CVE-2024-46743: of/irq: Prevent device address out-of-bounds read in interrupt map walk

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

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

When ofirqparseraw() 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 ofirqparse +p"):

OF: ofirqparseone: dev=/soc@0/picasso/watchdog, index=0 OF: parent=/soc@0/pci@878000000000/gpio0@17,0, intsize=2 OF: intspec=4 OF: ofirqparseraw: ipar=/soc@0/pci@878000000000/gpio0@17,0, size=2 OF: -> addrsize=3 ================================================================== BUG: KASAN: slab-out-of-bounds in ofirqparseraw+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-nokiasmarm64 #1 Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2023.01-12.24.03-dirty 01/01/2023 Call trace: dumpbacktrace+0xdc/0x130 showstack+0x1c/0x30 dumpstacklvl+0x6c/0x84 printreport+0x150/0x448 kasanreport+0x98/0x140 asanload4+0x78/0xa0 ofirqparseraw+0x2b8/0x8d0 ofirqparseone+0x24c/0x270 parseinterrupts+0xc0/0x120 offwnodeaddlinks+0x100/0x2d0 fwdevlinkparsefwtree+0x64/0xc0 deviceadd+0xb38/0xc30 ofdeviceadd+0x64/0x90 ofplatformdevicecreatepdata+0xd0/0x170 ofplatformbuscreate+0x244/0x600 ofplatformnotify+0x1b0/0x254 blockingnotifiercallchain+0x9c/0xd0 ofchangesetentrynotify+0x1b8/0x230 ofchangesetapplynotify+0x54/0xe4 ofoverlayfdtapply+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 compoundmapcount:0 compoundpincount: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.