[net-next-2.6.git] / fs / nfs_common / nfsacl.c

/*
 * 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");

EXPORT_SYMBOL_GPL(nfsacl_encode);
EXPORT_SYMBOL_GPL(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;
	__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(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);
	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;
	struct posix_acl *acl2 = NULL;

	if (entries > NFS_ACL_MAX_ENTRIES ||
	    xdr_encode_word(buf, base, entries))
		return -EINVAL;
	if (encode_entries && acl && acl->a_count == 3) {
		/* Fake up an ACL_MASK entry. */
		acl2 = posix_acl_alloc(4, GFP_KERNEL);
		if (!acl2)
			return -ENOMEM;
		/* 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 (acl2)
		posix_acl_release(acl2);
	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;
	__be32 *p = 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;
}
Commit	Line	Data
a257cdd0 AG	1	/*
	2	* fs/nfs_common/nfsacl.c
	3	*
	4	* Copyright (C) 2002-2003 Andreas Gruenbacher <agruen@suse.de>
	5	*/
	6
	7	/*
	8	* The Solaris nfsacl protocol represents some ACLs slightly differently
	9	* than POSIX 1003.1e draft 17 does (and we do):
	10	*
	11	* - Minimal ACLs always have an ACL_MASK entry, so they have
	12	* four instead of three entries.
	13	* - The ACL_MASK entry in such minimal ACLs always has the same
	14	* permissions as the ACL_GROUP_OBJ entry. (In extended ACLs
	15	* the ACL_MASK and ACL_GROUP_OBJ entries may differ.)
	16	* - The identifier fields of the ACL_USER_OBJ and ACL_GROUP_OBJ
	17	* entries contain the identifiers of the owner and owning group.
	18	* (In POSIX ACLs we always set them to ACL_UNDEFINED_ID).
	19	* - ACL entries in the kernel are kept sorted in ascending order
	20	* of (e_tag, e_id). Solaris ACLs are unsorted.
	21	*/
	22
	23	#include <linux/module.h>
	24	#include <linux/fs.h>
5a0e3ad6	25	#include <linux/gfp.h>
a257cdd0 AG	26	#include <linux/sunrpc/xdr.h>
	27	#include <linux/nfsacl.h>
	28	#include <linux/nfs3.h>
	29	#include <linux/sort.h>
	30
	31	MODULE_LICENSE("GPL");
	32
d716f0b8 TM	33	EXPORT_SYMBOL_GPL(nfsacl_encode);
d716f0b8 TM	34	EXPORT_SYMBOL_GPL(nfsacl_decode);
a257cdd0 AG	35
	36	struct nfsacl_encode_desc {
	37	struct xdr_array2_desc desc;
	38	unsigned int count;
	39	struct posix_acl *acl;
	40	int typeflag;
	41	uid_t uid;
	42	gid_t gid;
	43	};
	44
	45	static int
	46	xdr_nfsace_encode(struct xdr_array2_desc desc, void elem)
	47	{
	48	struct nfsacl_encode_desc *nfsacl_desc =
	49	(struct nfsacl_encode_desc *) desc;
83bbe2ef	50	__be32 *p = elem;
a257cdd0	51
22c1ea44 AG	52	struct posix_acl_entry *entry =
22c1ea44 AG	53	&nfsacl_desc->acl->a_entries[nfsacl_desc->count++];
a257cdd0	54
22c1ea44 AG	55	*p++ = htonl(entry->e_tag \| nfsacl_desc->typeflag);
	56	switch(entry->e_tag) {
	57	case ACL_USER_OBJ:
	58	*p++ = htonl(nfsacl_desc->uid);
	59	break;
	60	case ACL_GROUP_OBJ:
	61	*p++ = htonl(nfsacl_desc->gid);
	62	break;
	63	case ACL_USER:
	64	case ACL_GROUP:
	65	*p++ = htonl(entry->e_id);
	66	break;
	67	default: /* Solaris depends on that! */
	68	*p++ = 0;
	69	break;
a257cdd0	70	}
22c1ea44	71	*p++ = htonl(entry->e_perm & S_IRWXO);
a257cdd0 AG	72	return 0;
	73	}
	74
	75	unsigned int
