> From: linux-integrity-owner@xxxxxxxxxxxxxxx [mailto:linux-integrity-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Maurizio Drocco
> Sent: Friday, June 12, 2020 4:38 PM
> IMA is not considering TPM registers 8-9 when calculating the boot
> aggregate. When registers 8-9 are used to store measurements of the
> kernel and its command line (e.g., grub2 bootloader with tpm module
> enabled), IMA should include them in the boot aggregate.
>
> Signed-off-by: Maurizio Drocco <maurizio.drocco@xxxxxxx>
> ---
> security/integrity/ima/ima.h | 2 +-
> security/integrity/ima/ima_crypto.c | 15 ++++++++++++++-
> 2 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index df93ac258e01..9d94080bdad8 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -30,7 +30,7 @@
>
> enum ima_show_type { IMA_SHOW_BINARY,
> IMA_SHOW_BINARY_NO_FIELD_LEN,
> IMA_SHOW_BINARY_OLD_STRING_FMT,
> IMA_SHOW_ASCII };
> -enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
> +enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8, TPM_PCR10 = 10 };
>
> /* digest size for IMA, fits SHA1 or MD5 */
> #define IMA_DIGEST_SIZE SHA1_DIGEST_SIZE
> diff --git a/security/integrity/ima/ima_crypto.c
> b/security/integrity/ima/ima_crypto.c
> index 220b14920c37..64f5e3151e18 100644
> --- a/security/integrity/ima/ima_crypto.c
> +++ b/security/integrity/ima/ima_crypto.c
> @@ -809,7 +809,7 @@ static void ima_pcrread(u32 idx, struct tpm_digest *d)
> static int ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id,
> struct crypto_shash *tfm)
> {
> - struct tpm_digest d = { .alg_id = alg_id, .digest = {0} };
> + struct tpm_digest d = { .alg_id = alg_id, .digest = {0} }, d0 = d;
> int rc;
> u32 i;
> SHASH_DESC_ON_STACK(shash, tfm);
> @@ -830,6 +830,19 @@ static int ima_calc_boot_aggregate_tfm(char
> *digest, u16 alg_id,
> rc = crypto_shash_update(shash, d.digest,
> crypto_shash_digestsize(tfm));
> }
> + /*
> + * extend cumulative sha1 over tpm registers 8-9, which contain
Hi Maurizio
with recent patches, boot_aggregate can be calculated from non-SHA1
PCR banks. I would replace with:
Extend cumulative digest over ...
Given that with this patch boot_aggregate is calculated differently,
shouldn't we call it boot_aggregate_v2 and enable it with a new
option?
Thanks
Roberto
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Li Peng, Li Jian, Shi Yanli
> + * measurement for the kernel command line (reg. 8) and image
> (reg. 9)
> + * in a typical PCR allocation.
> + */
> + for (i = TPM_PCR8; i < TPM_PCR10; i++) {
> + ima_pcrread(i, &d);
> + /* if not zero, accumulate with current aggregate */
> + if (memcmp(d.digest, d0.digest,
> + crypto_shash_digestsize(tfm)) != 0)
> + rc = crypto_shash_update(shash, d.digest,
> +
> crypto_shash_digestsize(tfm));
> + }
> if (!rc)
> crypto_shash_final(shash, digest);
> return rc;
> --
> 2.17.1
--- Begin Message ---
- Subject: re: [PATCH 9/9] ima: Don't remove security.ima if file must not be appraised
- From: pmail_patchwork <patchwork@xxxxxxxxxx>
- Date: Thu, 28 May 2020 08:03:43 +0000
- Cc: pmail_hulkcommits <hulkcommits@xxxxxxxxxx>, pmail_hulkcommits <hulkcommits@xxxxxxxxxx>
- In-reply-to: <20200528065732.22351-4-roberto.sassu@huawei.com>
- Thread-index: AQHWNMJOo5mVCMbjDE6NnqkX1hFZvg==
- Thread-topic: [PATCH 9/9] ima: Don't remove security.ima if file must not be appraised
Total: 0 warnings, 0 errors, 3 items checked
All 3 test items SUCCESS.
Link: http://patchwork.huawei.com/patch/52890/
---
Hulk Robot
--- End Message ---