From: Youssef Samir Date: Tue, 7 Oct 2025 12:23:20 +0000 (+0200) Subject: accel/qaic: Treat remaining == 0 as error in find_and_map_user_pages() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=11f08c30a3e4157305ba692f1d44cca5fc9a8fca;p=users%2Fhch%2Fmisc.git accel/qaic: Treat remaining == 0 as error in find_and_map_user_pages() Currently, if find_and_map_user_pages() takes a DMA xfer request from the user with a length field set to 0, or in a rare case, the host receives QAIC_TRANS_DMA_XFER_CONT from the device where resources->xferred_dma_size is equal to the requested transaction size, the function will return 0 before allocating an sgt or setting the fields of the dma_xfer struct. In that case, encode_addr_size_pairs() will try to access the sgt which will lead to a general protection fault. Return an EINVAL in case the user provides a zero-sized ALP, or the device requests continuation after all of the bytes have been transferred. Fixes: 96d3c1cadedb ("accel/qaic: Clean up integer overflow checking in map_user_pages()") Signed-off-by: Youssef Samir Signed-off-by: Youssef Samir Reviewed-by: Jeff Hugo Reviewed-by: Carl Vanderlip Signed-off-by: Jeff Hugo Link: https://lore.kernel.org/r/20251007122320.339654-1-youssef.abdulrahman@oss.qualcomm.com --- diff --git a/drivers/accel/qaic/qaic_control.c b/drivers/accel/qaic/qaic_control.c index d8bdab69f800..b86a8e48e731 100644 --- a/drivers/accel/qaic/qaic_control.c +++ b/drivers/accel/qaic/qaic_control.c @@ -407,7 +407,7 @@ static int find_and_map_user_pages(struct qaic_device *qdev, return -EINVAL; remaining = in_trans->size - resources->xferred_dma_size; if (remaining == 0) - return 0; + return -EINVAL; if (check_add_overflow(xfer_start_addr, remaining, &end)) return -EINVAL;