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tpm: fix response size validation in tpm_get_random()

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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@vger.kernel.org
Fixes: c659af78eb ("tpm: Check size of response before accessing data")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
This commit is contained in:
Jarkko Sakkinen 2018-09-03 04:01:26 +03:00
parent 2ecefa0a15
commit 84b59f6487
2 changed files with 5 additions and 2 deletions
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3
drivers/char/tpm/tpm-interface.c
View File

@ -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;

4
drivers/char/tpm/tpm2-cmd.c
View File

@ -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;
}