Linux-NFS Archive on lore.kernel.org
 help / color / Atom feed
From: Frank van der Linden <fllinden@amazon.com>
To: <linux-nfs@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>
Subject: [RFC PATCH 29/35] nfsd: add xattr XDR decode functions
Date: Mon, 2 Sep 2019 19:58:35 +0000
Message-ID: <7c77f897843ccdc150550926bc9e6cd5290dfc8e.1568309119.git.fllinden@amazon.com> (raw)
In-Reply-To: <cover.1568309119.git.fllinden@amazon.com>

Implement the XDR decode functions for the user extended attribute
operations.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/nfs4xdr.c | 233 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 228 insertions(+), 5 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index c921945f0df0..acf606f764a2 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1793,6 +1793,222 @@ nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
 	DECODE_TAIL;
 }
 
+#ifdef CONFIG_NFSD_V4_XATTR
+/*
+ * XDR data that is more than PAGE_SIZE in size is normally part of a
+ * read or write. However, the size of extended attributes is limited
+ * by the maximum request size, and then further limited by the underlying
+ * filesystem limits. This can exceed PAGE_SIZE (currently, XATTR_SIZE_MAX
+ * is 64k). Since there is no kvec- or page-based interface to xattrs,
+ * and we're not dealing with contiguous pages, we need to do some copying.
+ */
+
+/*
+ * Decode int to buffer. Uses head and pages constructed by
+ * svcxdr_construct_vector.
+ */
+static int
+nfsd4_vbuf_from_stream(struct nfsd4_compoundargs *argp, struct kvec *head,
+		       struct page **pages, char **bufp, u32 buflen)
+{
+	char *tmp, *dp;
+	u32 len;
+
+	if (buflen <= head->iov_len) {
+		/*
+		 * We're in luck, the head has enough space. Just return
+		 * the head, no need for copying.
+		 */
+		*bufp = head->iov_base;
+		return 0;
+	}
+
+	tmp = svcxdr_tmpalloc(argp, buflen);
+	if (tmp == NULL)
+		return nfserr_jukebox;
+
+	dp = tmp;
+	memcpy(dp, head->iov_base, head->iov_len);
+	buflen -= head->iov_len;
+	dp += head->iov_len;
+
+	while (buflen > 0) {
+		len = min_t(u32, buflen, PAGE_SIZE);
+		memcpy(dp, page_address(*pages), len);
+
+		buflen -= len;
+		dp += len;
+		pages++;
+	}
+
+	*bufp = tmp;
+	return 0;
+}
+
+/*
+ * Get a user extended attribute name from the XDR buffer.
+ * It will not have the "user." prefix, so prepend it.
+ * Lastly, check for nul characters in the name.
+ */
+static int
+nfsd4_decode_xattr_name(struct nfsd4_compoundargs *argp, char **namep)
+{
+	DECODE_HEAD;
+	char *name, *sp, *dp;
+	u32 namelen, cnt;
+
+	READ_BUF(4);
+	namelen = be32_to_cpup(p++);
+
+	if (namelen > (XATTR_NAME_MAX - XATTR_USER_PREFIX_LEN))
+		return nfserr_nametoolong;
+
+	if (namelen == 0)
+		goto xdr_error;
+
+	READ_BUF(namelen);
+
+	name = svcxdr_tmpalloc(argp, namelen + XATTR_USER_PREFIX_LEN + 1);
+	if (!name)
+		return nfserr_jukebox;
+
+	memcpy(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
+
+	/*
+	 * Copy the extended attribute name over while checking for 0
+	 * characters.
+	 */
+	sp = (char *)p;
+	dp = name + XATTR_USER_PREFIX_LEN;
+	cnt = namelen;
+
+	while (cnt-- > 0) {
+		if (*sp == '\0')
+			goto xdr_error;
+		*dp++ = *sp++;
+	}
+	*dp = '\0';
+
+	*namep = name;
+
+	DECODE_TAIL;
+}
+
+/*
+ * A GETXATTR op request comes without a length specifier. We just set the
