* [PATCH] KEYS: trusted: defer execution of TPM-specific code until key instantiate
@ 2019-03-22 18:01 Roberto Sassu
2019-03-22 18:49 ` Dan Williams
2019-03-25 14:56 ` Jarkko Sakkinen
0 siblings, 2 replies; 3+ messages in thread
From: Roberto Sassu @ 2019-03-22 18:01 UTC (permalink / raw)
To: jarkko.sakkinen, dhowells, zohar, dan.j.williams
Cc: linux-integrity, keyrings, linux-security-module, linux-kernel,
linux-nvdimm, david.safford, jejb, silviu.vlasceanu,
Roberto Sassu, stable
Commit 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure from
tpm_default_chip()") changed the tpm_chip argument of every TPM function
from NULL to a pointer that is retrieved at module initialization time.
Unlike before this patch, the trusted module cannot be loaded if no TPM is
available. Unfortunately, this causes a dependency problem because the
encrypted key type requires the 'key_type_trusted' symbol when
CONFIG_TRUSTED_KEYS is defined.
This patch fixes the issue by deferring the execution of TPM-specific code
until a new trusted key is instantiated: init_tpm(), to obtain a tpm_chip
pointer; init_digests(), introduced by commit 0b6cf6b97b7e ("tpm: pass an
array of tpm_extend_digest structures to tpm_pcr_extend()"), to get random
bytes from the TPM to lock a PCR.
Cc: stable@vger.kernel.org
Fixes: 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure from tpm_default_chip()")
Reported-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
security/keys/trusted.c | 89 +++++++++++++++++++++++------------------
1 file changed, 50 insertions(+), 39 deletions(-)
diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index ecec672d3a77..c5162ca9c944 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -946,6 +946,44 @@ static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
return p;
}
+static int init_tpm(void)
+{
+ if (chip)
+ return 0;
+
+ chip = tpm_default_chip();
+ if (!chip)
+ return -ENODEV;
+
+ return 0;
+}
+
+static int init_digests(void)
+{
+ u8 digest[TPM_MAX_DIGEST_SIZE];
+ int ret;
+ int i;
+
+ if (digests)
+ return 0;
+
+ ret = tpm_get_random(chip, digest, TPM_MAX_DIGEST_SIZE);
+ if (ret < 0)
+ return ret;
+ if (ret < TPM_MAX_DIGEST_SIZE)
+ return -EFAULT;
+
+ digests = kcalloc(chip->nr_allocated_banks, sizeof(*digests),
+ GFP_KERNEL);
+ if (!digests)
+ return -ENOMEM;
+
+ for (i = 0; i < chip->nr_allocated_banks; i++)
+ memcpy(digests[i].digest, digest, TPM_MAX_DIGEST_SIZE);
+
+ return 0;
+}
+
/*
* trusted_instantiate - create a new trusted key
*
@@ -967,6 +1005,14 @@ static int trusted_instantiate(struct key *key,
size_t key_len;
int tpm2;
+ ret = init_tpm();
+ if (ret < 0)
+ return ret;
+
+ ret = init_digests();
+ if (ret < 0)
+ return ret;
+
tpm2 = tpm_is_tpm2(chip);
if (tpm2 < 0)
return tpm2;
@@ -1218,58 +1264,23 @@ static int __init trusted_shash_alloc(void)
return ret;
}
-static int __init init_digests(void)
-{
- u8 digest[TPM_MAX_DIGEST_SIZE];
- int ret;
- int i;
-
- ret = tpm_get_random(chip, digest, TPM_MAX_DIGEST_SIZE);
- if (ret < 0)
- return ret;
- if (ret < TPM_MAX_DIGEST_SIZE)
- return -EFAULT;
-
- digests = kcalloc(chip->nr_allocated_banks, sizeof(*digests),
- GFP_KERNEL);
- if (!digests)
- return -ENOMEM;
-
- for (i = 0; i < chip->nr_allocated_banks; i++)
- memcpy(digests[i].digest, digest, TPM_MAX_DIGEST_SIZE);
-
- return 0;
-}
-
static int __init init_trusted(void)
{
int ret;
- chip = tpm_default_chip();
- if (!chip)
- return -ENOENT;
- ret = init_digests();
- if (ret < 0)
- goto err_put;
ret = trusted_shash_alloc();
if (ret < 0)
- goto err_free;
+ return ret;
ret = register_key_type(&key_type_trusted);
if (ret < 0)
- goto err_release;
- return 0;
-err_release:
- trusted_shash_release();
-err_free:
- kfree(digests);
-err_put:
- put_device(&chip->dev);
+ trusted_shash_release();
return ret;
}
static void __exit cleanup_trusted(void)
