Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
While there, use struct_size() helper, instead of the open-coded
version.
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
fs/fhandle.c | 8 ++++----
include/linux/fs.h | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/fhandle.c b/fs/fhandle.c
index 57a12614addf..53ed54711cd2 100644
--- a/fs/fhandle.c
+++ b/fs/fhandle.c
@@ -36,7 +36,7 @@ static long do_sys_name_to_handle(const struct path *path,
if (f_handle.handle_bytes > MAX_HANDLE_SZ)
return -EINVAL;
- handle = kzalloc(sizeof(struct file_handle) + f_handle.handle_bytes,
+ handle = kzalloc(struct_size(handle, f_handle, f_handle.handle_bytes),
GFP_KERNEL);
if (!handle)
return -ENOMEM;
@@ -71,7 +71,7 @@ static long do_sys_name_to_handle(const struct path *path,
/* copy the mount id */
if (put_user(real_mount(path->mnt)->mnt_id, mnt_id) ||
copy_to_user(ufh, handle,
- sizeof(struct file_handle) + handle_bytes))
+ struct_size(handle, f_handle, handle_bytes)))
retval = -EFAULT;
kfree(handle);
return retval;
@@ -192,7 +192,7 @@ static int handle_to_path(int mountdirfd, struct file_handle __user *ufh,
retval = -EINVAL;
goto out_err;
}
- handle = kmalloc(sizeof(struct file_handle) + f_handle.handle_bytes,
+ handle = kmalloc(struct_size(handle, f_handle, f_handle.handle_bytes),
GFP_KERNEL);
if (!handle) {
retval = -ENOMEM;
@@ -202,7 +202,7 @@ static int handle_to_path(int mountdirfd, struct file_handle __user *ufh,
*handle = f_handle;
if (copy_from_user(&handle->f_handle,
&ufh->f_handle,
- f_handle.handle_bytes)) {
+ struct_size(ufh, f_handle, f_handle.handle_bytes))) {
retval = -EFAULT;
goto out_handle;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 034f0c918eea..1540e28d10d7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1033,7 +1033,7 @@ struct file_handle {
__u32 handle_bytes;
int handle_type;
/* file identifier */
- unsigned char f_handle[];
+ unsigned char f_handle[] __counted_by(handle_bytes);
};
static inline struct file *get_file(struct file *f)
--
2.34.1
