Am Mi., 19. Juli 2023 um 23:22 Uhr schrieb Andreas Grünbacher <andreas.gruenbacher@xxxxxxxxx>: > > Hi Jeff, > > this patch seems useful, thanks. > > Am Mi., 19. Juli 2023 um 19:56 Uhr schrieb Jeff Layton <jlayton@xxxxxxxxxx>: > > A well-formed NFSv4 ACL will always contain OWNER@/GROUP@/EVERYONE@ > > ACEs, but there is no requirement for inheritable entries for those > > entities. POSIX ACLs must always have owner/group/other entries, even for a > > default ACL. > > NFSv4 ACLs actually don't *need* to have OWNER@/GROUP@/EVERYONE@ > entries; that's merely a result of translating POSIX ACLs (or file > modes) to NFSv4 ACLs. > > > nfsd builds the default ACL from inheritable ACEs, but the current code > > just leaves any unspecified ACEs zeroed out. The result is that adding a > > default user or group ACE to an inode can leave it with unwanted deny > > entries. > > > > For instance, a newly created directory with no acl will look something > > like this: > > > > # NFSv4 translation by server > > A::OWNER@:rwaDxtTcCy > > A::GROUP@:rxtcy > > A::EVERYONE@:rxtcy > > > > # POSIX ACL of underlying file > > user::rwx > > group::r-x > > other::r-x > > > > ...if I then add new v4 ACE: > > > > nfs4_setfacl -a A:fd:1000:rwx /mnt/local/test > > > > ...I end up with a result like this today: > > > > user::rwx > > user:1000:rwx > > group::r-x > > mask::rwx > > other::r-x > > default:user::--- > > default:user:1000:rwx > > default:group::--- > > default:mask::rwx > > default:other::--- > > > > A::OWNER@:rwaDxtTcCy > > A::1000:rwaDxtcy > > A::GROUP@:rxtcy > > A::EVERYONE@:rxtcy > > D:fdi:OWNER@:rwaDx > > A:fdi:OWNER@:tTcCy > > A:fdi:1000:rwaDxtcy > > A:fdi:GROUP@:tcy > > A:fdi:EVERYONE@:tcy > > > > ...which is not at all expected. Adding a single inheritable allow ACE > > should not result in everyone else losing access. > > > > The setfacl command solves a silimar issue by copying owner/group/other > > entries from the effective ACL when none of them are set: > > > > "If a Default ACL entry is created, and the Default ACL contains no > > owner, owning group, or others entry, a copy of the ACL owner, > > owning group, or others entry is added to the Default ACL. > > > > Having nfsd do the same provides a more sane result (with no deny ACEs > > in the resulting set): > > > > user::rwx > > user:1000:rwx > > group::r-x > > mask::rwx > > other::r-x > > default:user::rwx > > default:user:1000:rwx > > default:group::r-x > > default:mask::rwx > > default:other::r-x > > > > A::OWNER@:rwaDxtTcCy > > A::1000:rwaDxtcy > > A::GROUP@:rxtcy > > A::EVERYONE@:rxtcy > > A:fdi:OWNER@:rwaDxtTcCy > > A:fdi:1000:rwaDxtcy > > A:fdi:GROUP@:rxtcy > > A:fdi:EVERYONE@:rxtcy > > This resulting NFSv4 ACL is still rather dull; we end up with an > inherit-only entry for each effective entry. Those could all be > combined, resulting in: > > A:fd:OWNER@:rwaDxtTcCy > A:fd:1000:rwaDxtcy > A:fd:GROUP@:rxtcy > A:fd:EVERYONE@:rxtcy > > This will be the common case, so maybe matching entry pairs can either > be recombined or not generated in the first place as a further > improvement. > > > Link: https://bugzilla.redhat.com/show_bug.cgi?id=2136452 > > Reported-by: Ondrej Valousek <ondrej.valousek@xxxxxxxxxxx> > > Suggested-by: Andreas Gruenbacher <agruen@xxxxxxxxxx> > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > > --- > > fs/nfsd/nfs4acl.c | 32 +++++++++++++++++++++++++++++--- > > 1 file changed, 29 insertions(+), 3 deletions(-) > > > > diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c > > index 518203821790..64e45551d1b6 100644 > > --- a/fs/nfsd/nfs4acl.c > > +++ b/fs/nfsd/nfs4acl.c > > @@ -441,7 +441,8 @@ struct posix_ace_state_array { > > * calculated so far: */ > > > > struct posix_acl_state { > > - int empty; > > + bool empty; > > + unsigned char valid; > > Hmm, "valid" is a bitmask here but it only matters whether it is zero. > Shouldn't a bool be good enough? Also, this variable indicates whether > special "who" values are present (and which), so the name "valid" > probably isn't the best choice. > > > struct posix_ace_state owner; > > struct posix_ace_state group; > > struct posix_ace_state other; > > @@ -457,7 +458,7 @@ init_state(struct posix_acl_state *state, int cnt) > > int alloc; > > > > memset(state, 0, sizeof(struct posix_acl_state)); > > - state->empty = 1; > > + state->empty = true; > > /* > > * In the worst case, each individual acl could be for a distinct > > * named user or group, but we don't know which, so we allocate > > @@ -624,7 +625,7 @@ static void process_one_v4_ace(struct posix_acl_state *state, > > u32 mask = ace->access_mask; > > int i; > > > > - state->empty = 0; > > + state->empty = false; > > > > switch (ace2type(ace)) { > > case ACL_USER_OBJ: > > @@ -633,6 +634,7 @@ static void process_one_v4_ace(struct posix_acl_state *state, > > } else { > > deny_bits(&state->owner, mask); > > } > > + state->valid |= ACL_USER_OBJ; > > break; > > case ACL_USER: > > i = find_uid(state, ace->who_uid); > > @@ -655,6 +657,7 @@ static void process_one_v4_ace(struct posix_acl_state *state, > > deny_bits_array(state->users, mask); > > deny_bits_array(state->groups, mask); > > } > > + state->valid |= ACL_GROUP_OBJ; > > break; > > case ACL_GROUP: > > i = find_gid(state, ace->who_gid); > > @@ -686,6 +689,7 @@ static void process_one_v4_ace(struct posix_acl_state *state, > > deny_bits_array(state->users, mask); > > deny_bits_array(state->groups, mask); > > } > > + state->valid |= ACL_OTHER; > > } > > } > > > > @@ -726,6 +730,28 @@ static int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, > > if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE)) > > process_one_v4_ace(&effective_acl_state, ace); > > } > > + > > + /* > > + * At this point, the default ACL may have zeroed-out entries for owner, > > + * group and other. That usually results in a non-sensical resulting ACL > > + * that denies all access except to any ACE that was explicitly added. > > + * > > + * The setfacl command solves a similar problem with this logic: > > + * > > + * "If a Default ACL entry is created, and the Default ACL contains > > + * no owner, owning group, or others entry, a copy of the ACL > > + * owner, owning group, or others entry is added to the Default ACL." > > + * > > + * If none of the requisite ACEs were set, and some explicit user or group > > + * ACEs were, copy the requisite entries from the effective set. > > + */ > > + if (!default_acl_state.valid && > > + (default_acl_state.users->n || default_acl_state.groups->n)) { > > + default_acl_state.owner = effective_acl_state.owner; > > + default_acl_state.group = effective_acl_state.group; > > + default_acl_state.other = effective_acl_state.other; > > + } > > + The other thing I'm wondering about is whether it would make more sense to fake up for missing entries individually as setfacl does: http://git.savannah.nongnu.org/cgit/acl.git/tree/tools/do_set.c#n368 > > *pacl = posix_state_to_acl(&effective_acl_state, flags); > > if (IS_ERR(*pacl)) { > > ret = PTR_ERR(*pacl); > > > > --- > > base-commit: 9d985ab8ed33176c3c0380b7de589ea2ae51a48d > > change-id: 20230719-nfsd-acl-5ab61537e4e6 > > > > Best regards, > > -- > > Jeff Layton <jlayton@xxxxxxxxxx> Thanks, Andreas
