On Mon, Sep 29, 2025 at 10:48:32PM +0300, Jarkko Sakkinen wrote:
From: Jarkko Sakkinen <[email protected]>
Decouple kzalloc from buffer creation, so that a managed allocation can be
done trivially:
struct tpm_buf *buf __free(kfree) buf = kzalloc(TPM_BUFSIZE,
^
In the code, we use PAGE_SIZE instead of TPM_BUFSIZE with kzalloc().
Should we do the same in this example? (Perhaps adding the reason, if
you think it would be useful)
GFP_KERNEL);
if (!buf)
return -ENOMEM;
tpm_buf_init(buf, TPM_BUFSIZE);
Alternatively, stack allocations are also possible:
u8 buf_data[512];
struct tpm_buf *buf = (struct tpm_buf *)buf_data;
tpm_buf_init(buf, sizeof(buf_data));
Reviewed-by: Stefan Berger <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
v3:
- A new patch from the earlier series with more scoped changes and
less abstract commit message.
---
drivers/char/tpm/tpm-buf.c | 122 +++++----
drivers/char/tpm/tpm-sysfs.c | 20 +-
drivers/char/tpm/tpm.h | 1 -
drivers/char/tpm/tpm1-cmd.c | 147 +++++------
drivers/char/tpm/tpm2-cmd.c | 290 ++++++++++------------
drivers/char/tpm/tpm2-sessions.c | 121 +++++----
drivers/char/tpm/tpm2-space.c | 44 ++--
drivers/char/tpm/tpm_vtpm_proxy.c | 30 +--
include/linux/tpm.h | 18 +-
security/keys/trusted-keys/trusted_tpm1.c | 34 ++-
security/keys/trusted-keys/trusted_tpm2.c | 176 ++++++-------
11 files changed, 482 insertions(+), 521 deletions(-)
diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index c9e6e5d097ca..1cb649938c01 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -7,82 +7,109 @@
#include <linux/module.h>
#include <linux/tpm.h>
-/**
- * tpm_buf_init() - Allocate and initialize a TPM command
- * @buf: A &tpm_buf
- * @tag: TPM_TAG_RQU_COMMAND, TPM2_ST_NO_SESSIONS or TPM2_ST_SESSIONS
- * @ordinal: A command ordinal
- *
- * Return: 0 or -ENOMEM
- */
-int tpm_buf_init(struct tpm_buf *buf, u16 tag, u32 ordinal)
+static void __tpm_buf_size_invariant(struct tpm_buf *buf, u16 buf_size)
{
- buf->data = (u8 *)__get_free_page(GFP_KERNEL);
- if (!buf->data)
- return -ENOMEM;
-
- tpm_buf_reset(buf, tag, ordinal);
- return 0;
+ u32 buf_size_2 = (u32)buf->capacity + (u32)sizeof(*buf);
+
+ if (!buf->capacity) {
+ if (buf_size > TPM_BUFSIZE) {
+ WARN(1, "%s: size overflow: %u\n", __func__, buf_size);
+ buf->flags |= TPM_BUF_INVALID;
+ }
+ } else {
+ if (buf_size != buf_size_2) {
+ WARN(1, "%s: size mismatch: %u != %u\n", __func__,
buf_size,
+ buf_size_2);
+ buf->flags |= TPM_BUF_INVALID;
+ }
+ }
}
-EXPORT_SYMBOL_GPL(tpm_buf_init);
-/**
- * tpm_buf_reset() - Initialize a TPM command
- * @buf: A &tpm_buf
- * @tag: TPM_TAG_RQU_COMMAND, TPM2_ST_NO_SESSIONS or TPM2_ST_SESSIONS
- * @ordinal: A command ordinal
- */
-void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal)
+static void __tpm_buf_reset(struct tpm_buf *buf, u16 buf_size, u16 tag, u32
ordinal)
{
struct tpm_header *head = (struct tpm_header *)buf->data;
