| Message ID | 20200623180122.209-1-maurizio.drocco@ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] ima_evm_utils: extended calc_bootaggr to PCRs 8 - 9 | expand |
On Tue, Jun 23, 2020 at 02:01:22PM -0400, Maurizio Drocco wrote: > From: Maurizio <maurizio.drocco@ibm.com> > > If PCRs 8 - 9 are set (i.e. not all-zeros), cal_bootaggr should include > them into the digest. > > Signed-off-by: Maurizio Drocco <maurizio.drocco@ibm.com> > --- > Changelog: > v2: > - Always include PCRs 8 & 9 to non-sha1 hashes > v1: > - Include non-zero PCRs 8 & 9 to boot aggregates > > src/evmctl.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/src/evmctl.c b/src/evmctl.c > index 1d065ce..46b7092 100644 > --- a/src/evmctl.c > +++ b/src/evmctl.c > @@ -1930,6 +1930,16 @@ static void calc_bootaggr(struct tpm_bank_info *bank) > } > } > > + if (strcmp(bank->algo_name, "sha1") != 0) { > + for (i = 8; i < 10; i++) { > + err = EVP_DigestUpdate(pctx, bank->pcr[i], bank->digest_size); > + if (!err) { > + log_err("EVP_DigestUpdate() failed\n"); > + return; > + } > + } > + } > + > err = EVP_DigestFinal(pctx, bank->digest, &mdlen); > if (!err) { > log_err("EVP_DigestFinal() failed\n"); > @@ -1972,8 +1982,9 @@ static int append_bootaggr(char *bootaggr, struct tpm_bank_info *tpm_banks) > /* > * The IMA measurement list boot_aggregate is the link between the preboot > * event log and the IMA measurement list. Read and calculate all the > - * possible per TPM bank boot_aggregate digests based on the existing > - * PCRs 0 - 7 to validate against the IMA boot_aggregate record. > + * possible per TPM bank boot_aggregate digests based on the existing PCRs > + * 0 - 9 to validate against the IMA boot_aggregate record. If the digest > + * algorithm is SHA1, only PCRs 0 - 7 are considered to avoid ambiguity. > */ > static int cmd_ima_bootaggr(struct command *cmd) > { > -- > 2.17.1 > Reviewed-by: Bruno Meneguele <bmeneg@redhat.com>
On 6/23/20 2:13 PM, Bruno Meneguele wrote: > On Tue, Jun 23, 2020 at 02:01:22PM -0400, Maurizio Drocco wrote: >> From: Maurizio <maurizio.drocco@ibm.com> >> >> If PCRs 8 - 9 are set (i.e. not all-zeros), cal_bootaggr should include >> them into the digest. Wouldn't you have to check for not all-zeros in your code? Stefan >> >> Signed-off-by: Maurizio Drocco <maurizio.drocco@ibm.com> >> --- >> Changelog: >> v2: >> - Always include PCRs 8 & 9 to non-sha1 hashes >> v1: >> - Include non-zero PCRs 8 & 9 to boot aggregates >> >> src/evmctl.c | 15 +++++++++++++-- >> 1 file changed, 13 insertions(+), 2 deletions(-) >> >> diff --git a/src/evmctl.c b/src/evmctl.c >> index 1d065ce..46b7092 100644 >> --- a/src/evmctl.c >> +++ b/src/evmctl.c >> @@ -1930,6 +1930,16 @@ static void calc_bootaggr(struct tpm_bank_info *bank) >> } >> } >> >> + if (strcmp(bank->algo_name, "sha1") != 0) { >> + for (i = 8; i < 10; i++) { >> + err = EVP_DigestUpdate(pctx, bank->pcr[i], bank->digest_size); >> + if (!err) { >> + log_err("EVP_DigestUpdate() failed\n"); >> + return; >> + } >> + } >> + } >> + >> err = EVP_DigestFinal(pctx, bank->digest, &mdlen); >> if (!err) { >> log_err("EVP_DigestFinal() failed\n"); >> @@ -1972,8 +1982,9 @@ static int append_bootaggr(char *bootaggr, struct tpm_bank_info *tpm_banks) >> /* >> * The IMA measurement list boot_aggregate is the link between the preboot >> * event log and the IMA measurement list. Read and calculate all the >> - * possible per TPM bank boot_aggregate digests based on the existing >> - * PCRs 0 - 7 to validate against the IMA boot_aggregate record. >> + * possible per TPM bank boot_aggregate digests based on the existing PCRs >> + * 0 - 9 to validate against the IMA boot_aggregate record. If the digest >> + * algorithm is SHA1, only PCRs 0 - 7 are considered to avoid ambiguity. >> */ >> static int cmd_ima_bootaggr(struct command *cmd) >> { >> -- >> 2.17.1 >> > Reviewed-by: Bruno Meneguele <bmeneg@redhat.com> >
