lkml.org 
[lkml]   [2018]   [Mar]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.15 008/122] tpm: st33zp24: fix potential buffer overruns caused by bit glitches on the bus
    Date
    4.15-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Jeremy Boone <jeremy.boone@nccgroup.trust>

    commit 6d24cd186d9fead3722108dec1b1c993354645ff upstream.

    Discrete TPMs are often connected over slow serial buses which, on
    some platforms, can have glitches causing bit flips. In all the
    driver _recv() functions, we need to use a u32 to unmarshal the
    response size, otherwise a bit flip of the 31st bit would cause the
    expected variable to go negative, which would then try to read a huge
    amount of data. Also sanity check that the expected amount of data is
    large enough for the TPM header.

    Signed-off-by: Jeremy Boone <jeremy.boone@nccgroup.trust>
    Cc: stable@vger.kernel.org
    Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
    Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    Signed-off-by: James Morris <james.morris@microsoft.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/char/tpm/st33zp24/st33zp24.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    --- a/drivers/char/tpm/st33zp24/st33zp24.c
    +++ b/drivers/char/tpm/st33zp24/st33zp24.c
    @@ -457,7 +457,7 @@ static int st33zp24_recv(struct tpm_chip
    size_t count)
    {
    int size = 0;
    - int expected;
    + u32 expected;

    if (!chip)
    return -EBUSY;
    @@ -474,7 +474,7 @@ static int st33zp24_recv(struct tpm_chip
    }

    expected = be32_to_cpu(*(__be32 *)(buf + 2));
    - if (expected > count) {
    + if (expected > count || expected < TPM_HEADER_SIZE) {
    size = -EIO;
    goto out;
    }

    \
     
     \ /
      Last update: 2018-03-07 20:41    [W:3.892 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site