From: Jarkko Sakkinen <jarkko.sakki...@opinsys.com>

Define a cleanup for tpm_buf, which will caused tpm_buf_destroy()
automatically called at the end of a function scope. This will
significantly decrease the likelihood of memory leaks.

Signed-off-by: Jarkko Sakkinen <jarkko.sakki...@opinsys.com>
---
 drivers/char/tpm/tpm1-cmd.c               | 47 +++++-----------
 drivers/char/tpm/tpm2-cmd.c               | 67 ++++++++---------------
 drivers/char/tpm/tpm2-sessions.c          | 19 ++-----
 drivers/char/tpm/tpm2-space.c             | 15 +----
 drivers/char/tpm/tpm_vtpm_proxy.c         | 11 +---
 include/linux/tpm.h                       |  2 +
 security/keys/trusted-keys/trusted_tpm1.c |  6 +-
 security/keys/trusted-keys/trusted_tpm2.c | 26 +++------
 8 files changed, 59 insertions(+), 134 deletions(-)

diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index cf64c7385105..c7421f3f4187 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -323,7 +323,7 @@ unsigned long tpm1_calc_ordinal_duration(struct tpm_chip 
*chip, u32 ordinal)
  */
 static int tpm1_startup(struct tpm_chip *chip)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
 
        dev_info(&chip->dev, "starting up the TPM manually\n");
@@ -335,7 +335,6 @@ static int tpm1_startup(struct tpm_chip *chip)
        tpm_buf_append_u16(&buf, TPM_ST_CLEAR);
 
        rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to start the TPM");
-       tpm_buf_destroy(&buf);
        return rc;
 }
 
@@ -463,7 +462,7 @@ int tpm1_get_timeouts(struct tpm_chip *chip)
 int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash,
                    const char *log_msg)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
 
        rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_PCR_EXTEND);
@@ -474,7 +473,6 @@ int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, 
const u8 *hash,
        tpm_buf_append(&buf, hash, TPM_DIGEST_SIZE);
 
        rc = tpm_transmit_cmd(chip, &buf, TPM_DIGEST_SIZE, log_msg);
-       tpm_buf_destroy(&buf);
        return rc;
 }
 
@@ -482,7 +480,7 @@ int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, 
const u8 *hash,
 ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
                    const char *desc, size_t min_cap_length)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
 
        rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_GET_CAP);
@@ -506,7 +504,6 @@ ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, 
cap_t *cap,
        rc = tpm_transmit_cmd(chip, &buf, min_cap_length, desc);
        if (!rc)
                *cap = *(cap_t *)&buf.data[TPM_HEADER_SIZE + 4];
-       tpm_buf_destroy(&buf);
        return rc;
 }
 EXPORT_SYMBOL_GPL(tpm1_getcap);
@@ -529,9 +526,9 @@ struct tpm1_get_random_out {
  */
 int tpm1_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
 {
+       CLASS(tpm_buf, buf)();
        struct tpm1_get_random_out *out;
        u32 num_bytes =  min_t(u32, max, TPM_MAX_RNG_DATA);
-       struct tpm_buf buf;
        u32 total = 0;
        int retries = 5;
        u32 recd;
@@ -549,22 +546,18 @@ int tpm1_get_random(struct tpm_chip *chip, u8 *dest, 
size_t max)
                if (rc) {
                        if (rc > 0)
                                rc = -EIO;
-                       goto out;
+                       return rc;
                }
 
                out = (struct tpm1_get_random_out *)&buf.data[TPM_HEADER_SIZE];
 
                recd = be32_to_cpu(out->rng_data_len);
-               if (recd > num_bytes) {
-                       rc = -EFAULT;
-                       goto out;
-               }
+               if (recd > num_bytes)
+                       return -EFAULT;
 
                if (tpm_buf_length(&buf) < TPM_HEADER_SIZE +
-                                          sizeof(out->rng_data_len) + recd) {
-                       rc = -EFAULT;
-                       goto out;
-               }
+                                          sizeof(out->rng_data_len) + recd)
+                       return -EFAULT;
                memcpy(dest, out->rng_data, recd);
 
                dest += recd;
@@ -575,15 +568,13 @@ int tpm1_get_random(struct tpm_chip *chip, u8 *dest, 
size_t max)
        } while (retries-- && total < max);
 
        rc = total ? (int)total : -EIO;
-out:
-       tpm_buf_destroy(&buf);
        return rc;
 }
 
