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greybus: clean up gb_connection_operation_recv()

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This patch does some cleanup of gb_connection_operation_recv().
    - Improve the header comments
    - Verify message is big enough for header before interpreting
      beginning of the message as a header
    - Verify at buffer creation time rather than receive time that
      no operation buffer is bigger than the maximum allowed.  We
      can then compare the incoming data size against the buffer.
    - When a response message arrives, record its status in the
      operation result, not in the buffer status.
    - Record a buffer overflow as an operation error.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
This commit is contained in:
Alex Elder 2014-11-17 08:08:39 -06:00 committed by Greg Kroah-Hartman
parent b37716f672
commit 78496db012
2 changed files with 20 additions and 6 deletions
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25
drivers/staging/greybus/operation.c
View file

@ -204,6 +204,9 @@ static struct gbuf *gb_operation_gbuf_create(struct gb_operation *operation,
struct gbuf *gbuf;
gfp_t gfp_flags = data_out ? GFP_KERNEL : GFP_ATOMIC;
if (size > GB_OPERATION_MESSAGE_SIZE_MAX)
return NULL; /* Message too big */
size += sizeof(*header);
gbuf = greybus_alloc_gbuf(operation, size, data_out, gfp_flags);
if (!gbuf)
@ -355,9 +358,18 @@ int gb_operation_response_send(struct gb_operation *operation)
}
/*
* Handle data arriving on a connection. This is called in
* interrupt context, so just copy the incoming data into a buffer
* and do remaining handling via a work queue.
* Handle data arriving on a connection. As soon as we return, the
* incoming data buffer will be reused, so we need to copy the data
* into one of our own operation message buffers.
*
* If the incoming data is an operation response message, look up
* the operation and copy the incoming data into its response
* buffer. Otherwise allocate a new operation and copy the incoming
* data into its request buffer.
*
* This is called in interrupt context, so just copy the incoming
* data into the buffer and do remaining handling via a work queue.
*
*/
void gb_connection_operation_recv(struct gb_connection *connection,
void *data, size_t size)
@ -370,8 +382,8 @@ void gb_connection_operation_recv(struct gb_connection *connection,
if (connection->state != GB_CONNECTION_STATE_ENABLED)
return;
if (size > GB_OPERATION_MESSAGE_SIZE_MAX) {
gb_connection_err(connection, "message too big");
if (size < sizeof(*header)) {
gb_connection_err(connection, "message too small");
return;
}
@ -388,11 +400,12 @@ void gb_connection_operation_recv(struct gb_connection *connection,
cancel_delayed_work(&operation->timeout_work);
gb_pending_operation_remove(operation);
gbuf = operation->response;
gbuf->status = GB_OP_SUCCESS; /* If we got here we're good */
if (size > gbuf->transfer_buffer_length) {
operation->result = GB_OP_OVERFLOW;
gb_connection_err(connection, "recv buffer too small");
return;
}
operation->result = GB_OP_SUCCESS;
} else {
WARN_ON(msg_size != size);
operation = gb_operation_create(connection, header->type,

1
drivers/staging/greybus/operation.h
View file

@ -18,6 +18,7 @@ enum gb_operation_status {
GB_OP_INTERRUPTED = 3,
GB_OP_RETRY = 4,
GB_OP_PROTOCOL_BAD = 5,
GB_OP_OVERFLOW = 6,
GB_OP_TIMEOUT = 0xff,
};