From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-iw0-f174.google.com ([209.85.214.174]:43660 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755080Ab0IJUKF (ORCPT ); Fri, 10 Sep 2010 16:10:05 -0400 Received: by iwn5 with SMTP id 5so2495581iwn.19 for ; Fri, 10 Sep 2010 13:10:04 -0700 (PDT) From: Chuck Lever Subject: [PATCH 08/11] NFS: Introduce new-style XDR decoding functions for NFSv2 To: trond.myklebust@netapp.com Cc: linux-nfs@vger.kernel.org Date: Fri, 10 Sep 2010 16:10:00 -0400 Message-ID: <20100910200959.13321.87119.stgit@seurat.1015granger.net> In-Reply-To: <20100910200512.13321.55605.stgit@seurat.1015granger.net> References: <20100910200512.13321.55605.stgit@seurat.1015granger.net> Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Signed-off-by: Chuck Lever --- fs/nfs/internal.h | 2 fs/nfs/nfs2xdr.c | 562 +++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/nfs/proc.c | 2 3 files changed, 563 insertions(+), 3 deletions(-) diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index 01da8d4..6246d40 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -181,7 +181,7 @@ extern void nfs_destroy_directcache(void); /* nfs2xdr.c */ extern int nfs_stat_to_errno(enum nfs_stat); extern struct rpc_procinfo nfs_procedures[]; -extern __be32 * nfs_decode_dirent(__be32 *, struct nfs_entry *, int); +extern __be32 *nfs2_decode_dirent(__be32 *, struct nfs_entry *, int); /* nfs3xdr.c */ extern struct rpc_procinfo nfs3_procedures[]; diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c index 769e74e..8ba3f34 100644 --- a/fs/nfs/nfs2xdr.c +++ b/fs/nfs/nfs2xdr.c @@ -77,6 +77,16 @@ static void prepare_reply_buffer(struct rpc_rqst *req, struct page **pages, xdr_inline_pages(&req->rq_rcv_buf, replen << 2, pages, base, len); } +/* + * Handle decode buffer overflows out-of-line. + */ +static void print_overflow_msg(const char *func, const struct xdr_stream *xdr) +{ + dprintk("NFS: %s prematurely hit the end of our receive buffer. " + "Remaining buffer length is %tu words.\n", + func, xdr->end - xdr->p); +} + /* * Common NFS XDR functions as inlines @@ -139,6 +149,74 @@ xdr_decode_fattr(__be32 *p, struct nfs_fattr *fattr) */ /* + * typedef opaque nfsdata<>; + */ +static int decode_nfsdata(struct xdr_stream *xdr, struct nfs_readres *result) +{ + u32 recvd, count; + size_t hdrlen; + __be32 *p; + + p = xdr_inline_decode(xdr, 4); + if (unlikely(p == NULL)) + goto out_overflow; + count = be32_to_cpup(p); + hdrlen = (u8 *)xdr->p - (u8 *)xdr->iov->iov_base; + recvd = xdr->buf->len - hdrlen; + if (unlikely(count > recvd)) + goto out_cheating; +out: + xdr_read_pages(xdr, count); + result->eof = 0; /* NFSv2 does not pass EOF flag on the wire. */ + result->count = count; + return count; +out_cheating: + dprintk("NFS: server cheating in read result: " + "count %u > recvd %u\n", count, recvd); + count = recvd; + goto out; +out_overflow: + print_overflow_msg(__func__, xdr); + return -EIO; +} + +/* + * enum stat { + * NFS_OK = 0, + * NFSERR_PERM = 1, + * NFSERR_NOENT = 2, + * NFSERR_IO = 5, + * NFSERR_NXIO = 6, + * NFSERR_ACCES = 13, + * NFSERR_EXIST = 17, + * NFSERR_NODEV = 19, + * NFSERR_NOTDIR = 20, + * NFSERR_ISDIR = 21, + * NFSERR_FBIG = 27, + * NFSERR_NOSPC = 28, + * NFSERR_ROFS = 30, + * NFSERR_NAMETOOLONG = 63, + * NFSERR_NOTEMPTY = 66, + * NFSERR_DQUOT = 69, + * NFSERR_STALE = 70, + * NFSERR_WFLUSH = 99 + * }; + */ +static int decode_stat(struct xdr_stream *xdr, enum nfs_stat *status) +{ + __be32 *p; + + p = xdr_inline_decode(xdr, 4); + if (unlikely(p == NULL)) + goto out_overflow; + *status = be32_to_cpup(p); + return 0; +out_overflow: + print_overflow_msg(__func__, xdr); + return -EIO; +} + +/* * 2.3.3. fhandle * * typedef opaque fhandle[FHSIZE]; @@ -153,6 +231,21 @@ static void encode_fhandle(struct xdr_stream *xdr, const struct nfs_fh *fh) memcpy(p, fh->data, NFS2_FHSIZE); } +static int decode_fhandle(struct xdr_stream *xdr, struct nfs_fh *fh) +{ + __be32 *p; + + p = xdr_inline_decode(xdr, NFS2_FHSIZE); + if (unlikely(p == NULL)) + goto out_overflow; + fh->size = NFS2_FHSIZE; + memcpy(fh->data, p, NFS2_FHSIZE); + return 0; +out_overflow: + print_overflow_msg(__func__, xdr); + return -EIO; +} + /* * 2.3.4. timeval * @@ -187,6 +280,41 @@ static __be32 *xdr_encode_current_server_time(__be32 *p, } /* + * 2.3.5. fattr + * + * struct fattr { + * ftype type; + * unsigned int mode; + * unsigned int nlink; + * unsigned int uid; + * unsigned int gid; + * unsigned int size; + * unsigned int blocksize; + * unsigned int rdev; + * unsigned int blocks; + * unsigned int fsid; + * unsigned int fileid; + * timeval atime; + * timeval mtime; + * timeval ctime; + * }; + * + */ +static int decode_fattr(struct xdr_stream *xdr, struct nfs_fattr *fattr) +{ + __be32 *p; + + p = xdr_inline_decode(xdr, NFS_fattr_sz << 2); + if (unlikely(p == NULL)) + goto out_overflow; + xdr_decode_fattr(p, fattr); + return 0; +out_overflow: + print_overflow_msg(__func__, xdr); + return -EIO; +} + +/* * 2.3.6. sattr * * struct sattr { @@ -278,6 +406,65 @@ static void encode_path(struct xdr_stream *xdr, struct page **pages, u32 length) xdr_write_pages(xdr, pages, 0, length); } +static int decode_path(struct xdr_stream *xdr) +{ + u32 length, recvd; + size_t hdrlen; + __be32 *p; + + p = xdr_inline_decode(xdr, 4); + if (unlikely(p == NULL)) + goto out_overflow; + length = be32_to_cpup(p); + if (unlikely(length >= xdr->buf->page_len || length > NFS_MAXPATHLEN)) + goto out_size; + hdrlen = (u8 *)xdr->p - (u8 *)xdr->iov->iov_base; + recvd = xdr->buf->len - hdrlen; + if (unlikely(length > recvd)) + goto out_cheating; + + xdr_read_pages(xdr, length); + xdr_terminate_string(xdr->buf, length); + return 0; +out_size: + dprintk("NFS: returned pathname too long: %u\n", length); + return -ENAMETOOLONG; +out_cheating: + dprintk("NFS: server cheating in pathname result: " + "length %u > received %u\n", length, recvd); + return -EIO; +out_overflow: + print_overflow_msg(__func__, xdr); + return -EIO; +} + +/* + * 2.3.9. attrstat + * + * union attrstat switch (stat status) { + * case NFS_OK: + * fattr attributes; + * default: + * void; + * }; + */ +static int decode_attrstat(struct xdr_stream *xdr, struct nfs_fattr *result) +{ + enum nfs_stat status; + int error; + + error = decode_stat(xdr, &status); + if (unlikely(error)) + goto out; + if (status != NFS_OK) + goto out_default; + error = decode_fattr(xdr, result); +out: + return error; +out_default: + return nfs_stat_to_errno(status); +} + /* * 2.3.10. diropargs * @@ -293,6 +480,48 @@ static void encode_diropargs(struct xdr_stream *xdr, const struct nfs_fh *fh, encode_filename(xdr, name, length); } +/* + * 2.3.11. diropres + * + * union diropres switch (stat status) { + * case NFS_OK: + * struct { + * fhandle file; + * fattr attributes; + * } diropok; + * default: + * void; + * }; + */ +static int decode_diropok(struct