On Tue, Mar 1, 2022 at 3:51 AM Darrick J. Wong <djwong@xxxxxxxxxx> wrote:
> From: Darrick J. Wong <djwong@xxxxxxxxxx>
>
> There are a few places where we test the current process' capability set
> to decide if we're going to be more or less generous with resource
> acquisition for a system call. If the process doesn't have the
> capability, we can continue the call, albeit in a degraded mode.
>
> These are /not/ the actual security decisions, so it's not proper to use
> capable(), which (in certain selinux setups) causes audit messages to
> get logged. Switch them to has_capability_noaudit.
>
> Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> Cc: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
> Cc: Dave Chinner <david@xxxxxxxxxxxxx>
> ---
> fs/xfs/xfs_fsmap.c | 4 ++--
> fs/xfs/xfs_ioctl.c | 2 +-
> fs/xfs/xfs_iops.c | 2 +-
> kernel/capability.c | 1 +
> 4 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
> index 48287caad28b..10e1cb71439e 100644
> --- a/fs/xfs/xfs_fsmap.c
> +++ b/fs/xfs/xfs_fsmap.c
> @@ -864,8 +864,8 @@ xfs_getfsmap(
> !xfs_getfsmap_is_valid_device(mp, &head->fmh_keys[1]))
> return -EINVAL;
>
> - use_rmap = capable(CAP_SYS_ADMIN) &&
> - xfs_has_rmapbt(mp);
> + use_rmap = xfs_has_rmapbt(mp) &&
> + has_capability_noaudit(current, CAP_SYS_ADMIN);
> head->fmh_entries = 0;
>
> /* Set up our device handlers. */
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 2515fe8299e1..83481005317a 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1189,7 +1189,7 @@ xfs_ioctl_setattr_get_trans(
> goto out_error;
>
> error = xfs_trans_alloc_ichange(ip, NULL, NULL, pdqp,
> - capable(CAP_FOWNER), &tp);
> + has_capability_noaudit(current, CAP_FOWNER), &tp);
> if (error)
> goto out_error;
>
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index b79b3846e71b..a65217f787cf 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -723,7 +723,7 @@ xfs_setattr_nonsize(
> }
>
> error = xfs_trans_alloc_ichange(ip, udqp, gdqp, NULL,
> - capable(CAP_FOWNER), &tp);
> + has_capability_noaudit(current, CAP_FOWNER), &tp);
> if (error)
> goto out_dqrele;
>
> diff --git a/kernel/capability.c b/kernel/capability.c
> index 46a361dde042..765194f5d678 100644
> --- a/kernel/capability.c
> +++ b/kernel/capability.c
> @@ -360,6 +360,7 @@ bool has_capability_noaudit(struct task_struct *t, int cap)
> {
> return has_ns_capability_noaudit(t, &init_user_ns, cap);
> }
> +EXPORT_SYMBOL(has_capability_noaudit);
>
> static bool ns_capable_common(struct user_namespace *ns,
> int cap,
>
Thank you for respinning the patch[1]! And sorry that I couldn't find
the time to do that :/
Reviewed-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
(Yes, we should still clean up and document the capability functions,
but if no one has the energy, let's at least do the minimal fix.)
[1] Link for reference:
https://lore.kernel.org/linux-xfs/20210316173226.2220046-1-omosnace@xxxxxxxxxx/T/
--
Ondrej Mosnacek
Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.
