[PATCH v1 2/2] s390/zcrypt: Validate length for CCA ECC private key requests

[Holger Dengler <dengler@linux.ibm.com>]

cca_ecc2protkey() derives the copy length for the CPRB parameter
block directly from the length field in the key token. Reject the
request early if the token length exceeds the available space in the
parameter block.

Fixes: fa6999e326fe ("s390/pkey: support CCA and EP11 secure ECC private keys")
Signed-off-by: Holger Dengler <dengler@linux.ibm.com>
Cc: stable@vger.kernel.org # 5.10+
---
 drivers/s390/crypto/zcrypt_ccamisc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/s390/crypto/zcrypt_ccamisc.c b/drivers/s390/crypto/zcrypt_ccamisc.c
index db6a4211a97e..322677a8d320 100644
--- a/drivers/s390/crypto/zcrypt_ccamisc.c
+++ b/drivers/s390/crypto/zcrypt_ccamisc.c
@@ -1428,6 +1428,9 @@ int cca_ecc2protkey(u16 cardnr, u16 domain, const u8 *key,
 	} __packed * prepparm;
 	int keylen = ((struct eccprivkeytoken *)key)->len;
 
+	if (keylen > PARMBSIZE - sizeof(struct aureqparm))
+		return -EINVAL;
+
 	/* get already prepared memory for 2 cprbs with param block each */
 	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem,
 				    &preqcblk, &prepcblk, xflags);
-- 
2.55.0