xdr_stream *xdr, struct nfs_diropok *result) +{ + int error; + + error = decode_fhandle(xdr, result->fh); + if (unlikely(error)) + goto out; + error = decode_fattr(xdr, result->fattr); +out: + return error; +} + +static int decode_diropres(struct xdr_stream *xdr, struct nfs_diropok *result) +{ + enum nfs_stat status; + int error; + + error = decode_stat(xdr, &status); + if (unlikely(error)) + goto out; + if (status != NFS_OK) + goto out_default; + error = decode_diropok(xdr, result); +out: + return error; +out_default: + return nfs_stat_to_errno(status); +} + /* * NFSv2 XDR encode functions @@ -726,6 +955,25 @@ nfs_xdr_stat(struct rpc_rqst *req, __be32 *p, void *dummy) return status; } +static int nfs2_xdr_dec_stat(struct rpc_rqst *req, __be32 *p, + void *__unused) +{ + struct xdr_stream xdr; + enum nfs_stat status; + int error; + + xdr_init_decode(&xdr, &req->rq_rcv_buf, p); + error = decode_stat(&xdr, &status); + if (unlikely(error)) + goto out; + if (status != NFS_OK) + goto out_default; +out: + return error; +out_default: + return nfs_stat_to_errno(status); +} + /* * Decode attrstat reply * GETATTR, SETATTR, WRITE @@ -741,6 +989,15 @@ nfs_xdr_attrstat(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr) return 0; } +static int nfs2_xdr_dec_attrstat(struct rpc_rqst *req, __be32 *p, + struct nfs_fattr *result) +{ + struct xdr_stream xdr; + + xdr_init_decode(&xdr, &req->rq_rcv_buf, p); + return decode_attrstat(&xdr, result); +} + /* * Decode diropres reply * LOOKUP, CREATE, MKDIR @@ -757,6 +1014,15 @@ nfs_xdr_diropres(struct rpc_rqst *req, __be32 *p, struct nfs_diropok *res) return 0; } +static int nfs2_xdr_dec_diropres(struct rpc_rqst *req, __be32 *p, + struct nfs_diropok *result) +{ + struct xdr_stream xdr; + + xdr_init_decode(&xdr, &req->rq_rcv_buf, p); + return decode_diropres(&xdr, result); +} + /* * Decode READLINK reply */ @@ -798,6 +1064,70 @@ nfs_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, void *dummy) } /* + * 2.2.6. readlinkres + * + * union readlinkres switch (stat status) { + * case NFS_OK: + * path data; + * default: + * void; + * }; + */ +static int nfs2_xdr_dec_readlinkres(struct rpc_rqst *req, __be32 *p, + void *__unused) +{ + struct xdr_stream xdr; + enum nfs_stat status; + int error; + + xdr_init_decode(&xdr, &req->rq_rcv_buf, p); + error = decode_stat(&xdr, &status); + if (unlikely(error)) + goto out; + if (status != NFS_OK) + goto out_default; + error = decode_path(&xdr); +out: + return error; +out_default: + return nfs_stat_to_errno(status); +} + +/* + * 2.2.7. readres + * + * union readres switch (stat status) { + * case NFS_OK: + * fattr attributes; + * nfsdata data; + * default: + * void; + * }; + */ +static int nfs2_xdr_dec_readres(struct rpc_rqst *req, __be32 *p, + struct nfs_readres *result) +{ + struct xdr_stream xdr; + enum nfs_stat status; + int error; + + xdr_init_decode(&xdr, &req->rq_rcv_buf, p); + error = decode_stat(&xdr, &status); + if (unlikely(error)) + goto out; + if (status != NFS_OK) + goto out_default; + error = decode_fattr(&xdr, result->fattr); + if (unlikely(error)) + goto out; + error = decode_nfsdata(&xdr, result); +out: + return error; +out_default: + return nfs_stat_to_errno(status); +} + +/* * Decode WRITE reply */ static int @@ -807,6 +1137,181 @@ nfs_xdr_writeres(struct rpc_rqst *req, __be32 *p, struct nfs_writeres *res) return nfs_xdr_attrstat(req, p, res->fattr); } +static int