Re: [PATCH 02/15] security: move LSM xattrnames to xattr.h

Mimi Zohar
2010-06-28T01:35:40Z

On Sun, 2010-06-27 at 09:54 -0700, Casey Schaufler wrote:
> Mimi Zohar wrote:
> > On Thu, 2010-06-24 at 20:49 -0700, Casey Schaufler wrote:
> >
> >> Mimi Zohar wrote:
> >>
> >>> Make the security extended attributes names global.
> >>>
> >>> Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
> >>> Acked-by: Serge Hallyn <serue@us.ibm.com>
> >>> ---
> >>> include/linux/capability.h | 3 ---
> >>> include/linux/xattr.h | 10 ++++++++++
> >>> security/selinux/hooks.c | 3 ---
> >>> security/smack/smack.h | 2 --
> >>> 4 files changed, 10 insertions(+), 8 deletions(-)
> >>>
> >>> diff --git a/include/linux/capability.h b/include/linux/capability.h
> >>> index 39e5ff5..90012b9 100644
> >>> --- a/include/linux/capability.h
> >>> +++ b/include/linux/capability.h
> >>> @@ -49,9 +49,6 @@ typedef struct __user_cap_data_struct {
> >>> } __user *cap_user_data_t;
> >>>
> >>>
> >>> -#define XATTR_CAPS_SUFFIX "capability"
> >>> -#define XATTR_NAME_CAPS XATTR_SECURITY_PREFIX XATTR_CAPS_SUFFIX
> >>> -
> >>> #define VFS_CAP_REVISION_MASK 0xFF000000
> >>> #define VFS_CAP_REVISION_SHIFT 24
> >>> #define VFS_CAP_FLAGS_MASK ~VFS_CAP_REVISION_MASK
> >>> diff --git a/include/linux/xattr.h b/include/linux/xattr.h
> >>> index 0cfa1e9..62ca853 100644
> >>> --- a/include/linux/xattr.h
> >>> +++ b/include/linux/xattr.h
> >>> @@ -33,6 +33,16 @@
> >>> #define XATTR_USER_PREFIX "user."
> >>> #define XATTR_USER_PREFIX_LEN (sizeof (XATTR_USER_PREFIX) - 1)
> >>>
> >>> +/* Security namespace */
> >>> +#define XATTR_SELINUX_SUFFIX "selinux"
> >>> +#define XATTR_NAME_SELINUX XATTR_SECURITY_PREFIX XATTR_SELINUX_SUFFIX
> >>> +
> >>> +#define XATTR_SMACK_SUFFIX "SMACK64"
> >>> +#define XATTR_NAME_SMACK XATTR_SECURITY_PREFIX XATTR_SMACK_SUFFIX
> >>> +
> >>> +#define XATTR_CAPS_SUFFIX "capability"
> >>> +#define XATTR_NAME_CAPS XATTR_SECURITY_PREFIX XATTR_CAPS_SUFFIX
> >>> +
> >>> struct inode;
> >>> struct dentry;
> >>>
> >>> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> >>> index 0f524b7..85338f0 100644
> >>> --- a/security/selinux/hooks.c
> >>> +++ b/security/selinux/hooks.c
> >>> @@ -87,9 +87,6 @@
> >>> #include "netlabel.h"
> >>> #include "audit.h"
> >>>
> >>> -#define XATTR_SELINUX_SUFFIX "selinux"
> >>> -#define XATTR_NAME_SELINUX XATTR_SECURITY_PREFIX XATTR_SELINUX_SUFFIX
> >>> -
> >>> #define NUM_SEL_MNT_OPTS 5
> >>>
> >>> extern int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm);
> >>> diff --git a/security/smack/smack.h b/security/smack/smack.h
> >>> index c6e9aca..9c773e3 100644
> >>> --- a/security/smack/smack.h
> >>> +++ b/security/smack/smack.h
> >>> @@ -126,10 +126,8 @@ struct smack_known {
> >>> /*
> >>> * xattr names
> >>> */
> >>> -#define XATTR_SMACK_SUFFIX "SMACK64"
> >>> #define XATTR_SMACK_IPIN "SMACK64IPIN"
> >>> #define XATTR_SMACK_IPOUT "SMACK64IPOUT"
> >>> -#define XATTR_NAME_SMACK XATTR_SECURITY_PREFIX XATTR_SMACK_SUFFIX
> >>> #define XATTR_NAME_SMACKIPIN XATTR_SECURITY_PREFIX XATTR_SMACK_IPIN
> >>> #define XATTR_NAME_SMACKIPOUT XATTR_SECURITY_PREFIX XATTR_SMACK_IPOUT
> >>>
> >>>
> >> Why just the SMACK64 attribute name, and not the others? They are
> >> manipulated with the same interfaces (well, fsetxattr, fgetxattr)
> >> as the SMACK64 attribute. There isn't any conceptual difference and
> >> the rationale for moving attribute names really ought to apply to
> >> them as well.
> >>
> >
> > Hi Casey,
> >
> > Moving the other SMACK xattrs is fine, but are they used on persistent
> > files and need to be EVM protected?
> >
>
> They are not persistent in any configuration available today, but
> as they say, tomorrow never knows. The real reason I'm concerned is
> that I always dislike having to go look in two places for something
> like attr names. Either global or local is fine, but it should be
> one or the other.

agreed. So I'll update the patch to move the remaining xattrs, without
including them in the HMAC.

Mimi