From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
RFC3530 notes that the 'dircount' field may be zero, in which case the
recommendation is to ignore it, and only enforce the 'maxcount' field.
In RFC5661, this recommendation to ignore a zero valued field becomes a
requirement.
Fixes: aee377644146 ("nfsd4: fix rd_dircount enforcement")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
fs/nfsd/nfs4xdr.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 7abeccb975b2..cf030ebe2827 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3544,15 +3544,18 @@ nfsd4_encode_dirent(void *ccdv, const char *name, int namlen,
goto fail;
cd->rd_maxcount -= entry_bytes;
/*
- * RFC 3530 14.2.24 describes rd_dircount as only a "hint", so
- * let's always let through the first entry, at least:
+ * RFC 3530 14.2.24 describes rd_dircount as only a "hint", and
+ * notes that it could be zero. If it is zero, then the server
+ * should enforce only the rd_maxcount value.
*/
- if (!cd->rd_dircount)
- goto fail;
- name_and_cookie = 4 + 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);
+ if (cd->rd_dircount) {
+ name_and_cookie = 4 + 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);
+ if (!cd->rd_dircount)
+ cd->rd_maxcount = 0;
+ }
cd->cookie_offset = cookie_offset;
skip_entry:
--
2.31.1
