From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Zimmerman Subject: [PATCH v3] tpm_tis: Check return values from get_burstcount. Date: Wed, 26 Oct 2016 09:33:41 -0700 Message-ID: <20161026163341.GA19855@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tpmdd-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Peter Huewe , Marcel Selhorst , Jarkko Sakkinen , Jason Gunthorpe , tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: tpmdd-devel@lists.sourceforge.net If the TPM we're connecting to uses a static burst count, it will report a burst count of zero throughout the response read. However, get_burstcount assumes that a response of zero indicates that the TPM is not ready to receive more data. In this case, it returns a negative error code, which is passed on to tpm_tis_{write,read}_bytes as a u16, causing them to read/write far too many bytes. This patch checks for negative return codes and bails out from recv_data and tpm_tis_send_data. Fixes: 1107d065fdf1 Signed-off-by: Josh Zimmerman --- Changelog v3: - Add signed-off-by. Changelog v2: - Fix typo (rc->burstcnt) --- drivers/char/tpm/tpm_tis_core.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index e3bf31b..aed92b3 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -186,6 +186,12 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count) chip->timeout_c, &priv->read_queue, true) == 0) { burstcnt = min_t(int, get_burstcount(chip), count - size); + if (burstcnt < 0) { + dev_err(&chip->dev, + "Unable to read burstcount in %s:%d (%s)\n", + __FILE__, __LINE__, __func__); + return burstcnt; + } rc = tpm_tis_read_bytes(priv, TPM_DATA_FIFO(priv->locality), burstcnt, buf + size); @@ -272,6 +278,13 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len) while (count < len - 1) { burstcnt = min_t(int, get_burstcount(chip), len - count - 1); + if (burstcnt < 0) { + dev_err(&chip->dev, + "Unable to read burstcount in %s:%d (%s)\n", + __FILE__, __LINE__, __func__); + rc = burstcnt; + goto out_err; + } rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality), burstcnt, buf + count); if (rc < 0) -- 2.8.0.rc3.226.g39d4020 ------------------------------------------------------------------------------ The Command Line: Reinvented for Modern Developers Did the resurgence of CLI tooling catch you by surprise? Reconnect with the command line and become more productive. Learn the new .NET and ASP.NET CLI. Get your free copy! http://sdm.link/telerik