linux/net/sunrpc/xdr.c
Jeff Layton 4c190e2f91 sunrpc: trim off trailing checksum before returning decrypted or integrity authenticated buffer
When GSSAPI integrity signatures are in use, or when we're using GSSAPI
privacy with the v2 token format, there is a trailing checksum on the
xdr_buf that is returned.

It's checked during the authentication stage, and afterward nothing
cares about it. Ordinarily, it's not a problem since the XDR code
generally ignores it, but it will be when we try to compute a checksum
over the buffer to help prevent XID collisions in the duplicate reply
cache.

Fix the code to trim off the checksums after verifying them. Note that
in unwrap_integ_data, we must avoid trying to reverify the checksum if
the request was deferred since it will no longer be present when it's
revisited.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
2013-02-08 15:19:10 -05:00

1331 lines
32 KiB
C

/*
* linux/net/sunrpc/xdr.c
*
* Generic XDR support.
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/pagemap.h>
#include <linux/errno.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/msg_prot.h>
/*
* XDR functions for basic NFS types
*/
__be32 *
xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
{
unsigned int quadlen = XDR_QUADLEN(obj->len);
p[quadlen] = 0; /* zero trailing bytes */
*p++ = cpu_to_be32(obj->len);
memcpy(p, obj->data, obj->len);
return p + XDR_QUADLEN(obj->len);
}
EXPORT_SYMBOL_GPL(xdr_encode_netobj);
__be32 *
xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
{
unsigned int len;
if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
return NULL;
obj->len = len;
obj->data = (u8 *) p;
return p + XDR_QUADLEN(len);
}
EXPORT_SYMBOL_GPL(xdr_decode_netobj);
/**
* xdr_encode_opaque_fixed - Encode fixed length opaque data
* @p: pointer to current position in XDR buffer.
* @ptr: pointer to data to encode (or NULL)
* @nbytes: size of data.
*
* Copy the array of data of length nbytes at ptr to the XDR buffer
* at position p, then align to the next 32-bit boundary by padding
* with zero bytes (see RFC1832).
* Note: if ptr is NULL, only the padding is performed.
*
* Returns the updated current XDR buffer position
*
*/
__be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
{
if (likely(nbytes != 0)) {
unsigned int quadlen = XDR_QUADLEN(nbytes);
unsigned int padding = (quadlen << 2) - nbytes;
if (ptr != NULL)
memcpy(p, ptr, nbytes);
if (padding != 0)
memset((char *)p + nbytes, 0, padding);
p += quadlen;
}
return p;
}
EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
/**
* xdr_encode_opaque - Encode variable length opaque data
* @p: pointer to current position in XDR buffer.
* @ptr: pointer to data to encode (or NULL)
* @nbytes: size of data.
*
* Returns the updated current XDR buffer position
*/
__be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
{
*p++ = cpu_to_be32(nbytes);
return xdr_encode_opaque_fixed(p, ptr, nbytes);
}
EXPORT_SYMBOL_GPL(xdr_encode_opaque);
__be32 *
xdr_encode_string(__be32 *p, const char *string)
{
return xdr_encode_array(p, string, strlen(string));
}
EXPORT_SYMBOL_GPL(xdr_encode_string);
__be32 *
xdr_decode_string_inplace(__be32 *p, char **sp,
unsigned int *lenp, unsigned int maxlen)
{
u32 len;
len = be32_to_cpu(*p++);
if (len > maxlen)
return NULL;
*lenp = len;
*sp = (char *) p;
return p + XDR_QUADLEN(len);
}
EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
/**
* xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
* @buf: XDR buffer where string resides
* @len: length of string, in bytes
*
*/
void
xdr_terminate_string(struct xdr_buf *buf, const u32 len)
{
char *kaddr;
kaddr = kmap_atomic(buf->pages[0]);
kaddr[buf->page_base + len] = '\0';
kunmap_atomic(kaddr);
}
EXPORT_SYMBOL_GPL(xdr_terminate_string);
void
xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
struct page **pages, unsigned int base, unsigned int len)
{
struct kvec *head = xdr->head;
struct kvec *tail = xdr->tail;
char *buf = (char *)head->iov_base;
unsigned int buflen = head->iov_len;
head->iov_len = offset;
xdr->pages = pages;
xdr->page_base = base;
xdr->page_len = len;
tail->iov_base = buf + offset;
tail->iov_len = buflen - offset;
xdr->buflen += len;
}
EXPORT_SYMBOL_GPL(xdr_inline_pages);
/*
* Helper routines for doing 'memmove' like operations on a struct xdr_buf
*/
/**
* _shift_data_right_pages
* @pages: vector of pages containing both the source and dest memory area.
