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nfsd4: fix rd_dircount enforcement 

Commit 3b29970909 "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: 3b29970909 "nfsd4: enforce rd_dircount"
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields 2014-08-20 14:49:50 -04:00
parent 7d1311b93e
commit aee3776441
1 changed files with 13 additions and 1 deletions
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14
fs/nfsd/nfs4xdr.c
View File

@ -2657,6 +2657,7 @@ nfsd4_encode_dirent(void *ccdv, const char *name, int namlen,
struct xdr_stream *xdr = cd->xdr; struct xdr_stream *xdr = cd->xdr;
int start_offset = xdr->buf->len; int start_offset = xdr->buf->len;
int cookie_offset; int cookie_offset;
u32 name_and_cookie;
int entry_bytes; int entry_bytes;
__be32 nfserr = nfserr_toosmall; __be32 nfserr = nfserr_toosmall;
__be64 wire_offset; __be64 wire_offset;
@ -2718,7 +2719,14 @@ nfsd4_encode_dirent(void *ccdv, const char *name, int namlen,
cd->rd_maxcount -= entry_bytes; cd->rd_maxcount -= entry_bytes;
if (!cd->rd_dircount) if (!cd->rd_dircount)
goto fail; 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; cd->cookie_offset = cookie_offset;
skip_entry: skip_entry:
cd->common.err = nfs_ok; 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); 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->xdr = xdr;
readdir->rd_maxcount = maxcount; readdir->rd_maxcount = maxcount;
readdir->common.err = 0; readdir->common.err = 0;