nfs2_xdr_dec_writeres(struct rpc_rqst *req, __be32 *p, + struct nfs_writeres *result) +{ + struct xdr_stream xdr; + + /* All NFSv2 writes are "file sync" writes */ + result->verf->committed = NFS_FILE_SYNC; + + xdr_init_decode(&xdr, &req->rq_rcv_buf, p); + return decode_attrstat(&xdr, result->fattr); +} + +/* + * 2.2.17. readdirres + * + * struct entry { + * unsigned fileid; + * filename name; + * nfscookie cookie; + * entry *nextentry; + * }; + * + * union readdirres switch (stat status) { + * case NFS_OK: + * struct { + * entry *entries; + * bool eof; + * } readdirok; + * default: + * void; + * }; + * + * The type (size) of nfscookie isn't defined in RFC 1094. + * + * The Linux implementation of readdir is limited to receiving not + * more than a single page of entries at a time. + * + * Here, the XDR buffer is checked for correct syntax. The actual + * decoding is done by nfs_decode_entry() during subsequent + * nfs_readdir() calls on readdir data cached in the page cache. + */ +static int decode_readdirok(struct xdr_stream *xdr) +{ + __be32 *p, *end, *entry, *kaddr; + unsigned int nr, pglen, recvd; + struct page **page; + size_t hdrlen; + u32 count; + + pglen = xdr->buf->page_len; + hdrlen = (u8 *)xdr->p - (u8 *)xdr->iov->iov_base; + recvd = xdr->buf->len - hdrlen; + if (pglen > recvd) + pglen = recvd; + xdr_read_pages(xdr, pglen); + + page = xdr->buf->pages; + kaddr = p = kmap_atomic(*page, KM_USER0); + end = (__be32 *)((char *)p + pglen); + entry = p; + + /* Make sure the packet actually has a value_follows and EOF entry */ + if (unlikely((entry + 1) > end)) + goto out_short_reply; + + nr = 0; + for (; *p++ != xdr_zero; nr++) { + if (unlikely(p + 2 > end)) + goto out_short_reply; + p++; /* fileid */ + count = be32_to_cpup(p++); + if (unlikely(count > NFS2_MAXNAMLEN)) + goto out_nametoolong; + p += XDR_QUADLEN(count) + 1; /* name plus cookie */ + if (unlikely(p + 2 > end)) + goto out_short_reply; + entry = p; + } + + /* + * Apparently some server sends responses that are a valid size, + * but contain no entries, and have value_follows==0 and EOF==0. + * For those, just set the EOF marker. + */ + if (unlikely(!nr && entry[1] == xdr_zero)) + goto out_truncated; +out: + kunmap_atomic(kaddr, KM_USER0); + return nr; +out_short_reply: + /* + * When we get a short reply there are 2 possibilities. We can + * return an error, or fix up the response to look like a valid + * response and return what we have so far. If there are no + * entries and the reply was short, then return -EIO. If there + * are valid entries in the response, return them and pretend + * that the call was successful, but incomplete. The caller can + * retry the readdir starting at the last cookie. + */ + dprintk("NFS: short readdir reply at entry %d\n", nr); + entry[0] = entry[1] = xdr_zero; + if (!nr) + nr = -EIO; + goto out; +out_nametoolong: + dprintk("NFS: filename too long during readdir (len 0x%x)\n", count); + nr = -EIO; + goto out; +out_truncated: + dprintk("NFS: readdir reply truncated\n"); + entry[1] = xdr_one; + goto out; +} + +static int nfs2_xdr_dec_readdirres(struct rpc_rqst *req, __be32 *p, + void *__unused) +{ + struct xdr_stream xdr; + enum nfs_stat status; + int error; + + xdr_init_decode(&xdr, &req->rq_rcv_buf, p); + error = decode_stat(&xdr, &status); + if (unlikely(error)) + goto out; + if (status != NFS_OK) + goto out_default; + error = decode_readdirok(&xdr); +out: + return error; +out_default: + return nfs_stat_to_errno(status); +} + +/** + * nfs2_decode_dirent - Decode a single NFSv2 directory entry stored in + * the local page cache. + * @p: pointer to buffer where entry resides + * @entry: entry struct to fill out with data + * @plus: boolean indicating whether this should be a readdirplus entry + * + * Returns the position of the next item in the buffer, or an ERR_PTR. + * + * This function is not invoked during READDIR reply decoding, but + * rather whenever an application invokes the getdents(2) system call. + * + * 2.2.17. entry + * + * struct entry { + * unsigned fileid; + * filename name; + * nfscookie cookie; + * entry *nextentry; + * }; + */ +__be32 *nfs2_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus) +{ + if (*p++ == xdr_zero) { + if (*p == xdr_zero) + return ERR_PTR(-EAGAIN); + entry->eof = 1; + return ERR_PTR(-EBADCOOKIE); + } + + entry->ino = be32_to_cpup(p++); + p = xdr_decode_string_inplace(p, (char **)&entry->name, + &entry->len, NFS2_MAXNAMLEN); + entry->prev_cookie = entry->cookie; + entry->cookie = be32_to_cpup(p++); + + /* Peek at the next entry */ + entry->eof = (p[0] == xdr_zero) && (p[1] != xdr_zero); + return p; +} + /* * Decode STATFS reply */ @@ -827,6 +1332,61 @@ nfs_xdr_statfsres(struct rpc_rqst *req, __be32 *p, struct nfs2_fsstat *res) } /* + * 2.2.18. statfsres + * + * union statfsres (stat status) { + * case NFS_OK: + * struct { + * unsigned tsize; + * unsigned bsize; + * unsigned blocks; + * unsigned bfree; + * unsigned bavail; + * } info; + * default: + * void; + * }; + */ +static int decode_info(struct xdr_stream *xdr, struct nfs2_fsstat *result) +{ + __be32 *p; + + p = xdr_inline_decode(xdr, NFS_info_sz << 2); + if (unlikely(p == NULL)) + goto out_overflow; + result->tsize = be32_to_cpup(p++); + result->bsize = be32_to_cpup(p++); + result->blocks = be32_to_cpup(p++); + result->bfree = be32_to_cpup(p++); + result->bavail = be32_to_cpup(p); + return 0; +out_overflow: + print_overflow_msg(__func__, xdr); + return -EIO; +} + +static int nfs2_xdr_dec_statfsres(struct rpc_rqst *req, __be32 *p, + struct nfs2_fsstat *result) +{ + struct xdr_stream xdr; + enum nfs_stat status; + int error; + + xdr_init_decode(&xdr, &req->rq_rcv_buf, p); + error = decode_stat(&xdr, &status); + if (unlikely(error)) + goto out; + if (status != NFS_OK) + goto out_default; + error = decode_info(&xdr, result); +out: + return error; +out_default: + return nfs_stat_to_errno(status); +} + + +/* * We need to translate between nfs status return values and * the local errno values which may not be the same. */ @@ -893,7 +1453,7 @@ int nfs_stat_to_errno(enum nfs_stat status) [NFSPROC_##proc] = { \ .p_proc = NFSPROC_##proc, \ .p_encode = (kxdrproc_t) nfs2_xdr_enc_##argtype, \ - .p_decode = (kxdrproc_t) nfs_xdr_##restype, \ + .p_decode = (kxdrproc_t) nfs2_xdr_dec_##restype, \ .p_arglen = NFS_##argtype##_sz, \ .p_replen = NFS_##restype##_sz, \ .p_timer = timer, \ diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c index 611bec2..12a0200 100644 --- a/fs/nfs/proc.c +++ b/fs/nfs/proc.c @@ -714,7 +714,7 @@ const struct nfs_rpc_ops nfs_v2_clientops = { .statfs = nfs_proc_statfs, .fsinfo = nfs_proc_fsinfo, .pathconf = nfs_proc_pathconf, - .decode_dirent = nfs_decode_dirent, + .decode_dirent = nfs2_decode_dirent, .read_setup = nfs_proc_read_setup, .read_done = nfs_read_done, .write_setup = nfs_proc_write_setup,