From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: x86@kernel.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>,
"Borislav Petkov" <bp@alien8.de>,
"Daniel P . Berrangé" <berrange@redhat.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Elena Reshetova" <elena.reshetova@intel.com>,
"H . Peter Anvin" <hpa@zytor.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
"Theodore Ts'o" <tytso@mit.edu>,
"Thomas Gleixner" <tglx@linutronix.de>
Subject: [PATCH v2 0/2] CoCo/RDRAND brokenness fixes
Date: Wed, 14 Feb 2024 20:56:46 +0100 [thread overview]
Message-ID: <20240214195744.8332-1-Jason@zx2c4.com> (raw)
This takes a two-pronged approach to the matter, now that we have
details from Intel and AMD:
- In the generic case, if RDRAND fails, simply WARN(), and don't try
again. It turns out the "try 10 times" thing isn't actually a correct
recommendation from Intel. Since RDRAND failure implies CPU failure, a
WARN() seems in order on all platforms.
- On CoCo machines, where RDRAND failure implies the whole threat model
is compromised and execution shouldn't continue, we ensure that the
RNG gets 256-bits of RDRAND at boot, or otherwise fails.
Cc: Borislav Petkov <bp@alien8.de>
Cc: Daniel P. Berrangé <berrange@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Jason A. Donenfeld (2):
x86/archrandom: WARN if RDRAND fails and don't retry
x86/coco: Require seeding RNG with RDRAND on CoCo systems
arch/x86/coco/core.c | 37 +++++++++++++++++++++++++++++++
arch/x86/include/asm/archrandom.h | 18 ++++++---------
arch/x86/include/asm/coco.h | 2 ++
arch/x86/kernel/setup.c | 2 ++
4 files changed, 48 insertions(+), 11 deletions(-)
--
2.43.0
next reply other threads:[~2024-02-14 19:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-14 19:56 Jason A. Donenfeld [this message]
2024-02-14 19:56 ` [PATCH v2 1/2] x86/archrandom: WARN if RDRAND fails and don't retry Jason A. Donenfeld
2024-02-14 19:56 ` [PATCH v2 2/2] x86/coco: Require seeding RNG with RDRAND on CoCo systems Jason A. Donenfeld
2024-02-15 7:30 ` Reshetova, Elena
2024-02-15 13:22 ` Jason A. Donenfeld
2024-02-16 7:57 ` Reshetova, Elena
2024-02-16 18:17 ` Jason A. Donenfeld
2024-02-21 7:52 ` Reshetova, Elena
2024-02-21 12:24 ` Jason A. Donenfeld
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