s390/zcrypt: additional check to avoid overflow in msg-type 6 requests
Signed-off-by: Ingo Tuchscherer <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
diff --git a/drivers/s390/crypto/zcrypt_msgtype6.c b/drivers/s390/crypto/zcrypt_msgtype6.c
index dc542e0..0bc91e4 100644
--- a/drivers/s390/crypto/zcrypt_msgtype6.c
+++ b/drivers/s390/crypto/zcrypt_msgtype6.c
@@ -311,7 +311,7 @@
} __packed * msg = ap_msg->message;
int rcblen = CEIL4(xcRB->request_control_blk_length);
- int replylen;
+ int replylen, req_sumlen, resp_sumlen;
char *req_data = ap_msg->message + sizeof(struct type6_hdr) + rcblen;
char *function_code;
@@ -321,12 +321,34 @@
xcRB->request_data_length;
if (ap_msg->length > MSGTYPE06_MAX_MSG_SIZE)
return -EINVAL;
+
+ /* Overflow check
+ sum must be greater (or equal) than the largest operand */
+ req_sumlen = CEIL4(xcRB->request_control_blk_length) +
+ xcRB->request_data_length;
+ if ((CEIL4(xcRB->request_control_blk_length) <=
+ xcRB->request_data_length) ?
+ (req_sumlen < xcRB->request_data_length) :
+ (req_sumlen < CEIL4(xcRB->request_control_blk_length))) {
+ return -EINVAL;
+ }
+
replylen = sizeof(struct type86_fmt2_msg) +
CEIL4(xcRB->reply_control_blk_length) +
xcRB->reply_data_length;
if (replylen > MSGTYPE06_MAX_MSG_SIZE)
return -EINVAL;
+ /* Overflow check
+ sum must be greater (or equal) than the largest operand */
+ resp_sumlen = CEIL4(xcRB->reply_control_blk_length) +
+ xcRB->reply_data_length;
+ if ((CEIL4(xcRB->reply_control_blk_length) <= xcRB->reply_data_length) ?
+ (resp_sumlen < xcRB->reply_data_length) :
+ (resp_sumlen < CEIL4(xcRB->reply_control_blk_length))) {
+ return -EINVAL;
+ }
+
/* prepare type6 header */
msg->hdr = static_type6_hdrX;
memcpy(msg->hdr.agent_id , &(xcRB->agent_ID), sizeof(xcRB->agent_ID));
