nfsd: Handle kuids and kgids in the nfs4acl to posix_acl conversion

In struct nfs4_ace remove the member who and replace it with an
anonymous union holding who_uid and who_gid.  Allowing typesafe
storage uids and gids.

Add a helper pace_gt for sorting posix_acl_entries.

In struct posix_user_ace_state to replace uid with a union
of kuid_t uid and kgid_t gid.

Remove all initializations of the deprecated posic_acl_entry
e_id field.  Which is not present when user namespaces are enabled.

Split find_uid into two functions find_uid and find_gid that work
in a typesafe manner.

In nfs4xdr update nfsd4_encode_fattr to deal with the changes
in struct nfs4_ace.

Rewrite nfsd4_encode_name to take a kuid_t and a kgid_t instead
of a generic id and flag if it is a group or a uid.  Replace
the group flag with a test for a valid gid.

Modify nfsd4_encode_user to take a kuid_t and call the modifed
nfsd4_encode_name.

Modify nfsd4_encode_group to take a kgid_t and call the modified
nfsd4_encode_name.

Modify nfsd4_encode_aclname to take an ace instead of taking the
fields of an ace broken out.  This allows it to detect if the ace is
for a user or a group and to pass the appropriate value while still
being typesafe.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

2 files changed, 71 insertions, 33 deletions

diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c
index 9c51aff02ae2..8a50b3c18093 100644
--- a/fs/nfsd/nfs4acl.c
+++ b/fs/nfsd/nfs4acl.c
@@ -264,7 +264,7 @@ _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
                         ace->flag = eflag;
                         ace->access_mask = deny_mask_from_posix(deny, flags);
                         ace->whotype = NFS4_ACL_WHO_NAMED;
-                        ace->who = pa->e_id;
+                        ace->who_uid = pa->e_uid;
                         ace++;
                         acl->naces++;
                 }
@@ -273,7 +273,7 @@ _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
                 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
                                                    flags);
                 ace->whotype = NFS4_ACL_WHO_NAMED;
-                ace->who = pa->e_id;
+                ace->who_uid = pa->e_uid;
                 ace++;
                 acl->naces++;
                 pa++;
@@ -300,7 +300,7 @@ _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
                 ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
                                                    flags);
                 ace->whotype = NFS4_ACL_WHO_NAMED;
-                ace->who = pa->e_id;
+                ace->who_gid = pa->e_gid;
                 ace++;
                 acl->naces++;
                 pa++;
@@ -329,7 +329,7 @@ _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
                         ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
                         ace->access_mask = deny_mask_from_posix(deny, flags);
                         ace->whotype = NFS4_ACL_WHO_NAMED;
-                        ace->who = pa->e_id;
+                        ace->who_gid = pa->e_gid;
                         ace++;
                         acl->naces++;
                 }
@@ -345,6 +345,18 @@ _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
         acl->naces++;
 }
 
+static bool
+pace_gt(struct posix_acl_entry *pace1, struct posix_acl_entry *pace2)
+{
+        if (pace1->e_tag != pace2->e_tag)
+                return pace1->e_tag > pace2->e_tag;
+        if (pace1->e_tag == ACL_USER)
+                return uid_gt(pace1->e_uid, pace2->e_uid);
+        if (pace1->e_tag == ACL_GROUP)
+                return gid_gt(pace1->e_gid, pace2->e_gid);
+        return false;
+}
+
 static void
 sort_pacl_range(struct posix_acl *pacl, int start, int end) {
         int sorted = 0, i;
@@ -355,8 +367,8 @@ sort_pacl_range(struct posix_acl *pacl, int start, int end) {
         while (!sorted) {
                 sorted = 1;
                 for (i = start; i < end; i++) {
-                        if (pacl->a_entries[i].e_id
-                                        > pacl->a_entries[i+1].e_id) {
+                        if (pace_gt(&pacl->a_entries[i],
+                                    &pacl->a_entries[i+1])) {
                                 sorted = 0;
                                 tmp = pacl->a_entries[i];
                                 pacl->a_entries[i] = pacl->a_entries[i+1];
@@ -398,7 +410,10 @@ struct posix_ace_state {
 };
 
 struct posix_user_ace_state {
-        uid_t uid;
+        union {
+                kuid_t uid;
+                kgid_t gid;
+        };
         struct posix_ace_state perms;
 };
 
