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authorDavid Howells <dhowells@redhat.com>2017-06-07 12:40:03 +0100
committerDavid Howells <dhowells@redhat.com>2017-06-07 17:15:46 +0100
commite754eba685aac2a9b5538176fa2d254ad25f464d (patch)
treec8e650d72b8451f7d4ab93cd92eaed6549e84ae5 /net/rxrpc/sendmsg.c
parent3ab26a6fd01ba211ba5dea0d86d53897b9e8430c (diff)
downloadlinux-e754eba685aac2a9b5538176fa2d254ad25f464d.tar.bz2
rxrpc: Provide a cmsg to specify the amount of Tx data for a call
Provide a control message that can be specified on the first sendmsg() of a client call or the first sendmsg() of a service response to indicate the total length of the data to be transmitted for that call. Currently, because the length of the payload of an encrypted DATA packet is encrypted in front of the data, the packet cannot be encrypted until we know how much data it will hold. By specifying the length at the beginning of the transmit phase, each DATA packet length can be set before we start loading data from userspace (where several sendmsg() calls may contribute to a particular packet). An error will be returned if too little or too much data is presented in the Tx phase. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'net/rxrpc/sendmsg.c')
-rw-r--r--net/rxrpc/sendmsg.c54
1 files changed, 52 insertions, 2 deletions
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index d939a5b1abc3..2e636a525a65 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -29,6 +29,7 @@ enum rxrpc_command {
};
struct rxrpc_send_params {
+ s64 tx_total_len; /* Total Tx data length (if send data) */
unsigned long user_call_ID; /* User's call ID */
u32 abort_code; /* Abort code to Tx (if abort) */
enum rxrpc_command command : 8; /* The command to implement */
@@ -207,6 +208,13 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
more = msg->msg_flags & MSG_MORE;
+ if (call->tx_total_len != -1) {
+ if (len > call->tx_total_len)
+ return -EMSGSIZE;
+ if (!more && len != call->tx_total_len)
+ return -EMSGSIZE;
+ }
+
skb = call->tx_pending;
call->tx_pending = NULL;
rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
@@ -299,6 +307,8 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
sp->remain -= copy;
skb->mark += copy;
copied += copy;
+ if (call->tx_total_len != -1)
+ call->tx_total_len -= copy;
}
/* check for the far side aborting the call or a network error
@@ -436,6 +446,14 @@ static int rxrpc_sendmsg_cmsg(struct msghdr *msg, struct rxrpc_send_params *p)
return -EINVAL;
break;
+ case RXRPC_TX_LENGTH:
+ if (p->tx_total_len != -1 || len != sizeof(__s64))
+ return -EINVAL;
+ p->tx_total_len = *(__s64 *)CMSG_DATA(cmsg);
+ if (p->tx_total_len < 0)
+ return -EINVAL;
+ break;
+
default:
return -EINVAL;
}
@@ -443,6 +461,8 @@ static int rxrpc_sendmsg_cmsg(struct msghdr *msg, struct rxrpc_send_params *p)
if (!got_user_ID)
return -EINVAL;
+ if (p->tx_total_len != -1 && p->command != RXRPC_CMD_SEND_DATA)
+ return -EINVAL;
_leave(" = 0");
return 0;
}
@@ -481,7 +501,8 @@ rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
cp.exclusive = rx->exclusive | p->exclusive;
cp.upgrade = p->upgrade;
cp.service_id = srx->srx_service;
- call = rxrpc_new_client_call(rx, &cp, srx, p->user_call_ID, GFP_KERNEL);
+ call = rxrpc_new_client_call(rx, &cp, srx, p->user_call_ID,
+ p->tx_total_len, GFP_KERNEL);
/* The socket is now unlocked */
_leave(" = %p\n", call);
@@ -501,6 +522,7 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
int ret;
struct rxrpc_send_params p = {
+ .tx_total_len = -1,
.user_call_ID = 0,
.abort_code = 0,
.command = RXRPC_CMD_SEND_DATA,
@@ -555,6 +577,15 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
ret = -ERESTARTSYS;
goto error_put;
}
+
+ if (p.tx_total_len != -1) {
+ ret = -EINVAL;
+ if (call->tx_total_len != -1 ||
+ call->tx_pending ||
+ call->tx_top != 0)
+ goto error_put;
+ call->tx_total_len = p.tx_total_len;
+ }
}
state = READ_ONCE(call->state);
@@ -672,5 +703,24 @@ bool rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
mutex_unlock(&call->user_mutex);
return aborted;
}
-
EXPORT_SYMBOL(rxrpc_kernel_abort_call);
+
+/**
+ * rxrpc_kernel_set_tx_length - Set the total Tx length on a call
+ * @sock: The socket the call is on
+ * @call: The call to be informed
+ * @tx_total_len: The amount of data to be transmitted for this call
+ *
+ * Allow a kernel service to set the total transmit length on a call. This
+ * allows buffer-to-packet encrypt-and-copy to be performed.
+ *
+ * This function is primarily for use for setting the reply length since the
+ * request length can be set when beginning the call.
+ */
+void rxrpc_kernel_set_tx_length(struct socket *sock, struct rxrpc_call *call,
+ s64 tx_total_len)
+{
+ WARN_ON(call->tx_total_len != -1);
+ call->tx_total_len = tx_total_len;
+}
+EXPORT_SYMBOL(rxrpc_kernel_set_tx_length);