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;a=summary
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@xxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: James Morris <james.morris@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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