* @pgto_base: page vector address of destination
* @pgfrom_base: page vector address of source
* @len: number of bytes to copy
*
* Note: the addresses pgto_base and pgfrom_base are both calculated in
* the same way:
* if a memory area starts at byte 'base' in page 'pages[i]',
* then its address is given as (i << PAGE_CACHE_SHIFT) + base
* Also note: pgfrom_base must be < pgto_base, but the memory areas
* they point to may overlap.
*/
static void
_shift_data_right_pages(struct page **pages, size_t pgto_base,
size_t pgfrom_base, size_t len)
{
struct page **pgfrom, **pgto;
char *vfrom, *vto;
size_t copy;
BUG_ON(pgto_base <= pgfrom_base);
pgto_base += len;
pgfrom_base += len;
pgto = pages + (pgto_base >> PAGE_CACHE_SHIFT);
pgfrom = pages + (pgfrom_base >> PAGE_CACHE_SHIFT);
pgto_base &= ~PAGE_CACHE_MASK;
pgfrom_base &= ~PAGE_CACHE_MASK;
do {
/* Are any pointers crossing a page boundary? */
if (pgto_base == 0) {
pgto_base = PAGE_CACHE_SIZE;
pgto--;
}
if (pgfrom_base == 0) {
pgfrom_base = PAGE_CACHE_SIZE;
pgfrom--;
}
copy = len;
if (copy > pgto_base)
copy = pgto_base;
if (copy > pgfrom_base)
copy = pgfrom_base;
pgto_base -= copy;
pgfrom_base -= copy;
vto = kmap_atomic(*pgto);
vfrom = kmap_atomic(*pgfrom);
memmove(vto + pgto_base, vfrom + pgfrom_base, copy);
flush_dcache_page(*pgto);
kunmap_atomic(vfrom);
kunmap_atomic(vto);
} while ((len -= copy) != 0);
}
/**
* _copy_to_pages
* @pages: array of pages
* @pgbase: page vector address of destination
* @p: pointer to source data
* @len: length
*
* Copies data from an arbitrary memory location into an array of pages
* The copy is assumed to be non-overlapping.
*/
static void
_copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
{
struct page **pgto;
char *vto;
size_t copy;
pgto = pages + (pgbase >> PAGE_CACHE_SHIFT);
pgbase &= ~PAGE_CACHE_MASK;
for (;;) {
copy = PAGE_CACHE_SIZE - pgbase;
if (copy > len)
copy = len;
vto = kmap_atomic(*pgto);
memcpy(vto + pgbase, p, copy);
kunmap_atomic(vto);
len -= copy;
if (len == 0)
break;
pgbase += copy;
if (pgbase == PAGE_CACHE_SIZE) {
flush_dcache_page(*pgto);
pgbase = 0;
pgto++;
}
p += copy;
}
flush_dcache_page(*pgto);
}
/**
* _copy_from_pages
* @p: pointer to destination
* @pages: array of pages
* @pgbase: offset of source data
* @len: length
*
* Copies data into an arbitrary memory location from an array of pages
* The copy is assumed to be non-overlapping.
*/
void
_copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
{
struct page **pgfrom;
char *vfrom;
size_t copy;
pgfrom = pages + (pgbase >> PAGE_CACHE_SHIFT);
pgbase &= ~PAGE_CACHE_MASK;
do {
copy = PAGE_CACHE_SIZE - pgbase;
if (copy > len)
copy = len;
vfrom = kmap_atomic(*pgfrom);
memcpy(p, vfrom + pgbase, copy);
kunmap_atomic(vfrom);
pgbase += copy;
if (pgbase == PAGE_CACHE_SIZE) {
pgbase = 0;
pgfrom++;
}
p += copy;
} while ((len -= copy) != 0);
}
EXPORT_SYMBOL_GPL(_copy_from_pages);
/**
* xdr_shrink_bufhead
* @buf: xdr_buf
* @len: bytes to remove from buf->head[0]
*
* Shrinks XDR buffer's header kvec buf->head[0] by
* 'len' bytes. The extra data is not lost, but is instead
* moved into the inlined pages and/or the tail.
