From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit 00b4492686e0497fdb924a9d4c8f6f99377e176c ]
Restore the previous limit on the @count argument to prevent a buffer overflow attack.
Fixes: 53b1119a6e50 ("NFSD: Fix READDIR buffer overflow") Signed-off-by: Chuck Lever chuck.lever@oracle.com Reviewed-by: Jeff Layton jlayton@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/nfsproc.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index 16cde315f454..f65eba938a57 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -557,12 +557,11 @@ static void nfsd_init_dirlist_pages(struct svc_rqst *rqstp, struct xdr_buf *buf = &resp->dirlist; struct xdr_stream *xdr = &resp->xdr;
- count = clamp(count, (u32)(XDR_UNIT * 2), svc_max_payload(rqstp)); - memset(buf, 0, sizeof(*buf));
/* Reserve room for the NULL ptr & eof flag (-2 words) */ - buf->buflen = count - XDR_UNIT * 2; + buf->buflen = clamp(count, (u32)(XDR_UNIT * 2), (u32)PAGE_SIZE); + buf->buflen -= XDR_UNIT * 2; buf->pages = rqstp->rq_next_page; rqstp->rq_next_page++;