 #define TPM_ORD_PCRREAD 21
 int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
 
        rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_PCRREAD);
@@ -595,17 +586,12 @@ int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 
*res_buf)
        rc = tpm_transmit_cmd(chip, &buf, TPM_DIGEST_SIZE,
                              "attempting to read a pcr value");
        if (rc)
-               goto out;
+               return rc;
 
-       if (tpm_buf_length(&buf) < TPM_DIGEST_SIZE) {
-               rc = -EFAULT;
-               goto out;
-       }
+       if (tpm_buf_length(&buf) < TPM_DIGEST_SIZE)
+               return -EFAULT;
 
        memcpy(res_buf, &buf.data[TPM_HEADER_SIZE], TPM_DIGEST_SIZE);
-
-out:
-       tpm_buf_destroy(&buf);
        return rc;
 }
 
@@ -619,7 +605,7 @@ int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 
*res_buf)
  */
 static int tpm1_continue_selftest(struct tpm_chip *chip)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
 
        rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_CONTINUE_SELFTEST);
@@ -627,7 +613,6 @@ static int tpm1_continue_selftest(struct tpm_chip *chip)
                return rc;
 
        rc = tpm_transmit_cmd(chip, &buf, 0, "continue selftest");
-       tpm_buf_destroy(&buf);
        return rc;
 }
 
@@ -742,7 +727,7 @@ int tpm1_auto_startup(struct tpm_chip *chip)
 int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr)
 {
        u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        unsigned int try;
        int rc;
 
@@ -782,8 +767,6 @@ int tpm1_pm_suspend(struct tpm_chip *chip, u32 
tpm_suspend_pcr)
                dev_warn(&chip->dev, "TPM savestate took %dms\n",
                         try * TPM_TIMEOUT_RETRY);
 
-       tpm_buf_destroy(&buf);
-
        return rc;
 }
 
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 524d802ede26..8b702c529794 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -165,9 +165,9 @@ struct tpm2_pcr_read_out {
 int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
                  struct tpm_digest *digest, u16 *digest_size_ptr)
 {
+       CLASS(tpm_buf, buf)();
        int i;
        int rc;
-       struct tpm_buf buf;
        struct tpm2_pcr_read_out *out;
        u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0};
        u16 digest_size;
@@ -216,7 +216,6 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 
        memcpy(digest->digest, out->digest, digest_size);
 out:
-       tpm_buf_destroy(&buf);
        return rc;
 }
 
@@ -232,7 +231,7 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
                    struct tpm_digest *digests)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
        int i;
 
@@ -271,8 +270,6 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
        if (!disable_pcr_integrity)
                rc = tpm_buf_check_hmac_response(chip, &buf, rc);
 
-       tpm_buf_destroy(&buf);
-
        return rc;
 }
 
@@ -294,9 +291,9 @@ struct tpm2_get_random_out {
  */
 int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
 {
+       CLASS(tpm_buf, buf)();
        struct tpm2_get_random_out *out;
        struct tpm_header *head;
-       struct tpm_buf buf;
        u32 recd;
        u32 num_bytes = max;
        int err;
@@ -358,11 +355,9 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, 
size_t max)
                num_bytes -= recd;
        } while (retries-- && total < max);
 
-       tpm_buf_destroy(&buf);
-
        return total ? total : -EIO;
+
 out:
-       tpm_buf_destroy(&buf);
        tpm2_end_auth_session(chip);
        return err;
 }
@@ -374,7 +369,7 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t 
max)
  */
 void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
 
        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_FLUSH_CONTEXT);
@@ -387,7 +382,6 @@ void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
        tpm_buf_append_u32(&buf, handle);
 
        tpm_transmit_cmd(chip, &buf, 0, "flushing context");
-       tpm_buf_destroy(&buf);
 }
 EXPORT_SYMBOL_GPL(tpm2_flush_context);
 
@@ -413,8 +407,8 @@ struct tpm2_get_cap_out {
 ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
                        const char *desc)
 {
+       CLASS(tpm_buf, buf)();
        struct tpm2_get_cap_out *out;
-       struct tpm_buf buf;
        int rc;
 