*/
static void
xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
{
struct kvec *head, *tail;
size_t copy, offs;
unsigned int pglen = buf->page_len;
tail = buf->tail;
head = buf->head;
WARN_ON_ONCE(len > head->iov_len);
if (len > head->iov_len)
len = head->iov_len;
/* Shift the tail first */
if (tail->iov_len != 0) {
if (tail->iov_len > len) {
copy = tail->iov_len - len;
memmove((char *)tail->iov_base + len,
tail->iov_base, copy);
}
/* Copy from the inlined pages into the tail */
copy = len;
if (copy > pglen)
copy = pglen;
offs = len - copy;
if (offs >= tail->iov_len)
copy = 0;
else if (copy > tail->iov_len - offs)
copy = tail->iov_len - offs;
if (copy != 0)
_copy_from_pages((char *)tail->iov_base + offs,
buf->pages,
buf->page_base + pglen + offs - len,
copy);
/* Do we also need to copy data from the head into the tail ? */
if (len > pglen) {
offs = copy = len - pglen;
if (copy > tail->iov_len)
copy = tail->iov_len;
memcpy(tail->iov_base,
(char *)head->iov_base +
head->iov_len - offs,
copy);
}
}
/* Now handle pages */
if (pglen != 0) {
if (pglen > len)
_shift_data_right_pages(buf->pages,
buf->page_base + len,
buf->page_base,
pglen - len);
copy = len;
if (len > pglen)
copy = pglen;
_copy_to_pages(buf->pages, buf->page_base,
(char *)head->iov_base + head->iov_len - len,
copy);
}
head->iov_len -= len;
buf->buflen -= len;
/* Have we truncated the message? */
if (buf->len > buf->buflen)
buf->len = buf->buflen;
}
/**
* xdr_shrink_pagelen
* @buf: xdr_buf
* @len: bytes to remove from buf->pages
*
* Shrinks XDR buffer's page array buf->pages by
* 'len' bytes. The extra data is not lost, but is instead
* moved into the tail.
*/
static void
xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
{
struct kvec *tail;
size_t copy;
unsigned int pglen = buf->page_len;
unsigned int tailbuf_len;
tail = buf->tail;
BUG_ON (len > pglen);
tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
/* Shift the tail first */
if (tailbuf_len != 0) {
unsigned int free_space = tailbuf_len - tail->iov_len;
if (len < free_space)
free_space = len;
tail->iov_len += free_space;
copy = len;
if (tail->iov_len > len) {
char *p = (char *)tail->iov_base + len;
memmove(p, tail->iov_base, tail->iov_len - len);
} else
copy = tail->iov_len;
/* Copy from the inlined pages into the tail */
_copy_from_pages((char *)tail->iov_base,
buf->pages, buf->page_base + pglen - len,
copy);
}
buf->page_len -= len;
buf->buflen -= len;
/* Have we truncated the message? */
if (buf->len > buf->buflen)
buf->len = buf->buflen;
}
void
xdr_shift_buf(struct xdr_buf *buf, size_t len)
{
xdr_shrink_bufhead(buf, len);
}
EXPORT_SYMBOL_GPL(xdr_shift_buf);
/**
* xdr_stream_pos - Return the current offset from the start of the xdr_stream
* @xdr: pointer to struct xdr_stream
*/
unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
{
return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
}
EXPORT_SYMBOL_GPL(xdr_stream_pos);
/**
* xdr_init_encode - Initialize a struct xdr_stream for sending data.
* @xdr: pointer to xdr_stream struct
* @buf: pointer to XDR buffer in which to encode data
* @p: current pointer inside XDR buffer
*
* Note: at the moment the RPC client only passes the length of our
* scratch buffer in the xdr_buf's header kvec. Previously this
* meant we needed to call xdr_adjust_iovec() after encoding the
* data. With the new scheme, the xdr_stream manages the details
* of the buffer length, and takes care of adjusting the kvec
* length for us.
