[SRU][Jammy/Lunar/Mantic/OEM-6.5][PATCH 0/3] CVE-2023-46813

[Magali Lemes]

[Impact]
An issue was discovered in the Linux kernel before 6.5.9, exploitable by local
users with userspace access to MMIO registers. Incorrect access checking in the
#VC handler and instruction emulation of the SEV-ES emulation of MMIO accesses
could lead to arbitrary write access to kernel memory (and thus privilege
escalation). This depends on a race condition through which userspace can
replace an instruction before the #VC handler reads it.

[Backport]
Clean cherry-picks.

[Test]
Compile and boot tested.

[Regression potential]
Limited to the users of AMD's SEV-ES feature.

Borislav Petkov (AMD) (1):
  x86/sev: Disable MMIO emulation from user mode

Joerg Roedel (2):
  x86/sev: Check IOBM for IOIO exceptions from user-space
  x86/sev: Check for user-space IOIO pointing to kernel space

 arch/x86/boot/compressed/sev.c | 10 +++++++
 arch/x86/kernel/sev-shared.c   | 53 ++++++++++++++++++++++++++++------
 arch/x86/kernel/sev.c          | 30 +++++++++++++++++++
 3 files changed, 84 insertions(+), 9 deletions(-)

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2.34.1