On Wed, Jun 24, 2020 at 05:17:52PM -0400, Stefan Berger wrote: > On 6/23/20 2:13 PM, Bruno Meneguele wrote: > > On Tue, Jun 23, 2020 at 02:01:22PM -0400, Maurizio Drocco wrote: > > > From: Maurizio <maurizio.drocco@ibm.com> > > > > > > If PCRs 8 - 9 are set (i.e. not all-zeros), cal_bootaggr should include > > > them into the digest. > > > Wouldn't you have to check for not all-zeros in your code? > boot_aggregate in kernel, after the following patch be applied: https://lkml.org/lkml/2020/6/23/833 is calculated regardless PCR 8 & 9 being zero or not. Thus evmctl is only reflecting the same behavior. I think it would be worth changing the commit log here. > > Stefan > > > > > > > > Signed-off-by: Maurizio Drocco <maurizio.drocco@ibm.com> > > > --- > > > Changelog: > > > v2: > > > - Always include PCRs 8 & 9 to non-sha1 hashes > > > v1: > > > - Include non-zero PCRs 8 & 9 to boot aggregates > > > > > > src/evmctl.c | 15 +++++++++++++-- > > > 1 file changed, 13 insertions(+), 2 deletions(-) > > > > > > diff --git a/src/evmctl.c b/src/evmctl.c > > > index 1d065ce..46b7092 100644 > > > --- a/src/evmctl.c > > > +++ b/src/evmctl.c > > > @@ -1930,6 +1930,16 @@ static void calc_bootaggr(struct tpm_bank_info *bank) > > > } > > > } > > > + if (strcmp(bank->algo_name, "sha1") != 0) { > > > + for (i = 8; i < 10; i++) { > > > + err = EVP_DigestUpdate(pctx, bank->pcr[i], bank->digest_size); > > > + if (!err) { > > > + log_err("EVP_DigestUpdate() failed\n"); > > > + return; > > > + } > > > + } > > > + } > > > + > > > err = EVP_DigestFinal(pctx, bank->digest, &mdlen); > > > if (!err) { > > > log_err("EVP_DigestFinal() failed\n"); > > > @@ -1972,8 +1982,9 @@ static int append_bootaggr(char *bootaggr, struct tpm_bank_info *tpm_banks) > > > /* > > > * The IMA measurement list boot_aggregate is the link between the preboot > > > * event log and the IMA measurement list. Read and calculate all the > > > - * possible per TPM bank boot_aggregate digests based on the existing > > > - * PCRs 0 - 7 to validate against the IMA boot_aggregate record. > > > + * possible per TPM bank boot_aggregate digests based on the existing PCRs > > > + * 0 - 9 to validate against the IMA boot_aggregate record. If the digest > > > + * algorithm is SHA1, only PCRs 0 - 7 are considered to avoid ambiguity. > > > */ > > > static int cmd_ima_bootaggr(struct command *cmd) > > > { > > > -- > > > 2.17.1 > > > > > Reviewed-by: Bruno Meneguele <bmeneg@redhat.com> > > >
diff --git a/src/evmctl.c b/src/evmctl.c index 1d065ce..46b7092 100644 --- a/src/evmctl.c +++ b/src/evmctl.c @@ -1930,6 +1930,16 @@ static void calc_bootaggr(struct tpm_bank_info *bank) } } + if (strcmp(bank->algo_name, "sha1") != 0) { + for (i = 8; i < 10; i++) { + err = EVP_DigestUpdate(pctx, bank->pcr[i], bank->digest_size); + if (!err) { + log_err("EVP_DigestUpdate() failed\n"); + return; + } + } + } + err = EVP_DigestFinal(pctx, bank->digest, &mdlen); if (!err) { log_err("EVP_DigestFinal() failed\n"); @@ -1972,8 +1982,9 @@ static int append_bootaggr(char *bootaggr, struct tpm_bank_info *tpm_banks) /* * The IMA measurement list boot_aggregate is the link between the preboot * event log and the IMA measurement list. Read and calculate all the - * possible per TPM bank boot_aggregate digests based on the existing - * PCRs 0 - 7 to validate against the IMA boot_aggregate record. + * possible per TPM bank boot_aggregate digests based on the existing PCRs + * 0 - 9 to validate against the IMA boot_aggregate record. If the digest + * algorithm is SHA1, only PCRs 0 - 7 are considered to avoid ambiguity. */ static int cmd_ima_bootaggr(struct command *cmd) {