*/
void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
{
struct kvec *iov = buf->head;
int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
BUG_ON(scratch_len < 0);
xdr->buf = buf;
xdr->iov = iov;
xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
BUG_ON(iov->iov_len > scratch_len);
if (p != xdr->p && p != NULL) {
size_t len;
BUG_ON(p < xdr->p || p > xdr->end);
len = (char *)p - (char *)xdr->p;
xdr->p = p;
buf->len += len;
iov->iov_len += len;
}
}
EXPORT_SYMBOL_GPL(xdr_init_encode);
/**
* xdr_reserve_space - Reserve buffer space for sending
* @xdr: pointer to xdr_stream
* @nbytes: number of bytes to reserve
*
* Checks that we have enough buffer space to encode 'nbytes' more
* bytes of data. If so, update the total xdr_buf length, and
* adjust the length of the current kvec.
*/
__be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
{
__be32 *p = xdr->p;
__be32 *q;
/* align nbytes on the next 32-bit boundary */
nbytes += 3;
nbytes &= ~3;
q = p + (nbytes >> 2);
if (unlikely(q > xdr->end || q < p))
return NULL;
xdr->p = q;
xdr->iov->iov_len += nbytes;
xdr->buf->len += nbytes;
return p;
}
EXPORT_SYMBOL_GPL(xdr_reserve_space);
/**
* xdr_write_pages - Insert a list of pages into an XDR buffer for sending
* @xdr: pointer to xdr_stream
* @pages: list of pages
* @base: offset of first byte
* @len: length of data in bytes
*
*/
void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
unsigned int len)
{
struct xdr_buf *buf = xdr->buf;
struct kvec *iov = buf->tail;
buf->pages = pages;
buf->page_base = base;
buf->page_len = len;
iov->iov_base = (char *)xdr->p;
iov->iov_len = 0;
xdr->iov = iov;
if (len & 3) {
unsigned int pad = 4 - (len & 3);
BUG_ON(xdr->p >= xdr->end);
iov->iov_base = (char *)xdr->p + (len & 3);
iov->iov_len += pad;
len += pad;
*xdr->p++ = 0;
}
buf->buflen += len;
buf->len += len;
}
EXPORT_SYMBOL_GPL(xdr_write_pages);
static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
unsigned int len)
{
if (len > iov->iov_len)
len = iov->iov_len;
xdr->p = (__be32*)iov->iov_base;
xdr->end = (__be32*)(iov->iov_base + len);
xdr->iov = iov;
xdr->page_ptr = NULL;
}
static int xdr_set_page_base(struct xdr_stream *xdr,
unsigned int base, unsigned int len)
{
unsigned int pgnr;
unsigned int maxlen;
unsigned int pgoff;
unsigned int pgend;
void *kaddr;
maxlen = xdr->buf->page_len;
if (base >= maxlen)
return -EINVAL;
maxlen -= base;
if (len > maxlen)
len = maxlen;
base += xdr->buf->page_base;
pgnr = base >> PAGE_SHIFT;
xdr->page_ptr = &xdr->buf->pages[pgnr];
kaddr = page_address(*xdr->page_ptr);
pgoff = base & ~PAGE_MASK;
xdr->p = (__be32*)(kaddr + pgoff);
pgend = pgoff + len;
if (pgend > PAGE_SIZE)
pgend = PAGE_SIZE;
xdr->end = (__be32*)(kaddr + pgend);
xdr->iov = NULL;
return 0;
}
static void xdr_set_next_page(struct xdr_stream *xdr)
{
unsigned int newbase;
newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
newbase -= xdr->buf->page_base;
if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
xdr_set_iov(xdr, xdr->buf->tail, xdr->buf->len);
}
static bool xdr_set_next_buffer(struct xdr_stream *xdr)
{
if (xdr->page_ptr != NULL)
xdr_set_next_page(xdr);
else if (xdr->iov == xdr->buf->head) {
if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
xdr_set_iov(xdr, xdr->buf->tail, xdr->buf->len);
}
return xdr->p != xdr->end;
}
/**
* xdr_init_decode - Initialize an xdr_stream for decoding data.
* @xdr: pointer to xdr_stream struct
* @buf: pointer to XDR buffer from which to decode data
* @p: current pointer inside XDR buffer
*/
void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
{
xdr->buf = buf;
xdr->scratch.iov_base = NULL;
xdr->scratch.iov_len = 0;
xdr->nwords = XDR_QUADLEN(buf->len);
if (buf->head[0].iov_len != 0)
xdr_set_iov(xdr, buf->head, buf->len);
else if (buf->page_len != 0)
xdr_set_page_base(xdr, 0, buf->len);
if (p != NULL && p > xdr->p && xdr->end >= p) {
xdr->nwords -= p - xdr->p;
xdr->p = p;
}
}
EXPORT_SYMBOL_GPL(xdr_init_decode);
/**
* xdr_init_decode - Initialize an xdr_stream for decoding data.
