UDMABUF_CREATE_LIST copies an array whose element count comes from userspace. The count is bounded by the list_limit module parameter, but that parameter does not need negative values.
Make list_limit unsigned so its type matches the u32 count field. Also use memdup_array_user() for the list copy so the element-count multiplication is checked before allocation and copying. Suggested-by: Christian König <[email protected]> Signed-off-by: Yousef Alhouseen <[email protected]> --- Changes in v2: - Make list_limit unsigned as suggested by Christian. - Keep the checked array copy and drop the local u32 byte-count temporary. drivers/dma-buf/udmabuf.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index bced421c0..e34a3b135 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -21,8 +21,8 @@ #include <linux/udmabuf.h> #include <linux/vmalloc.h> -static int list_limit = 1024; -module_param(list_limit, int, 0644); +static unsigned int list_limit = 1024; +module_param(list_limit, uint, 0644); MODULE_PARM_DESC(list_limit, "udmabuf_create_list->count limit. Default is 1024."); static int size_limit_mb = 64; module_param(size_limit_mb, int, 0644); @@ -471,12 +471,11 @@ static long udmabuf_ioctl_create_list(struct file *filp, unsigned long arg) struct udmabuf_create_list head; struct udmabuf_create_item *list; int ret = -EINVAL; - u32 lsize; if (copy_from_user(&head, (void __user *)arg, sizeof(head))) return -EFAULT; if (head.count > list_limit) return -EINVAL; - lsize = sizeof(struct udmabuf_create_item) * head.count; - list = memdup_user((void __user *)(arg + sizeof(head)), lsize); + list = memdup_array_user((void __user *)(arg + sizeof(head)), + head.count, sizeof(*list)); if (IS_ERR(list)) return PTR_ERR(list); -- 2.54.0
