Quoting Andrew Vagin (ava...@openvz.org):
> Without this patch it is really hard to interpret a bounding set,
> if CAP_LAST_CAP is unknown for a current kernel.
To be clear, note that you *can* figure it out using
prctl(PR_CAPBSET_DROP). But this is a nice improvement.
> Non-existant capabilities can not be deleted from a bounding set
> with help of prctl.
>
> E.g.: Here are two examples without/with this patch.
> CapBnd: ffffffe0fdecffff
> CapBnd: 00000000fdecffff
>
> I suggest to hide non-existent capabilities. Here is two reasons.
> * It's logically and easier for using.
> * It helps to checkpoint-restore capabilities of tasks, because tasks
> can be restored on another kernel, where CAP_LAST_CAP is bigger.
>
> Cc: Serge Hallyn <serge.hal...@canonical.com>
Thanks, Andrew. I saw your other email about having run LTP, I didn't
see any problems from userspace either. Great idea!
Reviewed-by: Serge Hallyn <serge.hal...@canonical.com>
Still it's been like that for so long that, just to be safe, I'm cc:ing
Andrew Morgan - can you see any problems with this?
> Cc: Pavel Emelyanov <xe...@parallels.com>
> Signed-off-by: Andrew Vagin <ava...@openvz.org>
> ---
> include/linux/capability.h | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/include/linux/capability.h b/include/linux/capability.h
> index d10b7ed..1642778 100644
> --- a/include/linux/capability.h
> +++ b/include/linux/capability.h
> @@ -420,7 +420,8 @@ extern const kernel_cap_t __cap_init_eff_set;
> #else /* HAND-CODED capability initializers */
>
> # define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }})
> -# define CAP_FULL_SET ((kernel_cap_t){{ ~0, ~0 }})
> +# define CAP_FULL_SET ((kernel_cap_t){{ ~0, \
> + CAP_TO_MASK(CAP_LAST_CAP + 1) - 1 } })
> # define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
> | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
> CAP_FS_MASK_B1 } })
> --
> 1.7.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