{
- put_device(&chip->dev);
+ if (chip)
+ put_device(&chip->dev);
kfree(digests);
trusted_shash_release();
unregister_key_type(&key_type_trusted);
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] KEYS: trusted: defer execution of TPM-specific code until key instantiate
2019-03-22 18:01 [PATCH] KEYS: trusted: defer execution of TPM-specific code until key instantiate Roberto Sassu
@ 2019-03-22 18:49 ` Dan Williams
2019-03-25 14:56 ` Jarkko Sakkinen
1 sibling, 0 replies; 3+ messages in thread
From: Dan Williams @ 2019-03-22 18:49 UTC (permalink / raw)
To: Roberto Sassu
Cc: Jarkko Sakkinen, David Howells, Mimi Zohar, linux-integrity,
keyrings, linux-security-module, Linux Kernel Mailing List,
linux-nvdimm, david.safford, James Bottomley, Silviu Vlasceanu,
stable
On Fri, Mar 22, 2019 at 11:04 AM Roberto Sassu <roberto.sassu@huawei.com> wrote:
>
> Commit 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure from
> tpm_default_chip()") changed the tpm_chip argument of every TPM function
> from NULL to a pointer that is retrieved at module initialization time.
>
> Unlike before this patch, the trusted module cannot be loaded if no TPM is
> available. Unfortunately, this causes a dependency problem because the
> encrypted key type requires the 'key_type_trusted' symbol when
> CONFIG_TRUSTED_KEYS is defined.
>
> This patch fixes the issue by deferring the execution of TPM-specific code
> until a new trusted key is instantiated: init_tpm(), to obtain a tpm_chip
> pointer; init_digests(), introduced by commit 0b6cf6b97b7e ("tpm: pass an
> array of tpm_extend_digest structures to tpm_pcr_extend()"), to get random
> bytes from the TPM to lock a PCR.
>
> Cc: stable@vger.kernel.org
> Fixes: 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure from tpm_default_chip()")
> Reported-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Thanks Robert!
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] KEYS: trusted: defer execution of TPM-specific code until key instantiate
2019-03-22 18:01 [PATCH] KEYS: trusted: defer execution of TPM-specific code until key instantiate Roberto Sassu
2019-03-22 18:49 ` Dan Williams
@ 2019-03-25 14:56 ` Jarkko Sakkinen
1 sibling, 0 replies; 3+ messages in thread
From: Jarkko Sakkinen @ 2019-03-25 14:56 UTC (permalink / raw)
To: Roberto Sassu
Cc: dhowells, zohar, dan.j.williams, linux-integrity, keyrings,
linux-security-module, linux-kernel, linux-nvdimm, david.safford,
jejb, silviu.vlasceanu, stable
On Fri, Mar 22, 2019 at 07:01:39PM +0100, Roberto Sassu wrote:
> Commit 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure from
> tpm_default_chip()") changed the tpm_chip argument of every TPM function
> from NULL to a pointer that is retrieved at module initialization time.
>
> Unlike before this patch, the trusted module cannot be loaded if no TPM is
> available. Unfortunately, this causes a dependency problem because the
> encrypted key type requires the 'key_type_trusted' symbol when
> CONFIG_TRUSTED_KEYS is defined.
>
> This patch fixes the issue by deferring the execution of TPM-specific code
> until a new trusted key is instantiated: init_tpm(), to obtain a tpm_chip
> pointer; init_digests(), introduced by commit 0b6cf6b97b7e ("tpm: pass an
> array of tpm_extend_digest structures to tpm_pcr_extend()"), to get random
> bytes from the TPM to lock a PCR.
>
> Cc: stable@vger.kernel.org
> Fixes: 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure from tpm_default_chip()")
> Reported-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Definitive NAK for the release. Sorting out the dependency problem is
definitely out of scope for v5.1.
/Jarkko
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-03-22 18:49 ` Dan Williams
2019-03-25 14:56 ` Jarkko Sakkinen
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