diff options
| -rw-r--r-- | fs/nfsd/nfs4acl.c | 627 |
1 files changed, 273 insertions, 354 deletions
diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c index edb107e61b9..f2f66b3da7a 100644 --- a/fs/nfsd/nfs4acl.c +++ b/fs/nfsd/nfs4acl.c @@ -96,24 +96,26 @@ deny_mask(u32 allow_mask, unsigned int flags) /* XXX: modify functions to return NFS errors; they're only ever * used by nfs code, after all.... */ -static int -mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags) +/* We only map from NFSv4 to POSIX ACLs when setting ACLs, when we err on the + * side of being more restrictive, so the mode bit mapping below is + * pessimistic. An optimistic version would be needed to handle DENY's, + * but we espect to coalesce all ALLOWs and DENYs before mapping to mode + * bits. */ + +static void +low_mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags) { - u32 ignore = 0; + u32 write_mode = NFS4_WRITE_MODE; - if (!(flags & NFS4_ACL_DIR)) - ignore |= NFS4_ACE_DELETE_CHILD; /* ignore it */ - perm |= ignore; + if (flags & NFS4_ACL_DIR) + write_mode |= NFS4_ACE_DELETE_CHILD; *mode = 0; if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE) *mode |= ACL_READ; - if ((perm & NFS4_WRITE_MODE) == NFS4_WRITE_MODE) + if ((perm & write_mode) == write_mode) *mode |= ACL_WRITE; if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE) *mode |= ACL_EXECUTE; - if (!MASK_EQUAL(perm, ignore|mask_from_posix(*mode, flags))) - return -EINVAL; - return 0; } struct ace_container { @@ -338,38 +340,6 @@ sort_pacl(struct posix_acl *pacl) return; } -static int -write_pace(struct nfs4_ace *ace, struct posix_acl *pacl, - struct posix_acl_entry **pace, short tag, unsigned int flags) -{ - struct posix_acl_entry *this = *pace; - - if (*pace == pacl->a_entries + pacl->a_count) - return -EINVAL; /* fell off the end */ - (*pace)++; - this->e_tag = tag; - if (tag == ACL_USER_OBJ) - flags |= NFS4_ACL_OWNER; - if (mode_from_nfs4(ace->access_mask, &this->e_perm, flags)) - return -EINVAL; - this->e_id = (tag == ACL_USER || tag == ACL_GROUP ? - ace->who : ACL_UNDEFINED_ID); - return 0; -} - -static struct nfs4_ace * -get_next_v4_ace(struct list_head **p, struct list_head *head) -{ - struct nfs4_ace *ace; - - *p = (*p)->next; - if (*p == head) - return NULL; - ace = list_entry(*p, struct nfs4_ace, l_ace); - - return ace; -} - int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl, struct posix_acl **dpacl, unsigned int flags) @@ -429,349 +399,311 @@ out: return error; } +/* + * While processing the NFSv4 ACE, this maintains bitmasks representing + * which permission bits have been allowed and which denied to a given + * entity: */ +struct posix_ace_state { + u32 allow; + u32 deny; +}; + +struct posix_user_ace_state { + uid_t uid; + struct posix_ace_state perms; +}; + +struct posix_ace_state_array { + int n; + struct posix_user_ace_state aces[]; +}; + +/* + * While processing the NFSv4 ACE, this maintains the partial permissions + * calculated so far: */ + +struct posix_acl_state { + struct posix_ace_state owner; + struct posix_ace_state group; + struct posix_ace_state other; + struct posix_ace_state everyone; + struct posix_ace_state mask; /* Deny unused in this case */ + struct posix_ace_state_array *users; + struct posix_ace_state_array *groups; +}; + static int -same_who(struct nfs4_ace *a, struct nfs4_ace *b) +init_state(struct posix_acl_state *state, int cnt) { - return a->whotype == b->whotype && - (a->whotype != NFS4_ACL_WHO_NAMED || a->who == b->who); + int alloc; + + memset(state, 0, sizeof(struct posix_acl_state)); + /* + * In the worst case, each individual acl could be for a distinct + * named user or group, but we don't no which, so we allocate + * enough space for either: + */ + alloc = sizeof(struct posix_ace_state_array) + + cnt*sizeof(struct posix_ace_state); + state->users = kzalloc(alloc, GFP_KERNEL); + if (!state->users) + return -ENOMEM; + state->groups = kzalloc(alloc, GFP_KERNEL); + if (!state->groups) { + kfree(state->users); + return -ENOMEM; + } + return 0; } -static int -complementary_ace_pair(struct nfs4_ace *allow, struct nfs4_ace *deny, - unsigned int flags) -{ - int ignore = 0; - if (!