redonkable
/
remarkable-linux
1
0
Fork 0
Code Releases Activity

tpm: st33zp24: fix potential buffer overruns caused by bit glitches on the bus 

commit 6d24cd186d 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>
pull/10/head
Jeremy Boone 2018-02-08 12:29:09 -08:00 committed by Greg Kroah-Hartman
parent 972b19e615
commit 703fca31ac
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/char/tpm/st33zp24/st33zp24.c
View File

@ -457,7 +457,7 @@ static int st33zp24_recv(struct tpm_chip *chip, unsigned char *buf,
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 *chip, unsigned char *buf,
}
expected = be32_to_cpu(*(__be32 *)(buf + 2));
if (expected > count) {
if (expected > count || expected < TPM_HEADER_SIZE) {
size = -EIO;
goto out;
}