From patchwork Fri Nov 1 00:21:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 13858515 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 72E5F196; Fri, 1 Nov 2024 00:22:05 +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=1730420525; cv=none; b=nllCHNINeJXOTXXNjOM/TEKNfYqv0SuDp5mkfipM8tDwrnYlI6gkrab9CqaNIA2zVNVZqzFC4/ILaCQTwslLbv+Fn7eU6hcX9spbpQTKKyWSbeA27RnKaO2iwlt1hS00jbbE4t8bLnIQQ2OVq2vorQRcQtWDZ5ce+8+h7gZ8H3E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730420525; c=relaxed/simple; bh=2qL387XEwi0QJoPJLdNwkpzU1ZgxjA26xwDKEWQ6jvc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=YFit5nQjhqJah2dLeS3MI5suWo1c45uMeJtoyOKlru8c9wICCqw3PPfeIfQaCeczCy47weUJXgar3j2Iw5JtUJKXIE5KNqfYawbkyb8XJYOZcNSrVDG6mmIlCv0vLtO1ggeKzUd1xeFdURwbp5GlxJveUO3ei6sUIxNrlNXqQ7s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mqoiMvoO; 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="mqoiMvoO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75433C4CEC3; Fri, 1 Nov 2024 00:22:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730420524; bh=2qL387XEwi0QJoPJLdNwkpzU1ZgxjA26xwDKEWQ6jvc=; h=From:To:Cc:Subject:Date:From; b=mqoiMvoOta5E9zcIZpB0NV9tHfGDDN0X0lzrTzlo0O6/BVzdFlfxEHlU4hq2vGxO7 g90sAw1euB6VUi1XvA5Uhz5MDoWSAxqrtxxYVGOTXU//Uq8kHHGzljAJSFiYNP5Lve eVi1tBDmAt+KU4NgpcPfLJyo+Lj3702HoL6eXiL/lJGjyhUPDbNqOoByJXFt2aGk99 ladAF3d5uiMeznt+oTozrJQ18UfQkJR/gS4DZv1XDku+SgcXpsZnicS7Gg6RqbquTN m9oRQ31dYVS8/UQr1+s7y8vRF4cBUoUFL4LTzDtm/223rGvJUN9QP/ijkH7YowSW2y pSEfsZQtpTraQ== 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 v3] tpm: Lock TPM chip in tpm_pm_suspend() first Date: Fri, 1 Nov 2024 02:21:56 +0200 Message-ID: <20241101002157.645874-1-jarkko@kernel.org> X-Mailer: git-send-email 2.47.0 Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Setting TPM_CHIP_FLAG_SUSPENDED in the end of tpm_pm_suspend() can be racy according, as this leaves window for tpm_hwrng_read() to be called while the operation is in progress. The recent bug report gives also evidence of this behaviour. Aadress this by locking the TPM chip before checking any chip->flags both in tpm_pm_suspend() and tpm_hwrng_read(). Move TPM_CHIP_FLAG_SUSPENDED check inside tpm_get_random() so that it will be always checked only when the lock is reserved. 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=219383 Signed-off-by: Jarkko Sakkinen --- v3: - Check TPM_CHIP_FLAG_SUSPENDED inside tpm_get_random() so that it is also done under the lock (suggested by Jerry Snitselaar). v2: - Addressed my own remark: https://lore.kernel.org/linux-integrity/D59JAI6RR2CD.G5E5T4ZCZ49W@kernel.org/ --- drivers/char/tpm/tpm-chip.c | 4 ---- drivers/char/tpm/tpm-interface.c | 32 ++++++++++++++++++++++---------- 2 files changed, 22 insertions(+), 14 deletions(-) diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 1ff99a7091bb..7df7abaf3e52 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -525,10 +525,6 @@ static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait) { struct tpm_chip *chip = container_of(rng, struct tpm_chip, hwrng); - /* Give back zero bytes, as TPM chip has not yet fully resumed: */ - if (chip->flags & TPM_CHIP_FLAG_SUSPENDED) - return 0; - return tpm_get_random(chip, data, max); } diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 8134f002b121..b1daa0d7b341 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; + rc = tpm_try_get_ops(chip); + if (rc) { + /* Can be safely set out of locks, as no action cannot race: */ + chip->flags |= TPM_CHIP_FLAG_SUSPENDED; + goto out; + } + if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED) goto suspended; @@ -377,21 +384,19 @@ int tpm_pm_suspend(struct device *dev) !pm_suspend_via_firmware()) goto suspended; - rc = 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 = 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; } + rc = tpm1_pm_suspend(chip, tpm_suspend_pcr); + suspended: chip->flags |= TPM_CHIP_FLAG_SUSPENDED; + tpm_put_ops(chip); +out: if (rc) dev_err(dev, "Ignoring error %d while suspending\n", rc); return 0; @@ -440,11 +445,18 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max) if (!chip) return -ENODEV; + /* Give back zero bytes, as TPM chip has not yet fully resumed: */ + if (chip->flags & TPM_CHIP_FLAG_SUSPENDED) { + rc = 0; + goto out; + } + if (chip->flags & TPM_CHIP_FLAG_TPM2) rc = tpm2_get_random(chip, out, max); else rc = tpm1_get_random(chip, out, max); +out: tpm_put_ops(chip); return rc; }