+ * maximum length for the reply based on XATTR_SIZE_MAX and the maximum
+ * channel reply size, allocate a buffer of that length and pass it to
+ * vfs_getxattr.
+ */
+static __be32
+nfsd4_decode_getxattr(struct nfsd4_compoundargs *argp, struct nfsd4_getxattr *getxattr)
+{
+	int status;
+	u32 maxcount;
+
+	status = nfsd4_decode_xattr_name(argp, &getxattr->getxa_name);
+	if (status)
+		return status;
+
+	maxcount = svc_max_payload(argp->rqstp);
+	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
+
+	getxattr->getxa_buf = svcxdr_tmpalloc(argp, maxcount);
+	if (!getxattr->getxa_buf)
+		status = nfserr_jukebox;
+	getxattr->getxa_len = maxcount;
+
+	return status;
+}
+
+static __be32
+nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp, struct nfsd4_setxattr *setxattr)
+{
+	DECODE_HEAD;
+	u32 flags, maxcount, size;
+	struct kvec head;
+	struct page **pagelist;
+
+	READ_BUF(4);
+	flags = be32_to_cpup(p++);
+
+	if (flags > SETXATTR4_REPLACE)
+		return nfserr_inval;
+	setxattr->setxa_flags = flags;
+
+	status = nfsd4_decode_xattr_name(argp, &setxattr->setxa_name);
+	if (status)
+		return status;
+
+	maxcount = svc_max_payload(argp->rqstp);
+	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
+
+	READ_BUF(4);
+	size = be32_to_cpup(p++);
+	if (size > maxcount)
+		return nfserr_xattr2big;
+
+	setxattr->setxa_len = size;
+	if (size > 0) {
+		status = svcxdr_construct_vector(argp, &head, &pagelist, size);
+		if (status)
+			return status;
+
+		status = nfsd4_vbuf_from_stream(argp, &head, pagelist,
+		    &setxattr->setxa_buf, size);
+	}
+
+	DECODE_TAIL;
+}
+
+static __be32
+nfsd4_decode_listxattrs(struct nfsd4_compoundargs *argp, struct nfsd4_listxattrs *listxattrs)
+{
+	DECODE_HEAD;
+	u32 maxcount;
+
+	READ_BUF(12);
+	p = xdr_decode_hyper(p, &listxattrs->lsxa_cookie);
+
+	/*
+	 * If the cookie  is too large to have even one user.x attribute
+	 * plus trailing '\0' left in a maximum size buffer, it's invalid.
+	 */
+	if (listxattrs->lsxa_cookie >=
+	    (XATTR_LIST_MAX / (XATTR_USER_PREFIX_LEN + 2)))
+		return nfserr_badcookie;
+
+	maxcount = be32_to_cpup(p++);
+	if (maxcount < 8)
+		/* Always need at least 2 words (length and one character) */
+		return nfserr_inval;
+
+	maxcount = min(maxcount, svc_max_payload(argp->rqstp));
+	listxattrs->lsxa_maxcount = maxcount;
+
+	/*
+	 * Unfortunately, there is no interface to only list xattrs for
+	 * one prefix. So there is no good way to convert maxcount to
+	 * a maximum value to pass to vfs_listxattr, as we don't know
+	 * how many of the returned attributes will be user attributes.
+	 *
+	 * So, always ask vfs_listxattr for the maximum size, and encode
+	 * as many as possible.
+	 */
+	listxattrs->lsxa_buf = svcxdr_tmpalloc(argp, XATTR_LIST_MAX);
+	if (!listxattrs->lsxa_buf)
+		status = nfserr_jukebox;
+
+	DECODE_TAIL;
+}
+
+static __be32
+nfsd4_decode_removexattr(struct nfsd4_compoundargs *argp, struct nfsd4_removexattr *removexattr)
+{
+	return nfsd4_decode_xattr_name(argp, &removexattr->rmxa_name);
+}
+#endif
+
 static __be32
 nfsd4_decode_noop(struct nfsd4_compoundargs *argp, void *p)
 {
@@ -1890,11 +2106,18 @@ static const nfsd4_dec nfsd4_dec_ops[] = {
 	[OP_WRITE_SAME]		= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_CLONE]		= (nfsd4_dec)nfsd4_decode_clone,
 
