CVE-2025-40155

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

iommu/vt-d: debugfs: Fix legacy mode page table dump logic

In legacy mode, SSPTPTR is ignored if TT is not 00b or 01b. SSPTPTR

maybe uninitialized or zero in that case and may cause oops like:

Oops: general protection fault, probably for non-canonical address

0xf00087d3f000f000: 0000 [#1] SMP NOPTI

CPU: 2 UID: 0 PID: 786 Comm: cat Not tainted 6.16.0 #191 PREEMPT(voluntary)

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-5.fc42 04/01/2014

RIP: 0010:pgtable_walk_level+0x98/0x150

RSP: 0018:ffffc90000f279c0 EFLAGS: 00010206

RAX: 0000000040000000 RBX: ffffc90000f27ab0 RCX: 000000000000001e

RDX: 0000000000000003 RSI: f00087d3f000f000 RDI: f00087d3f0010000

RBP: ffffc90000f27a00 R08: ffffc90000f27a98 R09: 0000000000000002

R10: 0000000000000000 R11: 0000000000000000 R12: f00087d3f000f000

R13: 0000000000000000 R14: 0000000040000000 R15: ffffc90000f27a98

FS: 0000764566dcb740(0000) GS:ffff8881f812c000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000764566d44000 CR3: 0000000109d81003 CR4: 0000000000772ef0

PKRU: 55555554

Call Trace:

<TASK>

pgtable_walk_level+0x88/0x150

domain_translation_struct_show.isra.0+0x2d9/0x300

dev_domain_translation_struct_show+0x20/0x40

seq_read_iter+0x12d/0x490

...

Avoid walking the page table if TT is not 00b or 01b.