fpga: dfl-afu: validate DMA mapping length in afu_dma_map_region()

[ Upstream commit fc3b071a7c ]

afu_ioctl_dma_map() accepts a 64-bit length from userspace via
DFL_FPGA_PORT_DMA_MAP ioctl without an upper bound check. The value
is passed to afu_dma_pin_pages() where npages is derived as
length >> PAGE_SHIFT and passed to pin_user_pages_fast() which takes
int nr_pages, causing implicit truncation if length is very large.

Validate map.length at the ioctl entry point before calling
afu_dma_map_region(), rejecting values whose page count exceeds
INT_MAX.

Fixes: fa8dda1ede ("fpga: dfl: afu: add DFL_FPGA_PORT_DMA_MAP/UNMAP ioctls support")
Cc: stable@vger.kernel.org
Signed-off-by: Sebastian Alba Vives <sebasjosue84@gmail.com>
Reviewed-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20260518190742.61426-3-sebasjosue84@gmail.com
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sebastian Alba Vives
2026-08-03 11:15:33 +02:00
committed by Greg Kroah-Hartman
parent 0db56e7eae
commit 16381bda90
+3
View File
@@ -720,6 +720,9 @@ afu_ioctl_dma_map(struct dfl_feature_platform_data *pdata, void __user *arg)
if (map.argsz < minsz || map.flags)
return -EINVAL;
if (map.length >> PAGE_SHIFT > (u64)INT_MAX)
return -EINVAL;
ret = afu_dma_map_region(pdata, map.user_addr, map.length, &map.iova);
if (ret)
return ret;