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authorAleksa Sarai <cyphar@cyphar.com>2019-10-01 03:10:53 +0200
committerChristian Brauner <christian.brauner@ubuntu.com>2019-10-01 15:45:10 +0200
commitf14c234b4bc5184fd40d9a47830e5b32c3b36d49 (patch)
tree03dd3b1cb5035fa6cec8389cf10ea30ddd1ec3e3 /kernel
parentlib: introduce copy_struct_from_user() helper (diff)
downloadlinux-f14c234b4bc5184fd40d9a47830e5b32c3b36d49.tar.xz
linux-f14c234b4bc5184fd40d9a47830e5b32c3b36d49.zip
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. Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> [christian.brauner@ubuntu.com: improve commit message] Link: https://lore.kernel.org/r/20191001011055.19283-3-cyphar@cyphar.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/fork.c34
1 files changed, 7 insertions, 27 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index f9572f416126..2ef529869c64 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2525,39 +2525,19 @@ 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))
+ 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(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;
/*
* Verify that higher 32bits of exit_signal are unset and that