nfs4xdr.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 2,595 行 · 第 1/5 页

/*
 *  fs/nfs/nfs4xdr.c
 *
 *  Server-side XDR for NFSv4
 *
 *  Copyright (c) 2002 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Kendrick Smith <[e-mail]>
 *  Andy Adamson   <[e-mail]>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * TODO: Neil Brown made the following observation:  We currently
 * initially reserve NFSD_BUFSIZE space on the transmit queue and
 * never release any of that until the request is complete.
 * It would be good to calculate a new maximum response size while
 * decoding the COMPOUND, and call svc_reserve with this number
 * at the end of nfs4svc_decode_compoundargs.
 */

#include <linux/param.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/vfs.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/state.h>
#include <linux/nfsd/xdr4.h>
#include <linux/nfsd_idmap.h>
#include <linux/nfs4.h>
#include <linux/nfs4_acl.h>

#define NFSDDBG_FACILITY		NFSDDBG_XDR

static const char utf8_byte_len[256] = {
	1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
	1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
	1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
	1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
	3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, 4,4,4,4,4,4,4,4,5,5,5,5,6,6,0,0
};

static inline int
is_legal_utf8_sequence(unsigned char *source, int length)
{
	unsigned char *ptr;
	unsigned char c;

	if (length==1) return 1;

	/* Check for overlong sequence, and check second byte */
	c = *(source + 1);
	switch (*source) {
	case 0xE0: /* 3 bytes */
		if ( c < 0xA0 ) return 0;
		break;
	case 0xF0: /* 4 bytes */
		if ( c < 0x90 ) return 0;
		break;
	case 0xF8: /* 5 bytes */
		if ( c < 0xC8 ) return 0;
		break;
	case 0xFC: /* 6 bytes */
		if ( c < 0x84 ) return 0;
		break;
	default:
		if ( (c & 0xC0) != 0x80) return 0;
	}

	/* Check that trailing bytes look like 10xxxxxx */
	for (ptr = source++ + length - 1; ptr>source; ptr--)
		if ( ((*ptr) & 0xC0) != 0x80 ) return 0;
	return 1;
}

/* This does some screening on disallowed unicode characters.  It is NOT
 * comprehensive.
 */
static int
is_allowed_utf8_char(unsigned char *source, int length)
{
	/* We assume length and source point to a valid utf8 sequence */
	unsigned char c;

	/* Disallow F0000 and up (in utf8, F3B08080) */
	if (*source > 0xF3 ) return 0;
	c = *(source + 1);
	switch (*source) {
	case 0xF3:
		if (c >= 0xB0) return 0;
		break;
	/* Disallow D800-F8FF (in utf8, EDA080-EFA3BF */
	case 0xED:
		if (c >= 0xA0) return 0;
		break;
	case 0xEE:
		return 0;
		break;
	case 0xEF:
		if (c <= 0xA3) return 0;
	/* Disallow FFF9-FFFF (EFBFB9-EFBFBF) */
		if (c==0xBF)
			/* Don't need to check <=0xBF, since valid utf8 */
			if ( *(source+2) >= 0xB9) return 0;
		break;
	}
	return 1;
}

/* This routine should really check to see that the proper stringprep
 * mappings have been applied.  Instead, we do a simple screen of some
 * of the more obvious illegal values by calling is_allowed_utf8_char.
 * This will allow many illegal strings through, but if a client behaves,
 * it will get full functionality.  The other option (apart from full
 * stringprep checking) is to limit everything to an easily handled subset,
 * such as 7-bit ascii.
 *
 * Note - currently calling routines ignore return value except as boolean.
 */
static int
check_utf8(char *str, int len)
{
	unsigned char *chunk, *sourceend;
	int chunklen;

	chunk = str;
	sourceend = str + len;

	while (chunk < sourceend) {
		chunklen = utf8_byte_len[*chunk];
		if (!chunklen)
			return nfserr_inval;
		if (chunk + chunklen > sourceend)
			return nfserr_inval;
		if (!is_legal_utf8_sequence(chunk, chunklen))
			return nfserr_inval;
		if (!is_allowed_utf8_char(chunk, chunklen))
			return nfserr_inval;
		if ( (chunklen==1) && (!*chunk) )
			return nfserr_inval; /* Disallow embedded nulls */
		chunk += chunklen;
	}

	return 0;
}

static int
check_filename(char *str, int len, int err)
{
	int i;

	if (len == 0)
		return nfserr_inval;
	if (isdotent(str, len))
		return err;
	for (i = 0; i < len; i++)
		if (str[i] == '/')
			return err;
	return check_utf8(str, len);
}