(flags & NFS4_ACL_DIR)) - ignore |= NFS4_ACE_DELETE_CHILD; - return MASK_EQUAL(ignore|deny_mask(allow->access_mask, flags), - ignore|deny->access_mask) && - allow->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE && - deny->type == NFS4_ACE_ACCESS_DENIED_ACE_TYPE && - allow->flag == deny->flag && - same_who(allow, deny); +static void +free_state(struct posix_acl_state *state) { + kfree(state->users); + kfree(state->groups); } -static inline int -user_obj_from_v4(struct nfs4_acl *n4acl, struct list_head **p, - struct posix_acl *pacl, struct posix_acl_entry **pace, - unsigned int flags) +static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate) { - int error = -EINVAL; - struct nfs4_ace *ace, *ace2; - - ace = get_next_v4_ace(p, &n4acl->ace_head); - if (ace == NULL) - goto out; - if (ace2type(ace) != ACL_USER_OBJ) - goto out; - error = write_pace(ace, pacl, pace, ACL_USER_OBJ, flags); - if (error < 0) - goto out; - error = -EINVAL; - ace2 = get_next_v4_ace(p, &n4acl->ace_head); - if (ace2 == NULL) - goto out; - if (!complementary_ace_pair(ace, ace2, flags)) - goto out; - error = 0; -out: - return error; + state->mask.allow |= astate->allow; } -static inline int -users_from_v4(struct nfs4_acl *n4acl, struct list_head **p, - struct nfs4_ace **mask_ace, - struct posix_acl *pacl, struct posix_acl_entry **pace, - unsigned int flags) -{ - int error = -EINVAL; - struct nfs4_ace *ace, *ace2; +/* + * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS, + * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate + * to traditional read/write/execute permissions. + * + * It's problematic to reject acls that use certain mode bits, because it + * places the burden on users to learn the rules about which bits one + * particular server sets, without giving the user a lot of help--we return an + * error that could mean any number of different things. To make matters + * worse, the problematic bits might be introduced by some application that's + * automatically mapping from some other acl model. + * + * So wherever possible we accept anything, possibly erring on the side of + * denying more permissions than necessary. + * + * However we do reject *explicit* DENY's of a few bits representing + * permissions we could never deny: + */ - ace = get_next_v4_ace(p, &n4acl->ace_head); - if (ace == NULL) - goto out; - while (ace2type(ace) == ACL_USER) { - if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE) - goto out; - if (*mask_ace && - !MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask)) - goto out; - *mask_ace = ace; - ace = get_next_v4_ace(p, &n4acl->ace_head); - if (ace == NULL) - goto out; - if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) - goto out; - error = write_pace(ace, pacl, pace, ACL_USER, flags); - if (error < 0) - goto out; - error = -EINVAL; - ace2 = get_next_v4_ace(p, &n4acl->ace_head); - if (ace2 == NULL) - goto out; - if (!complementary_ace_pair(ace, ace2, flags)) - goto out; - if ((*mask_ace)->flag != ace2->flag || - !same_who(*mask_ace, ace2)) - goto out; - ace = get_next_v4_ace(p, &n4acl->ace_head); - if (ace == NULL) - goto out; - } - error = 0; -out: - return error; +static inline int check_deny(u32 mask, int isowner) +{ + if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL)) + return -EINVAL; + if (!isowner) + return 0; + if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)) + return -EINVAL; + return 0; } -static inline int -group_obj_and_groups_from_v4(struct nfs4_acl *n4acl, struct