* @xdr: pointer to xdr_stream struct
* @buf: pointer to XDR buffer from which to decode data
* @pages: list of pages to decode into
* @len: length in bytes of buffer in pages
*/
void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
struct page **pages, unsigned int len)
{
memset(buf, 0, sizeof(*buf));
buf->pages = pages;
buf->page_len = len;
buf->buflen = len;
buf->len = len;
xdr_init_decode(xdr, buf, NULL);
}
EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
{
unsigned int nwords = XDR_QUADLEN(nbytes);
__be32 *p = xdr->p;
__be32 *q = p + nwords;
if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
return NULL;
xdr->p = q;
xdr->nwords -= nwords;
return p;
}
/**
* xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
* @xdr: pointer to xdr_stream struct
* @buf: pointer to an empty buffer
* @buflen: size of 'buf'
*
* The scratch buffer is used when decoding from an array of pages.
* If an xdr_inline_decode() call spans across page boundaries, then
* we copy the data into the scratch buffer in order to allow linear
* access.
*/
void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
{
xdr->scratch.iov_base = buf;
xdr->scratch.iov_len = buflen;
}
EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
{
__be32 *p;
void *cpdest = xdr->scratch.iov_base;
size_t cplen = (char *)xdr->end - (char *)xdr->p;
if (nbytes > xdr->scratch.iov_len)
return NULL;
memcpy(cpdest, xdr->p, cplen);
cpdest += cplen;
nbytes -= cplen;
if (!xdr_set_next_buffer(xdr))
return NULL;
p = __xdr_inline_decode(xdr, nbytes);
if (p == NULL)
return NULL;
memcpy(cpdest, p, nbytes);
return xdr->scratch.iov_base;
}
/**
* xdr_inline_decode - Retrieve XDR data to decode
* @xdr: pointer to xdr_stream struct
* @nbytes: number of bytes of data to decode
*
* Check if the input buffer is long enough to enable us to decode
* 'nbytes' more bytes of data starting at the current position.
* If so return the current pointer, then update the current
* pointer position.
*/
__be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
{
__be32 *p;
if (nbytes == 0)
return xdr->p;
if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
return NULL;
p = __xdr_inline_decode(xdr, nbytes);
if (p != NULL)
return p;
return xdr_copy_to_scratch(xdr, nbytes);
}
EXPORT_SYMBOL_GPL(xdr_inline_decode);
static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
{
struct xdr_buf *buf = xdr->buf;
struct kvec *iov;
unsigned int nwords = XDR_QUADLEN(len);
unsigned int cur = xdr_stream_pos(xdr);
if (xdr->nwords == 0)
return 0;
/* Realign pages to current pointer position */
iov = buf->head;
if (iov->iov_len > cur) {
xdr_shrink_bufhead(buf, iov->iov_len - cur);
xdr->nwords = XDR_QUADLEN(buf->len - cur);
}
if (nwords > xdr->nwords) {
nwords = xdr->nwords;
len = nwords << 2;
}
if (buf->page_len <= len)
len = buf->page_len;
else if (nwords < xdr->nwords) {
/* Truncate page data and move it into the tail */
xdr_shrink_pagelen(buf, buf->page_len - len);
xdr->nwords = XDR_QUADLEN(buf->len - cur);
}
return len;
}
/**
* xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
* @xdr: pointer to xdr_stream struct
* @len: number of bytes of page data
*
* Moves data beyond the current pointer position from the XDR head[] buffer
* into the page list. Any data that lies beyond current position + "len"
* bytes is moved into the XDR tail[].
*
* Returns the number of XDR encoded bytes now contained in the pages
*/
unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
{
struct xdr_buf *buf = xdr->buf;
struct kvec *iov;
unsigned int nwords;
unsigned int end;
unsigned int padding;
len = xdr_align_pages(xdr, len);
if (len == 0)
return 0;
nwords = XDR_QUADLEN(len);
padding = (nwords << 2) - len;
xdr->iov = iov = buf->tail;
/* Compute remaining message length. */
end = ((xdr->nwords - nwords) << 2) + padding;
if (end > iov->iov_len)
end = iov->iov_len;
/*
* Position current pointer at beginning of tail, and
* set remaining message length.
