| Message ID | 20171021134558.21195-1-nicolas@belouin.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Quoting Nicolas Belouin (nicolas@belouin.fr): > with CAP_SYS_ADMIN being bloated, the usefulness of using it to > flag a process to be entrusted for e.g reading and writing trusted > xattr is near zero. > CAP_TRUSTED aims to provide userland with a way to mark a process as > entrusted to do specific (not specially admin-centered) actions. It > would for example allow a process to red/write the trusted xattrs. You say "for example". Are you intending to add more uses? If so, what are they? If not, how about renaming it CAP_TRUSTED_XATTR? What all does allowing writes to trusted xattrs give you? There are the overlayfs whiteouts, what else?
On 10/21/2017 6:45 AM, Nicolas Belouin wrote: > with CAP_SYS_ADMIN being bloated, the usefulness of using it to > flag a process to be entrusted for e.g reading and writing trusted > xattr is near zero. > CAP_TRUSTED aims to provide userland with a way to mark a process as > entrusted to do specific (not specially admin-centered) actions. It > would for example allow a process to red/write the trusted xattrs. Please explain how this is different from CAP_MAC_ADMIN in any existing use case. If it is significantly different, how would the two interact? > Signed-off-by: Nicolas Belouin <nicolas@belouin.fr> > --- > include/uapi/linux/capability.h | 6 +++++- > security/selinux/include/classmap.h | 5 +++-- > 2 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h > index ce230aa6d928..27e457b93c84 100644 > --- a/include/uapi/linux/capability.h > +++ b/include/uapi/linux/capability.h > @@ -369,7 +369,11 @@ struct vfs_ns_cap_data { > > #define CAP_SYS_MOUNT 38 > > -#define CAP_LAST_CAP CAP_SYS_MOUNT > +/* Allow read/write trusted xattr */ > + > +#define CAP_TRUSTED 39 > + > +#define CAP_LAST_CAP CAP_TRUSTED > > #define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP) > > diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h > index a873dce97fd5..f5dc8e109f5a 100644 > --- a/security/selinux/include/classmap.h > +++ b/security/selinux/include/classmap.h > @@ -24,9 +24,10 @@ > "audit_control", "setfcap" > > #define COMMON_CAP2_PERMS "mac_override", "mac_admin", "syslog", \ > - "wake_alarm", "block_suspend", "audit_read", "sys_mount" > + "wake_alarm", "block_suspend", "audit_read", "sys_mount", \ > + "trusted" > > -#if CAP_LAST_CAP > CAP_SYS_MOUNT > +#if CAP_LAST_CAP > CAP_TRUSTED > #error New capability defined, please update COMMON_CAP2_PERMS. > #endif >
diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h index ce230aa6d928..27e457b93c84 100644 --- a/include/uapi/linux/capability.h +++ b/include/uapi/linux/capability.h @@ -369,7 +369,11 @@ struct vfs_ns_cap_data { #define CAP_SYS_MOUNT 38 -#define CAP_LAST_CAP CAP_SYS_MOUNT +/* Allow read/write trusted xattr */ + +#define CAP_TRUSTED 39 + +#define CAP_LAST_CAP CAP_TRUSTED #define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP) diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index a873dce97fd5..f5dc8e109f5a 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -24,9 +24,10 @@ "audit_control", "setfcap" #define COMMON_CAP2_PERMS "mac_override", "mac_admin", "syslog", \ - "wake_alarm", "block_suspend", "audit_read", "sys_mount" + "wake_alarm", "block_suspend", "audit_read", "sys_mount", \ + "trusted" -#if CAP_LAST_CAP > CAP_SYS_MOUNT +#if CAP_LAST_CAP > CAP_TRUSTED #error New capability defined, please update COMMON_CAP2_PERMS. #endif
with CAP_SYS_ADMIN being bloated, the usefulness of using it to flag a process to be entrusted for e.g reading and writing trusted xattr is near zero. CAP_TRUSTED aims to provide userland with a way to mark a process as entrusted to do specific (not specially admin-centered) actions. It would for example allow a process to red/write the trusted xattrs. Signed-off-by: Nicolas Belouin <nicolas@belouin.fr> --- include/uapi/linux/capability.h | 6 +++++- security/selinux/include/classmap.h | 5 +++-- 2 files changed, 8 insertions(+), 3 deletions(-)