CVE-2022-50320

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

ACPI: tables: FPDT: Don't call acpi_os_map_memory() on invalid phys address

On a Packard Bell Dot SC (Intel Atom N2600 model) there is a FPDT table which contains invalid physical addresses, with high bits set which fall outside the range of the CPU-s supported physical address range.

Calling acpi_os_map_memory() on such an invalid phys address leads to the below WARN_ON in ioremap triggering resulting in an oops/stacktrace.

Add code to verify the physical address before calling acpi_os_map_memory() to fix / avoid the oops.

[ 1.226900] ioremap: invalid physical address 3001000000000000 [ 1.226949] ------------[ cut here ]------------ [ 1.226962] WARNING: CPU: 1 PID: 1 at arch/x86/mm/ioremap.c:200 __ioremap_caller.cold+0x43/0x5f [ 1.226996] Modules linked in: [ 1.227016] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.0.0-rc3+ #490 [ 1.227029] Hardware name: Packard Bell dot s/SJE01_CT, BIOS V1.10 07/23/2013 [ 1.227038] RIP: 0010:__ioremap_caller.cold+0x43/0x5f [ 1.227054] Code: 96 00 00 e9 f8 af 24 ff 89 c6 48 c7 c7 d8 0c 84 99 e8 6a 96 00 00 e9 76 af 24 ff 48 89 fe 48 c7 c7 a8 0c 84 99 e8 56 96 00 00 <0f> 0b e9 60 af 24 ff 48 8b 34 24 48 c7 c7 40 0d 84 99 e8 3f 96 00 [ 1.227067] RSP: 0000:ffffb18c40033d60 EFLAGS: 00010286 [ 1.227084] RAX: 0000000000000032 RBX: 3001000000000000 RCX: 0000000000000000 [ 1.227095] RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00000000ffffffff [ 1.227105] RBP: 3001000000000000 R08: 0000000000000000 R09: ffffb18c40033c18 [ 1.227115] R10: 0000000000000003 R11: ffffffff99d62fe8 R12: 0000000000000008 [ 1.227124] R13: 0003001000000000 R14: 0000000000001000 R15: 3001000000000000 [ 1.227135] FS: 0000000000000000(0000) GS:ffff913a3c080000(0000) knlGS:0000000000000000 [ 1.227146] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.227156] CR2: 0000000000000000 CR3: 0000000018c26000 CR4: 00000000000006e0 [ 1.227167] Call Trace: [ 1.227176] <TASK> [ 1.227185] ? acpi_os_map_iomem+0x1c9/0x1e0 [ 1.227215] ? kmem_cache_alloc_trace+0x187/0x370 [ 1.227254] acpi_os_map_iomem+0x1c9/0x1e0 [ 1.227288] acpi_init_fpdt+0xa8/0x253 [ 1.227308] ? acpi_debugfs_init+0x1f/0x1f [ 1.227339] do_one_initcall+0x5a/0x300 [ 1.227406] ? rcu_read_lock_sched_held+0x3f/0x80 [ 1.227442] kernel_init_freeable+0x28b/0x2cc [ 1.227512] ? rest_init+0x170/0x170 [ 1.227538] kernel_init+0x16/0x140 [ 1.227552] ret_from_fork+0x1f/0x30 [ 1.227639] </TASK> [ 1.227647] irq event stamp: 186819 [ 1.227656] hardirqs last enabled at (186825): [<ffffffff98184a6e>] __up_console_sem+0x5e/0x70 [ 1.227672] hardirqs last disabled at (186830): [<ffffffff98184a53>] __up_console_sem+0x43/0x70 [ 1.227686] softirqs last enabled at (186576): [<ffffffff980fbc9d>] __irq_exit_rcu+0xed/0x160 [ 1.227701] softirqs last disabled at (186569): [<ffffffff980fbc9d>] __irq_exit_rcu+0xed/0x160 [ 1.227715] ---[ end trace 0000000000000000 ]---

The bug in the ACPI FPDT parser could cause a kernel crash during boot on systems with firmware tables containing invalid physical addresses. It cannot be exploited remotely, as the invalid values originate from BIOS/UEFI tables, making it a reliability issue rather than a security risk. The patch ensures that only valid physical addresses are passed to acpi_os_map_memory(), preventing such boot-time crashes.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.