/*
 * START OF "GENERIC" DECODE ROUTINES.
 *   These may look a little ugly since they are imported from a "generic"
 * set of XDR encode/decode routines which are intended to be shared by
 * all of our NFSv4 implementations (OpenBSD, MacOS X...).
 *
 * If the pain of reading these is too great, it should be a straightforward
 * task to translate them into Linux-specific versions which are more
 * consistent with the style used in NFSv2/v3...
 */
#define DECODE_HEAD				\
	u32 *p;					\
	int status
#define DECODE_TAIL				\
	status = 0;				\
out:						\
	return status;				\
xdr_error:					\
	printk(KERN_NOTICE "xdr error! (%s:%d)\n", __FILE__, __LINE__);	\
	status = nfserr_bad_xdr;		\
	goto out

#define READ32(x)         (x) = ntohl(*p++)
#define READ64(x)         do {			\
	(x) = (u64)ntohl(*p++) << 32;		\
	(x) |= ntohl(*p++);			\
} while (0)
#define READTIME(x)       do {			\
	p++;					\
	(x) = ntohl(*p++);			\
	p++;					\
} while (0)
#define READMEM(x,nbytes) do {			\
	x = (char *)p;				\
	p += XDR_QUADLEN(nbytes);		\
} while (0)
#define SAVEMEM(x,nbytes) do {			\
	if (!(x = (p==argp->tmp || p == argp->tmpp) ? \
 		savemem(argp, p, nbytes) :	\
 		(char *)p)) {			\
		printk(KERN_NOTICE "xdr error! (%s:%d)\n", __FILE__, __LINE__); \
		goto xdr_error;			\
		}				\
	p += XDR_QUADLEN(nbytes);		\
} while (0)
#define COPYMEM(x,nbytes) do {			\
	memcpy((x), p, nbytes);			\
	p += XDR_QUADLEN(nbytes);		\
} while (0)

/* READ_BUF, read_buf(): nbytes must be <= PAGE_SIZE */
#define READ_BUF(nbytes)  do {			\
	if (nbytes <= (u32)((char *)argp->end - (char *)argp->p)) {	\
		p = argp->p;			\
		argp->p += XDR_QUADLEN(nbytes);	\
	} else if (!(p = read_buf(argp, nbytes))) { \
		printk(KERN_NOTICE "xdr error! (%s:%d)\n", __FILE__, __LINE__); \
		goto xdr_error;			\
	}					\
} while (0)

u32 *read_buf(struct nfsd4_compoundargs *argp, int nbytes)
{
	/* We want more bytes than seem to be available.
	 * Maybe we need a new page, maybe we have just run out
	 */
	int avail = (char*)argp->end - (char*)argp->p;
	u32 *p;
	if (avail + argp->pagelen < nbytes)
		return NULL;
	if (avail + PAGE_SIZE < nbytes) /* need more than a page !! */
		return NULL;
	/* ok, we can do it with the current plus the next page */
	if (nbytes <= sizeof(argp->tmp))
		p = argp->tmp;
	else {
		if (argp->tmpp)
			kfree(argp->tmpp);
		p = argp->tmpp = kmalloc(nbytes, GFP_KERNEL);
		if (!p)
			return NULL;
		