+ __tpm_buf_size_invariant(buf, buf_size);
+
+ if (buf->flags & TPM_BUF_INVALID)
+ return;
+
WARN_ON(tag != TPM_TAG_RQU_COMMAND && tag != TPM2_ST_NO_SESSIONS &&
tag != TPM2_ST_SESSIONS && tag != 0);
buf->flags = 0;
buf->length = sizeof(*head);
+ buf->capacity = buf_size - sizeof(*buf);
+ buf->handles = 0;
head->tag = cpu_to_be16(tag);
head->length = cpu_to_be32(sizeof(*head));
head->ordinal = cpu_to_be32(ordinal);
+}
+
+static void __tpm_buf_reset_sized(struct tpm_buf *buf, u16 buf_size)
+{
+ __tpm_buf_size_invariant(buf, buf_size);
+
+ if (buf->flags & TPM_BUF_INVALID)
+ return;
+
+ buf->flags = TPM_BUF_TPM2B;
+ buf->length = 2;
+ buf->capacity = buf_size - sizeof(*buf);
buf->handles = 0;
+ buf->data[0] = 0;
+ buf->data[1] = 0;
}
-EXPORT_SYMBOL_GPL(tpm_buf_reset);
/**
- * tpm_buf_init_sized() - Allocate and initialize a sized (TPM2B) buffer
- * @buf: A @tpm_buf
- *
- * Return: 0 or -ENOMEM
+ * tpm_buf_init() - Initialize a TPM command
+ * @buf: A &tpm_buf
+ * @buf_size: Size of the buffer.
*/
-int tpm_buf_init_sized(struct tpm_buf *buf)
+void tpm_buf_init(struct tpm_buf *buf, u16 buf_size)
{
- buf->data = (u8 *)__get_free_page(GFP_KERNEL);
- if (!buf->data)
- return -ENOMEM;
+ memset(buf, 0, buf_size);
+ __tpm_buf_reset(buf, buf_size, TPM_TAG_RQU_COMMAND, 0);
+}
+EXPORT_SYMBOL_GPL(tpm_buf_init);
- tpm_buf_reset_sized(buf);
- return 0;
+/**
+ * tpm_buf_init_sized() - Initialize a sized buffer
+ * @buf: A &tpm_buf
+ * @buf_size: Size of the buffer.
+ */
+void tpm_buf_init_sized(struct tpm_buf *buf, u16 buf_size)
+{
+ memset(buf, 0, buf_size);
+ __tpm_buf_reset_sized(buf, buf_size);
}
EXPORT_SYMBOL_GPL(tpm_buf_init_sized);
/**
- * tpm_buf_reset_sized() - Initialize a sized buffer
+ * tpm_buf_reset() - Re-initialize a TPM command
* @buf: A &tpm_buf
+ * @tag: TPM_TAG_RQU_COMMAND, TPM2_ST_NO_SESSIONS or TPM2_ST_SESSIONS
+ * @ordinal: A command ordinal
*/
-void tpm_buf_reset_sized(struct tpm_buf *buf)
+void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal)
{
- buf->flags = TPM_BUF_TPM2B;
- buf->length = 2;
- buf->data[0] = 0;
- buf->data[1] = 0;
+ u16 buf_size = buf->capacity + sizeof(*buf);
+
+ __tpm_buf_reset(buf, buf_size, tag, ordinal);
}
-EXPORT_SYMBOL_GPL(tpm_buf_reset_sized);
+EXPORT_SYMBOL_GPL(tpm_buf_reset);
-void tpm_buf_destroy(struct tpm_buf *buf)
+/**
+ * tpm_buf_reset_sized() - Re-initialize a sized buffer
+ * @buf: A &tpm_buf
+ */
+void tpm_buf_reset_sized(struct tpm_buf *buf)
{
- free_page((unsigned long)buf->data);
+ u16 buf_size = buf->capacity + sizeof(*buf);
+
+ __tpm_buf_reset_sized(buf, buf_size);
}
-EXPORT_SYMBOL_GPL(tpm_buf_destroy);
+EXPORT_SYMBOL_GPL(tpm_buf_reset_sized);
/**
* tpm_buf_length() - Return the number of bytes consumed by the data
@@ -92,6 +119,9 @@ EXPORT_SYMBOL_GPL(tpm_buf_destroy);
*/
u32 tpm_buf_length(struct tpm_buf *buf)
Should we update the return value to u16?
