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| author | Trond Myklebust <trond.myklebust@hammerspace.com> | 2021-09-30 15:44:41 -0400 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2021-09-30 16:53:17 -0400 |
| commit | f2e717d655040d632c9015f19aa4275f8b16e7f2 (patch) | |
| tree | e94de61245fb6108c742ca1ba6fca97e81605c41 /fs/nfsd/nfs4xdr.c | |
| parent | 1d625050c7c2dd877e108e382b8aaf1ae3cfe1f4 (diff) | |
| download | lwn-f2e717d655040d632c9015f19aa4275f8b16e7f2.tar.gz lwn-f2e717d655040d632c9015f19aa4275f8b16e7f2.zip | |
nfsd4: Handle the NFSv4 READDIR 'dircount' hint being zero
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@vger.kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs/nfsd/nfs4xdr.c')
| -rw-r--r-- | fs/nfsd/nfs4xdr.c | 19 |
1 files 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: |