        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
@@ -438,7 +432,6 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 
property_id,  u32 *value,
                else
                        rc = -ENODATA;
        }
-       tpm_buf_destroy(&buf);
        return rc;
 }
 EXPORT_SYMBOL_GPL(tpm2_get_tpm_pt);
@@ -455,7 +448,7 @@ EXPORT_SYMBOL_GPL(tpm2_get_tpm_pt);
  */
 void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
 
        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SHUTDOWN);
@@ -463,7 +456,6 @@ void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
                return;
        tpm_buf_append_u16(&buf, shutdown_type);
        tpm_transmit_cmd(chip, &buf, 0, "stopping the TPM");
-       tpm_buf_destroy(&buf);
 }
 
 /**
@@ -481,7 +473,7 @@ void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
  */
 static int tpm2_do_selftest(struct tpm_chip *chip)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int full;
        int rc;
 
@@ -493,7 +485,6 @@ static int tpm2_do_selftest(struct tpm_chip *chip)
                tpm_buf_append_u8(&buf, full);
                rc = tpm_transmit_cmd(chip, &buf, 0,
                                      "attempting the self test");
-               tpm_buf_destroy(&buf);
 
                if (rc == TPM2_RC_TESTING)
                        rc = TPM2_RC_SUCCESS;
@@ -518,8 +509,8 @@ static int tpm2_do_selftest(struct tpm_chip *chip)
  */
 int tpm2_probe(struct tpm_chip *chip)
 {
+       CLASS(tpm_buf, buf)();
        struct tpm_header *out;
-       struct tpm_buf buf;
        int rc;
 
        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
@@ -535,7 +526,6 @@ int tpm2_probe(struct tpm_chip *chip)
                if (be16_to_cpu(out->tag) == TPM2_ST_NO_SESSIONS)
                        chip->flags |= TPM_CHIP_FLAG_TPM2;
        }
-       tpm_buf_destroy(&buf);
        return 0;
 }
 EXPORT_SYMBOL_GPL(tpm2_probe);
@@ -574,8 +564,8 @@ struct tpm2_pcr_selection {
 
 ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 {
+       CLASS(tpm_buf, buf)();
        struct tpm2_pcr_selection pcr_selection;
-       struct tpm_buf buf;
        void *marker;
        void *end;
        void *pcr_select_offset;
@@ -597,7 +587,7 @@ ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 
        rc = tpm_transmit_cmd(chip, &buf, 9, "get tpm pcr allocation");
        if (rc)
-               goto out;
+               return rc;
 
        nr_possible_banks = be32_to_cpup(
                (__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);
@@ -605,23 +595,20 @@ ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
        chip->allocated_banks = kcalloc(nr_possible_banks,
                                        sizeof(*chip->allocated_banks),
                                        GFP_KERNEL);
-       if (!chip->allocated_banks) {
-               rc = -ENOMEM;
-               goto out;
-       }
+       if (!chip->allocated_banks)
+               return -ENOMEM;
 
        marker = &buf.data[TPM_HEADER_SIZE + 9];
 
        rsp_len = be32_to_cpup((__be32 *)&buf.data[2]);
        end = &buf.data[rsp_len];
 
+       return rc;
        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) {
-                       rc = -EFAULT;
-                       break;
-               }
+               if (pcr_select_offset >= end)
+                       return -EFAULT;
 
                memcpy(&pcr_selection, marker, sizeof(pcr_selection));
                hash_alg = be16_to_cpu(pcr_selection.hash_alg);
@@ -633,7 +620,7 @@ ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 
                        rc = tpm2_init_bank_info(chip, nr_alloc_banks);
                        if (rc < 0)
-                               break;
+                               return rc;
 
                        nr_alloc_banks++;
                }
@@ -645,15 +632,12 @@ ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
        }
 
        chip->nr_allocated_banks = nr_alloc_banks;
-out:
-       tpm_buf_destroy(&buf);
-
-       return rc;
+       return 0;
 }
 
 int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        u32 nr_commands;
        __be32 *attrs;
        u32 cc;
@@ -685,15 +669,12 @@ int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
        tpm_buf_append_u32(&buf, nr_commands);
 
        rc = tpm_transmit_cmd(chip, &buf, 9 + 4 * nr_commands, NULL);
-       if (rc) {
-               tpm_buf_destroy(&buf);
+       if (rc)
                goto out;
-       }
 
        if (nr_commands !=
            be32_to_cpup((__be32 *)&buf.data[TPM_HEADER_SIZE + 5])) {
                rc = -EFAULT;
-               tpm_buf_destroy(&buf);
                goto out;
        }
 