list_head **p, - struct nfs4_ace **mask_ace, - struct posix_acl *pacl, struct posix_acl_entry **pace, - unsigned int flags) +static struct posix_acl * +posix_state_to_acl(struct posix_acl_state *state, unsigned int flags) { - int error = -EINVAL; - struct nfs4_ace *ace, *ace2; - struct ace_container *ac; - struct list_head group_l; - - INIT_LIST_HEAD(&group_l); - ace = list_entry(*p, struct nfs4_ace, l_ace); - - /* group owner (mask and allow aces) */ + struct posix_acl_entry *pace; + struct posix_acl *pacl; + int nace; + int i, error = 0; - if (pacl->a_count != 3) { - /* then the group owner should be preceded by mask */ - if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE) - goto out; - if (*mask_ace && - !MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask)) - goto out; - *mask_ace = ace; - ace = get_next_v4_ace(p, &n4acl->ace_head); - if (ace == NULL) - goto out; + nace = 4 + state->users->n + state->groups->n; + pacl = posix_acl_alloc(nace, GFP_KERNEL); + if (!pacl) + return ERR_PTR(-ENOMEM); - if ((*mask_ace)->flag != ace->flag || !same_who(*mask_ace, ace)) - goto out; + pace = pacl->a_entries; + pace->e_tag = ACL_USER_OBJ; + error = check_deny(state->owner.deny, 1); + 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++; + pace->e_tag = ACL_USER; + error = check_deny(state->users->aces[i].perms.deny, 0); + if (error) + 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; + add_to_mask(state, &state->users->aces[i].perms); } - if (ace2type(ace) != ACL_GROUP_OBJ) - goto out; - - ac = kmalloc(sizeof(*ac), GFP_KERNEL); - error = -ENOMEM; - if (ac == NULL) - goto out; - ac->ace = ace; - list_add_tail(&ac->ace_l, &group_l); - - error = -EINVAL; - if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) - goto out; - - error = write_pace(ace, pacl, pace, ACL_GROUP_OBJ, flags); - if (error < 0) - goto out; - - error = -EINVAL; - ace = get_next_v4_ace(p, &n4acl->ace_head); - if (ace == NULL) - goto out; - - /* groups (mask and allow aces) */ - - while (ace2type(ace) == ACL_GROUP) { - if (*mask_ace == NULL) - goto out; - - if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE || - !MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask)) - goto out; - *mask_ace = ace; + pace++; + pace->e_tag = ACL_GROUP_OBJ; + error = check_deny(state->group.deny, 0); + 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++) { + pace++; + pace->e_tag = ACL_GROUP; + error = check_deny(state->groups->aces[i].perms.deny, 0); + if (error) + 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; + add_to_mask(state, &state->groups->aces[i].perms); + } - ace = get_next_v4_ace(p, &n4acl->ace_head); - if (ace == NULL) - goto out; - ac = kmalloc(sizeof(*ac), GFP_KERNEL); - error = -ENOMEM; - if (ac == NULL) - goto out; - error = -EINVAL; - if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE || - !same_who(ace, *mask_ace)) - goto out; + pace++; + pace->e_tag = ACL_MASK; + low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags); + pace->e_id = ACL_UNDEFINED_ID; - ac->ace = ace; - list_add_tail(&ac->ace_l, &group_l); + pace++; + pace->e_tag = ACL_OTHER; + error = check_deny(state->other.deny, 0); + if (error) + goto out_err; + low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags); + pace->e_id = ACL_UNDEFINED_ID; - error = write_pace(ace, pacl, pace, ACL_GROUP, flags); - if (error < 0) - goto out; - error = -EINVAL; - ace = get_next_v4_ace(p, &n4acl->ace_head); - if (ace == NULL) - goto out; - } + return pacl; +out_err: + posix_acl_release(pacl); + return ERR_PTR(error); +} - /* group owner (deny ace) */ +static inline void allow_bits(struct posix_ace_state *astate, u32 mask) +{ + /* Allow all bits in the mask not already denied: */ + astate->allow |= mask & ~astate->deny; +} - if (ace2type(ace) != ACL_GROUP_OBJ) - goto out; - ac = list_entry(group_l.next, struct