/* * fs/nfs_common/nfsacl.c * * Copyright (C) 2002-2003 Andreas Gruenbacher <agruen@suse.de> */ /* * The Solaris nfsacl protocol represents some ACLs slightly differently * than POSIX 1003.1e draft 17 does (and we do): * * - Minimal ACLs always have an ACL_MASK entry, so they have * four instead of three entries. * - The ACL_MASK entry in such minimal ACLs always has the same * permissions as the ACL_GROUP_OBJ entry. (In extended ACLs * the ACL_MASK and ACL_GROUP_OBJ entries may differ.) * - The identifier fields of the ACL_USER_OBJ and ACL_GROUP_OBJ * entries contain the identifiers of the owner and owning group. * (In POSIX ACLs we always set them to ACL_UNDEFINED_ID). * - ACL entries in the kernel are kept sorted in ascending order * of (e_tag, e_id). Solaris ACLs are unsorted. */ #include <linux/module.h> #include <linux/fs.h> #include <linux/sunrpc/xdr.h> #include <linux/nfsacl.h> #include <linux/nfs3.h> #include <linux/sort.h> MODULE_LICENSE("GPL"); EXPORT_SYMBOL(nfsacl_encode); EXPORT_SYMBOL(nfsacl_decode); struct nfsacl_encode_desc { struct xdr_array2_desc desc; unsigned int count; struct posix_acl *acl; int typeflag; uid_t uid; gid_t gid; }; static int xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem) { struct nfsacl_encode_desc *nfsacl_desc = (struct nfsacl_encode_desc *) desc; u32 *p = (u32 *) elem; if (nfsacl_desc->count < nfsacl_desc->acl->a_count) { struct posix_acl_entry *entry = &nfsacl_desc->acl->a_entries[nfsacl_desc->count++]; *p++ = htonl(entry->e_tag | nfsacl_desc->typeflag); switch(entry->e_tag) { case ACL_USER_OBJ: *p++ = htonl(nfsacl_desc->uid); break; case ACL_GROUP_OBJ: *p++ = htonl(nfsacl_desc->gid); break; case ACL_USER: case ACL_GROUP: *p++ = htonl(entry->e_id); break; default: /* Solaris depends on that! */ *p++ = 0; break; } *p++ = htonl(entry->e_perm & S_IRWXO); } else { const struct posix_acl_entry *pa, *pe; int group_obj_perm = ACL_READ|ACL_WRITE|ACL_EXECUTE; FOREACH_ACL_ENTRY(pa, nfsacl_desc->acl, pe) { if (pa->e_tag == ACL_GROUP_OBJ) { group_obj_perm = pa->e_perm & S_IRWXO; break; } } /* fake up ACL_MASK entry */ *p++ = htonl(ACL_MASK | nfsacl_desc->typeflag); *p++ = htonl(0); *p++ = htonl(group_obj_perm); } return 0; } unsigned int nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode, struct posix_acl *acl, int encode_entries, int typeflag) { int entries = (acl && acl->a_count) ? max_t(int, acl->a_count, 4) : 0; struct nfsacl_encode_desc nfsacl_desc = { .desc = { .elem_size = 12, .array_len = encode_entries ? entries : 0, .xcode = xdr_nfsace_encode, }, .acl = acl, .typeflag = typeflag, .uid = inode->i_uid, .gid = inode->i_gid, }; int err; if (entries > NFS_ACL_MAX_ENTRIES || xdr_encode_word(buf, base, entries)) return -EINVAL; err = xdr_encode_array2(buf, base + 4, &nfsacl_desc.desc); if (!err) err = 8 + nfsacl_desc.desc.elem_size * nfsacl_desc.desc.array_len; return err; } struct nfsacl_decode_desc { struct xdr_array2_desc desc; unsigned int count; struct posix_acl *acl; }; static int xdr_nfsace_decode(struct xdr_array2_desc *desc, void *elem) { struct nfsacl_decode_desc *nfsacl_desc = (struct nfsacl_decode_desc *) desc; u32 *p = (u32 *) elem; struct posix_acl_entry *entry; if (!nfsacl_desc->acl) { if (desc->array_len > NFS_ACL_MAX_ENTRIES) return -EINVAL; nfsacl_desc->acl = posix_acl_alloc(desc->array_len, GFP_KERNEL); if (!nfsacl_desc->acl) return -ENOMEM; nfsacl_desc->count = 0; } entry = &nfsacl_desc->acl->a_entries[nfsacl_desc->count++]; entry->e_tag = ntohl(*p++) & ~NFS_ACL_DEFAULT; entry->e_id = ntohl(*p++); entry->e_perm = ntohl(*p++); switch(entry->e_tag) { case ACL_USER_OBJ: case ACL_USER: case ACL_GROUP_OBJ: case ACL_GROUP: case ACL_OTHER: if (entry->e_perm & ~S_IRWXO) return -EINVAL; break; case ACL_MASK: /* Solaris sometimes sets additonal bits in the mask */ entry->e_perm &= S_IRWXO; break; default: return -EINVAL; } return 0; } static int cmp_acl_entry(const void *x, const void *y) { const struct posix_acl_entry *a = x, *b = y; if (a->e_tag != b->e_tag) return a->e_tag - b->e_tag; else if (a->e_id > b->e_id) return 1; else if (a->e_id < b->e_id) return -1; else return 0; } /* * Convert from a Solaris ACL to a POSIX 1003.1e draft 17 ACL. */ static int posix_acl_from_nfsacl(struct posix_acl *acl) { struct posix_acl_entry *pa, *pe, *group_obj = NULL, *mask = NULL; if (!acl) return 0; sort(acl->a_entries, acl->a_count, sizeof(struct posix_acl_entry), cmp_acl_entry, NULL); /* Clear undefined identifier fields and find the ACL_GROUP_OBJ and ACL_MASK entries. */ FOREACH_ACL_ENTRY(pa, acl, pe) { switch(pa->e_tag) { case ACL_USER_OBJ: pa->e_id = ACL_UNDEFINED_ID; break; case ACL_GROUP_OBJ: pa->e_id = ACL_UNDEFINED_ID; group_obj = pa; break; case ACL_MASK: mask = pa; /* fall through */ case ACL_OTHER: pa->e_id = ACL_UNDEFINED_ID; break; } } if (acl->a_count == 4 && group_obj && mask && mask->e_perm == group_obj->e_perm) { /* remove bogus ACL_MASK entry */ memmove(mask, mask+1, (3 - (mask - acl->a_entries)) * sizeof(struct posix_acl_entry)); acl->a_count = 3; } return 0; } unsigned int nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt, struct posix_acl **pacl) { struct nfsacl_decode_desc nfsacl_desc = { .desc = { .elem_size = 12, .xcode = pacl ? xdr_nfsace_decode : NULL, }, }; u32 entries; int err; if (xdr_decode_word(buf, base, &entries) || entries > NFS_ACL_MAX_ENTRIES) return -EINVAL; nfsacl_desc.desc.array_maxlen = entries; err = xdr_decode_array2(buf, base + 4, &nfsacl_desc.desc); if (err) return err; if (pacl) { if (entries != nfsacl_desc.desc.array_len || posix_acl_from_nfsacl(nfsacl_desc.acl) != 0) { posix_acl_release(nfsacl_desc.acl); return -EINVAL; } *pacl = nfsacl_desc.acl; } if (aclcnt) *aclcnt = entries; return 8 + nfsacl_desc.desc.elem_size * nfsacl_desc.desc.array_len; }