@@ -521,7 +536,6 @@ posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
         if (error)
                 goto out_err;
         low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
-        pace->e_id = ACL_UNDEFINED_ID;
 
         for (i=0; i < state->users->n; i++) {
                 pace++;
@@ -531,7 +545,7 @@ posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
                         goto out_err;
                 low_mode_from_nfs4(state->users->aces[i].perms.allow,
                                         &pace->e_perm, flags);
-                pace->e_id = state->users->aces[i].uid;
+                pace->e_uid = state->users->aces[i].uid;
                 add_to_mask(state, &state->users->aces[i].perms);
         }
 
@@ -541,7 +555,6 @@ posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
         if (error)
                 goto out_err;
         low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
-        pace->e_id = ACL_UNDEFINED_ID;
         add_to_mask(state, &state->group);
 
         for (i=0; i < state->groups->n; i++) {
@@ -552,14 +565,13 @@ posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
                         goto out_err;
                 low_mode_from_nfs4(state->groups->aces[i].perms.allow,
                                         &pace->e_perm, flags);
-                pace->e_id = state->groups->aces[i].uid;
+                pace->e_gid = state->groups->aces[i].gid;
                 add_to_mask(state, &state->groups->aces[i].perms);
         }
 
         pace++;
         pace->e_tag = ACL_MASK;
         low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
-        pace->e_id = ACL_UNDEFINED_ID;
 
         pace++;
         pace->e_tag = ACL_OTHER;
@@ -567,7 +579,6 @@ posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
         if (error)
                 goto out_err;
         low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
-        pace->e_id = ACL_UNDEFINED_ID;
 
         return pacl;
 out_err:
@@ -587,12 +598,13 @@ static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
         astate->deny |= mask & ~astate->allow;
 }
 
-static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array *a, uid_t uid)
+static int find_uid(struct posix_acl_state *state, kuid_t uid)
 {
+        struct posix_ace_state_array *a = state->users;
         int i;
 
         for (i = 0; i < a->n; i++)
-                if (a->aces[i].uid == uid)
+                if (uid_eq(a->aces[i].uid, uid))
                         return i;
         /* Not found: */
         a->n++;
@@ -603,6 +615,23 @@ static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array
         return i;
 }
 
+static int find_gid(struct posix_acl_state *state, kgid_t gid)
+{
+        struct posix_ace_state_array *a = state->groups;
+        int i;
+
+        for (i = 0; i < a->n; i++)
+                if (gid_eq(a->aces[i].gid, gid))
+                        return i;
+        /* Not found: */
+        a->n++;
+        a->aces[i].gid = gid;
+        a->aces[i].perms.allow = state->everyone.allow;
+        a->aces[i].perms.deny  = state->everyone.deny;
+
+        return i;
+}
+
 static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
 {
         int i;
@@ -636,7 +665,7 @@ static void process_one_v4_ace(struct posix_acl_state *state,
                 }
                 break;
         case ACL_USER:
-                i = find_uid(state, state->users, ace->who);
+                i = find_uid(state, ace->who_uid);
                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
                         allow_bits(&state->users->aces[i].perms, mask);
                 } else {
@@ -658,7 +687,7 @@ static void process_one_v4_ace(struct posix_acl_state *state,
                 }
                 break;
         case ACL_GROUP:
-                i = find_uid(state, state->groups, ace->who);
+                i = find_gid(state, ace->who_gid);
                 if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
                         allow_bits(&state->groups->aces[i].perms, mask);
                 } else {
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 0dc11586682f..3812b06d24b1 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -293,13 +293,13 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
                         ace->whotype = nfs4_acl_get_whotype(buf, dummy32);
                         status = nfs_ok;
                         if (ace->whotype != NFS4_ACL_WHO_NAMED)
-                                ace->who = 0;
+                                ;
                         else if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
                                 status = nfsd_map_name_to_gid(argp->rqstp,
-                                                buf, dummy32, &ace->who);
+                                                buf, dummy32, &ace->who_gid);
                         else
                                 status = nfsd_map_name_to_uid(argp->rqstp,
-                                                buf, dummy32, &ace->who);
+                                                buf, dummy32, &ace->who_uid);
                         if (status)
                                 return status;
                 }
@@ -1926,7 +1926,7 @@ static u32 nfs4_file_type(umode_t mode)
 }
 
