From a5ad9642846f548f95067464415c98bd207cd1bf Mon Sep 17 00:00:00 2001 From: Aleksa Sarai Date: Tue, 1 Oct 2019 11:10:53 +1000 Subject: [PATCH] UPSTREAM: clone3: switch to copy_struct_from_user() Switch clone3() syscall from it's own copying struct clone_args from userspace to the new dedicated copy_struct_from_user() helper. The change is very straightforward, and helps unify the syscall interface for struct-from-userspace syscalls. Additionally, explicitly define CLONE_ARGS_SIZE_VER0 to match the other users of the struct-extension pattern. Change-Id: Ib09f7bf0cdfed775b606fb7f1698e12515cd0a6b Signed-off-by: Aleksa Sarai Reviewed-by: Kees Cook Reviewed-by: Christian Brauner [christian.brauner@ubuntu.com: improve commit message] Link: https://lore.kernel.org/r/20191001011055.19283-3-cyphar@cyphar.com Signed-off-by: Christian Brauner --- kernel/fork.c | 34 +++++++--------------------------- 1 file changed, 7 insertions(+), 27 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index 0306158bb0ea..5a710ce09316 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2561,40 +2561,20 @@ 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; pid_t *kset_tid = kargs->set_tid; - if (unlikely(size > PAGE_SIZE)) + if (unlikely(usize > PAGE_SIZE)) return -E2BIG; - - if (unlikely(size < sizeof(struct clone_args))) + if (unlikely(usize < CLONE_ARGS_SIZE_VER0)) return -EINVAL; - if (unlikely(!access_ok(VERIFY_READ, 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; if (unlikely(args.set_tid_size > MAX_PID_NS_LEVEL)) return -EINVAL;