NFSv4: include bitmap in nfsv4 get acl data
The NFSv4 bitmap size is unbounded: a server can return an arbitrary
sized bitmap in an FATTR4_WORD0_ACL request. Replace using the
nfs4_fattr_bitmap_maxsz as a guess to the maximum bitmask returned by a server
with the inclusion of the bitmap (xdr length plus bitmasks) and the acl data
xdr length to the (cached) acl page data.
This is a general solution to commit e5012d1f "NFSv4.1: update
nfs4_fattr_bitmap_maxsz" and fixes hitting a BUG_ON in xdr_shrink_bufhead
when getting ACLs.
Fix a bug in decode_getacl that returned -EINVAL on ACLs > page when getxattr
was called with a NULL buffer, preventing ACL > PAGE_SIZE from being retrieved.
Cc: stable@kernel.org
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Andy Adamson
Trond Myklebust
Родитель
3476f114ad
Коммит
bf118a342f
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@ -3426,19 +3426,6 @@ static inline int nfs4_server_supports_acls(struct nfs_server *server)
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*/
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#define NFS4ACL_MAXPAGES (XATTR_SIZE_MAX >> PAGE_CACHE_SHIFT)
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static void buf_to_pages(const void *buf, size_t buflen,
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struct page **pages, unsigned int *pgbase)
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{
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const void *p = buf;
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*pgbase = offset_in_page(buf);
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p -= *pgbase;
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while (p < buf + buflen) {
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*(pages++) = virt_to_page(p);
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p += PAGE_CACHE_SIZE;
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}
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}
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static int buf_to_pages_noslab(const void *buf, size_t buflen,
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struct page **pages, unsigned int *pgbase)
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{
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@ -3535,9 +3522,19 @@ out:
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nfs4_set_cached_acl(inode, acl);
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}
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/*
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* The getxattr API returns the required buffer length when called with a
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* NULL buf. The NFSv4 acl tool then calls getxattr again after allocating
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* the required buf. On a NULL buf, we send a page of data to the server
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* guessing that the ACL request can be serviced by a page. If so, we cache
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* up to the page of ACL data, and the 2nd call to getxattr is serviced by
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* the cache. If not so, we throw away the page, and cache the required
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* length. The next getxattr call will then produce another round trip to
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* the server, this time with the input buf of the required size.
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*/
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static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t buflen)
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{
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struct page *pages[NFS4ACL_MAXPAGES];
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struct page *pages[NFS4ACL_MAXPAGES] = {NULL, };
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struct nfs_getaclargs args = {
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.fh = NFS_FH(inode),
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.acl_pages = pages,
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@ -3552,41 +3549,60 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu
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.rpc_argp = &args,
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.rpc_resp = &res,
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};
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struct page *localpage = NULL;
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int ret;
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int ret = -ENOMEM, npages, i, acl_len = 0;
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if (buflen < PAGE_SIZE) {
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/* As long as we're doing a round trip to the server anyway,
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* let's be prepared for a page of acl data. */
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localpage = alloc_page(GFP_KERNEL);
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resp_buf = page_address(localpage);
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if (localpage == NULL)
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return -ENOMEM;
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args.acl_pages[0] = localpage;
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args.acl_pgbase = 0;
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args.acl_len = PAGE_SIZE;
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} else {
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resp_buf = buf;
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buf_to_pages(buf, buflen, args.acl_pages, &args.acl_pgbase);
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npages = (buflen + PAGE_SIZE - 1) >> PAGE_SHIFT;
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/* As long as we're doing a round trip to the server anyway,
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* let's be prepared for a page of acl data. */
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if (npages == 0)
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npages = 1;
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for (i = 0; i < npages; i++) {
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pages[i] = alloc_page(GFP_KERNEL);
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if (!pages[i])
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goto out_free;
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}
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ret = nfs4_call_sync(NFS_SERVER(inode)->client, NFS_SERVER(inode), &msg, &args.seq_args, &res.seq_res, 0);
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if (npages > 1) {
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/* for decoding across pages */
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args.acl_scratch = alloc_page(GFP_KERNEL);
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if (!args.acl_scratch)
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goto out_free;
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}
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args.acl_len = npages * PAGE_SIZE;
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args.acl_pgbase = 0;
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/* Let decode_getfacl know not to fail if the ACL data is larger than
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* the page we send as a guess */
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if (buf == NULL)
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res.acl_flags |= NFS4_ACL_LEN_REQUEST;
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resp_buf = page_address(pages[0]);
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dprintk("%s buf %p buflen %ld npages %d args.acl_len %ld\n",
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__func__, buf, buflen, npages, args.acl_len);
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ret = nfs4_call_sync(NFS_SERVER(inode)->client, NFS_SERVER(inode),
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&msg, &args.seq_args, &res.seq_res, 0);
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if (ret)
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goto out_free;
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if (res.acl_len > args.acl_len)
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nfs4_write_cached_acl(inode, NULL, res.acl_len);
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acl_len = res.acl_len - res.acl_data_offset;
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if (acl_len > args.acl_len)
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nfs4_write_cached_acl(inode, NULL, acl_len);
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else
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nfs4_write_cached_acl(inode, resp_buf, res.acl_len);
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nfs4_write_cached_acl(inode, resp_buf + res.acl_data_offset,
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acl_len);
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if (buf) {
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ret = -ERANGE;
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if (res.acl_len > buflen)
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if (acl_len > buflen)
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goto out_free;
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if (localpage)
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memcpy(buf, resp_buf, res.acl_len);
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_copy_from_pages(buf, pages, res.acl_data_offset,
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res.acl_len);
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}
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ret = res.acl_len;
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ret = acl_len;
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out_free:
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if (localpage)
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__free_page(localpage);
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for (i = 0; i < npages; i++)
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if (pages[i])
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__free_page(pages[i]);
