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* [PATCH] tpm: Define TPM2_SPACE_BUFFER_SIZE to replace the use of PAGE_SIZE
@ 2020-06-26 14:34 Jarkko Sakkinen
  2020-06-26 16:47 ` Stefan Berger
  0 siblings, 1 reply; 2+ messages in thread
From: Jarkko Sakkinen @ 2020-06-26 14:34 UTC (permalink / raw)
  To: linux-integrity
  Cc: Jarkko Sakkinen, Stefan Berger, stable, Peter Huewe,
	Jason Gunthorpe, Arnd Bergmann, Greg Kroah-Hartman,
	James Bottomley, open list

The size of the buffers for storing context's and sessions can vary from
arch to arch as PAGE_SIZE can be anything between 4 kB and 256 kB (the
maximum for PPC64). Define a fixed buffer size set to 16 kB. This should
be enough for most use with three handles (that is how many we allow at
the moment).

Reported-by: Stefan Berger <stefanb@linux.ibm.com>
Cc: stable@vger.kernel.org
Fixes: 745b361e989a ("tpm: infrastructure for TPM spaces")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/tpm2-space.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 982d341d8837..9bef646093d1 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -15,6 +15,8 @@
 #include <asm/unaligned.h>
 #include "tpm.h"
 
+#define TPM2_SPACE_BUFFER_SIZE		16384 /* 16 kB */
+
 enum tpm2_handle_types {
 	TPM2_HT_HMAC_SESSION	= 0x02000000,
 	TPM2_HT_POLICY_SESSION	= 0x03000000,
@@ -40,11 +42,11 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
 
 int tpm2_init_space(struct tpm_space *space)
 {
-	space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	space->context_buf = kzalloc(TPM2_SPACE_BUFFER_SIZE, GFP_KERNEL);
 	if (!space->context_buf)
 		return -ENOMEM;
 
-	space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	space->session_buf = kzalloc(TPM2_SPACE_BUFFER_SIZE, GFP_KERNEL);
 	if (space->session_buf == NULL) {
 		kfree(space->context_buf);
 		return -ENOMEM;
@@ -311,8 +313,10 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
 	       sizeof(space->context_tbl));
 	memcpy(&chip->work_space.session_tbl, &space->session_tbl,
 	       sizeof(space->session_tbl));
-	memcpy(chip->work_space.context_buf, space->context_buf, PAGE_SIZE);
-	memcpy(chip->work_space.session_buf, space->session_buf, PAGE_SIZE);
+	memcpy(chip->work_space.context_buf, space->context_buf,
+	       TPM2_SPACE_BUFFER_SIZE);
+	memcpy(chip->work_space.session_buf, space->session_buf,
+	       TPM2_SPACE_BUFFER_SIZE);
 
 	rc = tpm2_load_space(chip);
 	if (rc) {
@@ -492,8 +496,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
 			continue;
 
 		rc = tpm2_save_context(chip, space->context_tbl[i],
-				       space->context_buf, PAGE_SIZE,
-				       &offset);
+				       space->context_buf,
+				       TPM2_SPACE_BUFFER_SIZE, &offset);
 		if (rc == -ENOENT) {
 			space->context_tbl[i] = 0;
 			continue;
@@ -509,9 +513,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
 			continue;
 
 		rc = tpm2_save_context(chip, space->session_tbl[i],
-				       space->session_buf, PAGE_SIZE,
-				       &offset);
-
+				       space->session_buf,
+				       TPM2_SPACE_BUFFER_SIZE, &offset);
 		if (rc == -ENOENT) {
 			/* handle error saving session, just forget it */
 			space->session_tbl[i] = 0;
@@ -557,8 +560,10 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
 	       sizeof(space->context_tbl));
 	memcpy(&space->session_tbl, &chip->work_space.session_tbl,
 	       sizeof(space->session_tbl));
-	memcpy(space->context_buf, chip->work_space.context_buf, PAGE_SIZE);
-	memcpy(space->session_buf, chip->work_space.session_buf, PAGE_SIZE);
+	memcpy(space->context_buf, chip->work_space.context_buf,
+	       TPM2_SPACE_BUFFER_SIZE);
+	memcpy(space->session_buf, chip->work_space.session_buf,
+	       TPM2_SPACE_BUFFER_SIZE);
 
 	return 0;
 out:
-- 
2.25.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] tpm: Define TPM2_SPACE_BUFFER_SIZE to replace the use of PAGE_SIZE
  2020-06-26 14:34 [PATCH] tpm: Define TPM2_SPACE_BUFFER_SIZE to replace the use of PAGE_SIZE Jarkko Sakkinen
@ 2020-06-26 16:47 ` Stefan Berger
  0 siblings, 0 replies; 2+ messages in thread
From: Stefan Berger @ 2020-06-26 16:47 UTC (permalink / raw)
  To: Jarkko Sakkinen, linux-integrity
  Cc: stable, Peter Huewe, Jason Gunthorpe, Arnd Bergmann,
	Greg Kroah-Hartman, James Bottomley, open list

