FAILED: patch "[PATCH] tpm: Unify the mismatching TPM space buffer sizes" failed to apply to 4.14-stable tree

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6c4e79d99e6f42b79040f1a33cd4018f5425030b Mon Sep 17 00:00:00 2001
From: Jarkko Sakkinen <[email protected]>
Date: Fri, 3 Jul 2020 01:55:59 +0300
Subject: [PATCH] tpm: Unify the mismatching TPM space buffer sizes

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). Parametrize the buffer size while doing this, so that it is easier to revisit this later on if required.

Cc [email protected]

Reported-by Stefan Berger <[email protected]>

Fixes 745b361e989a ("tpm: infrastructure for TPM spaces")

Reviewed-by Jerry Snitselaar <[email protected]>

Tested-by Stefan Berger <[email protected]>

Signed-off-by Jarkko Sakkinen <[email protected]>

drivers/char/tpm/tpm-chip.c +2 -7

index 8c77e88012e9..ddaeceb7e109 100644
@@ -386,13 +386,8 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 	chip->cdev.owner = THIS_MODULE;
 	chip->cdevs.owner = THIS_MODULE;
 
-	chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
-	if (!chip->work_space.context_buf) {
-		rc = -ENOMEM;
-		goto out;
-	}
-	chip->work_space.session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
-	if (!chip->work_space.session_buf) {
+	rc = tpm2_init_space(&chip->work_space, TPM2_SPACE_BUFFER_SIZE);
+	if (rc) {
 		rc = -ENOMEM;
 		goto out;
 	}

drivers/char/tpm/tpm.h +4 -1

index 0fbcede241ea..947d1db0a5cc 100644
@@ -59,6 +59,9 @@ enum tpm_addr {
 
 #define TPM_TAG_RQU_COMMAND 193
 
+/* TPM2 specific constants. */
+#define TPM2_SPACE_BUFFER_SIZE		16384 /* 16 kB */
+
 struct	stclear_flags_t {
 	__be16	tag;
 	u8	deactivated;

@@ -228,7 +231,7 @@ unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
 int tpm2_probe(struct tpm_chip *chip);
 int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip);
 int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
-int tpm2_init_space(struct tpm_space *space);
+int tpm2_init_space(struct tpm_space *space, unsigned int buf_size);
 void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space);
 void tpm2_flush_space(struct tpm_chip *chip);
 int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,

drivers/char/tpm/tpm2-space.c +16 -10

index 982d341d8837..784b8b3cb903 100644
@@ -38,18 +38,21 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
 	}
 }
 
-int tpm2_init_space(struct tpm_space *space)
+int tpm2_init_space(struct tpm_space *space, unsigned int buf_size)
 {
-	space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	space->context_buf = kzalloc(buf_size, GFP_KERNEL);
 	if (!space->context_buf)
 		return -ENOMEM;
 
-	space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	space->session_buf = kzalloc(buf_size, GFP_KERNEL);
 	if (space->session_buf == NULL) {
 		kfree(space->context_buf);
+		/* Prevent caller getting a dangling pointer. */
+		space->context_buf = NULL;
 		return -ENOMEM;
 	}
 
+	space->buf_size = buf_size;
 	return 0;
 }
 

@@ -311,8 +314,10 @@ 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,
+	       space->buf_size);
+	memcpy(chip->work_space.session_buf, space->session_buf,
+	       space->buf_size);
 
 	rc = tpm2_load_space(chip);
 	if (rc) {

@@ -492,7 +497,7 @@ static int tpm2_save_space(struct tpm_chip *chip)
 			continue;
 
 		rc = tpm2_save_context(chip, space->context_tbl[i],
-				       space->context_buf, PAGE_SIZE,
+				       space->context_buf, space->buf_size,
 				       &offset);
 		if (rc == -ENOENT) {
 			space->context_tbl[i] = 0;

@@ -509,9 +514,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
 			continue;
 
 		rc = tpm2_save_context(chip, space->session_tbl[i],
-				       space->session_buf, PAGE_SIZE,
+				       space->session_buf, space->buf_size,
 				       &offset);
-
 		if (rc == -ENOENT) {
 			/* handle error saving session, just forget it */
 			space->session_tbl[i] = 0;

@@ -557,8 +561,10 @@ 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,
+	       space->buf_size);
+	memcpy(space->session_buf, chip->work_space.session_buf,
+	       space->buf_size);
 
 	return 0;
 out:

drivers/char/tpm/tpmrm-dev.c +1 -1

index 7a0a7051a06f..eef0fb06ea83 100644
@@ -21,7 +21,7 @@ static int tpmrm_open(struct inode *inode, struct file *file)
 	if (priv == NULL)
 		return -ENOMEM;
 
-	rc = tpm2_init_space(&priv->space);
+	rc = tpm2_init_space(&priv->space, TPM2_SPACE_BUFFER_SIZE);
 	if (rc) {
 		kfree(priv);
 		return -ENOMEM;

include/linux/tpm.h +1 -0

index 03e9b184411b..8f4ff39f51e7 100644
@@ -96,6 +96,7 @@ struct tpm_space {
 	u8 *context_buf;
 	u32 session_tbl[3];
 	u8 *session_buf;
+	u32 buf_size;
 };
 
 struct tpm_bios_log {

Stefan, are you concerned of not having this in 4.14 and 4.19?

Quoted 1 line · Jarkko Sakkinen

Stefan, are you concerned of not having this in 4.14 and 4.19?

Yes. The problematic scenario is when libtpms  is updated to a version (future v0.8.0) that supports 3072 bit RSA keys and software inside a VM is using /dev/tpmrm0 and things start failing because of this. My hope would be that the distro run inside the VM has a way forward and the long term stable kernels seem to help here. Because of this scenario I have to delay the release of libtpms v0.8.0 for several months.

Quoted 5 lines · Stefan Berger

Quoted 1 line · Jarkko Sakkinen

Stefan, are you concerned of not having this in 4.14 and 4.19?

Yes. The problematic scenario is when libtpms  is updated to a version (future v0.8.0) that supports 3072 bit RSA keys and software inside a VM is using /dev/tpmrm0 and things start failing because of this. My hope would be that the distro run inside the VM has a way forward and the long term stable kernels seem to help here. Because of this scenario I have to delay the release of libtpms v0.8.0 for several months.

I just ported it to 4.19.139 and will try to do the port to 4.14.191++ as well. I will post it here once I ran some (basic) tests with it.