dfl.c utilizes memdup_user() and array_size() to copy a userspace array. array_size() will likely never trigger thanks to the preceeding check. Nevertheless, in the theoretical event that it would, it would return SIZE_MAX to memdup_user(), resulting in an attempt to allocate huge amounts of memory. string.h from the core-api now provides memdup_array_user() which also performs an overflow check and returns an error-pointer with -EOVERFLOW to the caller. As an additional advantage it standardizes how userspace-arrays are being copied and, thus, makes it more obvious to readers that an array is being copied. Replace memdup_user() with memdup_array_user(). Suggested-by: Dave Airlie <airlied@xxxxxxxxxx> Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx> --- Changes in v2: - Rewrite commit's name and message to clarify the patch's advantages --- drivers/fpga/dfl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c index dd7a783d53b5..e69b9f1f2a50 100644 --- a/drivers/fpga/dfl.c +++ b/drivers/fpga/dfl.c @@ -2008,8 +2008,8 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev, (hdr.start + hdr.count < hdr.start)) return -EINVAL; - fds = memdup_user((void __user *)(arg + sizeof(hdr)), - array_size(hdr.count, sizeof(s32))); + fds = memdup_array_user((void __user *)(arg + sizeof(hdr)), + hdr.count, sizeof(s32)); if (IS_ERR(fds)) return PTR_ERR(fds); -- 2.41.0