*/
xdr->p = (__be32 *)((char *)iov->iov_base + padding);
xdr->end = (__be32 *)((char *)iov->iov_base + end);
xdr->page_ptr = NULL;
xdr->nwords = XDR_QUADLEN(end - padding);
return len;
}
EXPORT_SYMBOL_GPL(xdr_read_pages);
/**
* xdr_enter_page - decode data from the XDR page
* @xdr: pointer to xdr_stream struct
* @len: number of bytes of page data
*
* Moves data beyond the current pointer position from the XDR head[] buffer
* into the page list. Any data that lies beyond current position + "len"
* bytes is moved into the XDR tail[]. The current pointer is then
* repositioned at the beginning of the first XDR page.
*/
void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
{
len = xdr_align_pages(xdr, len);
/*
* Position current pointer at beginning of tail, and
* set remaining message length.
*/
if (len != 0)
xdr_set_page_base(xdr, 0, len);
}
EXPORT_SYMBOL_GPL(xdr_enter_page);
static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
void
xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
{
buf->head[0] = *iov;
buf->tail[0] = empty_iov;
buf->page_len = 0;
buf->buflen = buf->len = iov->iov_len;
}
EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
/* Sets subbuf to the portion of buf of length len beginning base bytes
* from the start of buf. Returns -1 if base of length are out of bounds. */
int
xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
unsigned int base, unsigned int len)
{
subbuf->buflen = subbuf->len = len;
if (base < buf->head[0].iov_len) {
subbuf->head[0].iov_base = buf->head[0].iov_base + base;
subbuf->head[0].iov_len = min_t(unsigned int, len,
buf->head[0].iov_len - base);
len -= subbuf->head[0].iov_len;
base = 0;
} else {
subbuf->head[0].iov_base = NULL;
subbuf->head[0].iov_len = 0;
base -= buf->head[0].iov_len;
}
if (base < buf->page_len) {
subbuf->page_len = min(buf->page_len - base, len);
base += buf->page_base;
subbuf->page_base = base & ~PAGE_CACHE_MASK;
subbuf->pages = &buf->pages[base >> PAGE_CACHE_SHIFT];
len -= subbuf->page_len;
base = 0;
} else {
base -= buf->page_len;
subbuf->page_len = 0;
}
if (base < buf->tail[0].iov_len) {
subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
subbuf->tail[0].iov_len = min_t(unsigned int, len,
buf->tail[0].iov_len - base);
len -= subbuf->tail[0].iov_len;
base = 0;
} else {
subbuf->tail[0].iov_base = NULL;
subbuf->tail[0].iov_len = 0;
base -= buf->tail[0].iov_len;
}
if (base || len)
return -1;
return 0;
}
EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
/**
* xdr_buf_trim - lop at most "len" bytes off the end of "buf"
* @buf: buf to be trimmed
* @len: number of bytes to reduce "buf" by
*
* Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
* that it's possible that we'll trim less than that amount if the xdr_buf is
* too small, or if (for instance) it's all in the head and the parser has
* already read too far into it.
*/
void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
{
size_t cur;
unsigned int trim = len;
if (buf->tail[0].iov_len) {
cur = min_t(size_t, buf->tail[0].iov_len, trim);
buf->tail[0].iov_len -= cur;
trim -= cur;
if (!trim)
goto fix_len;
}
if (buf->page_len) {
cur = min_t(unsigned int, buf->page_len, trim);
buf->page_len -= cur;
trim -= cur;
if (!trim)
goto fix_len;
}
if (buf->head[0].iov_len) {
cur = min_t(size_t, buf->head[0].iov_len, trim);
buf->head[0].iov_len -= cur;
trim -= cur;
}
fix_len:
buf->len -= (len - trim);
}
EXPORT_SYMBOL_GPL(xdr_buf_trim);
static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
{
unsigned int this_len;
this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
memcpy(obj, subbuf->head[0].iov_base, this_len);
len -= this_len;
obj += this_len;
this_len = min_t(unsigned int, len, subbuf->page_len);
if (this_len)
_copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
len -= this_len;
obj += this_len;
this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
memcpy(obj, subbuf->tail[0].iov_base, this_len);
}
/* obj is assumed to point to allocated memory of size at least len: */
int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
{
struct xdr_buf subbuf;
