The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 84b59f6487d82d3ab4247a099aba66d4d17e8b08 Mon Sep 17 00:00:00 2001
From: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Date: Mon, 3 Sep 2018 04:01:26 +0300
Subject: [PATCH] tpm: fix response size validation in tpm_get_random()
When checking whether the response is large enough to be able to contain
the received random bytes in tpm_get_random() and tpm2_get_random(),
they fail to take account the header size, which should be added to the
minimum size. This commit fixes this issue.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: c659af78eb7b ("tpm: Check size of response before accessing data")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 1a803b0cf980..318a7078b2ba 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -1321,7 +1321,8 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
}
rlength = be32_to_cpu(tpm_cmd.header.out.length);
- if (rlength < offsetof(struct tpm_getrandom_out, rng_data) +
+ if (rlength < TPM_HEADER_SIZE +
+ offsetof(struct tpm_getrandom_out, rng_data) +
recd) {
total = -EFAULT;
break;
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index c31b490bd41d..3acf4fd4e5a5 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -329,7 +329,9 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
&buf.data[TPM_HEADER_SIZE];
recd = min_t(u32, be16_to_cpu(out->size), num_bytes);
if (tpm_buf_length(&buf) <
- offsetof(struct tpm2_get_random_out, buffer) + recd) {
+ TPM_HEADER_SIZE +
+ offsetof(struct tpm2_get_random_out, buffer) +
+ recd) {
err = -EFAULT;
goto out;
}
