Commit d4247970 authored by Jeff Layton's avatar Jeff Layton Committed by Chuck Lever
Browse files

nfsd: inherit required unset default acls from effective set 



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.

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

Reported-by: default avatarOndrej Valousek <ondrej.valousek@diasemi.com>
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2136452


Suggested-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent f8077478

fs/nfsd/nfs4acl.c

+29 −5
Original line number Diff line number Diff line
@@ -441,7 +441,7 @@ struct posix_ace_state_array { 
 * calculated so far: */



struct posix_acl_state {

	int empty;

	unsigned char valid;

	struct posix_ace_state owner;

	struct posix_ace_state group;

	struct posix_ace_state other;
@@ -457,7 +457,6 @@ init_state(struct posix_acl_state *state, int cnt) 
	int alloc;



	memset(state, 0, sizeof(struct posix_acl_state));

	state->empty = 1;

	/*

	 * 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
@@ -500,7 +499,7 @@ posix_state_to_acl(struct posix_acl_state *state, unsigned int flags) 
	 * and effective cases: when there are no inheritable ACEs,

	 * calls ->set_acl with a NULL ACL structure.

	 */

	if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT))

	if (!state->valid && (flags & NFS4_ACL_TYPE_DEFAULT))

		return NULL;



	/*
@@ -622,11 +621,12 @@ static void process_one_v4_ace(struct posix_acl_state *state, 
				struct nfs4_ace *ace)

{

	u32 mask = ace->access_mask;

	short type = ace2type(ace);

	int i;



	state->empty = 0;

	state->valid |= type;



	switch (ace2type(ace)) {

	switch (type) {

	case ACL_USER_OBJ:

		if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {

			allow_bits(&state->owner, mask);
@@ -726,6 +726,30 @@ 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."

	 *

	 * Copy any missing ACEs from the effective set, if any ACEs were

	 * explicitly set.

	 */

	if (default_acl_state.valid) {

		if (!(default_acl_state.valid & ACL_USER_OBJ))

			default_acl_state.owner = effective_acl_state.owner;

		if (!(default_acl_state.valid & ACL_GROUP_OBJ))

			default_acl_state.group = effective_acl_state.group;

		if (!(default_acl_state.valid & ACL_OTHER))

			default_acl_state.other = effective_acl_state.other;

	}



	*pacl = posix_state_to_acl(&effective_acl_state, flags);

	if (IS_ERR(*pacl)) {

		ret = PTR_ERR(*pacl);