Messages in this thread | | | Subject | Re: [PATCH] tpm: fix response size validation in tpm_get_random() | From | Stefan Berger <> | Date | Wed, 5 Sep 2018 09:16:01 -0400 |
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On 09/02/2018 09:10 PM, Jarkko Sakkinen wrote: > When checking whether the response is large enough to be able to contain > the received random bytes in tpm_get_random() and tpm2_get_random(), > they fail to take account the header size, which should be added to the > minimum size. This commit fixes this issue. > > Cc: stable@vger.kernel.org > Fixes: c659af78eb7b ("tpm: Check size of response before accessing data") > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > --- > drivers/char/tpm/tpm-interface.c | 3 ++- > drivers/char/tpm/tpm2-cmd.c | 4 +++- > 2 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c > index 1a803b0cf980..318a7078b2ba 100644 > --- a/drivers/char/tpm/tpm-interface.c > +++ b/drivers/char/tpm/tpm-interface.c > @@ -1321,7 +1321,8 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max) > } > > rlength = be32_to_cpu(tpm_cmd.header.out.length); > - if (rlength < offsetof(struct tpm_getrandom_out, rng_data) + > + if (rlength < TPM_HEADER_SIZE + > + offsetof(struct tpm_getrandom_out, rng_data) + > recd) { > total = -EFAULT; > break; > diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c > index c31b490bd41d..3acf4fd4e5a5 100644 > --- a/drivers/char/tpm/tpm2-cmd.c > +++ b/drivers/char/tpm/tpm2-cmd.c > @@ -329,7 +329,9 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max) > &buf.data[TPM_HEADER_SIZE]; > recd = min_t(u32, be16_to_cpu(out->size), num_bytes); > if (tpm_buf_length(&buf) < > - offsetof(struct tpm2_get_random_out, buffer) + recd) { > + TPM_HEADER_SIZE + > + offsetof(struct tpm2_get_random_out, buffer) + > + recd) { > err = -EFAULT; > goto out; > }
Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
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