Under certain conditions uninitialized memory will be accessed.
As described by TCG Trusted Platform Module Library Specification,
rev. 1.59 (Part 3: Commands), if a TPM2_GetCapability is received,
requesting a capability, the TPM in field upgrade mode may return a
zero length list.
Check the property count in tpm2_get_tpm_pt().
Fixes: 2ab3241161b3 ("tpm: migrate tpm2_get_tpm_pt() to use struct tpm_buf")
Cc: stable(a)vger.kernel.org
Signed-off-by: Stefan Mahnke-Hartmann <stefan.mahnke-hartmann(a)infineon.com>
---
Changelog:
* v2:
* Add inline comment to indicate the root cause to may access unitilized
memory.
* Change 'field upgrade mode' to lower case.
drivers/char/tpm/tpm2-cmd.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 4704fa553098..04a3e23a4afc 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -400,7 +400,16 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id, u32 *value,
if (!rc) {
out = (struct tpm2_get_cap_out *)
&buf.data[TPM_HEADER_SIZE];
- *value = be32_to_cpu(out->value);
+ /*
+ * To prevent failing boot up of some systems, Infineon TPM2.0
+ * returns SUCCESS on TPM2_Startup in field upgrade mode. Also
+ * the TPM2_Getcapability command returns a zero length list
+ * in field upgrade mode.
+ */
+ if (be32_to_cpu(out->property_cnt) > 0)
+ *value = be32_to_cpu(out->value);
+ else
+ rc = -ENODATA;
}
tpm_buf_destroy(&buf);
return rc;
--
2.25.1
For some sev ioctl interfaces, input may be passed that is less than or
equal to SEV_FW_BLOB_MAX_SIZE, but larger than the data that PSP
firmware returns. In this case, kmalloc will allocate memory that is the
size of the input rather than the size of the data. Since PSP firmware
doesn't fully overwrite the buffer, the sev ioctl interfaces with the
issue may return uninitialized slab memory.
Currently, all of the ioctl interfaces in the ccp driver are safe, but
to prevent future problems, change all ioctl interfaces that allocate
memory with kmalloc to use kzalloc.
Fixes: e799035609e15 ("crypto: ccp: Implement SEV_PEK_CSR ioctl command")
Fixes: 76a2b524a4b1d ("crypto: ccp: Implement SEV_PDH_CERT_EXPORT ioctl command")
Fixes: d6112ea0cb344 ("crypto: ccp - introduce SEV_GET_ID2 command")
Cc: stable(a)vger.kernel.org
Reported-by: Andy Nguyen <theflow(a)google.com>
Suggested-by: David Rientjes <rientjes(a)google.com>
Suggested-by: Peter Gonda <pgonda(a)google.com>
Signed-off-by: John Allen <john.allen(a)amd.com>
---
v2:
- Add fixes tags and CC stable(a)vger.kernel.org
---
drivers/crypto/ccp/sev-dev.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 6ab93dfd478a..e2298843ea8a 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -604,7 +604,7 @@ static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp, bool writable)
if (input.length > SEV_FW_BLOB_MAX_SIZE)
return -EFAULT;
- blob = kmalloc(input.length, GFP_KERNEL);
+ blob = kzalloc(input.length, GFP_KERNEL);
if (!blob)
return -ENOMEM;
@@ -828,7 +828,7 @@ static int sev_ioctl_do_get_id2(struct sev_issue_cmd *argp)
input_address = (void __user *)input.address;
if (input.address && input.length) {
- id_blob = kmalloc(input.length, GFP_KERNEL);
+ id_blob = kzalloc(input.length, GFP_KERNEL);
if (!id_blob)
return -ENOMEM;
@@ -947,14 +947,14 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
if (input.cert_chain_len > SEV_FW_BLOB_MAX_SIZE)
return -EFAULT;
- pdh_blob = kmalloc(input.pdh_cert_len, GFP_KERNEL);
+ pdh_blob = kzalloc(input.pdh_cert_len, GFP_KERNEL);
if (!pdh_blob)
return -ENOMEM;
data.pdh_cert_address = __psp_pa(pdh_blob);
data.pdh_cert_len = input.pdh_cert_len;
- cert_blob = kmalloc(input.cert_chain_len, GFP_KERNEL);
+ cert_blob = kzalloc(input.cert_chain_len, GFP_KERNEL);
if (!cert_blob) {
ret = -ENOMEM;
goto e_free_pdh;
--
2.34.1