| Message ID | 20161027215009.GA12733@google.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Oct 27, 2016 at 02:50:09PM -0700, Josh Zimmerman wrote: > 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 (tpm_tis: Introduce intermediate layer for TPM access) > Signed-off-by: Josh Zimmerman <joshz@google.com> > > --- > Changelog v5: > - Move burstcnt < 0 check to before the min_t() call for enhanced readability. > Changelog v4: > - Add short description to Fixes tag line. > - Remove some unnecessary information in dev_err statements. > Changelog v3: > - Add signed-off-by. > Changelog v2: > - Fix typo (rc->burstcnt) > > --- > drivers/char/tpm/tpm_tis_core.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index e3bf31b..a1ce060 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -185,7 +185,12 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count) > TPM_STS_DATA_AVAIL | TPM_STS_VALID, > chip->timeout_c, > &priv->read_queue, true) == 0) { > - burstcnt = min_t(int, get_burstcount(chip), count - size); > + burstcnt = get_burstcount(chip); > + if (burstcnt < 0) { > + dev_err(&chip->dev, "Unable to read burstcount\n"); > + return burstcnt; > + } > + burstcnt = min_t(int, burstcnt, count - size); > > rc = tpm_tis_read_bytes(priv, TPM_DATA_FIFO(priv->locality), > burstcnt, buf + size); > @@ -271,7 +276,13 @@ 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); > + burstcnt = get_burstcount(chip); > + if (burstcnt < 0) { > + dev_err(&chip->dev, "Unable to read burstcount\n"); > + rc = burstcnt; > + goto out_err; > + } > + burstcnt = min_t(int, burstcnt, len - count - 1); > rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality), > burstcnt, buf + count); > if (rc < 0) > -- > 2.8.0.rc3.226.g39d4020 > LGTM Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> /Jarkko ------------------------------------------------------------------------------ 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
On Fri, Oct 28, 2016 at 07:28:15PM +0300, Jarkko Sakkinen wrote: > On Thu, Oct 27, 2016 at 02:50:09PM -0700, Josh Zimmerman wrote: > > 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 (tpm_tis: Introduce intermediate layer for TPM access) > > Signed-off-by: Josh Zimmerman <joshz@google.com> > > > > --- > > Changelog v5: > > - Move burstcnt < 0 check to before the min_t() call for enhanced readability. > > Changelog v4: > > - Add short description to Fixes tag line. > > - Remove some unnecessary information in dev_err statements. > > Changelog v3: > > - Add signed-off-by. > > Changelog v2: > > - Fix typo (rc->burstcnt) > > > > --- > > drivers/char/tpm/tpm_tis_core.c | 15 +++++++++++++-- > > 1 file changed, 13 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > > index e3bf31b..a1ce060 100644 > > --- a/drivers/char/tpm/tpm_tis_core.c > > +++ b/drivers/char/tpm/tpm_tis_core.c > > @@ -185,7 +185,12 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count) > > TPM_STS_DATA_AVAIL | TPM_STS_VALID, > > chip->timeout_c, > > &priv->read_queue, true) == 0) { > > - burstcnt = min_t(int, get_burstcount(chip), count - size); > > + burstcnt = get_burstcount(chip); > > + if (burstcnt < 0) { > > + dev_err(&chip->dev, "Unable to read burstcount\n"); > > + return burstcnt; > > + } > > + burstcnt = min_t(int, burstcnt, count - size); > > > > rc = tpm_tis_read_bytes(priv, TPM_DATA_FIFO(priv->locality), > > burstcnt, buf + size); > > @@ -271,7 +276,13 @@ 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); > > + burstcnt = get_burstcount(chip); > > + if (burstcnt < 0) { > > + dev_err(&chip->dev, "Unable to read burstcount\n"); > > + rc = burstcnt; > > + goto out_err; > > + } > > + burstcnt = min_t(int, burstcnt, len - count - 1); > > rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality), > > burstcnt, buf + count); > > if (rc < 0) > > -- > > 2.8.0.rc3.226.g39d4020 > > > > LGTM > > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> I'm sorry for the delay with testing but I cannot test this during this week. The network connection is terrible at the Linux Plumbers Conference and also at the hotel. I can barely read my email and LWN. /Jarkko ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi
On Wed, Nov 02, 2016 at 04:40:06AM -0600, Jarkko Sakkinen wrote: > On Fri, Oct 28, 2016 at 07:28:15PM +0300, Jarkko Sakkinen wrote: > > On Thu, Oct 27, 2016 at 02:50:09PM -0700, Josh Zimmerman wrote: > > > 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 (tpm_tis: Introduce intermediate layer for TPM access) > > > Signed-off-by: Josh Zimmerman <joshz@google.com> > > > > > > --- > > > Changelog v5: > > > - Move burstcnt < 0 check to before the min_t() call for enhanced readability. > > > Changelog v4: > > > - Add short description to Fixes tag line. > > > - Remove some unnecessary information in dev_err statements. > > > Changelog v3: > > > - Add signed-off-by. > > > Changelog v2: > > > - Fix typo (rc->burstcnt) > > > > > > --- > > > drivers/char/tpm/tpm_tis_core.c | 15 +++++++++++++-- > > > 1 file changed, 13 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > > > index e3bf31b..a1ce060 100644 > > > --- a/drivers/char/tpm/tpm_tis_core.c > > > +++ b/drivers/char/tpm/tpm_tis_core.c > > > @@ -185,7 +185,12 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count) > > > TPM_STS_DATA_AVAIL | TPM_STS_VALID, > > > chip->timeout_c, > > > &priv->read_queue, true) == 0) { > > > - burstcnt = min_t(int, get_burstcount(chip), count - size); > > > + burstcnt = get_burstcount(chip); > > > + if (burstcnt < 0) { > > > + dev_err(&chip->dev, "Unable to read burstcount\n"); > > > + return burstcnt; > > > + } > > > + burstcnt = min_t(int, burstcnt, count - size); > > > > > > rc = tpm_tis_read_bytes(priv, TPM_DATA_FIFO(priv->locality), > > > burstcnt, buf + size); > > > @@ -271,7 +276,13 @@ 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); > > > + burstcnt = get_burstcount(chip); > > > + if (burstcnt < 0) { > > > + dev_err(&chip->dev, "Unable to read burstcount\n"); > > > + rc = burstcnt; > > > + goto out_err; > > > + } > > > + burstcnt = min_t(int, burstcnt, len - count - 1); > > > rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality), > > > burstcnt, buf + count); > > > if (rc < 0) > > > -- > > > 2.8.0.rc3.226.g39d4020 > > > > > > > LGTM > > > > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > > I'm sorry for the delay with testing but I cannot test this during this > week. The network connection is terrible at the Linux Plumbers > Conference and also at the hotel. I can barely read my email and LWN. Applied. /Jarkko ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index e3bf31b..a1ce060 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -185,7 +185,12 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count) TPM_STS_DATA_AVAIL | TPM_STS_VALID, chip->timeout_c, &priv->read_queue, true) == 0) { - burstcnt = min_t(int, get_burstcount(chip), count - size); + burstcnt = get_burstcount(chip); + if (burstcnt < 0) { + dev_err(&chip->dev, "Unable to read burstcount\n"); + return burstcnt; + } + burstcnt = min_t(int, burstcnt, count - size); rc = tpm_tis_read_bytes(priv, TPM_DATA_FIFO(priv->locality), burstcnt, buf + size); @@ -271,7 +276,13 @@ 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); + burstcnt = get_burstcount(chip); + if (burstcnt < 0) { + dev_err(&chip->dev, "Unable to read burstcount\n"); + rc = burstcnt; + goto out_err; + } + burstcnt = min_t(int, burstcnt, len - count - 1); rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality), burstcnt, buf + count); if (rc < 0)
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 (tpm_tis: Introduce intermediate layer for TPM access) Signed-off-by: Josh Zimmerman <joshz@google.com> --- Changelog v5: - Move burstcnt < 0 check to before the min_t() call for enhanced readability. Changelog v4: - Add short description to Fixes tag line. - Remove some unnecessary information in dev_err statements. Changelog v3: - Add signed-off-by. Changelog v2: - Fix typo (rc->burstcnt) --- drivers/char/tpm/tpm_tis_core.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)