tpm: dynamically allocate the allocated_banks array

This patch renames active_banks (member of tpm_chip) to allocated_banks,
stores the number of allocated PCR banks in nr_allocated_banks (new member
of tpm_chip), and replaces the static array with a pointer to a dynamically
allocated array.

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(). If a bank is not allocated, the TPM returns that
bank in TPML_PCR_SELECTION, with all bits in the mask set to zero. In this
case, the bank is not included in chip->allocated_banks, to avoid that TPM
driver users unnecessarily calculate a digest for that bank.

One PCR bank with algorithm set to SHA1 is always allocated for TPM 1.x.

As a consequence of the introduction of nr_allocated_banks,
tpm_pcr_extend() does not check anymore if the algorithm stored in tpm_chip
is equal to zero.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 4eb48cf6a03af30e0c5f00dc73a7628f94bf8956..8804c9e916fd560a04c369795cd1ed6cf5add2b3 100644 (file)
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -266,6 +266,7 @@ 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 498809bf1bf04434569b40130a09f901f4ac4d48..2b31eff06b0e24e312dd8536d7bb673c834447c5 100644 (file)
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -318,8 +318,7 @@ 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);
@@ -327,16 +326,19 @@ 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 183e2b93e0fe9086c2b2364e4508b019f23ae3d9..cd330ace62481f5b5705751747e0d26d8d0d93d1 100644 (file)
--- 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 ec5f3693c0963b179c70bdbbcdc5eaf70ad128c3..e7d3228a0f37d5b44106545840bbb7a0be3c3619 100644 (file)
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -696,6 +696,16 @@ 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 971d46efaca5e1a4b690476f05ea7ab0017db0d5..bd20b9a61fc011e7d43cb4ca8aef567c8e49a8f6 100644 (file)
--- 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);
@@ -808,8 +808,10 @@ 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;
@@ -826,11 +828,14 @@ 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;
        }
 
@@ -839,7 +844,7 @@ 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) {
@@ -848,17 +853,23 @@ 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);
+
+               pcr_select_offset = memchr_inv(pcr_selection.pcr_select, 0,
+                                              pcr_selection.size_of_select);
+               if (pcr_select_offset) {
+                       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;