-        /* Placeholders for RFC 8276 extended atributes operations */
-        [OP_GETXATTR]           = (nfsd4_dec)nfsd4_decode_notsupp,
-        [OP_SETXATTR]           = (nfsd4_dec)nfsd4_decode_notsupp,
-        [OP_LISTXATTRS]         = (nfsd4_dec)nfsd4_decode_notsupp,
-        [OP_REMOVEXATTR]        = (nfsd4_dec)nfsd4_decode_notsupp,
+#ifdef CONFIG_NFSD_V4_XATTR
+	/* RFC 8276 extended atributes operations */
+	[OP_GETXATTR]		= (nfsd4_dec)nfsd4_decode_getxattr,
+	[OP_SETXATTR]		= (nfsd4_dec)nfsd4_decode_setxattr,
+	[OP_LISTXATTRS]		= (nfsd4_dec)nfsd4_decode_listxattrs,
+	[OP_REMOVEXATTR]	= (nfsd4_dec)nfsd4_decode_removexattr,
+#else
+	[OP_GETXATTR]		= (nfsd4_dec)nfsd4_decode_notsupp,
+	[OP_SETXATTR]		= (nfsd4_dec)nfsd4_decode_notsupp,
+	[OP_LISTXATTRS]		= (nfsd4_dec)nfsd4_decode_notsupp,
+	[OP_REMOVEXATTR]	= (nfsd4_dec)nfsd4_decode_notsupp,
+#endif
 };
 