@@ -711,8 +692,6 @@ int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
                }
        }
 
-       tpm_buf_destroy(&buf);
-
 out:
        if (rc > 0)
                rc = -ENODEV;
@@ -733,7 +712,7 @@ EXPORT_SYMBOL_GPL(tpm2_get_cc_attrs_tbl);
 
 static int tpm2_startup(struct tpm_chip *chip)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
 
        dev_info(&chip->dev, "starting up the TPM manually\n");
@@ -743,10 +722,8 @@ static int tpm2_startup(struct tpm_chip *chip)
                return rc;
 
        tpm_buf_append_u16(&buf, TPM2_SU_CLEAR);
-       rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to start the TPM");
-       tpm_buf_destroy(&buf);
 
-       return rc;
+       return tpm_transmit_cmd(chip, &buf, 0, "attempting to start the TPM");
 }
 
 /**
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 7b5049b3d476..94af69a66252 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -182,7 +182,7 @@ static int tpm2_parse_read_public(char *name, struct 
tpm_buf *buf)
 
 static int tpm2_read_public(struct tpm_chip *chip, u32 handle, char *name)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
 
        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_READ_PUBLIC);
@@ -194,8 +194,6 @@ static int tpm2_read_public(struct tpm_chip *chip, u32 
handle, char *name)
        if (rc == TPM2_RC_SUCCESS)
                rc = tpm2_parse_read_public(name, &buf);
 
-       tpm_buf_destroy(&buf);
-
        return rc;
 }
 #endif /* CONFIG_TCG_TPM2_HMAC */
@@ -968,8 +966,8 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 
*null_key)
  */
 int tpm2_start_auth_session(struct tpm_chip *chip)
 {
+       CLASS(tpm_buf, buf)();
        struct tpm2_auth *auth;
-       struct tpm_buf buf;
        u32 null_key;
        int rc;
 
@@ -1022,8 +1020,6 @@ int tpm2_start_auth_session(struct tpm_chip *chip)
        if (rc == TPM2_RC_SUCCESS)
                rc = tpm2_parse_start_auth_session(auth, &buf);
 
-       tpm_buf_destroy(&buf);
-
        if (rc == TPM2_RC_SUCCESS) {
                chip->auth = auth;
                return 0;
@@ -1243,19 +1239,17 @@ static int tpm2_parse_create_primary(struct tpm_chip 
*chip, struct tpm_buf *buf,
 static int tpm2_create_primary(struct tpm_chip *chip, u32 hierarchy,
                               u32 *handle, u8 *name)
 {
+       CLASS(tpm_buf, buf)();
+       CLASS(tpm_buf, template)();
        int rc;
-       struct tpm_buf buf;
-       struct tpm_buf template;
 
        rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE_PRIMARY);
        if (rc)
                return rc;
 
        rc = tpm_buf_init_sized(&template);
-       if (rc) {
-               tpm_buf_destroy(&buf);
+       if (rc)
                return rc;
-       }
 
        /*
         * create the template.  Note: in order for userspace to
@@ -1319,7 +1313,6 @@ static int tpm2_create_primary(struct tpm_chip *chip, u32 
hierarchy,
 
        /* the public template */
        tpm_buf_append(&buf, template.data, template.length);
-       tpm_buf_destroy(&template);
 
        /* outside info (empty) */
        tpm_buf_append_u16(&buf, 0);
@@ -1334,8 +1327,6 @@ static int tpm2_create_primary(struct tpm_chip *chip, u32 
hierarchy,
                rc = tpm2_parse_create_primary(chip, &buf, handle, hierarchy,
                                               name);
 
