From 358b2b131ad6c095696f20dcfa62b8305263f898 Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Tue, 1 Aug 2017 17:16:46 +0200 Subject: [PATCH] tftp: reject file name lengths that don't fit ... and thereby avoid telling send() to send off more bytes than the size of the buffer! CVE-2017-1000100 Bug: https://curl.haxx.se/docs/adv_20170809B.html Reported-by: Even Rouault Credit to OSS-Fuzz for the discovery --- lib/tftp.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/lib/tftp.c +++ b/lib/tftp.c @@ -5,7 +5,7 @@ * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * - * Copyright (C) 1998 - 2016, Daniel Stenberg, , et al. + * Copyright (C) 1998 - 2017, Daniel Stenberg, , et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms @@ -490,6 +490,11 @@ static CURLcode tftp_send_first(tftp_sta if(result) return result; + if(strlen(filename) > (state->blksize - strlen(mode) - 4)) { + failf(data, "TFTP file name too long\n"); + return CURLE_TFTP_ILLEGAL; /* too long file name field */ + } + snprintf((char *)state->spacket.data+2, state->blksize, "%s%c%s%c", filename, '\0', mode, '\0');