--- /dev/null
+/*
+ * 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/gfp.h>
+#include <linux/sunrpc/xdr.h>
+#include <linux/nfsacl.h>
+#include <linux/nfs3.h>
+#include <linux/sort.h>
+
+MODULE_LICENSE("GPL");
+
+struct nfsacl_encode_desc {
+ struct xdr_array2_desc desc;
+ unsigned int count;
+ struct posix_acl *acl;
+ int typeflag;
+ kuid_t uid;
+ kgid_t gid;
+};
+
+struct nfsacl_simple_acl {
+ struct posix_acl acl;
+ struct posix_acl_entry ace[4];
+};
+
+static int
+xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem)
+{
+ struct nfsacl_encode_desc *nfsacl_desc =
+ (struct nfsacl_encode_desc *) desc;
+ __be32 *p = elem;
+
+ 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(from_kuid(&init_user_ns, nfsacl_desc->uid));
+ break;
+ case ACL_GROUP_OBJ:
+ *p++ = htonl(from_kgid(&init_user_ns, nfsacl_desc->gid));
+ break;
+ case ACL_USER:
+ *p++ = htonl(from_kuid(&init_user_ns, entry->e_uid));
+ break;
+ case ACL_GROUP:
+ *p++ = htonl(from_kgid(&init_user_ns, entry->e_gid));
+ break;
+ default: /* Solaris depends on that! */
+ *p++ = 0;
+ break;
+ }
+ *p++ = htonl(entry->e_perm & S_IRWXO);
+ return 0;
+}
+
+/**
+ * nfsacl_encode - Encode an NFSv3 ACL
+ *
+ * @buf: destination xdr_buf to contain XDR encoded ACL
+ * @base: byte offset in xdr_buf where XDR'd ACL begins
+ * @inode: inode of file whose ACL this is
+ * @acl: posix_acl to encode
+ * @encode_entries: whether to encode ACEs as well
+ * @typeflag: ACL type: NFS_ACL_DEFAULT or zero
+ *
+ * Returns size of encoded ACL in bytes or a negative errno value.
+ */
+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,
+ };
+ struct nfsacl_simple_acl aclbuf;
+ int err;
+
+ if (entries > NFS_ACL_MAX_ENTRIES ||
+ xdr_encode_word(buf, base, entries))
+ return -EINVAL;
+ if (encode_entries && acl && acl->a_count == 3) {
+ struct posix_acl *acl2 = &aclbuf.acl;
+
+ /* Avoid the use of posix_acl_alloc(). nfsacl_encode() is
+ * invoked in contexts where a memory allocation failure is
+ * fatal. Fortunately this fake ACL is small enough to
+ * construct on the stack. */
+ posix_acl_init(acl2, 4);
+
+ /* Insert entries in canonical order: other orders seem
+ to confuse Solaris VxFS. */
+ acl2->a_entries[0] = acl->a_entries[0]; /* ACL_USER_OBJ */
+ acl2->a_entries[1] = acl->a_entries[1]; /* ACL_GROUP_OBJ */
+ acl2->a_entries[2] = acl->a_entries[1]; /* ACL_MASK */
+ acl2->a_entries[2].e_tag = ACL_MASK;
+ acl2->a_entries[3] = acl->a_entries[2]; /* ACL_OTHER */
+ nfsacl_desc.acl = acl2;
+ }
+ 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;
+}
+EXPORT_SYMBOL_GPL(nfsacl_encode);
+
+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;
+ __be32 *p = elem;
+ struct posix_acl_entry *entry;
+ unsigned int id;
+
+ 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;
+ id = ntohl(*p++);
+ entry->e_perm = ntohl(*p++);
+
+ switch(entry->e_tag) {
+ case ACL_USER:
+ entry->e_uid = make_kuid(&init_user_ns, id);
+ if (!uid_valid(entry->e_uid))
+ return -EINVAL;
+ break;
+ case ACL_GROUP:
+ entry->e_gid = make_kgid(&init_user_ns, id);
+ if (!gid_valid(entry->e_gid))
+ return -EINVAL;
+ break;
+ case ACL_USER_OBJ:
+ case ACL_GROUP_OBJ:
+ case ACL_OTHER:
+ if (entry->e_perm & ~S_IRWXO)
+ return -EINVAL;
+ break;
+ case ACL_MASK:
+ /* Solaris sometimes sets additional 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_tag == ACL_USER) && uid_gt(a->e_uid, b->e_uid))
+ return 1;
+ else if ((a->e_tag == ACL_USER) && uid_lt(a->e_uid, b->e_uid))
+ return -1;
+ else if ((a->e_tag == ACL_GROUP) && gid_gt(a->e_gid, b->e_gid))
+ return 1;
+ else if ((a->e_tag == ACL_GROUP) && gid_lt(a->e_gid, b->e_gid))
+ 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);
+
+ /* Find the ACL_GROUP_OBJ and ACL_MASK entries. */
+ FOREACH_ACL_ENTRY(pa, acl, pe) {
+ switch(pa->e_tag) {
+ case ACL_USER_OBJ:
+ break;
+ case ACL_GROUP_OBJ:
+ group_obj = pa;
+ break;
+ case ACL_MASK:
+ mask = pa;
+ /* fall through */
+ case ACL_OTHER:
+ 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;
+}
+
+/**
+ * nfsacl_decode - Decode an NFSv3 ACL
+ *
+ * @buf: xdr_buf containing XDR'd ACL data to decode
+ * @base: byte offset in xdr_buf where XDR'd ACL begins
+ * @aclcnt: count of ACEs in decoded posix_acl
+ * @pacl: buffer in which to place decoded posix_acl
+ *
+ * Returns the length of the decoded ACL in bytes, or a negative errno value.
+ */
+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;
+}
+EXPORT_SYMBOL_GPL(nfsacl_decode);
Code Review / kvmfornfv.git / blobdiff