From: Dan Carpenter dan.carpenter@linaro.org
[ Upstream commit 96d3c1cadedb6ae2e8965e19cd12caa244afbd9c ]
The encode_dma() function has some validation on in_trans->size but it would be more clear to move those checks to find_and_map_user_pages().
The encode_dma() had two checks:
if (in_trans->addr + in_trans->size < in_trans->addr || !in_trans->size) return -EINVAL;
The in_trans->addr variable is the starting address. The in_trans->size variable is the total size of the transfer. The transfer can occur in parts and the resources->xferred_dma_size tracks how many bytes we have already transferred.
This patch introduces a new variable "remaining" which represents the amount we want to transfer (in_trans->size) minus the amount we have already transferred (resources->xferred_dma_size).
I have modified the check for if in_trans->size is zero to instead check if in_trans->size is less than resources->xferred_dma_size. If we have already transferred more bytes than in_trans->size then there are negative bytes remaining which doesn't make sense. If there are zero bytes remaining to be copied, just return success.
The check in encode_dma() checked that "addr + size" could not overflow and barring a driver bug that should work, but it's easier to check if we do this in parts. First check that "in_trans->addr + resources->xferred_dma_size" is safe. Then check that "xfer_start_addr + remaining" is safe.
My final concern was that we are dealing with u64 values but on 32bit systems the kmalloc() function will truncate the sizes to 32 bits. So I calculated "total = in_trans->size + offset_in_page(xfer_start_addr);" and returned -EINVAL if it were >= SIZE_MAX. This will not affect 64bit systems.
Fixes: 129776ac2e38 ("accel/qaic: Add control path") Signed-off-by: Dan Carpenter dan.carpenter@linaro.org Reviewed-by: Jeffrey Hugo quic_jhugo@quicinc.com Reviewed-by: Carl Vanderlip quic_carlv@quicinc.com Signed-off-by: Jeffrey Hugo quic_jhugo@quicinc.com Link: https://patchwork.freedesktop.org/patch/msgid/24d3348b-25ac-4c1b-b171-9dae7c... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/accel/qaic/qaic_control.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/drivers/accel/qaic/qaic_control.c b/drivers/accel/qaic/qaic_control.c index cfbc92da426fa..388abd40024ba 100644 --- a/drivers/accel/qaic/qaic_control.c +++ b/drivers/accel/qaic/qaic_control.c @@ -392,18 +392,31 @@ static int find_and_map_user_pages(struct qaic_device *qdev, struct qaic_manage_trans_dma_xfer *in_trans, struct ioctl_resources *resources, struct dma_xfer *xfer) { + u64 xfer_start_addr, remaining, end, total; unsigned long need_pages; struct page **page_list; unsigned long nr_pages; struct sg_table *sgt; - u64 xfer_start_addr; int ret; int i;
- xfer_start_addr = in_trans->addr + resources->xferred_dma_size; + if (check_add_overflow(in_trans->addr, resources->xferred_dma_size, &xfer_start_addr)) + return -EINVAL;
- need_pages = DIV_ROUND_UP(in_trans->size + offset_in_page(xfer_start_addr) - - resources->xferred_dma_size, PAGE_SIZE); + if (in_trans->size < resources->xferred_dma_size) + return -EINVAL; + remaining = in_trans->size - resources->xferred_dma_size; + if (remaining == 0) + return 0; + + if (check_add_overflow(xfer_start_addr, remaining, &end)) + return -EINVAL; + + total = remaining + offset_in_page(xfer_start_addr); + if (total >= SIZE_MAX) + return -EINVAL; + + need_pages = DIV_ROUND_UP(total, PAGE_SIZE);
nr_pages = need_pages;
@@ -435,7 +448,7 @@ static int find_and_map_user_pages(struct qaic_device *qdev,
ret = sg_alloc_table_from_pages(sgt, page_list, nr_pages, offset_in_page(xfer_start_addr), - in_trans->size - resources->xferred_dma_size, GFP_KERNEL); + remaining, GFP_KERNEL); if (ret) { ret = -ENOMEM; goto free_sgt; @@ -566,9 +579,6 @@ static int encode_dma(struct qaic_device *qdev, void *trans, struct wrapper_list QAIC_MANAGE_EXT_MSG_LENGTH) return -ENOMEM;
- if (in_trans->addr + in_trans->size < in_trans->addr || !in_trans->size) - return -EINVAL; - xfer = kmalloc(sizeof(*xfer), GFP_KERNEL); if (!xfer) return -ENOMEM;