From nobody Mon Nov 25 01:58:56 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 38440156CF; Thu, 31 Oct 2024 00:45:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730335509; cv=none; b=qOCTztoPaNrOLkSSHCglt1DlsFxWGcKxPpkG6NsATn7bn2D3ah3WClYOgMYKJi55NfyhwDlGw+m0NLcpjmaAnrlK1vIWEq2qMSuQFpMfaSgrJ+9Ft17MObo5PxBadw13GPaQ0UOyqVNaOnepmNZda56/EsWgIzNHrrjsUmGoYWY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730335509; c=relaxed/simple; bh=L9TwB0ET8ic5Y1NDlL9zdzcEuTRfwOrfk8W3N9skWyI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=GvoMLEsIJZTC1kRJBJUZN0CCJ0t3DonRH26ipHf1BPhRb0v9px3DfIax1RXmy843CLD5EDtUoXjFqx46MGuSbFOU5O3Shy8iM+Uzqo05dpbbK1bekvp7Hx+C+vSsq8x1mQmdUNb+nrTanHumCuLpYA0B9WtJgrzmGb1sckKs8Bo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QYe5dU0l; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QYe5dU0l" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5972FC4CED4; Thu, 31 Oct 2024 00:45:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730335508; bh=L9TwB0ET8ic5Y1NDlL9zdzcEuTRfwOrfk8W3N9skWyI=; h=From:To:Cc:Subject:Date:From; b=QYe5dU0lkJnPHBlc/5STC0DRhfE6NID7VgLv8zjxrPS5yLbS1UjcAFtScmxyum8HV DnQIc9e18/ZiZQAlPNsICXIaJu5rkC57AfCSvSKZtz9vyULkuzRUSfy5T+6yGWsjkN n29RxR9ILcvD2DD9PvpsWo7mKnWKKH7HVJHscPhZjQakJF80bli+v4/s4qcl+8kYpy lQRtPh4y8ROZvqG2p/dxloVX0q9WXpJtla23d+tTm4iRfYdj/U3HpIGaXF5rEL4g6O mLrGY/8gUSKURZD0LLceucVRD8S2q19Xq0/gben8RlmB2rOruieAH2O4pUlTzeWTk7 04y7hOvTl+Jbw== From: Jarkko Sakkinen To: Peter Huewe , Jarkko Sakkinen , Jason Gunthorpe , Jerry Snitselaar Cc: stable@vger.kernel.org, Mike Seo , linux-integrity@vger.kernel.org (open list:TPM DEVICE DRIVER), linux-kernel@vger.kernel.org (open list) Subject: [PATCH v2] tpm: Lock TPM chip in tpm_pm_suspend() first Date: Thu, 31 Oct 2024 02:45:00 +0200 Message-ID: <20241031004501.165027-1-jarkko@kernel.org> X-Mailer: git-send-email 2.47.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Setting TPM_CHIP_FLAG_SUSPENDED in the end of tpm_pm_suspend() can be racy according to the bug report, as this leaves window for tpm_hwrng_read() to be called while the operation is in progress. To address this, lock the TPM chip before checking any possible flags. This will guarantee that tpm_hwrng_read() and tpm_pm_suspend() won't conflict with each other. Cc: stable@vger.kernel.org # v6.4+ Fixes: 99d464506255 ("tpm: Prevent hwrng from activating during resume") Reported-by: Mike Seo Closes: https://bugzilla.kernel.org/show_bug.cgi?id=3D219383 Signed-off-by: Jarkko Sakkinen --- v2: - Addressed my own remark: https://lore.kernel.org/linux-integrity/D59JAI6RR2CD.G5E5T4ZCZ49W@kernel.= org/ --- drivers/char/tpm/tpm-interface.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interf= ace.c index 8134f002b121..e37fcf9361bc 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -370,6 +370,13 @@ int tpm_pm_suspend(struct device *dev) if (!chip) return -ENODEV; =20 + rc =3D tpm_try_get_ops(chip); + if (rc) { + /* Can be safely set out of locks, as no action cannot race: */ + chip->flags |=3D TPM_CHIP_FLAG_SUSPENDED; + goto out; + } + if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED) goto suspended; =20 @@ -377,23 +384,22 @@ int tpm_pm_suspend(struct device *dev) !pm_suspend_via_firmware()) goto suspended; =20 - rc =3D tpm_try_get_ops(chip); - if (!rc) { - if (chip->flags & TPM_CHIP_FLAG_TPM2) { - tpm2_end_auth_session(chip); - tpm2_shutdown(chip, TPM2_SU_STATE); - } else { - rc =3D tpm1_pm_suspend(chip, tpm_suspend_pcr); - } - - tpm_put_ops(chip); + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + tpm2_end_auth_session(chip); + tpm2_shutdown(chip, TPM2_SU_STATE); + goto suspended; } =20 + rc =3D tpm1_pm_suspend(chip, tpm_suspend_pcr); + suspended: chip->flags |=3D TPM_CHIP_FLAG_SUSPENDED; + tpm_put_ops(chip); =20 +out: if (rc) dev_err(dev, "Ignoring error %d while suspending\n", rc); + return 0; } EXPORT_SYMBOL_GPL(tpm_pm_suspend); --=20 2.47.0