int status;
status = xdr_buf_subsegment(buf, &subbuf, base, len);
if (status != 0)
return status;
__read_bytes_from_xdr_buf(&subbuf, obj, len);
return 0;
}
EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
{
unsigned int this_len;
this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
memcpy(subbuf->head[0].iov_base, obj, this_len);
len -= this_len;
obj += this_len;
this_len = min_t(unsigned int, len, subbuf->page_len);
if (this_len)
_copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
len -= this_len;
obj += this_len;
this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
memcpy(subbuf->tail[0].iov_base, obj, this_len);
}
/* obj is assumed to point to allocated memory of size at least len: */
int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
{
struct xdr_buf subbuf;
int status;
status = xdr_buf_subsegment(buf, &subbuf, base, len);
if (status != 0)
return status;
__write_bytes_to_xdr_buf(&subbuf, obj, len);
return 0;
}
EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
int
xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
{
__be32 raw;
int status;
status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
if (status)
return status;
*obj = be32_to_cpu(raw);
return 0;
}
EXPORT_SYMBOL_GPL(xdr_decode_word);
int
xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
{
__be32 raw = cpu_to_be32(obj);
return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
}
EXPORT_SYMBOL_GPL(xdr_encode_word);
/* If the netobj starting offset bytes from the start of xdr_buf is contained
* entirely in the head or the tail, set object to point to it; otherwise
* try to find space for it at the end of the tail, copy it there, and
* set obj to point to it. */
int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
{
struct xdr_buf subbuf;
if (xdr_decode_word(buf, offset, &obj->len))
return -EFAULT;
if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
return -EFAULT;
/* Is the obj contained entirely in the head? */
obj->data = subbuf.head[0].iov_base;
if (subbuf.head[0].iov_len == obj->len)
return 0;
/* ..or is the obj contained entirely in the tail? */
obj->data = subbuf.tail[0].iov_base;
if (subbuf.tail[0].iov_len == obj->len)
return 0;
/* use end of tail as storage for obj:
* (We don't copy to the beginning because then we'd have
* to worry about doing a potentially overlapping copy.
* This assumes the object is at most half the length of the
* tail.) */
if (obj->len > buf->buflen - buf->len)
return -ENOMEM;
if (buf->tail[0].iov_len != 0)
obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
else
obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
__read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
return 0;
}
EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
/* Returns 0 on success, or else a negative error code. */
static int
xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
struct xdr_array2_desc *desc, int encode)
{
char *elem = NULL, *c;
unsigned int copied = 0, todo, avail_here;
struct page **ppages = NULL;
int err;
if (encode) {
if (xdr_encode_word(buf, base, desc->array_len) != 0)
return -EINVAL;
} else {
if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
desc->array_len > desc->array_maxlen ||
(unsigned long) base + 4 + desc->array_len *
desc->elem_size > buf->len)
return -EINVAL;
}
base += 4;
if (!desc->xcode)
return 0;
todo = desc->array_len * desc->elem_size;
/* process head */
if (todo && base < buf->head->iov_len) {
c = buf->head->iov_base + base;
avail_here = min_t(unsigned int, todo,
buf->head->iov_len - base);
todo -= avail_here;
while (avail_here >= desc->elem_size) {
err = desc->xcode(desc, c);
if (err)
goto out;
c += desc->elem_size;
avail_here -= desc->elem_size;
}
if (avail_here) {
if (!elem) {
elem = kmalloc(desc->elem_size, GFP_KERNEL);
err = -ENOMEM;
if (!elem)
goto out;
}
if (encode) {
err = desc->xcode(desc, elem);
if (err)
goto out;
memcpy(c, elem, avail_here);
} else
memcpy(elem, c, avail_here);
copied = avail_here;
}
base = buf->head->iov_len; /* align to start of pages */
}
/* process pages array */
base -= buf->head->iov_len;
