.kernel.org/stable/c/defcaa426ba0bc89ffdafb799d2e50b52f74ffc4