-       tpm_buf_destroy(&buf);
-
        return rc;
 }
 
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 60354cd53b5c..c549111b60e4 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -71,7 +71,7 @@ void tpm2_del_space(struct tpm_chip *chip, struct tpm_space 
*space)
 int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
                      unsigned int *offset, u32 *handle)
 {
-       struct tpm_buf tbuf;
+       CLASS(tpm_buf, tbuf)();
        struct tpm2_context *ctx;
        unsigned int body_size;
        int rc;
@@ -88,7 +88,6 @@ int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
        if (rc < 0) {
                dev_warn(&chip->dev, "%s: failed with a system error %d\n",
                         __func__, rc);
-               tpm_buf_destroy(&tbuf);
                return -EFAULT;
        } else if (tpm2_rc_value(rc) == TPM2_RC_HANDLE ||
                   rc == TPM2_RC_REFERENCE_H0) {
@@ -103,29 +102,24 @@ int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
                 * flushed outside the space
                 */
                *handle = 0;
-               tpm_buf_destroy(&tbuf);
                return -ENOENT;
        } else if (tpm2_rc_value(rc) == TPM2_RC_INTEGRITY) {
-               tpm_buf_destroy(&tbuf);
                return -EINVAL;
        } else if (rc > 0) {
                dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
                         __func__, rc);
-               tpm_buf_destroy(&tbuf);
                return -EFAULT;
        }
 
        *handle = be32_to_cpup((__be32 *)&tbuf.data[TPM_HEADER_SIZE]);
        *offset += body_size;
-
-       tpm_buf_destroy(&tbuf);
        return 0;
 }
 
 int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
                      unsigned int buf_size, unsigned int *offset)
 {
-       struct tpm_buf tbuf;
+       CLASS(tpm_buf, tbuf)();
        unsigned int body_size;
        int rc;
 
@@ -139,28 +133,23 @@ int tpm2_save_context(struct tpm_chip *chip, u32 handle, 
u8 *buf,
        if (rc < 0) {
                dev_warn(&chip->dev, "%s: failed with a system error %d\n",
                         __func__, rc);
-               tpm_buf_destroy(&tbuf);
                return -EFAULT;
        } else if (tpm2_rc_value(rc) == TPM2_RC_REFERENCE_H0) {
-               tpm_buf_destroy(&tbuf);
                return -ENOENT;
        } else if (rc) {
                dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
                         __func__, rc);
-               tpm_buf_destroy(&tbuf);
                return -EFAULT;
        }
 
        body_size = tpm_buf_length(&tbuf) - TPM_HEADER_SIZE;
        if ((*offset + body_size) > buf_size) {
                dev_warn(&chip->dev, "%s: out of backing storage\n", __func__);
-               tpm_buf_destroy(&tbuf);
                return -ENOMEM;
        }
 
        memcpy(&buf[*offset], &tbuf.data[TPM_HEADER_SIZE], body_size);
        *offset += body_size;
-       tpm_buf_destroy(&tbuf);
        return 0;
 }
 
diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c 
b/drivers/char/tpm/tpm_vtpm_proxy.c
index 0818bb517805..e21cf709481e 100644
--- a/drivers/char/tpm/tpm_vtpm_proxy.c
+++ b/drivers/char/tpm/tpm_vtpm_proxy.c
@@ -395,7 +395,7 @@ static bool vtpm_proxy_tpm_req_canceled(struct tpm_chip  
*chip, u8 status)
 
 static int vtpm_proxy_request_locality(struct tpm_chip *chip, int locality)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        int rc;
        const struct tpm_header *header;
        struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
@@ -416,19 +416,14 @@ static int vtpm_proxy_request_locality(struct tpm_chip 
*chip, int locality)
 
        proxy_dev->state &= ~STATE_DRIVER_COMMAND;
 
-       if (rc < 0) {
-               locality = rc;
-               goto out;
-       }
+       if (rc < 0)
+               return rc;
 
        header = (const struct tpm_header *)buf.data;
        rc = be32_to_cpu(header->return_code);
        if (rc)
                locality = -1;
 
-out:
-       tpm_buf_destroy(&buf);
-
        return locality;
 }
 
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 804fbbe3873d..b39cd7ca7471 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -427,6 +427,8 @@ u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset);
 u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset);
 void tpm_buf_append_handle(struct tpm_chip *chip, struct tpm_buf *buf, u32 
handle);
 
