diff options
Diffstat (limited to 'fs/nfs_common/nfsacl.c')
| -rw-r--r-- | fs/nfs_common/nfsacl.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/fs/nfs_common/nfsacl.c b/fs/nfs_common/nfsacl.c new file mode 100644 index 0000000000000..18c58c32e3262 --- /dev/null +++ b/fs/nfs_common/nfsacl.c @@ -0,0 +1,257 @@ +/* + * 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; + 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; +} |