4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
commit 8569defde8057258835c51ce01a33de82e14b148 upstream.
Make sure size of response buffer is at least 6 bytes, or
we will underflow and pass large size_t to memcpy_fromio().
This was encountered while testing earlier version of
locality patchset.
Fixes: 30fc8d138e912 ("tpm: TPM 2.0 CRB Interface")
Signed-off-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/char/tpm/tpm_crb.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -118,8 +118,7 @@ static int crb_recv(struct tpm_chip *chi
memcpy_fromio(buf, priv->rsp, 6);
expected = be32_to_cpup((__be32 *) &buf[2]);
-
- if (expected > count)
+ if (expected > count || expected < 6)
return -EIO;
memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);