On Tue, Sep 01, 2026 at 11:58:06PM +0300, Jarkko Sakkinen wrote:
tpm2_load_cmd() does boundary checks against the ASN.1 size i.e.,
payload->blob_len. Address this by passing the decoded blob size to
tpm2_load_cmd(), and use it for the boundary checks.
Cc: [email protected] # v5.13+
Fixes: f2219745250f ("security: keys: trusted: use ASN.1 TPM2 key format for the
blobs")
Reported-by: [email protected]
Closes: https://bugs.sh/b/6a581c4284f721d4/
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
security/keys/trusted-keys/trusted_tpm2.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/security/keys/trusted-keys/trusted_tpm2.c
b/security/keys/trusted-keys/trusted_tpm2.c
index 67225dd562a9..01f18bb37047 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -99,7 +99,7 @@ struct tpm2_key_context {
static int tpm2_key_decode(struct trusted_key_payload *payload,
struct trusted_key_options *options,
- u8 **buf)
+ u8 **buf, unsigned int *blob_len)
{
int ret;
struct tpm2_key_context ctx;
@@ -120,6 +120,7 @@ static int tpm2_key_decode(struct trusted_key_payload
*payload,
blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL);
Pre-existing, but is `+ 4` here useless?
I'm not asking to fix here, just noticed while reviewing.
Maybe we can set *blob_len earlier and use it also in the kmalloc().
Not a strong opinion, that said this LGTM:
Reviewed-by: Stefano Garzarella <[email protected]>
if (!blob)
return -ENOMEM;
*buf = blob;
+ *blob_len = ctx.priv_len + ctx.pub_len;
options->keyhandle = ctx.parent;
memcpy(blob, ctx.priv, ctx.priv_len);
@@ -384,10 +385,11 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
int rc;
u32 attrs;
- rc = tpm2_key_decode(payload, options, &blob);
+ rc = tpm2_key_decode(payload, options, &blob, &blob_len);
if (rc) {
/* old form */
blob = payload->blob;
+ blob_len = payload->blob_len;
payload->old_format = 1;
} else {
/* Bind for cleanup: */
@@ -399,17 +401,17 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
return -EINVAL;
/* must be big enough for at least the two be16 size counts */
- if (payload->blob_len < 4)
+ if (blob_len < 4)
return -EINVAL;
private_len = get_unaligned_be16(blob);
/* must be big enough for following public_len */
- if (private_len + 2 + 2 > (payload->blob_len))
+ if (private_len + 2 + 2 > blob_len)
return -E2BIG;
public_len = get_unaligned_be16(blob + 2 + private_len);
- if (private_len + 2 + public_len + 2 > payload->blob_len)
+ if (private_len + 2 + public_len + 2 > blob_len)
return -E2BIG;
pub = blob + 2 + private_len + 2;
--
2.47.3
