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Commit aee37764 authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

nfsd4: fix rd_dircount enforcement 



Commit 3b299709 "nfsd4: enforce rd_dircount" totally misunderstood
rd_dircount; it refers to total non-attribute bytes returned, not number
of directory entries returned.

Bring the code into agreement with RFC 3530 section 14.2.24.

Cc: stable@vger.kernel.org
Fixes: 3b299709 "nfsd4: enforce rd_dircount"
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 7d1311b9

fs/nfsd/nfs4xdr.c

+13 −1
Original line number Diff line number Diff line
@@ -2657,6 +2657,7 @@ nfsd4_encode_dirent(void *ccdv, const char *name, int namlen, 
	struct xdr_stream *xdr = cd->xdr;

	int start_offset = xdr->buf->len;

	int cookie_offset;

	u32 name_and_cookie;

	int entry_bytes;

	__be32 nfserr = nfserr_toosmall;

	__be64 wire_offset;
@@ -2718,7 +2719,14 @@ nfsd4_encode_dirent(void *ccdv, const char *name, int namlen, 
	cd->rd_maxcount -= entry_bytes;

	if (!cd->rd_dircount)

		goto fail;

	cd->rd_dircount--;

	/*

	 * RFC 3530 14.2.24 describes rd_dircount as only a "hint", so

	 * let's always let through the first entry, at least:

	 */

	name_and_cookie = 4 * XDR_QUADLEN(namlen) + 8;

	if (name_and_cookie > cd->rd_dircount && cd->cookie_offset)

		goto fail;

	cd->rd_dircount -= min(cd->rd_dircount, name_and_cookie);

	cd->cookie_offset = cookie_offset;

skip_entry:

	cd->common.err = nfs_ok;
@@ -3321,6 +3329,10 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4 
	}

	maxcount = min_t(int, maxcount-16, bytes_left);



	/* RFC 3530 14.2.24 allows us to ignore dircount when it's 0: */

	if (!readdir->rd_dircount)

		readdir->rd_dircount = INT_MAX;



	readdir->xdr = xdr;

	readdir->rd_maxcount = maxcount;

	readdir->common.err = 0;