On Fri, Apr 24, 2015 at 01:04:16PM +0200, Andreas Gruenbacher wrote:
> So far, richacl_equiv_mode() is relatively limited in the types of acl it
> considers equivalent to a file mode: it only accepts masked acls with a single
> everyone@:rwpxd::allow entry.
>
> Change this to consider all acls equivalent to file modes if they only consist
> of owner@, group@, and everyone@ entries and the owner@ permissions do not
> depend on whether the owner is a member in the owning group.
>
> Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
> ---
> fs/richacl_base.c | 150 ++++++++++++++++++++++++++++++++++++++----------
> include/linux/richacl.h | 1 +
> 2 files changed, 122 insertions(+), 29 deletions(-)
>
> diff --git a/fs/richacl_base.c b/fs/richacl_base.c
> index db27542..54cb482 100644
> --- a/fs/richacl_base.c
> +++ b/fs/richacl_base.c
> @@ -439,49 +439,141 @@ richacl_inherit(const struct richacl *dir_acl, int isdir)
> }
>
> /**
> - * richacl_equiv_mode - check if @acl is equivalent to file permission bits
> - * @mode_p: the file mode (including the file type)
> + * __richacl_equiv_mode - compute the mode equivalent of @acl
> *
> - * If @acl can be fully represented by file permission bits, this function
> - * returns 0, and the file permission bits in @mode_p are set to the equivalent
> - * of @acl.
This comment is a little confusing:
> + * This function does not consider the masks in @acl.
Given that we do this later:
> + if (acl->a_flags & RICHACL_MASKED) {
> + owner.allowed &= acl->a_owner_mask;
> + group.allowed &= acl->a_group_mask;
> + everyone.allowed &= acl->a_other_mask;
> + }
I think the difference is that here you're checking that the end result
after applying masks is mode-equivalent, whereas in riachacl_equiv_mode:
> + if (acl->a_flags & RICHACL_MASKED) {
> + mode_t mask = richacl_masks_to_mode(acl);
> + unsigned int x;
> +
> + /* Mask flags we can ignore */
> + x = ~(RICHACE_POSIX_ALWAYS_ALLOWED |
> + (S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD));
> +
> + if (((acl->a_group_mask ^ richacl_mode_to_mask(mask >> 3)) & x) ||
> + ((acl->a_other_mask ^ richacl_mode_to_mask(mask)) & x))
> + return -1;
> +
> + x &= ~RICHACE_POSIX_OWNER_ALLOWED;
> + if ((acl->a_owner_mask ^ richacl_mode_to_mask(mask >> 6)) & x)
> + return -1;
> +
> + mode &= ~S_IRWXUGO | mask;
> + }
... you're also checking whether the masks themselves are
mode-equivalent? Is that the right thing to do?
I've probably misread the code again....
--b.
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