From: Chuck Lever Date: Thu, 1 Sep 2022 19:10:05 +0000 (-0400) Subject: NFSD: Protect against send buffer overflow in NFSv2 READDIR X-Git-Tag: v6.6.17~6123^2~51 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=00b4492686e0497fdb924a9d4c8f6f99377e176c;p=platform%2Fkernel%2Flinux-rpi.git NFSD: Protect against send buffer overflow in NFSv2 READDIR 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 Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever --- diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index 7381972..ddb1902 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -567,12 +567,11 @@ 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++;