+DEFINE_CLASS(tpm_buf, struct tpm_buf, tpm_buf_destroy(&_T), (struct tpm_buf) 
{}, void)
+
 /*
  * Check if TPM device is in the firmware upgrade mode.
  */
diff --git a/security/keys/trusted-keys/trusted_tpm1.c 
b/security/keys/trusted-keys/trusted_tpm1.c
index 89c9798d1800..fabd8ee12aee 100644
--- a/security/keys/trusted-keys/trusted_tpm1.c
+++ b/security/keys/trusted-keys/trusted_tpm1.c
@@ -672,7 +672,7 @@ static int tpm_unseal(struct tpm_buf *tb,
 static int key_seal(struct trusted_key_payload *p,
                    struct trusted_key_options *o)
 {
-       struct tpm_buf tb;
+       CLASS(tpm_buf, tb)();
        int ret;
 
        ret = tpm_buf_init(&tb, 0, 0);
@@ -688,7 +688,6 @@ static int key_seal(struct trusted_key_payload *p,
        if (ret < 0)
                pr_info("srkseal failed (%d)\n", ret);
 
-       tpm_buf_destroy(&tb);
        return ret;
 }
 
@@ -698,7 +697,7 @@ static int key_seal(struct trusted_key_payload *p,
 static int key_unseal(struct trusted_key_payload *p,
                      struct trusted_key_options *o)
 {
-       struct tpm_buf tb;
+       CLASS(tpm_buf, tb)();
        int ret;
 
        ret = tpm_buf_init(&tb, 0, 0);
@@ -713,7 +712,6 @@ static int key_unseal(struct trusted_key_payload *p,
                /* pull migratable flag out of sealed key */
                p->migratable = p->key[--p->key_len];
 
-       tpm_buf_destroy(&tb);
        return ret;
 }
 
diff --git a/security/keys/trusted-keys/trusted_tpm2.c 
b/security/keys/trusted-keys/trusted_tpm2.c
index 024be262702f..6d787e2fdc19 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -241,8 +241,9 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
                      struct trusted_key_payload *payload,
                      struct trusted_key_options *options)
 {
+       CLASS(tpm_buf, buf)();
+       CLASS(tpm_buf, sized)();
        off_t offset = TPM_HEADER_SIZE;
-       struct tpm_buf buf, sized;
        int blob_len = 0;
        u32 hash;
        u32 flags;
@@ -278,7 +279,6 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 
        rc = tpm_buf_init_sized(&sized);
        if (rc) {
-               tpm_buf_destroy(&buf);
                tpm2_end_auth_session(chip);
                goto out_put;
        }
@@ -350,9 +350,6 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
        blob_len = tpm2_key_encode(payload, options, &buf.data[offset], 
blob_len);
 
 out:
-       tpm_buf_destroy(&sized);
-       tpm_buf_destroy(&buf);
-
        if (rc > 0) {
                if (tpm2_rc_value(rc) == TPM2_RC_HASH)
                        rc = -EINVAL;
@@ -387,7 +384,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
                         struct trusted_key_options *options,
                         u32 *blob_handle)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        unsigned int private_len;
        unsigned int public_len;
        unsigned int blob_len;
@@ -466,7 +463,6 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 out:
        if (blob != payload->blob)
                kfree(blob);
-       tpm_buf_destroy(&buf);
 
        if (rc > 0)
                rc = -EPERM;
@@ -491,7 +487,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
                           struct trusted_key_options *options,
                           u32 blob_handle)
 {
-       struct tpm_buf buf;
+       CLASS(tpm_buf, buf)();
        u16 data_len;
        u8 *data;
        int rc;
@@ -540,15 +536,11 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
        if (!rc) {
                data_len = be16_to_cpup(
                        (__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
-               if (data_len < MIN_KEY_SIZE ||  data_len > MAX_KEY_SIZE) {
-                       rc = -EFAULT;
-                       goto out;
-               }
+               if (data_len < MIN_KEY_SIZE ||  data_len > MAX_KEY_SIZE)
+                       return -EFAULT;
 
-               if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) {
-                       rc = -EFAULT;
-                       goto out;
-               }
+               if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len)
+                       return -EFAULT;
                data = &buf.data[TPM_HEADER_SIZE + 6];
 
                if (payload->old_format) {
@@ -566,8 +558,6 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
                }
        }
 
-out:
-       tpm_buf_destroy(&buf);
        return rc;
 }
 
-- 
2.39.5


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