{
+ if (buf->flags & TPM_BUF_INVALID)
+ return 0;
+
return buf->length;
}
EXPORT_SYMBOL_GPL(tpm_buf_length);
@@ -104,10 +134,12 @@ EXPORT_SYMBOL_GPL(tpm_buf_length);
*/
void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length)
{
+ u32 total_length = (u32)buf->length + (u32)new_length;
+
if (buf->flags & TPM_BUF_INVALID)
return;
- if ((buf->length + new_length) > PAGE_SIZE) {
+ if (total_length > (u32)buf->capacity) {
WARN(1, "tpm_buf: write overflow\n");
buf->flags |= TPM_BUF_INVALID;
return;
[...]
diff --git a/security/keys/trusted-keys/trusted_tpm1.c
b/security/keys/trusted-keys/trusted_tpm1.c
index 636acb66a4f6..6e6a9fb48e63 100644
--- a/security/keys/trusted-keys/trusted_tpm1.c
+++ b/security/keys/trusted-keys/trusted_tpm1.c
@@ -310,9 +310,8 @@ static int TSS_checkhmac2(unsigned char *buffer,
* For key specific tpm requests, we will generate and send our
* own TPM command packets using the drivers send function.
*/
-static int trusted_tpm_send(unsigned char *cmd, size_t buflen)
+static int trusted_tpm_send(void *cmd, size_t buflen)
{
- struct tpm_buf buf;
int rc;
if (!chip)
@@ -322,15 +321,12 @@ static int trusted_tpm_send(unsigned char *cmd, size_t
buflen)
if (rc)
return rc;
- buf.flags = 0;
- buf.length = buflen;
- buf.data = cmd;
dump_tpm_buf(cmd);
- rc = tpm_transmit_cmd(chip, &buf, 4, "sending data");
+ rc = tpm_transmit_cmd(chip, cmd, 4, "sending data");
Is it fine here to remove the intermediate tpm_buf ?
IIUC tpm_transmit_cmd() needs a tpm_buf, while here we are passing just
the "data", or in some way it's a nested tpm_buf?
(Sorry if it's a stupid question, but I'm still a bit new with this
code).
dump_tpm_buf(cmd);
+ /* Convert TPM error to -EPERM. */
if (rc > 0)
- /* TPM error */
rc = -EPERM;
tpm_put_ops(chip);
@@ -624,23 +620,23 @@ 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;
int ret;
- ret = tpm_buf_init(&tb, 0, 0);
- if (ret)
- return ret;
+ struct tpm_buf *tb __free(kfree) = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!tb)
+ return -ENOMEM;
+
+ tpm_buf_init(tb, TPM_BUFSIZE);
/* include migratable flag at end of sealed key */
p->key[p->key_len] = p->migratable;
- ret = tpm_seal(&tb, o->keytype, o->keyhandle, o->keyauth,
+ ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth,
p->key, p->key_len + 1, p->blob, &p->blob_len,
o->blobauth, o->pcrinfo, o->pcrinfo_len);
if (ret < 0)
pr_info("srkseal failed (%d)\n", ret);
- tpm_buf_destroy(&tb);
return ret;
}
@@ -650,14 +646,15 @@ 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;
int ret;
- ret = tpm_buf_init(&tb, 0, 0);
- if (ret)
- return ret;
+ struct tpm_buf *tb __free(kfree) = kzalloc(PAGE_SIZE,
GFP_KERNEL);
+ if (!tb)
+ return -ENOMEM;
+
+ tpm_buf_init(tb, TPM_BUFSIZE);
- ret = tpm_unseal(&tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
+ ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
o->blobauth, p->key, &p->key_len);
if (ret < 0)
pr_info("srkunseal failed (%d)\n", ret);
@@ -665,7 +662,6 @@ 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;
}
The rest LGTM, but it's a huge patch (not your issue at all), so yeah
not sure :-)
Thanks,
Stefano
