CVE-2026-31697

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

crypto: ccp: Don't attempt to copy ID to userspace if PSP command failed

When retrieving the ID for the CPU, don't attempt to copy the ID blob to

userspace if the firmware command failed. If the failure was due to an

invalid length, i.e. the userspace buffer+length was too small, copying

the number of bytes _firmware_ requires will overflow the kernel-allocated

buffer and leak data to userspace.

BUG: KASAN: slab-out-of-bounds in instrument_copy_to_user ../include/linux/instrumented.h:129 [inline]

BUG: KASAN: slab-out-of-bounds in _inline_copy_to_user ../include/linux/uaccess.h:205 [inline]

BUG: KASAN: slab-out-of-bounds in _copy_to_user+0x66/0xa0 ../lib/usercopy.c:26

Read of size 64 at addr ffff8881867f5960 by task syz.0.906/24388

CPU: 130 UID: 0 PID: 24388 Comm: syz.0.906 Tainted: G U O 7.0.0-smp-DEV #28 PREEMPTLAZY

Tainted: [U]=USER, [O]=OOT_MODULE

Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 12.62.0-0 11/19/2025

Call Trace:

<TASK>

dump_stack_lvl+0xc5/0x110 ../lib/dump_stack.c:120

print_address_description ../mm/kasan/report.c:378 [inline]

print_report+0xbc/0x260 ../mm/kasan/report.c:482

kasan_report+0xa2/0xe0 ../mm/kasan/report.c:595

check_region_inline ../mm/kasan/generic.c:-1 [inline]

kasan_check_range+0x264/0x2c0 ../mm/kasan/generic.c:200

instrument_copy_to_user ../include/linux/instrumented.h:129 [inline]

_inline_copy_to_user ../include/linux/uaccess.h:205 [inline]

_copy_to_user+0x66/0xa0 ../lib/usercopy.c:26

copy_to_user ../include/linux/uaccess.h:236 [inline]

sev_ioctl_do_get_id2+0x361/0x490 ../drivers/crypto/ccp/sev-dev.c:2222

sev_ioctl+0x25f/0x490 ../drivers/crypto/ccp/sev-dev.c:2575

vfs_ioctl ../fs/ioctl.c:51 [inline]

__do_sys_ioctl ../fs/ioctl.c:597 [inline]

__se_sys_ioctl+0x11d/0x1b0 ../fs/ioctl.c:583

do_syscall_x64 ../arch/x86/entry/syscall_64.c:63 [inline]

do_syscall_64+0xe0/0x800 ../arch/x86/entry/syscall_64.c:94

entry_SYSCALL_64_after_hwframe+0x76/0x7e

</TASK>

WARN if the driver says the command succeeded, but the firmware error code

says otherwise, as __sev_do_cmd_locked() is expected to return -EIO on any

firwmware error.