CVE-2023-52874 - x86/tdx: Zero out the missing RSI in TDX_HYPERCALL macro

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HIGH

x86/tdx: Zero out the missing RSI in TDX_HYPERCALL macro

Published May 21, 2024

7.1

HIGH

CVSS 3.1

EPSS 0.26%

Description

In the TDX_HYPERCALL asm, after the TDCALL instruction returns from the untrusted VMM, the registers that the TDX guest shares to the VMM need to be cleared to avoid speculative execution of VMM-provided values.

RSI is specified in the bitmap of those registers, but it is missing when zeroing out those registers in the current TDX_HYPERCALL.

It was there when it was originally added in commit 752d13305c78 ("x86/tdx: Expand __tdx_hypercall() to handle more arguments"), but was later removed in commit 1e70c680375a ("x86/tdx: Do not corrupt frame-pointer in __tdx_hypercall()"), which was correct because %rsi is later restored in the "pop %rsi". However a later commit 7a3a401874be ("x86/tdx: Drop flags from __tdx_hypercall()") removed that "pop %rsi" but forgot to add the "xor %rsi, %rsi" back.

Fix by adding it back.

Affected products

Vendor Linux Product Linux Default
unaffected
- Version
  
  Status
  affected
  Constraints
- Version
  
  Status
  affected
  Constraints
- Version
  
  Status
  affected
  Constraints
Vendor Linux Product Linux Default
affected
- Version
  6.4
  Status
  affected
  Constraints
  -
- Version
  0
  Status
  unaffected
  Constraints
  <6.4
- Version
  6.5.12
  Status
  unaffected
  Constraints
  <=6.5.*
- Version
  6.6.2
  Status
  unaffected
  Constraints
  <=6.6.*
- Version
  6.7
  Status
  unaffected
  Constraints
  <=*

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor

Product

Default status

Versions

Linux

unaffected

Version	Status	Constraints
	affected
	affected
	affected

Linux

affected

Version	Status	Constraints
6.4	affected	-
0	unaffected	<6.4
6.5.12	unaffected	<=6.5.*
6.6.2	unaffected	<=6.6.*
6.7	unaffected	<=*

Red Hat Enterprise Linux 6

kernel

Out of support scope
Red Hat Enterprise Linux 7

kernel

Not affected
Red Hat Enterprise Linux 7

kernel-rt

Not affected
Red Hat Enterprise Linux 8

kernel

Not affected
Red Hat Enterprise Linux 8

kernel-rt

Not affected
Red Hat Enterprise Linux 9

kernel

Not affected
Red Hat Enterprise Linux 9

kernel-rt

Not affected

Product	Package	State	Advisory
Red Hat Enterprise Linux 6	kernel	Out of support scope	n/a
Red Hat Enterprise Linux 7	kernel	Not affected	n/a
Red Hat Enterprise Linux 7	kernel-rt	Not affected	n/a
Red Hat Enterprise Linux 8	kernel	Not affected	n/a
Red Hat Enterprise Linux 8	kernel-rt	Not affected	n/a
Red Hat Enterprise Linux 9	kernel	Not affected	n/a
Red Hat Enterprise Linux 9	kernel-rt	Not affected	n/a

Remediation

No remediation recorded yet.

Weaknesses (1)

CWE-15

References (8)

Link	Providers	Tags
https://access.redhat.com/security/cve/CVE-2023-52874		Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2282630		Issue Tracking
https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-59587		Advisory
https://git.kernel.org/stable/c/2191950d35d8f81620ea8d4e04d983f664fe3a8a		Patch
https://git.kernel.org/stable/c/5d092b66119d774853cc9308522620299048a662		Patch
https://git.kernel.org/stable/c/de4c5bacca4f50233f1f791bec9eeb4dee1b14cd		Patch
https://nvd.nist.gov/vuln/detail/CVE-2023-52874
https://www.cve.org/CVERecord?id=CVE-2023-52874