On 6/26/20 10:34 AM, Jarkko Sakkinen wrote:
> The size of the buffers for storing context's and sessions can vary from
> arch to arch as PAGE_SIZE can be anything between 4 kB and 256 kB (the
> maximum for PPC64). Define a fixed buffer size set to 16 kB. This should
> be enough for most use with three handles (that is how many we allow at
> the moment).
>
> Reported-by: Stefan Berger <stefanb@linux.ibm.com>
> Cc: stable@vger.kernel.org
> Fixes: 745b361e989a ("tpm: infrastructure for TPM spaces")
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>   drivers/char/tpm/tpm2-space.c | 27 ++++++++++++++++-----------
>   1 file changed, 16 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index 982d341d8837..9bef646093d1 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -15,6 +15,8 @@
>   #include <asm/unaligned.h>
>   #include "tpm.h"
>   
> +#define TPM2_SPACE_BUFFER_SIZE		16384 /* 16 kB */
> +
>   enum tpm2_handle_types {
>   	TPM2_HT_HMAC_SESSION	= 0x02000000,
>   	TPM2_HT_POLICY_SESSION	= 0x03000000,
> @@ -40,11 +42,11 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
>   
>   int tpm2_init_space(struct tpm_space *space)
>   {
> -	space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> +	space->context_buf = kzalloc(TPM2_SPACE_BUFFER_SIZE, GFP_KERNEL);
>   	if (!space->context_buf)
>   		return -ENOMEM;
>   
> -	space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> +	space->session_buf = kzalloc(TPM2_SPACE_BUFFER_SIZE, GFP_KERNEL);
>   	if (space->session_buf == NULL) {
>   		kfree(space->context_buf);
>   		return -ENOMEM;
> @@ -311,8 +313,10 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
>   	       sizeof(space->context_tbl));
>   	memcpy(&chip->work_space.session_tbl, &space->session_tbl,
>   	       sizeof(space->session_tbl));
> -	memcpy(chip->work_space.context_buf, space->context_buf, PAGE_SIZE);
> -	memcpy(chip->work_space.session_buf, space->session_buf, PAGE_SIZE);
> +	memcpy(chip->work_space.context_buf, space->context_buf,
> +	       TPM2_SPACE_BUFFER_SIZE);
> +	memcpy(chip->work_space.session_buf, space->session_buf,
> +	       TPM2_SPACE_BUFFER_SIZE);
>   
>   	rc = tpm2_load_space(chip);
>   	if (rc) {
> @@ -492,8 +496,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
>   			continue;
>   
>   		rc = tpm2_save_context(chip, space->context_tbl[i],
> -				       space->context_buf, PAGE_SIZE,
> -				       &offset);
> +				       space->context_buf,
> +				       TPM2_SPACE_BUFFER_SIZE, &offset);
>   		if (rc == -ENOENT) {
>   			space->context_tbl[i] = 0;
>   			continue;
> @@ -509,9 +513,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
>   			continue;
>   
>   		rc = tpm2_save_context(chip, space->session_tbl[i],
> -				       space->session_buf, PAGE_SIZE,
> -				       &offset);
> -
> +				       space->session_buf,
> +				       TPM2_SPACE_BUFFER_SIZE, &offset);
>   		if (rc == -ENOENT) {
>   			/* handle error saving session, just forget it */
>   			space->session_tbl[i] = 0;
> @@ -557,8 +560,10 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
>   	       sizeof(space->context_tbl));
>   	memcpy(&space->session_tbl, &chip->work_space.session_tbl,
>   	       sizeof(space->session_tbl));
> -	memcpy(space->context_buf, chip->work_space.context_buf, PAGE_SIZE);
> -	memcpy(space->session_buf, chip->work_space.session_buf, PAGE_SIZE);
> +	memcpy(space->context_buf, chip->work_space.context_buf,
> +	       TPM2_SPACE_BUFFER_SIZE);
> +	memcpy(space->session_buf, chip->work_space.session_buf,
> +	       TPM2_SPACE_BUFFER_SIZE);


work_space.session_buf and context_buf also need allocation changes, 
otherwise we read from a smaller buffer here. See comment to other patch 
about tpm-chip.c .


>   
>   	return 0;
>   out:



^ permalink raw reply	[flat|nested] 2+ messages in thread

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2020-06-26 14:34 [PATCH] tpm: Define TPM2_SPACE_BUFFER_SIZE to replace the use of PAGE_SIZE Jarkko Sakkinen
2020-06-26 16:47 ` Stefan Berger

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