Message ID | 20181204082138.24600-2-roberto.sassu@huawei.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | tpm: retrieve digest size of unknown algorithms from TPM | expand |
On Tue, Dec 04, 2018 at 09:21:32AM +0100, Roberto Sassu wrote: > tpm2_get_pcr_allocation() determines if a PCR bank is allocated by checking > the mask in the TPML_PCR_SELECTION structure returned by the TPM for > TPM2_Get_Capability(). One PCR bank with algorithm set to SHA1 is always > allocated for TPM 1.x. ... > + for (j = 0; j < pcr_selection.size_of_select; j++) > + if (pcr_selection.pcr_select[j]) > + break; > + > + if (j < pcr_selection.size_of_select) { > + chip->allocated_banks[nr_alloc_banks] = hash_alg; > + nr_alloc_banks++; > + } > + Why was this needed? Can CAP_PCRS return completely unallocated banks? Kind of out-of-context for the rest of the changes. Should this be a bug fix of its own because it looks like as this is a bug fix for existing code, and not a new feature? Just asking because I don't yet fully understand this change. Anyway, I believe that you can streamline this by: /* Check that at least some of the PCRs have been allocated. This is * required because CAP_PCRS ... */ if (memchr_inv(pcr_selection.pcr_select, 0, pcr_selection.size_of_select)) nr_allocated_banks++; [yeah, comment would be awesome about CAP_PCRS. Did not finish up the comment because I don't know the answer] In addition, it would be consistent to call the local variable also nr_allocated_banks (not nr_alloc_banks). /Jarkko
On 12/5/2018 12:18 AM, Jarkko Sakkinen wrote: > On Tue, Dec 04, 2018 at 09:21:32AM +0100, Roberto Sassu wrote: >> tpm2_get_pcr_allocation() determines if a PCR bank is allocated by checking >> the mask in the TPML_PCR_SELECTION structure returned by the TPM for >> TPM2_Get_Capability(). One PCR bank with algorithm set to SHA1 is always >> allocated for TPM 1.x. > > ... > >> + for (j = 0; j < pcr_selection.size_of_select; j++) >> + if (pcr_selection.pcr_select[j]) >> + break; >> + >> + if (j < pcr_selection.size_of_select) { >> + chip->allocated_banks[nr_alloc_banks] = hash_alg; >> + nr_alloc_banks++; >> + } >> + > > Why was this needed? Can CAP_PCRS return completely unallocated banks? This was discussed for patch v4 1/6: --- Nayna wrote: # /usr/local/bin/tssgetcapability -cap 5 2 PCR selections hash TPM_ALG_SHA1 TPMS_PCR_SELECTION length 3 ff ff ff hash TPM_ALG_SHA256 TPMS_PCR_SELECTION length 3 00 00 00 The pcr_select fields - "ff ff ff" and "00 00 00" - are bit masks for the enabled PCRs. The SHA1 bank is enabled for all PCRs (0-23), while the SHA256 bank is not enabled. --- > Kind of out-of-context for the rest of the changes. > > Should this be a bug fix of its own because it looks like as this is a > bug fix for existing code, and not a new feature? Just asking because > I don't yet fully understand this change. If we store in tpm_chip the possible banks, IMA would calculate more digests unnecessarily. But this problem does not happen without my patch set, because tpm_pcr_extend() only accepts a SHA1 digest. > Anyway, I believe that you can streamline this by: > > /* Check that at least some of the PCRs have been allocated. This is > * required because CAP_PCRS ... > */ > if (memchr_inv(pcr_selection.pcr_select, 0, pcr_selection.size_of_select)) > nr_allocated_banks++; > > [yeah, comment would be awesome about CAP_PCRS. Did not finish up the > comment because I don't know the answer] > > In addition, it would be consistent to call the local variable also > nr_allocated_banks (not nr_alloc_banks). Unfortunately, I exceed the limit of characters per line. Roberto > /Jarkko >