ace_container, ace_l); - ace2 = ac->ace; - if (!complementary_ace_pair(ace2, ace, flags)) - goto out; - list_del(group_l.next); - kfree(ac); +static inline void deny_bits(struct posix_ace_state *astate, u32 mask) +{ + /* Deny all bits in the mask not already allowed: */ + astate->deny |= mask & ~astate->allow; +} - /* groups (deny aces) */ +static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array *a, uid_t uid) +{ + int i; - while (!list_empty(&group_l)) { - ace = get_next_v4_ace(p, &n4acl->ace_head); - if (ace == NULL) - goto out; - if (ace2type(ace) != ACL_GROUP) - goto out; - ac = list_entry(group_l.next, struct ace_container, ace_l); - ace2 = ac->ace; - if (!complementary_ace_pair(ace2, ace, flags)) - goto out; - list_del(group_l.next); - kfree(ac); - } + for (i = 0; i < a->n; i++) + if (a->aces[i].uid == uid) + return i; + /* Not found: */ + a->n++; + a->aces[i].uid = uid; + a->aces[i].perms.allow = state->everyone.allow; + a->aces[i].perms.deny = state->everyone.deny; - ace = get_next_v4_ace(p, &n4acl->ace_head); - if (ace == NULL) - goto out; - if (ace2type(ace) != ACL_OTHER) - goto out; - error = 0; -out: - while (!list_empty(&group_l)) { - ac = list_entry(group_l.next, struct ace_container, ace_l); - list_del(group_l.next); - kfree(ac); - } - return error; + return i; } -static inline int -mask_from_v4(struct nfs4_acl *n4acl, struct list_head **p, - struct nfs4_ace **mask_ace, - struct posix_acl *pacl, struct posix_acl_entry **pace, - unsigned int flags) +static void deny_bits_array(struct posix_ace_state_array *a, u32 mask) { - int error = -EINVAL; - struct nfs4_ace *ace; + int i; - ace = list_entry(*p, struct nfs4_ace, l_ace); - if (pacl->a_count != 3) { - if (*mask_ace == NULL) - goto out; - (*mask_ace)->access_mask = deny_mask((*mask_ace)->access_mask, flags); - write_pace(*mask_ace, pacl, pace, ACL_MASK, flags); - } - error = 0; -out: - return error; + for (i=0; i < a->n; i++) + deny_bits(&a->aces[i].perms, mask); } -static inline int -other_from_v4(struct nfs4_acl *n4acl, struct list_head **p, - struct posix_acl *pacl, struct posix_acl_entry **pace, - unsigned int flags) +static void allow_bits_array(struct posix_ace_state_array *a, u32 mask) { - int error = -EINVAL; - struct nfs4_ace *ace, *ace2; + int i; - ace = list_entry(*p, struct nfs4_ace, l_ace); - if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) - goto out; - error = write_pace(ace, pacl, pace, ACL_OTHER, flags); - if (error < 0) - goto out; - error = -EINVAL; - ace2 = get_next_v4_ace(p, &n4acl->ace_head); - if (ace2 == NULL) - goto out; - if (!complementary_ace_pair(ace, ace2, flags)) - goto out; - error = 0; -out: - return error; + for (i=0; i < a->n; i++) + allow_bits(&a->aces[i].perms, mask); } -static int -calculate_posix_ace_count(struct nfs4_acl *n4acl) +static void process_one_v4_ace(struct posix_acl_state *state, + struct nfs4_ace *ace) { - if (n4acl->naces == 6) /* owner, owner group, and other only */ - return 3; - else { /* Otherwise there must be a mask entry. */ - /* Also, the remaining entries are for named users and - * groups, and come in threes (mask, allow, deny): */ - if (n4acl->naces < 7) - return -EINVAL; - if ((n4acl->naces - 7) % 3) - return -EINVAL; - return 4 + (n4acl->naces - 7)/3; + u32 mask = ace->access_mask; + int i; + + switch (ace2type(ace)) { + case ACL_USER_OBJ: + if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) { + allow_bits(&state->owner, mask); + } else { + deny_bits(&state->owner, mask); + } + break; + case ACL_USER: + i = find_uid(state, state->users, ace->who); + if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) { + allow_bits(&state->users->aces[i].perms, mask); + } else { + deny_bits(&state->users->aces[i].perms, mask); + mask = state->users->aces[i].perms.deny; + deny_bits(&state->owner, mask); + } + break; + case