Re: [PATCH v3 05/11] syslog_ns: make permisiion check per usernamespace

From: Ben Hutchings
Date: Wed Aug 07 2013 - 14:41:51 EST


On Wed, 2013-08-07 at 15:37 +0800, Rui Xiang wrote:
> Use ns_capable to check capability in user ns,
> instead of capable function. The user ns is the
> owner of current syslog ns.
>
> Signed-off-by: Rui Xiang <rui.xiang@xxxxxxxxxx>
> ---
> kernel/printk.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/printk.c b/kernel/printk.c
> index e508ab2..ca951e7 100644
> --- a/kernel/printk.c
> +++ b/kernel/printk.c
> @@ -374,13 +374,13 @@ static int check_syslog_permissions(int type, bool from_file,
> return 0;
>
> if (syslog_action_restricted(type, ns)) {
> - if (capable(CAP_SYSLOG))
> + if (ns_capable(ns->owner, CAP_SYSLOG))
> return 0;
> /*
> * For historical reasons, accept CAP_SYS_ADMIN too, with
> * a warning.
> */
> - if (capable(CAP_SYS_ADMIN)) {
> + if (ns_capable(ns->owner, CAP_SYS_ADMIN)) {
> pr_warn_once("%s (%d): Attempt to access syslog with "
> "CAP_SYS_ADMIN but no CAP_SYSLOG "
> "(deprecated).\n",

Since CAP_SYS_ADMIN is only accepted for backward compatibility, is it
really necessary to accept it as a per-namespace capability too?

Ben.

--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

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