On 12/4/2018 6:18 PM, Jarkko Sakkinen wrote: > >> + for (j = 0; j < pcr_selection.size_of_select; j++) >> + if (pcr_selection.pcr_select[j]) >> + break; >> + >> + if (j < pcr_selection.size_of_select) { >> + chip->allocated_banks[nr_alloc_banks] = hash_alg; >> + nr_alloc_banks++; >> + } >> + > > Why was this needed? Can CAP_PCRS return completely unallocated banks? > Yes. E.g., here's a TPM with 4 hash algorithms and two banks with allocated PCRs. > getcapability -cap 5 4 PCR selections hash TPM_ALG_SHA1 TPMS_PCR_SELECTION length 3 ff ff ff hash TPM_ALG_SHA256 TPMS_PCR_SELECTION length 3 ff ff ff hash TPM_ALG_SHA384 TPMS_PCR_SELECTION length 3 00 00 00 hash TPM_ALG_SHA512 TPMS_PCR_SELECTION length 3 00 00 00
On Thu, Dec 06, 2018 at 06:56:33PM +0100, Roberto Sassu wrote: > 2 PCR selections > hash TPM_ALG_SHA1 > TPMS_PCR_SELECTION length 3 > ff ff ff > hash TPM_ALG_SHA256 > TPMS_PCR_SELECTION length 3 > 00 00 00 > > The pcr_select fields - "ff ff ff" and "00 00 00" - are bit masks for > the enabled PCRs. The SHA1 bank is enabled for all PCRs (0-23), while > the SHA256 bank is not enabled. Uh, thanks. Can you add a note to the commit message? > > > > /* Check that at least some of the PCRs have been allocated. This is > > * required because CAP_PCRS ... > > */ > > if (memchr_inv(pcr_selection.pcr_select, 0, pcr_selection.size_of_select)) > > nr_allocated_banks++; > > > > [yeah, comment would be awesome about CAP_PCRS. Did not finish up the > > comment because I don't know the answer] > > > > In addition, it would be consistent to call the local variable also > > nr_allocated_banks (not nr_alloc_banks). > > Unfortunately, I exceed the limit of characters per line. Not sure what you mean? /Jarkko
On 12/12/2018 7:32 PM, Jarkko Sakkinen wrote: > On Thu, Dec 06, 2018 at 06:56:33PM +0100, Roberto Sassu wrote: >> 2 PCR selections >> hash TPM_ALG_SHA1 >> TPMS_PCR_SELECTION length 3 >> ff ff ff >> hash TPM_ALG_SHA256 >> TPMS_PCR_SELECTION length 3 >> 00 00 00 >> >> The pcr_select fields - "ff ff ff" and "00 00 00" - are bit masks for >> the enabled PCRs. The SHA1 bank is enabled for all PCRs (0-23), while >> the SHA256 bank is not enabled. > > Uh, thanks. Can you add a note to the commit message? Ok. >>> >>> /* Check that at least some of the PCRs have been allocated. This is >>> * required because CAP_PCRS ... >>> */ >>> if (memchr_inv(pcr_selection.pcr_select, 0, pcr_selection.size_of_select)) >>> nr_allocated_banks++; >>> >>> [yeah, comment would be awesome about CAP_PCRS. Did not finish up the >>> comment because I don't know the answer] >>> >>> In addition, it would be consistent to call the local variable also >>> nr_allocated_banks (not nr_alloc_banks). >> >> Unfortunately, I exceed the limit of characters per line. > > Not sure what you mean? --- - chip->allocated_banks[nr_alloc_banks] = hash_alg; + chip->allocated_banks[nr_alloc_banks].alg_id = hash_alg; --- If I use nr_allocated_banks, the line above (see patch 5/7) exceeds the limit of 80 characters. Roberto > /Jarkko >
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 32db84683c40..ce851c62bb68 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -160,6 +160,7 @@ static void tpm_dev_release(struct device *dev) kfree(chip->log.bios_event_log); kfree(chip->work_space.context_buf); kfree(chip->work_space.session_buf); + kfree(chip->allocated_banks); kfree(chip); } diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index d9439f9abe78..7b80919228be 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -488,8 +488,7 @@ EXPORT_SYMBOL_GPL(tpm_pcr_read); int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash) { int rc; - struct tpm2_digest digest_list[ARRAY_SIZE(chip->active_banks)]; - u32 count = 0; + struct tpm2_digest *digest_list; int i; chip = tpm_find_get_ops(chip); @@ -497,16 +496,19 @@ int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash) return -ENODEV; if (chip->flags & TPM_CHIP_FLAG_TPM2) { - memset(digest_list, 0, sizeof(digest_list)); + digest_list = kcalloc(chip->nr_allocated_banks, + sizeof(*digest_list), GFP_KERNEL); + if (!digest_list) + return -ENOMEM; - for (i = 0; i < ARRAY_SIZE(chip->active_banks) && - chip->active_banks[i] != TPM2_ALG_ERROR; i++) { - digest_list[i].alg_id = chip->active_banks[i]; + for (i = 0; i < chip->nr_allocated_banks; i++) { + digest_list[i].alg_id = chip->allocated_banks[i]; memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE); - count++; } - rc = tpm2_pcr_extend(chip, pcr_idx, count, digest_list); + rc = tpm2_pcr_extend(chip, pcr_idx, chip->nr_allocated_banks, + digest_list); + kfree(digest_list); tpm_put_ops(chip); return rc; } diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index f27d1f38a93d..6b94306ab7c5 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -257,7 +257,8 @@ struct tpm_chip { const struct attribute_group *groups[3]; unsigned int groups_cnt; - u16 active_banks[7]; + u32 nr_allocated_banks; + u16 *allocated_banks; #ifdef CONFIG_ACPI acpi_handle acpi_dev_handle; char ppi_version[TPM_PPI_VERSION_LEN + 1]; diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c index 6f306338953b..0874743ca96d 100644 --- a/drivers/char/tpm/tpm1-cmd.c +++ b/drivers/char/tpm/tpm1-cmd.c @@ -709,6 +709,16 @@ int tpm1_auto_startup(struct tpm_chip *chip) goto out; } + chip->allocated_banks = kcalloc(1, sizeof(*chip->allocated_banks), + GFP_KERNEL); + if (!chip->allocated_banks) { + rc = -ENOMEM; + goto out; + } + + chip->allocated_banks[0] = TPM2_ALG_SHA1; + chip->nr_allocated_banks = 1; + return rc; out: if (rc > 0) diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index a6bec13afa69..245669a7aba5 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -234,7 +234,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count, int i; int j; - if (count > ARRAY_SIZE(chip->active_banks)) + if (count > chip->nr_allocated_banks) return -EINVAL; rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND); @@ -825,11 +825,14 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip) void *marker; void *end; void *pcr_select_offset; - unsigned int count; u32 sizeof_pcr_selection; + u32 nr_possible_banks; + u32 nr_alloc_banks = 0; + u16 hash_alg; u32 rsp_len; int rc; int i = 0; + int j; rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY); if (rc) @@ -844,11 +847,14 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip) if (rc) goto out; - count = be32_to_cpup( + nr_possible_banks = be32_to_cpup( (__be32 *)&buf.data[TPM_HEADER_SIZE + 5]); - if (count > ARRAY_SIZE(chip->active_banks)) { - rc = -ENODEV; + chip->allocated_banks = kcalloc(nr_possible_banks, + sizeof(*chip->allocated_banks), + GFP_KERNEL); + if (!chip->allocated_banks) { + rc = -ENOMEM; goto out; } @@ -857,7 +863,7 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip) rsp_len = be32_to_cpup((__be32 *)&buf.data[2]); end = &buf.data[rsp_len]; - for (i = 0; i < count; i++) { + for (i = 0; i < nr_possible_banks; i++) { pcr_select_offset = marker + offsetof(struct tpm2_pcr_selection, size_of_select); if (pcr_select_offset >= end) { @@ -866,17 +872,25 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip) } memcpy(&pcr_selection, marker, sizeof(pcr_selection)); - chip->active_banks[i] = be16_to_cpu(pcr_selection.hash_alg); + hash_alg = be16_to_cpu(pcr_selection.hash_alg); + + for (j = 0; j < pcr_selection.size_of_select; j++) + if (pcr_selection.pcr_select[j]) + break; + + if (j < pcr_selection.size_of_select) { + chip->allocated_banks[nr_alloc_banks] = hash_alg; + nr_alloc_banks++; + } + sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) + sizeof(pcr_selection.size_of_select) + pcr_selection.size_of_select; marker = marker + sizeof_pcr_selection; } + chip->nr_allocated_banks = nr_alloc_banks; out: - if (i < ARRAY_SIZE(chip->active_banks)) - chip->active_banks[i] = TPM2_ALG_ERROR; - tpm_buf_destroy(&buf); return rc;