if (todo && base < buf->page_len) {
unsigned int avail_page;
avail_here = min(todo, buf->page_len - base);
todo -= avail_here;
base += buf->page_base;
ppages = buf->pages + (base >> PAGE_CACHE_SHIFT);
base &= ~PAGE_CACHE_MASK;
avail_page = min_t(unsigned int, PAGE_CACHE_SIZE - base,
avail_here);
c = kmap(*ppages) + base;
while (avail_here) {
avail_here -= avail_page;
if (copied || avail_page < desc->elem_size) {
unsigned int l = min(avail_page,
desc->elem_size - copied);
if (!elem) {
elem = kmalloc(desc->elem_size,
GFP_KERNEL);
err = -ENOMEM;
if (!elem)
goto out;
}
if (encode) {
if (!copied) {
err = desc->xcode(desc, elem);
if (err)
goto out;
}
memcpy(c, elem + copied, l);
copied += l;
if (copied == desc->elem_size)
copied = 0;
} else {
memcpy(elem + copied, c, l);
copied += l;
if (copied == desc->elem_size) {
err = desc->xcode(desc, elem);
if (err)
goto out;
copied = 0;
}
}
avail_page -= l;
c += l;
}
while (avail_page >= desc->elem_size) {
err = desc->xcode(desc, c);
if (err)
goto out;
c += desc->elem_size;
avail_page -= desc->elem_size;
}
if (avail_page) {
unsigned int l = min(avail_page,
desc->elem_size - copied);
if (!elem) {
elem = kmalloc(desc->elem_size,
GFP_KERNEL);
err = -ENOMEM;
if (!elem)
goto out;
}
if (encode) {
if (!copied) {
err = desc->xcode(desc, elem);
if (err)
goto out;
}
memcpy(c, elem + copied, l);
copied += l;
if (copied == desc->elem_size)
copied = 0;
} else {
memcpy(elem + copied, c, l);
copied += l;
if (copied == desc->elem_size) {
err = desc->xcode(desc, elem);
if (err)
goto out;
copied = 0;
}
}
}
if (avail_here) {
kunmap(*ppages);
ppages++;
c = kmap(*ppages);
}
avail_page = min(avail_here,
(unsigned int) PAGE_CACHE_SIZE);
}
base = buf->page_len; /* align to start of tail */
}
/* process tail */
base -= buf->page_len;
if (todo) {
c = buf->tail->iov_base + base;
if (copied) {
unsigned int l = desc->elem_size - copied;
if (encode)
memcpy(c, elem + copied, l);
else {
memcpy(elem + copied, c, l);
err = desc->xcode(desc, elem);
if (err)
goto out;
}
todo -= l;
c += l;
}
while (todo) {
err = desc->xcode(desc, c);
if (err)
goto out;
c += desc->elem_size;
todo -= desc->elem_size;
}
}
err = 0;
out:
kfree(elem);
if (ppages)
kunmap(*ppages);
return err;
}
int
xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
struct xdr_array2_desc *desc)
{
if (base >= buf->len)
return -EINVAL;
return xdr_xcode_array2(buf, base, desc, 0);
}
EXPORT_SYMBOL_GPL(xdr_decode_array2);
int
xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
struct xdr_array2_desc *desc)
{
if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
buf->head->iov_len + buf->page_len + buf->tail->iov_len)
return -EINVAL;
return xdr_xcode_array2(buf, base, desc, 1);
}
EXPORT_SYMBOL_GPL(xdr_encode_array2);
int
xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
int (*actor)(struct scatterlist *, void *), void *data)
{
int i, ret = 0;
unsigned int page_len, thislen, page_offset;
struct scatterlist sg[1];
sg_init_table(sg, 1);
if (offset >= buf->head[0].iov_len) {
offset -= buf->head[0].iov_len;
} else {
thislen = buf->head[0].iov_len - offset;
if (thislen > len)
thislen = len;
sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
ret = actor(sg, data);
if (ret)
goto out;
offset = 0;
len -= thislen;
}
if (len == 0)
goto out;
if (offset >= buf->page_len) {
offset -= buf->page_len;
} else {
page_len = buf->page_len - offset;
if (page_len > len)
page_len = len;
len -= page_len;
page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
thislen = PAGE_CACHE_SIZE - page_offset;
do {
if (thislen > page_len)
thislen = page_len;
sg_set_page(sg, buf->pages[i], thislen, page_offset);
ret = actor(sg, data);
if (ret)
goto out;
page_len -= thislen;
i++;
page_offset = 0;
thislen = PAGE_CACHE_SIZE;
} while (page_len != 0);
offset = 0;
}
if (len == 0)
goto out;
if (offset < buf->tail[0].iov_len) {
thislen = buf->tail[0].iov_len - offset;
if (thislen > len)
thislen = len;
sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
ret = actor(sg, data);
len -= thislen;
}
if (len != 0)
ret = -EINVAL;
out:
return ret;
}
EXPORT_SYMBOL_GPL(xdr_process_buf);