ACL_GROUP_OBJ: + if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) { + allow_bits(&state->group, mask); + } else { + deny_bits(&state->group, mask); + mask = state->group.deny; + deny_bits(&state->owner, mask); + deny_bits(&state->everyone, mask); + deny_bits_array(state->users, mask); + deny_bits_array(state->groups, mask); + } + break; + case ACL_GROUP: + i = find_uid(state, state->groups, ace->who); + if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) { + allow_bits(&state->groups->aces[i].perms, mask); + } else { + deny_bits(&state->groups->aces[i].perms, mask); + mask = state->groups->aces[i].perms.deny; + deny_bits(&state->owner, mask); + deny_bits(&state->group, mask); + deny_bits(&state->everyone, mask); + deny_bits_array(state->users, mask); + deny_bits_array(state->groups, mask); + } + break; + case ACL_OTHER: + if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) { + allow_bits(&state->owner, mask); + allow_bits(&state->group, mask); + allow_bits(&state->other, mask); + allow_bits(&state->everyone, mask); + allow_bits_array(state->users, mask); + allow_bits_array(state->groups, mask); + } else { + deny_bits(&state->owner, mask); + deny_bits(&state->group, mask); + deny_bits(&state->other, mask); + deny_bits(&state->everyone, mask); + deny_bits_array(state->users, mask); + deny_bits_array(state->groups, mask); + } } } - static struct posix_acl * _nfsv4_to_posix_one(struct nfs4_acl *n4acl, unsigned int flags) { + struct posix_acl_state state; struct posix_acl *pacl; - int error = -EINVAL, nace = 0; - struct list_head *p; - struct nfs4_ace *mask_ace = NULL; - struct posix_acl_entry *pace; - - nace = calculate_posix_ace_count(n4acl); - if (nace < 0) - goto out_err; - - pacl = posix_acl_alloc(nace, GFP_KERNEL); - error = -ENOMEM; - if (pacl == NULL) - goto out_err; - - pace = &pacl->a_entries[0]; - p = &n4acl->ace_head; - - error = user_obj_from_v4(n4acl, &p, pacl, &pace, flags); - if (error) - goto out_acl; - - error = users_from_v4(n4acl, &p, &mask_ace, pacl, &pace, flags); - if (error) - goto out_acl; + struct nfs4_ace *ace; + int ret; - error = group_obj_and_groups_from_v4(n4acl, &p, &mask_ace, pacl, &pace, - flags); - if (error) - goto out_acl; + ret = init_state(&state, n4acl->naces); + if (ret) + return ERR_PTR(ret); - error = mask_from_v4(n4acl, &p, &mask_ace, pacl, &pace, flags); - if (error) - goto out_acl; - error = other_from_v4(n4acl, &p, pacl, &pace, flags); - if (error) - goto out_acl; + list_for_each_entry(ace, &n4acl->ace_head, l_ace) + process_one_v4_ace(&state, ace); - error = -EINVAL; - if (p->next != &n4acl->ace_head) - goto out_acl; - if (pace != pacl->a_entries + pacl->a_count) - goto out_acl; + pacl = posix_state_to_acl(&state, flags); - sort_pacl(pacl); + free_state(&state); - return pacl; -out_acl: - posix_acl_release(pacl); -out_err: - pacl = ERR_PTR(error); + if (!IS_ERR(pacl)) + sort_pacl(pacl); return pacl; } @@ -785,6 +717,10 @@ nfs4_acl_split(struct nfs4_acl *acl, struct nfs4_acl *dacl) list_for_each_safe(h, n, &acl->ace_head) { ace = list_entry(h, struct nfs4_ace, l_ace); + if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE && + ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE) + return -EINVAL; + if ((ace->flag & NFS4_INHERITANCE_FLAGS) != NFS4_INHERITANCE_FLAGS) continue; @@ -930,23 +866,6 @@ nfs4_acl_write_who(int who, char *p) return -1; } -static inline int -match_who(struct nfs4_ace *ace, uid_t owner, gid_t group, uid_t who) -{ - switch (ace->whotype) { - case NFS4_ACL_WHO_NAMED: - return who == ace->who; - case NFS4_ACL_WHO_OWNER: - return who == owner; - case NFS4_ACL_WHO_GROUP: - return who == group; - case NFS4_ACL_WHO_EVERYONE: - return 1; - default: - return 0; - } -} - EXPORT_SYMBOL(nfs4_acl_new); EXPORT_SYMBOL(nfs4_acl_free); EXPORT_SYMBOL(nfs4_acl_add_ace); |