	}
	memcpy(p, argp->p, avail);
	/* step to next page */
	argp->p = page_address(argp->pagelist[0]);
	argp->pagelist++;
	if (argp->pagelen < PAGE_SIZE) {
		argp->end = p + (argp->pagelen>>2);
		argp->pagelen = 0;
	} else {
		argp->end = p + (PAGE_SIZE>>2);
		argp->pagelen -= PAGE_SIZE;
	}
	memcpy(((char*)p)+avail, argp->p, (nbytes - avail));
	argp->p += XDR_QUADLEN(nbytes - avail);
	return p;
}

static int
defer_free(struct nfsd4_compoundargs *argp,
		void (*release)(const void *), void *p)
{
	struct tmpbuf *tb;

	tb = kmalloc(sizeof(*tb), GFP_KERNEL);
	if (!tb)
		return -ENOMEM;
	tb->buf = p;
	tb->release = release;
	tb->next = argp->to_free;
	argp->to_free = tb;
	return 0;
}

char *savemem(struct nfsd4_compoundargs *argp, u32 *p, int nbytes)
{
	void *new = NULL;
	if (p == argp->tmp) {
		new = kmalloc(nbytes, GFP_KERNEL);
		if (!new) return NULL;
		p = new;
		memcpy(p, argp->tmp, nbytes);
	} else {
		if (p != argp->tmpp)
			BUG();
		argp->tmpp = NULL;
	}
	if (defer_free(argp, kfree, p)) {
		kfree(new);
		return NULL;
	} else
		return (char *)p;
}


static int
nfsd4_decode_bitmap(struct nfsd4_compoundargs *argp, u32 *bmval)
{
	u32 bmlen;
	DECODE_HEAD;

	bmval[0] = 0;
	bmval[1] = 0;

	READ_BUF(4);
	READ32(bmlen);
	if (bmlen > 1000)
		goto xdr_error;

	READ_BUF(bmlen << 2);
	if (bmlen > 0)
		READ32(bmval[0]);
	if (bmlen > 1)
		READ32(bmval[1]);

	DECODE_TAIL;
}

static int
nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval, struct iattr *iattr,
    struct nfs4_acl **acl)
{
	int expected_len, len = 0;
	u32 dummy32;
	char *buf;

	DECODE_HEAD;
	iattr->ia_valid = 0;
	if ((status = nfsd4_decode_bitmap(argp, bmval)))
		return status;

	/*
	 * According to spec, unsupported attributes return ERR_NOTSUPP;
	 * read-only attributes return ERR_INVAL.
	 */
	if ((bmval[0] & ~NFSD_SUPPORTED_ATTRS_WORD0) || (bmval[1] & ~NFSD_SUPPORTED_ATTRS_WORD1))
		return nfserr_attrnotsupp;
	if ((bmval[0] & ~NFSD_WRITEABLE_ATTRS_WORD0) || (bmval[1] & ~NFSD_WRITEABLE_ATTRS_WORD1))
		return nfserr_inval;

	READ_BUF(4);
	READ32(expected_len);

	if (bmval[0] & FATTR4_WORD0_SIZE) {
		READ_BUF(8);
		len += 8;
		READ64(iattr->ia_size);
		iattr->ia_valid |= ATTR_SIZE;
	}
	if (bmval[0] & FATTR4_WORD0_ACL) {
		int nace, i;
		struct nfs4_ace ace;

		READ_BUF(4); len += 4;
		READ32(nace);

		*acl = nfs4_acl_new();
		if (*acl == NULL) {
			status = -ENOMEM;
			goto out_nfserr;
		}
		defer_free(argp, (void (*)(const void *))nfs4_acl_free, *acl);

