KVM: SEV: Protect *all* of sev_mem_enc_register_region() with kvm->lock
Summary
KVM: SEV: Protect all of sev_mem_enc_register_region() with kvm->lock
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
KVM: SEV: Protect all of sev_mem_enc_register_region() with kvm->lock
Take and hold kvm->lock for before checking sev_guest() in
sev_mem_enc_register_region(), as sev_guest() isn't stable unless kvm->lock
is held (or KVM can guarantee KVM_SEV_INIT{2} has completed and can't
rollack state). If KVM_SEV_INIT{2} fails, KVM can end up trying to add to
a not-yet-initialized sev->regions_list, e.g. triggering a #GP
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 110 UID: 0 PID: 72717 Comm: syz.15.11462 Tainted: G U W O 6.16.0-smp-DEV #1 NONE
Tainted: [U]=USER, [W]=WARN, [O]=OOT_MODULE
Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 12.52.0-0 10/28/2024
RIP: 0010:sev_mem_enc_register_region+0x3f0/0x4f0 ../include/linux/list.h:83
Code: <41> 80 3c 04 00 74 08 4c 89 ff e8 f1 c7 a2 00 49 39 ed 0f 84 c6 00
RSP: 0018:ffff88838647fbb8 EFLAGS: 00010256
RAX: dffffc0000000000 RBX: 1ffff92015cf1e0b RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000001000 RDI: ffff888367870000
RBP: ffffc900ae78f050 R08: ffffea000d9e0007 R09: 1ffffd4001b3c000
R10: dffffc0000000000 R11: fffff94001b3c001 R12: 0000000000000000
R13: ffff8982ab0bde00 R14: ffffc900ae78f058 R15: 0000000000000000
FS: 00007f34e9dc66c0(0000) GS:ffff89ee64d33000(000…
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2026-31592 linux-lts
- Debian DEBIAN-CVE-2026-31592 linux
- Ubuntu UBUNTU-CVE-2026-31592 linux-hwe-edge
References
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org