On 9/2/26 2:28 AM, 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]>
Tested-by: Srish Srinivasan <[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, 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;
