From 15b3048aeed8bf8232156456c884ae94ed52d6cd Mon Sep 17 00:00:00 2001 From: Wenwen Wang Date: Tue, 4 Dec 2018 09:16:41 -0600 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- drivers/misc/mic/scif/scif_fence.c | 22 +++++++++++++++++----- drivers/misc/mic/scif/scif_rma.h | 13 +++++++++++++ 2 files changed, 30 insertions(+), 5 deletions(-) diff --git a/drivers/misc/mic/scif/scif_fence.c b/drivers/misc/mic/scif/scif_fence.c index 7bb929f05d85..2e7ce6ae9dd2 100644 --- 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 fa6722279196..84af3033a473 100644 --- a/drivers/misc/mic/scif/scif_rma.h +++ b/drivers/misc/mic/scif/scif_rma.h @@ -206,6 +206,19 @@ struct scif_status { }; /* + * 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 * * @nr_pages: Number of pages which is defined as a s64 instead of an int -- 2.11.0