	76	nfsacl_encode(struct xdr_buf buf, unsigned int base, struct inode inode,
	77	struct posix_acl *acl, int encode_entries, int typeflag)
	78	{
	79	int entries = (acl && acl->a_count) ? max_t(int, acl->a_count, 4) : 0;
	80	struct nfsacl_encode_desc nfsacl_desc = {
	81	.desc = {
	82	.elem_size = 12,
	83	.array_len = encode_entries ? entries : 0,
	84	.xcode = xdr_nfsace_encode,
	85	},
	86	.acl = acl,
	87	.typeflag = typeflag,
	88	.uid = inode->i_uid,
	89	.gid = inode->i_gid,
	90	};
	91	int err;
22c1ea44	92	struct posix_acl *acl2 = NULL;
a257cdd0 AG	93
	94	if (entries > NFS_ACL_MAX_ENTRIES \|\|
	95	xdr_encode_word(buf, base, entries))
	96	return -EINVAL;
22c1ea44 AG	97	if (encode_entries && acl && acl->a_count == 3) {
	98	/* Fake up an ACL_MASK entry. */
	99	acl2 = posix_acl_alloc(4, GFP_KERNEL);
	100	if (!acl2)
	101	return -ENOMEM;
	102	/* Insert entries in canonical order: other orders seem
	103	to confuse Solaris VxFS. */
	104	acl2->a_entries[0] = acl->a_entries[0]; /* ACL_USER_OBJ */
	105	acl2->a_entries[1] = acl->a_entries[1]; /* ACL_GROUP_OBJ */
	106	acl2->a_entries[2] = acl->a_entries[1]; /* ACL_MASK */
	107	acl2->a_entries[2].e_tag = ACL_MASK;
	108	acl2->a_entries[3] = acl->a_entries[2]; /* ACL_OTHER */
	109	nfsacl_desc.acl = acl2;
	110	}
a257cdd0	111	err = xdr_encode_array2(buf, base + 4, &nfsacl_desc.desc);
22c1ea44 AG	112	if (acl2)
22c1ea44 AG	113	posix_acl_release(acl2);
a257cdd0 AG	114	if (!err)
	115	err = 8 + nfsacl_desc.desc.elem_size *
	116	nfsacl_desc.desc.array_len;
	117	return err;
	118	}
	119
	120	struct nfsacl_decode_desc {
	121	struct xdr_array2_desc desc;
	122	unsigned int count;
	123	struct posix_acl *acl;
	124	};
	125
	126	static int
	127	xdr_nfsace_decode(struct xdr_array2_desc desc, void elem)
	128	{
	129	struct nfsacl_decode_desc *nfsacl_desc =
	130	(struct nfsacl_decode_desc *) desc;
83bbe2ef	131	__be32 *p = elem;
a257cdd0 AG	132	struct posix_acl_entry *entry;
	133
	134	if (!nfsacl_desc->acl) {
	135	if (desc->array_len > NFS_ACL_MAX_ENTRIES)
	136	return -EINVAL;
	137	nfsacl_desc->acl = posix_acl_alloc(desc->array_len, GFP_KERNEL);
	138	if (!nfsacl_desc->acl)
	139	return -ENOMEM;
	140	nfsacl_desc->count = 0;
	141	}
	142
	143	entry = &nfsacl_desc->acl->a_entries[nfsacl_desc->count++];
	144	entry->e_tag = ntohl(*p++) & ~NFS_ACL_DEFAULT;
	145	entry->e_id = ntohl(*p++);
	146	entry->e_perm = ntohl(*p++);
	147
	148	switch(entry->e_tag) {
	149	case ACL_USER_OBJ:
	150	case ACL_USER:
	151	case ACL_GROUP_OBJ:
	152	case ACL_GROUP:
	153	case ACL_OTHER:
	154	if (entry->e_perm & ~S_IRWXO)
	155	return -EINVAL;
	156	break;
	157	case ACL_MASK:
	158	/* Solaris sometimes sets additonal bits in the mask */
	159	entry->e_perm &= S_IRWXO;
	160	break;
	161	default:
	162	return -EINVAL;
	163	}
	164
	165	return 0;
	166	}
	167
	168	static int
	169	cmp_acl_entry(const void x, const void y)
	170	{
	171	const struct posix_acl_entry a = x, b = y;
	172
	173	if (a->e_tag != b->e_tag)
	174	return a->e_tag - b->e_tag;
	175	else if (a->e_id > b->e_id)
	176	return 1;
	177	else if (a->e_id < b->e_id)
	178	return -1;
	179	else
	180	return 0;
	181	}
	182
	183	/*
	184	* Convert from a Solaris ACL to a POSIX 1003.1e draft 17 ACL.