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if (args.acl_scratch)
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__free_page(args.acl_scratch);
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return ret;
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}
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@ -3617,6 +3633,8 @@ static ssize_t nfs4_proc_get_acl(struct inode *inode, void *buf, size_t buflen)
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nfs_zap_acl_cache(inode);
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ret = nfs4_read_cached_acl(inode, buf, buflen);
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if (ret != -ENOENT)
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/* -ENOENT is returned if there is no ACL or if there is an ACL
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* but no cached acl data, just the acl length */
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return ret;
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return nfs4_get_acl_uncached(inode, buf, buflen);
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}
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@ -2517,11 +2517,13 @@ static void nfs4_xdr_enc_getacl(struct rpc_rqst *req, struct xdr_stream *xdr,
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encode_compound_hdr(xdr, req, &hdr);
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encode_sequence(xdr, &args->seq_args, &hdr);
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encode_putfh(xdr, args->fh, &hdr);
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replen = hdr.replen + op_decode_hdr_maxsz + nfs4_fattr_bitmap_maxsz + 1;
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replen = hdr.replen + op_decode_hdr_maxsz + 1;
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encode_getattr_two(xdr, FATTR4_WORD0_ACL, 0, &hdr);
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xdr_inline_pages(&req->rq_rcv_buf, replen << 2,
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args->acl_pages, args->acl_pgbase, args->acl_len);
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xdr_set_scratch_buffer(xdr, page_address(args->acl_scratch), PAGE_SIZE);
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encode_nops(&hdr);
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}
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@ -4957,17 +4959,18 @@ decode_restorefh(struct xdr_stream *xdr)
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}
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static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
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size_t *acl_len)
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struct nfs_getaclres *res)
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{
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__be32 *savep;
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__be32 *savep, *bm_p;
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uint32_t attrlen,
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bitmap[3] = {0};
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struct kvec *iov = req->rq_rcv_buf.head;
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int status;
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*acl_len = 0;
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res->acl_len = 0;
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if ((status = decode_op_hdr(xdr, OP_GETATTR)) != 0)
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goto out;
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bm_p = xdr->p;
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if ((status = decode_attr_bitmap(xdr, bitmap)) != 0)
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goto out;
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if ((status = decode_attr_length(xdr, &attrlen, &savep)) != 0)
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@ -4979,18 +4982,30 @@ static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
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size_t hdrlen;
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u32 recvd;
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/* The bitmap (xdr len + bitmaps) and the attr xdr len words
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* are stored with the acl data to handle the problem of
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* variable length bitmaps.*/
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xdr->p = bm_p;
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res->acl_data_offset = be32_to_cpup(bm_p) + 2;
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res->acl_data_offset <<= 2;
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/* We ignore &savep and don't do consistency checks on
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* the attr length. Let userspace figure it out.... */
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hdrlen = (u8 *)xdr->p - (u8 *)iov->iov_base;
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attrlen += res->acl_data_offset;
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recvd = req->rq_rcv_buf.len - hdrlen;
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if (attrlen > recvd) {
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dprintk("NFS: server cheating in getattr"
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" acl reply: attrlen %u > recvd %u\n",
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if (res->acl_flags & NFS4_ACL_LEN_REQUEST) {
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/* getxattr interface called with a NULL buf */
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res->acl_len = attrlen;
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goto out;
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}
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dprintk("NFS: acl reply: attrlen %u > recvd %u\n",
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attrlen, recvd);
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return -EINVAL;
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}
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xdr_read_pages(xdr, attrlen);
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*acl_len = attrlen;
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res->acl_len = attrlen;
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} else
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status = -EOPNOTSUPP;
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@ -6028,7 +6043,7 @@ nfs4_xdr_dec_getacl(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
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status = decode_putfh(xdr);
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if (status)
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goto out;
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status = decode_getacl(xdr, rqstp, &res->acl_len);
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status = decode_getacl(xdr, rqstp, res);
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out:
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return status;
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@ -602,11 +602,16 @@ struct nfs_getaclargs {
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size_t acl_len;
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unsigned int acl_pgbase;
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struct page ** acl_pages;
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struct page * acl_scratch;
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struct nfs4_sequence_args seq_args;
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};
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/* getxattr ACL interface flags */
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#define NFS4_ACL_LEN_REQUEST 0x0001 /* zero length getxattr buffer */
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struct nfs_getaclres {
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size_t acl_len;
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size_t acl_data_offset;
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int acl_flags;
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struct nfs4_sequence_res seq_res;
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};
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@ -191,6 +191,8 @@ extern int xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
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struct xdr_array2_desc *desc);
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extern int xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
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struct xdr_array2_desc *desc);
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extern void _copy_from_pages(char *p, struct page **pages, size_t pgbase,
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size_t len);
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/*
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* Provide some simple tools for XDR buffer overflow-checking etc.
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@ -296,7 +296,7 @@ _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
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* Copies data into an arbitrary memory location from an array of pages
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* The copy is assumed to be non-overlapping.
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*/
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static void
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void
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_copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
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{
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struct page **pgfrom;
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@ -324,6 +324,7 @@ _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
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} while ((len -= copy) != 0);
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}
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EXPORT_SYMBOL_GPL(_copy_from_pages);
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/*
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* xdr_shrink_bufhead
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