This is a note to let you know that I've just added the patch titled
tpm_tis: fix potential buffer overruns caused by bit glitches on the bus
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: tpm_tis-fix-potential-buffer-overruns-caused-by-bit-glitches-on-the-bus.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 6bb320ca4a4a7b5b3db8c8d7250cc40002046878 Mon Sep 17 00:00:00 2001
From: Jeremy Boone jeremy.boone@nccgroup.trust Date: Thu, 8 Feb 2018 12:32:06 -0800 Subject: tpm_tis: fix potential buffer overruns caused by bit glitches on the bus
From: Jeremy Boone jeremy.boone@nccgroup.trust
commit 6bb320ca4a4a7b5b3db8c8d7250cc40002046878 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 Tested-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.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/tpm_tis.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/char/tpm/tpm_tis.c +++ b/drivers/char/tpm/tpm_tis.c @@ -283,7 +283,8 @@ static int recv_data(struct tpm_chip *ch static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) { int size = 0; - int expected, status; + int status; + u32 expected;
if (count < TPM_HEADER_SIZE) { size = -EIO; @@ -298,7 +299,7 @@ static int tpm_tis_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; }
Patches currently in stable-queue which might be from jeremy.boone@nccgroup.trust are
queue-4.4/tpm-fix-potential-buffer-overruns-caused-by-bit-glitches-on-the-bus.patch queue-4.4/tpm_tis-fix-potential-buffer-overruns-caused-by-bit-glitches-on-the-bus.patch