On Tue, Jan 30, 2024 at 01:48:27PM -0800, Bart Van Assche wrote:
> Reject values that are valid rw_hints after truncation but not before
> truncation by passing an untruncated value to rw_hint_valid().
>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Cc: Jeff Layton <jlayton@xxxxxxxxxx>
> Cc: Chuck Lever <chuck.lever@xxxxxxxxxx>
> Cc: Jens Axboe <axboe@xxxxxxxxx>
> Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Fixes: 5657cb0797c4 ("fs/fcntl: use copy_to/from_user() for u64 types")
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
The fs parts of this should go through a vfs tree as this is vfs infra.
I can then give you a stable tag that you can merge and base the big
block and scsci bits on. It'll minimize merge conflicts and makes it
easier to coordinate imho.
> fs/fcntl.c | 12 +++++-------
> 1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/fs/fcntl.c b/fs/fcntl.c
> index c80a6acad742..3ff707bf2743 100644
> --- a/fs/fcntl.c
> +++ b/fs/fcntl.c
> @@ -268,7 +268,7 @@ static int f_getowner_uids(struct file *filp, unsigned long arg)
> }
> #endif
>
> -static bool rw_hint_valid(enum rw_hint hint)
> +static bool rw_hint_valid(u64 hint)
> {
> switch (hint) {
> case RWH_WRITE_LIFE_NOT_SET:
> @@ -288,19 +288,17 @@ static long fcntl_rw_hint(struct file *file, unsigned int cmd,
> {
> struct inode *inode = file_inode(file);
> u64 __user *argp = (u64 __user *)arg;
> - enum rw_hint hint;
> - u64 h;
> + u64 hint;
>
> switch (cmd) {
> case F_GET_RW_HINT:
> - h = inode->i_write_hint;
> - if (copy_to_user(argp, &h, sizeof(*argp)))
> + hint = inode->i_write_hint;
> + if (copy_to_user(argp, &hint, sizeof(*argp)))
> return -EFAULT;
> return 0;
> case F_SET_RW_HINT:
> - if (copy_from_user(&h, argp, sizeof(h)))
> + if (copy_from_user(&hint, argp, sizeof(hint)))
> return -EFAULT;
> - hint = (enum rw_hint) h;
> if (!rw_hint_valid(hint))
> return -EINVAL;
>