		for (i = 0; i < nace; i++) {
			READ_BUF(16); len += 16;
			READ32(ace.type);
			READ32(ace.flag);
			READ32(ace.access_mask);
			READ32(dummy32);
			READ_BUF(dummy32);
			len += XDR_QUADLEN(dummy32) << 2;
			READMEM(buf, dummy32);
			if (check_utf8(buf, dummy32))
				return nfserr_inval;
			ace.whotype = nfs4_acl_get_whotype(buf, dummy32);
			status = 0;
			if (ace.whotype != NFS4_ACL_WHO_NAMED)
				ace.who = 0;
			else if (ace.flag & NFS4_ACE_IDENTIFIER_GROUP)
				status = nfsd_map_name_to_gid(argp->rqstp,
						buf, dummy32, &ace.who);
			else
				status = nfsd_map_name_to_uid(argp->rqstp,
						buf, dummy32, &ace.who);
			if (status)
				goto out_nfserr;
			if (nfs4_acl_add_ace(*acl, ace.type, ace.flag,
				 ace.access_mask, ace.whotype, ace.who) != 0) {
				status = -ENOMEM;
				goto out_nfserr;
			}
		}
	} else
		*acl = NULL;
	if (bmval[1] & FATTR4_WORD1_MODE) {
		READ_BUF(4);
		len += 4;
		READ32(iattr->ia_mode);
		iattr->ia_mode &= (S_IFMT | S_IALLUGO);
		iattr->ia_valid |= ATTR_MODE;
	}
	if (bmval[1] & FATTR4_WORD1_OWNER) {
		READ_BUF(4);
		len += 4;
		READ32(dummy32);
		READ_BUF(dummy32);
		len += (XDR_QUADLEN(dummy32) << 2);
		READMEM(buf, dummy32);
		if (check_utf8(buf, dummy32))
			return nfserr_inval;
		if ((status = nfsd_map_name_to_uid(argp->rqstp, buf, dummy32, &iattr->ia_uid)))
			goto out_nfserr;
		iattr->ia_valid |= ATTR_UID;
	}
	if (bmval[1] & FATTR4_WORD1_OWNER_GROUP) {
		READ_BUF(4);
		len += 4;
		READ32(dummy32);
		READ_BUF(dummy32);
		len += (XDR_QUADLEN(dummy32) << 2);
		READMEM(buf, dummy32);
		if (check_utf8(buf, dummy32))
			return nfserr_inval;
		if ((status = nfsd_map_name_to_gid(argp->rqstp, buf, dummy32, &iattr->ia_gid)))
			goto out_nfserr;
		iattr->ia_valid |= ATTR_GID;
	}
	if (bmval[1] & FATTR4_WORD1_TIME_ACCESS_SET) {
		READ_BUF(4);
		len += 4;
		READ32(dummy32);
		switch (dummy32) {
		case NFS4_SET_TO_CLIENT_TIME:
			/* We require the high 32 bits of 'seconds' to be 0, and we ignore
			   all 32 bits of 'nseconds'. */
			READ_BUF(12);
			len += 12;
			READ32(dummy32);
			if (dummy32)
				return nfserr_inval;
			READ32(iattr->ia_atime.tv_sec);
			READ32(iattr->ia_atime.tv_nsec);
			if (iattr->ia_atime.tv_nsec >= (u32)1000000000)
				return nfserr_inval;
			iattr->ia_valid |= (ATTR_ATIME | ATTR_ATIME_SET);
			break;
		case NFS4_SET_TO_SERVER_TIME:
			iattr->ia_valid |= ATTR_ATIME;
			break;
		default:
			goto xdr_error;
		}
	}
	if (bmval[1] & FATTR4_WORD1_TIME_METADATA) {
		/* We require the high 32 bits of 'seconds' to be 0, and we ignore
		   all 32 bits of 'nseconds'. */
		READ_BUF(12);
		len += 12;
		READ32(dummy32);
		if (dummy32)
			return nfserr_inval;
		READ32(iattr->ia_ctime.tv_sec);
		READ32(iattr->ia_ctime.tv_nsec);
		if (iattr->ia_ctime.tv_nsec >= (u32)1000000000)
			return nfserr_inval;
		iattr->ia_valid |= ATTR_CTIME;
	}
	if (bmval[1] & FATTR4_WORD1_TIME_MODIFY_SET) {
		READ_BUF(4);
		len += 4;
		READ32(dummy32);
		switch (dummy32) {
		case NFS4_SET_TO_CLIENT_TIME:
			/* We require the high 32 bits of 'seconds' to be 0, and we ignore
			   all 32 bits of 'nseconds'. */
			READ_BUF(12);
			len += 12;
			READ32(dummy32);
			if (dummy32)
				return nfserr_inval;
			READ32(iattr->ia_mtime.tv_sec);
			READ32(iattr->ia_mtime.tv_nsec);
			if (iattr->ia_mtime.tv_nsec >= (u32)1000000000)
				return nfserr_inval;
			iattr->ia_valid |= (ATTR_MTIME | ATTR_MTIME_SET);
			break;