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(unknown [9.47.158.152]) by b01ledav004.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 29 Jul 2021 16:19:35 +0000 (GMT) From: Stefan Berger To: jarkko@kernel.org Cc: peterhuewe@gmx.de, jgg@ziepe.ca, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Stefan Berger , Nayna Jain , George Wilson , Nageswara R Sastry Subject: [PATCH] tpm: ibmvtpm: Avoid error message when process gets signal while waiting Date: Thu, 29 Jul 2021 12:19:31 -0400 Message-Id: <20210729161931.3609894-1-stefanb@linux.vnet.ibm.com> X-Mailer: git-send-email 2.31.1 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: V3FyMKd6o9AAKRLhO-IlNn338K0xZY0W X-Proofpoint-GUID: HnvNjbmutjbe-adenl_3hw59qTn9Lczq X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-07-29_12:2021-07-29,2021-07-29 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 spamscore=0 phishscore=0 malwarescore=0 bulkscore=0 clxscore=1015 impostorscore=0 adultscore=0 mlxlogscore=999 suspectscore=0 mlxscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2107140000 definitions=main-2107290101 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Stefan Berger When rngd is run as root then lots of these types of message will appear in the kernel log if the TPM has been configure to provide random bytes: [ 7406.275163] tpm tpm0: tpm_transmit: tpm_recv: error -4 The issue is caused by the following call that is interrupted while waiting for the TPM's response. sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd); Rather than waiting for the response in the low level driver, have it use the polling loop in tpm_try_transmit() that uses a command's duration to poll until a result has been returned by the TPM, thus ending when the timeout has occurred but not responding to signals and ctrl-c anymore. To stay in this polling loop we now extend tpm_ibmvtpm_status() to return PM_STATUS_BUSY for as long as the vTPM is busy. Since we will need the timeouts in this loop now we get the TPM 1.2 and TPM 2 timeouts with tpm_get_timeouts(). Rename the tpm_processing_cmd to tpm_status in ibmvtpm_dev and set the TPM_STATUS_BUSY flag while the vTPM is busy processing a command. To recreat the issue start rngd like this: sudo rngd -r /dev/hwrng -t Link: https://bugzilla.redhat.com/show_bug.cgi?id=1981473 Fixes: 6674ff145eef ("tpm_ibmvtpm: properly handle interrupted packet receptions") Cc: Nayna Jain Cc: George Wilson Reported-by: Nageswara R Sastry Signed-off-by: Stefan Berger Tested-by: Nageswara R Sastry --- drivers/char/tpm/tpm_ibmvtpm.c | 31 ++++++++++++++++++------------- drivers/char/tpm/tpm_ibmvtpm.h | 3 ++- 2 files changed, 20 insertions(+), 14 deletions(-) diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c index 903604769de9..5d795866b483 100644 --- a/drivers/char/tpm/tpm_ibmvtpm.c +++ b/drivers/char/tpm/tpm_ibmvtpm.c @@ -106,17 +106,12 @@ static int tpm_ibmvtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count) { struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev); u16 len; - int sig; if (!ibmvtpm->rtce_buf) { dev_err(ibmvtpm->dev, "ibmvtpm device is not ready\n"); return 0; } - sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd); - if (sig) - return -EINTR; - len = ibmvtpm->res_len; if (count < len) { @@ -220,11 +215,12 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) return -EIO; } - if (ibmvtpm->tpm_processing_cmd) { + if ((ibmvtpm->tpm_status & TPM_STATUS_BUSY)) { dev_info(ibmvtpm->dev, "Need to wait for TPM to finish\n"); /* wait for previous command to finish */ - sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd); + sig = wait_event_interruptible(ibmvtpm->wq, + (ibmvtpm->tpm_status & TPM_STATUS_BUSY) == 0); if (sig) return -EINTR; } @@ -237,7 +233,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) * set the processing flag before the Hcall, since we may get the * result (interrupt) before even being able to check rc. */ - ibmvtpm->tpm_processing_cmd = true; + ibmvtpm->tpm_status |= TPM_STATUS_BUSY; again: rc = ibmvtpm_send_crq(ibmvtpm->vdev, @@ -255,7 +251,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) goto again; } dev_err(ibmvtpm->dev, "tpm_ibmvtpm_send failed rc=%d\n", rc); - ibmvtpm->tpm_processing_cmd = false; + ibmvtpm->tpm_status &= ~TPM_STATUS_BUSY; } spin_unlock(&ibmvtpm->rtce_lock); @@ -269,7 +265,9 @@ static void tpm_ibmvtpm_cancel(struct tpm_chip *chip) static u8 tpm_ibmvtpm_status(struct tpm_chip *chip) { - return 0; + struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev); + + return ibmvtpm->tpm_status; } /** @@ -457,7 +455,7 @@ static const struct tpm_class_ops tpm_ibmvtpm = { .send = tpm_ibmvtpm_send, .cancel = tpm_ibmvtpm_cancel, .status = tpm_ibmvtpm_status, - .req_complete_mask = 0, + .req_complete_mask = TPM_STATUS_BUSY, .req_complete_val = 0, .req_canceled = tpm_ibmvtpm_req_canceled, }; @@ -550,7 +548,7 @@ static void ibmvtpm_crq_process(struct ibmvtpm_crq *crq, case VTPM_TPM_COMMAND_RES: /* len of the data in rtce buffer */ ibmvtpm->res_len = be16_to_cpu(crq->len); - ibmvtpm->tpm_processing_cmd = false; + ibmvtpm->tpm_status &= ~TPM_STATUS_BUSY; wake_up_interruptible(&ibmvtpm->wq); return; default: @@ -688,8 +686,15 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev, goto init_irq_cleanup; } - if (!strcmp(id->compat, "IBM,vtpm20")) { + + if (!strcmp(id->compat, "IBM,vtpm20")) chip->flags |= TPM_CHIP_FLAG_TPM2; + + rc = tpm_get_timeouts(chip); + if (rc) + goto init_irq_cleanup; + + if (chip->flags & TPM_CHIP_FLAG_TPM2) { rc = tpm2_get_cc_attrs_tbl(chip); if (rc) goto init_irq_cleanup; diff --git a/drivers/char/tpm/tpm_ibmvtpm.h b/drivers/char/tpm/tpm_ibmvtpm.h index b92aa7d3e93e..252f1cccdfc5 100644 --- a/drivers/char/tpm/tpm_ibmvtpm.h +++ b/drivers/char/tpm/tpm_ibmvtpm.h @@ -41,7 +41,8 @@ struct ibmvtpm_dev { wait_queue_head_t wq; u16 res_len; u32 vtpm_version; - bool tpm_processing_cmd; + u8 tpm_status; +#define TPM_STATUS_BUSY (1 << 0) /* vtpm is processing a command */ }; #define CRQ_RES_BUF_SIZE PAGE_SIZE