	185	*/
	186	static int
	187	posix_acl_from_nfsacl(struct posix_acl *acl)
	188	{
	189	struct posix_acl_entry pa, pe,
	190	group_obj = NULL, mask = NULL;
	191
	192	if (!acl)
	193	return 0;
	194
	195	sort(acl->a_entries, acl->a_count, sizeof(struct posix_acl_entry),
196	cmp_acl_entry, NULL);
197
198	/* Clear undefined identifier fields and find the ACL_GROUP_OBJ
199	and ACL_MASK entries. */
200	FOREACH_ACL_ENTRY(pa, acl, pe) {
201	switch(pa->e_tag) {
202	case ACL_USER_OBJ:
203	pa->e_id = ACL_UNDEFINED_ID;
204	break;
205	case ACL_GROUP_OBJ:
206	pa->e_id = ACL_UNDEFINED_ID;
207	group_obj = pa;
208	break;
209	case ACL_MASK:
210	mask = pa;
211	/* fall through */
212	case ACL_OTHER:
213	pa->e_id = ACL_UNDEFINED_ID;
214	break;
215	}
216	}
217	if (acl->a_count == 4 && group_obj && mask &&
218	mask->e_perm == group_obj->e_perm) {
219	/* remove bogus ACL_MASK entry */
220	memmove(mask, mask+1, (3 - (mask - acl->a_entries)) *
221	sizeof(struct posix_acl_entry));
222	acl->a_count = 3;
223	}
224	return 0;
225	}
226
227	unsigned int
228	nfsacl_decode(struct xdr_buf buf, unsigned int base, unsigned int aclcnt,
229	struct posix_acl **pacl)
230	{
231	struct nfsacl_decode_desc nfsacl_desc = {
232	.desc = {
233	.elem_size = 12,
234	.xcode = pacl ? xdr_nfsace_decode : NULL,
235	},
236	};
237	u32 entries;
238	int err;
239
240	if (xdr_decode_word(buf, base, &entries) \|\|
241	entries > NFS_ACL_MAX_ENTRIES)
242	return -EINVAL;
58fcb8df	243	nfsacl_desc.desc.array_maxlen = entries;
a257cdd0 AG	244	err = xdr_decode_array2(buf, base + 4, &nfsacl_desc.desc);
	245	if (err)
	246	return err;
	247	if (pacl) {
	248	if (entries != nfsacl_desc.desc.array_len \|\|
	249	posix_acl_from_nfsacl(nfsacl_desc.acl) != 0) {
	250	posix_acl_release(nfsacl_desc.acl);
	251	return -EINVAL;
	252	}
	253	*pacl = nfsacl_desc.acl;
	254	}
	255	if (aclcnt)
	256	*aclcnt = entries;
	257	return 8 + nfsacl_desc.desc.elem_size *
	258	nfsacl_desc.desc.array_len;
	259	}