On Sat, Sep 05, 2015 at 12:27:22PM +0200, Andreas Gruenbacher wrote: > A file can have "no acl" in the sense that only the file mode permission > bits determine access. In that case, the getxattr system call fails with > errno == ENODATA (No such attribute). > > Over the NFSv4 protocol, a file always has an acl, and we convert the file > mode permission bits into an equivalent acl with richacl_from_mode. Such > "trivial" acls can be converted back to a file mode with > richacl_equiv_mode. Reviewed-by: J. Bruce Fields <bfields@xxxxxxxxxx> > > Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx> > --- > fs/richacl_compat.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/richacl.h | 1 + > 2 files changed, 89 insertions(+) > > diff --git a/fs/richacl_compat.c b/fs/richacl_compat.c > index 9681efe..632409f 100644 > --- a/fs/richacl_compat.c > +++ b/fs/richacl_compat.c > @@ -840,3 +840,91 @@ richacl_apply_masks(struct richacl **acl, kuid_t owner) > return 0; > } > EXPORT_SYMBOL_GPL(richacl_apply_masks); > + > +/** > + * richacl_from_mode - create an acl which corresponds to @mode > + * > + * The resulting acl doesn't have the RICHACL_MASKED flag set. > + * > + * @mode: file mode including the file type > + */ > +struct richacl * > +richacl_from_mode(mode_t mode) > +{ > + unsigned int owner_mask = richacl_mode_to_mask(mode >> 6); > + unsigned int group_mask = richacl_mode_to_mask(mode >> 3); > + unsigned int other_mask = richacl_mode_to_mask(mode); > + unsigned int denied; > + unsigned int entries = 0; > + struct richacl *acl; > + struct richace *ace; > + > + /* RICHACE_DELETE_CHILD is meaningless for non-directories. */ > + if (!S_ISDIR(mode)) { > + owner_mask &= ~RICHACE_DELETE_CHILD; > + group_mask &= ~RICHACE_DELETE_CHILD; > + other_mask &= ~RICHACE_DELETE_CHILD; > + } > + > + denied = ~owner_mask & (group_mask | other_mask); > + if (denied) > + entries++; /* owner@ deny entry needed */ > + if (owner_mask & ~(group_mask & other_mask)) > + entries++; /* owner@ allow entry needed */ > + denied = ~group_mask & other_mask; > + if (denied) > + entries++; /* group@ deny entry needed */ > + if (group_mask & ~other_mask) > + entries++; /* group@ allow entry needed */ > + if (other_mask) > + entries++; /* everyone@ allow entry needed */ > + > + acl = richacl_alloc(entries, GFP_KERNEL); > + if (!acl) > + return NULL; > + acl->a_owner_mask = owner_mask; > + acl->a_group_mask = group_mask; > + acl->a_other_mask = other_mask; > + ace = acl->a_entries; > + > + denied = ~owner_mask & (group_mask | other_mask); > + if (denied) { > + ace->e_type = RICHACE_ACCESS_DENIED_ACE_TYPE; > + ace->e_flags = RICHACE_SPECIAL_WHO; > + ace->e_mask = denied; > + ace->e_id.special = RICHACE_OWNER_SPECIAL_ID; > + ace++; > + } > + if (owner_mask & ~(group_mask & other_mask)) { > + ace->e_type = RICHACE_ACCESS_ALLOWED_ACE_TYPE; > + ace->e_flags = RICHACE_SPECIAL_WHO; > + ace->e_mask = owner_mask; > + ace->e_id.special = RICHACE_OWNER_SPECIAL_ID; > + ace++; > + } > + denied = ~group_mask & other_mask; > + if (denied) { > + ace->e_type = RICHACE_ACCESS_DENIED_ACE_TYPE; > + ace->e_flags = RICHACE_SPECIAL_WHO; > + ace->e_mask = denied; > + ace->e_id.special = RICHACE_GROUP_SPECIAL_ID; > + ace++; > + } > + if (group_mask & ~other_mask) { > + ace->e_type = RICHACE_ACCESS_ALLOWED_ACE_TYPE; > + ace->e_flags = RICHACE_SPECIAL_WHO; > + ace->e_mask = group_mask; > + ace->e_id.special = RICHACE_GROUP_SPECIAL_ID; > + ace++; > + } > + if (other_mask) { > + ace->e_type = RICHACE_ACCESS_ALLOWED_ACE_TYPE; > + ace->e_flags = RICHACE_SPECIAL_WHO; > + ace->e_mask = other_mask; > + ace->e_id.special = RICHACE_EVERYONE_SPECIAL_ID; > + ace++; > + } > + > + return acl; > +} > +EXPORT_SYMBOL_GPL(richacl_from_mode); > diff --git a/include/linux/richacl.h b/include/linux/richacl.h > index a945f3c..f48c04e 100644 > --- a/include/linux/richacl.h > +++ b/include/linux/richacl.h > @@ -334,5 +334,6 @@ extern struct richacl *richacl_create(struct inode *, struct inode *); > > /* richacl_compat.c */ > extern int richacl_apply_masks(struct richacl **, kuid_t); > +extern struct richacl *richacl_from_mode(mode_t); > > #endif /* __RICHACL_H */ > -- > 2.4.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html