 static inline bool
-- 
2.17.2


  parent reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-12 17:25 [RFC PATCH 00/35] user xattr support (RFC8276) Frank van der Linden
2019-07-01 17:56 ` [RFC PATCH 02/35] nfs/nfsd: basic NFS4 extended attribute definitions Frank van der Linden
2019-08-26 21:38 ` [RFC PATCH 03/35] NFSv4.2: query the server for extended attribute support Frank van der Linden
2019-08-26 21:53 ` [RFC PATCH 04/35] nfs: parse the {no}user_xattr option Frank van der Linden
2019-08-26 22:06 ` [RFC PATCH 05/35] NFSv4.2: define a function to compute the maximum XDR size for listxattr Frank van der Linden
2019-08-26 22:23 ` [RFC PATCH 06/35] NFSv4.2: define and set initial limits for extended attributes Frank van der Linden
2019-08-26 22:32 ` [RFC PATCH 07/35] NFSv4.2: define argument and response structures for xattr operations Frank van der Linden
2019-08-26 22:44 ` [RFC PATCH 08/35] NFSv4.2: define the encode/decode sizes for the XATTR operations Frank van der Linden
2019-08-26 23:09 ` [RFC PATCH 09/35] NFSv4.2: define and use extended attribute overhead sizes Frank van der Linden
2019-08-27 15:34 ` [RFC PATCH 10/35] NFSv4.2: add client side XDR handling for extended attributes Frank van der Linden
2019-08-27 15:46 ` [RFC PATCH 11/35] nfs: define nfs_access_get_cached function Frank van der Linden
2019-08-27 16:01 ` [RFC PATCH 12/35] NFSv4.2: query the extended attribute access bits Frank van der Linden
2019-08-27 22:51 ` [RFC PATCH 13/35] nfs: modify update_changeattr to deal with regular files Frank van der Linden
2019-08-30 22:48 ` [RFC PATCH 14/35] nfs: define and use the NFS_INO_INVALID_XATTR flag Frank van der Linden
2019-08-30 22:56 ` [RFC PATCH 15/35] nfs: make the buf_to_pages_noslab function available to the nfs code Frank van der Linden
2019-08-30 23:15 ` [RFC PATCH 16/35] NFSv4.2: add the extended attribute proc functions Frank van der Linden
2019-08-30 23:31 ` [RFC PATCH 17/35] NFSv4.2: hook in the user extended attribute handlers Frank van der Linden
2019-08-30 23:38 ` [RFC PATCH 18/35] NFSv4.2: add client side xattr caching functions Frank van der Linden
2019-08-30 23:45 ` [RFC PATCH 19/35] NFSv4.2: call the xattr cache functions Frank van der Linden
2019-08-30 23:59 ` [RFC PATCH 20/35] nfs: add the NFS_V4_XATTR config option Frank van der Linden
2019-08-31  2:12 ` [RFC PATCH 21/35] xattr: modify vfs_{set,remove}xattr for NFS server use Frank van der Linden
2019-08-31 19:00 ` [RFC PATCH 22/35] nfsd: split off the write decode code in to a seperate function Frank van der Linden
2019-08-31 19:19 ` [RFC PATCH 23/35] nfsd: add defines for NFSv4.2 extended attribute support Frank van der Linden
2019-08-31 21:35 ` [RFC PATCH 26/35] nfsd: add structure definitions for xattr requests / responses Frank van der Linden
2019-08-31 23:53 ` [RFC PATCH 24/35] nfsd: define xattr functions to call in to their vfs counterparts Frank van der Linden
2019-09-01  0:13 ` [RFC PATCH 25/35] nfsd: take xattr access bits in to account when checking Frank van der Linden
2019-09-01  1:19 ` [RFC PATCH 27/35] nfsd: implement the xattr procedure functions Frank van der Linden
2019-09-01  2:46 ` [RFC PATCH 01/35] nfsd: make sure the nfsd4_ops array has the right size Frank van der Linden
2019-09-02 19:40 ` [RFC PATCH 28/35] nfsd: define xattr reply size functions Frank van der Linden
2019-09-02 19:58 ` Frank van der Linden [this message]
2019-09-02 20:09 ` [RFC PATCH 30/35] nfsd: add xattr XDR encode functions Frank van der Linden
2019-09-02 20:19 ` [RFC PATCH 31/35] nfsd: add xattr operations to ops array Frank van der Linden
2019-09-02 20:34 ` [RFC PATCH 32/35] xattr: add a function to check if a namespace is supported Frank van der Linden
2019-09-02 21:30 ` [RFC PATCH 33/35] nfsd: add fattr support for user extended attributes Frank van der Linden
2019-09-02 23:06 ` [RFC PATCH 34/35] nfsd: add export flag to disable " Frank van der Linden
2019-09-02 23:17 ` [RFC PATCH 35/35] nfsd: add NFSD_V4_XATTR config option Frank van der Linden
2019-10-24 20:16 ` [RFC PATCH 00/35] user xattr support (RFC8276) Chuck Lever
2019-10-24 23:15   ` Frank van der Linden
2019-10-25 19:55     ` Chuck Lever
2019-11-04  3:01       ` bfields
2019-11-04 15:36         ` Chuck Lever
2019-11-04 16:21           ` Frank van der Linden
2019-11-04 22:58             ` Bruce Fields
2019-11-05  0:06               ` Frank van der Linden
2019-11-05 15:44               ` Chuck Lever

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=7c77f897843ccdc150550926bc9e6cd5290dfc8e.1568309119.git.fllinden@amazon.com \
    --to=fllinden@amazon.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-nfs@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-NFS Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-nfs/0 linux-nfs/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-nfs linux-nfs/ https://lore.kernel.org/linux-nfs \
		linux-nfs@vger.kernel.org
	public-inbox-index linux-nfs

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-nfs


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git