misc: mic: fix a DMA pool free failure

In _scif_prog_signal(), a DMA pool is allocated if the MIC Coprocessor is
not X100, i.e., the boolean variable 'x100' is false. This DMA pool will be
freed eventually through the callback function scif_prog_signal_cb() with
the parameter of 'status', which actually points to the start of DMA pool.
Specifically, in scif_prog_signal_cb(), the 'ep' field and the
'src_dma_addr' field of 'status' are used to free the DMA pool by invoking
dma_pool_free(). Given that 'status' points to the start address of the DMA
pool, both 'status->ep' and 'status->src_dma_addr' are in the DMA pool. And
so, the device has the permission to access them. Even worse, a malicious
device can modify them. As a result, dma_pool_free() will not succeed.

To avoid the above issue, this patch introduces a new data structure, i.e.,
scif_cb_arg, to store the arguments required by the call back function. A
variable 'cb_arg' is allocated in _scif_prog_signal() to pass the
arguments. 'cb_arg' will be freed after dma_pool_free() in
scif_prog_signal_cb().

Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/mic/scif/scif_fence.c b/drivers/misc/mic/scif/scif_fence.c
index 7bb929f05d85227b1f6b16f5d037ac58ad3e2200..2e7ce6ae9dd24d54d8b82fa379b510bc7cd71d2e 100644 (file)
--- a/drivers/misc/mic/scif/scif_fence.c
+++ b/drivers/misc/mic/scif/scif_fence.c
@@ -195,10 +195,11 @@ static inline void *scif_get_local_va(off_t off, struct scif_window *window)
 
 static void scif_prog_signal_cb(void *arg)
 {
-       struct scif_status *status = arg;
+       struct scif_cb_arg *cb_arg = arg;
 
-       dma_pool_free(status->ep->remote_dev->signal_pool, status,
-                     status->src_dma_addr);
+       dma_pool_free(cb_arg->ep->remote_dev->signal_pool, cb_arg->status,
+                     cb_arg->src_dma_addr);
+       kfree(cb_arg);
 }
 
 static int _scif_prog_signal(scif_epd_t epd, dma_addr_t dst, u64 val)
@@ -209,6 +210,7 @@ static int _scif_prog_signal(scif_epd_t epd, dma_addr_t dst, u64 val)
        bool x100 = !is_dma_copy_aligned(chan->device, 1, 1, 1);
        struct dma_async_tx_descriptor *tx;
        struct scif_status *status = NULL;
+       struct scif_cb_arg *cb_arg = NULL;
        dma_addr_t src;
        dma_cookie_t cookie;
        int err;
@@ -257,8 +259,16 @@ static int _scif_prog_signal(scif_epd_t epd, dma_addr_t dst, u64 val)
                goto dma_fail;
        }
        if (!x100) {
+               cb_arg = kmalloc(sizeof(*cb_arg), GFP_KERNEL);
+               if (!cb_arg) {
+                       err = -ENOMEM;
+                       goto dma_fail;
+               }
+               cb_arg->src_dma_addr = src;
+               cb_arg->status = status;
+               cb_arg->ep = ep;
                tx->callback = scif_prog_signal_cb;
-               tx->callback_param = status;
+               tx->callback_param = cb_arg;
        }
        cookie = tx->tx_submit(tx);
        if (dma_submit_error(cookie)) {
@@ -270,9 +280,11 @@ static int _scif_prog_signal(scif_epd_t epd, dma_addr_t dst, u64 val)
        dma_async_issue_pending(chan);
        return 0;
 dma_fail:
-       if (!x100)
+       if (!x100) {
                dma_pool_free(ep->remote_dev->signal_pool, status,
                              src - offsetof(struct scif_status, val));
+               kfree(cb_arg);
+       }
 alloc_fail:
        return err;
 }

diff --git a/drivers/misc/mic/scif/scif_rma.h b/drivers/misc/mic/scif/scif_rma.h
index fa6722279196c98239050cccb9967906ae597f3c..84af3033a4730cf6d4f1a0903dac46ddc557161c 100644 (file)
--- a/drivers/misc/mic/scif/scif_rma.h
+++ b/drivers/misc/mic/scif/scif_rma.h
@@ -205,6 +205,19 @@ struct scif_status {
        struct scif_endpt *ep;
 };
 
+/*
+ * struct scif_cb_arg - Stores the argument of the callback func
+ *
+ * @src_dma_addr: Source buffer DMA address
+ * @status: DMA status
+ * @ep: SCIF endpoint
+ */
+struct scif_cb_arg {
+       dma_addr_t src_dma_addr;
+       struct scif_status *status;
+       struct scif_endpt *ep;
+};
+
 /*
  * struct scif_window - Registration Window for Self and Remote
  *