 static __be32
-nfsd4_encode_name(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
+nfsd4_encode_name(struct svc_rqst *rqstp, int whotype, kuid_t uid, kgid_t gid,
                         __be32 **p, int *buflen)
 {
         int status;
@@ -1935,10 +1935,10 @@ nfsd4_encode_name(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
                 return nfserr_resource;
         if (whotype != NFS4_ACL_WHO_NAMED)
                 status = nfs4_acl_write_who(whotype, (u8 *)(*p + 1));
-        else if (group)
-                status = nfsd_map_gid_to_name(rqstp, id, (u8 *)(*p + 1));
+        else if (gid_valid(gid))
+                status = nfsd_map_gid_to_name(rqstp, gid, (u8 *)(*p + 1));
         else
-                status = nfsd_map_uid_to_name(rqstp, id, (u8 *)(*p + 1));
+                status = nfsd_map_uid_to_name(rqstp, uid, (u8 *)(*p + 1));
         if (status < 0)
                 return nfserrno(status);
         *p = xdr_encode_opaque(*p, NULL, status);
@@ -1948,22 +1948,33 @@ nfsd4_encode_name(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
 }
 
 static inline __be32
-nfsd4_encode_user(struct svc_rqst *rqstp, uid_t uid, __be32 **p, int *buflen)
+nfsd4_encode_user(struct svc_rqst *rqstp, kuid_t user, __be32 **p, int *buflen)
 {
-        return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, uid, 0, p, buflen);
+        return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, user, INVALID_GID,
+                                 p, buflen);
 }
 
 static inline __be32
-nfsd4_encode_group(struct svc_rqst *rqstp, uid_t gid, __be32 **p, int *buflen)
+nfsd4_encode_group(struct svc_rqst *rqstp, kgid_t group, __be32 **p, int *buflen)
 {
-        return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, gid, 1, p, buflen);
+        return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, INVALID_UID, group,
+                                 p, buflen);
 }
 
 static inline __be32
-nfsd4_encode_aclname(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
+nfsd4_encode_aclname(struct svc_rqst *rqstp, struct nfs4_ace *ace,
                 __be32 **p, int *buflen)
 {
-        return nfsd4_encode_name(rqstp, whotype, id, group, p, buflen);
+        kuid_t uid = INVALID_UID;
+        kgid_t gid = INVALID_GID;
+
+        if (ace->whotype == NFS4_ACL_WHO_NAMED) {
+                if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
+                        gid = ace->who_gid;
+                else
+                        uid = ace->who_uid;
+        }
+        return nfsd4_encode_name(rqstp, ace->whotype, uid, gid, p, buflen);
 }
 
 #define WORD0_ABSENT_FS_ATTRS (FATTR4_WORD0_FS_LOCATIONS | FATTR4_WORD0_FSID | \
@@ -2224,9 +2235,7 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
                         WRITE32(ace->type);
                         WRITE32(ace->flag);
                         WRITE32(ace->access_mask & NFS4_ACE_MASK_ALL);
-                        status = nfsd4_encode_aclname(rqstp, ace->whotype,
-                                ace->who, ace->flag & NFS4_ACE_IDENTIFIER_GROUP,
-                                &p, &buflen);
+                        status = nfsd4_encode_aclname(rqstp, ace, &p, &buflen);
                         if (status == nfserr_resource)
                                 goto out_resource;
                         if (status)