tpm2_key_encode() allocates a memory chunk from scratch with kmalloc(),
but it is never freed, which leads to a memory leak. Free the memory
chunk with kfree() in the return path.
Signed-off-by: Jianglei Nie <[email protected]>
---
security/keys/trusted-keys/trusted_tpm2.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 0165da386289..dc9efd6c8b14 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -57,8 +57,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
unsigned char bool[3], *w = bool;
/* tag 0 is emptyAuth */
w = asn1_encode_boolean(w, w + sizeof(bool), true);
- if (WARN(IS_ERR(w), "BUG: Boolean failed to encode"))
+ if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) {
+ kfree(scratch);
return PTR_ERR(w);
+ }
work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
}
@@ -69,8 +71,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
* trigger, so if it does there's something nefarious going on
*/
if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
- "BUG: scratch buffer is too small"))
+ "BUG: scratch buffer is too small")) {
+ kfree(scratch);
return -EINVAL;
+ }
work = asn1_encode_integer(work, end_work, options->keyhandle);
work = asn1_encode_octet_string(work, end_work, pub, pub_len);
@@ -79,8 +83,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
work1 = payload->blob;
work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob),
scratch, work - scratch);
- if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed"))
+ if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) {
+ kfree(scratch);
return PTR_ERR(work1);
+ }
return work1 - payload->blob;
}
--
2.25.1
The short summary (as mentioned in review):
"KEYS: trusted: Fix memory leak in tpm2_key_encode()"
Also, you should version your patches, and provide a change log.
See: https://www.kernel.org/doc/html/v5.18/process/submitting-patches.html#the-canonical-patch-format
For git format-patch you can simply supply "-vX" to get
the-canonical-patch-format version included.
On Wed, Jun 08, 2022 at 10:59:38AM +0800, Jianglei Nie wrote:
> tpm2_key_encode() allocates a memory chunk from scratch with kmalloc(),
> but it is never freed, which leads to a memory leak. Free the memory
> chunk with kfree() in the return path.
>
> Signed-off-by: Jianglei Nie <[email protected]>
> ---
Here you can write:
v3:
...
v2:
...
> security/keys/trusted-keys/trusted_tpm2.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
> index 0165da386289..dc9efd6c8b14 100644
> --- a/security/keys/trusted-keys/trusted_tpm2.c
> +++ b/security/keys/trusted-keys/trusted_tpm2.c
> @@ -57,8 +57,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
> unsigned char bool[3], *w = bool;
> /* tag 0 is emptyAuth */
> w = asn1_encode_boolean(w, w + sizeof(bool), true);
> - if (WARN(IS_ERR(w), "BUG: Boolean failed to encode"))
> + if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) {
> + kfree(scratch);
> return PTR_ERR(w);
> + }
> work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
> }
>
> @@ -69,8 +71,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
> * trigger, so if it does there's something nefarious going on
> */
> if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
> - "BUG: scratch buffer is too small"))
> + "BUG: scratch buffer is too small")) {
> + kfree(scratch);
> return -EINVAL;
> + }
>
> work = asn1_encode_integer(work, end_work, options->keyhandle);
> work = asn1_encode_octet_string(work, end_work, pub, pub_len);
> @@ -79,8 +83,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
> work1 = payload->blob;
> work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob),
> scratch, work - scratch);
> - if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed"))
> + if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) {
> + kfree(scratch);
> return PTR_ERR(work1);
> + }
>
> return work1 - payload->blob;
> }
> --
> 2.25.1
>
BR, Jarkko
Hello Jianglei,
On 08.06.22 04:59, Jianglei Nie wrote:
> tpm2_key_encode() allocates a memory chunk from scratch with kmalloc(),
> but it is never freed, which leads to a memory leak. Free the memory
> chunk with kfree() in the return path.
Repeating my question in your implicit v1:
Are you sure, scratch need not be freed in the successful return case?
asn1_encode_sequence() copies bytes out of scratch into payload->blob,
so it looks like the buffer is unused after function return.
Cheers,
Ahmad
>
> Signed-off-by: Jianglei Nie <[email protected]>
> ---
> security/keys/trusted-keys/trusted_tpm2.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
> index 0165da386289..dc9efd6c8b14 100644
> --- a/security/keys/trusted-keys/trusted_tpm2.c
> +++ b/security/keys/trusted-keys/trusted_tpm2.c
> @@ -57,8 +57,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
> unsigned char bool[3], *w = bool;
> /* tag 0 is emptyAuth */
> w = asn1_encode_boolean(w, w + sizeof(bool), true);
> - if (WARN(IS_ERR(w), "BUG: Boolean failed to encode"))
> + if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) {
> + kfree(scratch);
> return PTR_ERR(w);
> + }
> work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
> }
>
> @@ -69,8 +71,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
> * trigger, so if it does there's something nefarious going on
> */
> if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
> - "BUG: scratch buffer is too small"))
> + "BUG: scratch buffer is too small")) {
> + kfree(scratch);
> return -EINVAL;
> + }
>
> work = asn1_encode_integer(work, end_work, options->keyhandle);
> work = asn1_encode_octet_string(work, end_work, pub, pub_len);
> @@ -79,8 +83,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
> work1 = payload->blob;
> work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob),
> scratch, work - scratch);
> - if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed"))
> + if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) {
> + kfree(scratch);
> return PTR_ERR(work1);
> + }
>
> return work1 - payload->blob;
> }
--
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