From 98d23edcd41432286cf03672252507a841323c8c Mon Sep 17 00:00:00 2001 From: Harald Freudenberger Date: Tue, 25 Aug 2026 18:01:54 +0200 Subject: [PATCH] s390/zcrypt: Fix uninitialized padding in CRT key structure The zcrypt_type6_crt_key() function leaves padding bytes uninitialized between key components and the modulus in the CCA CRT key token. These padding bytes are sent to the crypto card, potentially leaking kernel memory contents. The initial memset() only zeros fixed structure fields, not the flexible array member key_parts[] where the padding resides. While key components are properly copied from userspace, the calculated pad_len bytes between them remain uninitialized. Fix by explicitly zeroing the padding bytes after copying the CRT key components. Signed-off-by: Harald Freudenberger Reviewed-by: Finn Callies Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens --- drivers/s390/crypto/zcrypt_cca_key.h | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/s390/crypto/zcrypt_cca_key.h b/drivers/s390/crypto/zcrypt_cca_key.h index f5907b67db29..8a69eed75040 100644 --- a/drivers/s390/crypto/zcrypt_cca_key.h +++ b/drivers/s390/crypto/zcrypt_cca_key.h @@ -219,6 +219,7 @@ static inline int zcrypt_type6_crt_key(struct ica_rsa_modexpo_crt *crt, void *p) copy_from_user(key->key_parts + 2 * long_len + 2 * short_len, crt->u_mult_inv, long_len)) return -EFAULT; + memset(key->key_parts + 3 * long_len + 2 * short_len, 0, pad_len); memset(key->key_parts + 3 * long_len + 2 * short_len + pad_len, 0xff, crt->inputdatalength); pub = (struct cca_public_sec *)(key->key_parts + key_len);