@@ -47,6 +47,8 @@ struct clone_args {
__aligned_u64 tls;
};
+#define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */
+
/*
* Scheduling policies
*/
@@ -2528,39 +2528,17 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
#ifdef __ARCH_WANT_SYS_CLONE3
noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
struct clone_args __user *uargs,
- size_t size)
+ size_t usize)
{
+ int err;
struct clone_args args;
- if (unlikely(size > PAGE_SIZE))
- return -E2BIG;
-
- if (unlikely(size < sizeof(struct clone_args)))
+ if (unlikely(usize < CLONE_ARGS_SIZE_VER0))
return -EINVAL;
- if (unlikely(!access_ok(uargs, size)))
- return -EFAULT;
-
- if (size > sizeof(struct clone_args)) {
- unsigned char __user *addr;
- unsigned char __user *end;
- unsigned char val;
-
- addr = (void __user *)uargs + sizeof(struct clone_args);
- end = (void __user *)uargs + size;
-
- for (; addr < end; addr++) {
- if (get_user(val, addr))
- return -EFAULT;
- if (val)
- return -E2BIG;
- }
-
- size = sizeof(struct clone_args);
- }
-
- if (copy_from_user(&args, uargs, size))
- return -EFAULT;
+ err = copy_struct_from_user(&args, sizeof(args), uargs, usize);
+ if (err)
+ return err;
*kargs = (struct kernel_clone_args){
.flags = args.flags,
The change is very straightforward, and takes advantage of the (very minor) efficiency improvements in copy_struct_from_user() -- that the memchr_inv() check is done on a buffer instead of one-at-at-time with get_user(). Additionally, explicitly define CLONE_ARGS_SIZE_VER0 to match the other users of the struct-extension pattern. Cc: Christian Brauner <christian@brauner.io> Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> --- include/uapi/linux/sched.h | 2 ++ kernel/fork.c | 34 ++++++---------------------------- 2 files changed, 8 insertions(+), 28 deletions(-)