From 9f231af307b80eb222d9761bbd81fa4e130bb3d7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Dag-Erling=20Sm=C3=B8rgrav?= Date: Thu, 25 Apr 2024 20:35:28 +0200 Subject: tftpd: Immediately reject any request shorter than 4 bytes. MFC after: 1 week Sponsored by: Klara, Inc. Reviewed by: kevans Differential Revision: https://reviews.freebsd.org/D44957 --- libexec/tftpd/tests/functional.c | 19 +++++++++++++++++++ libexec/tftpd/tftpd.c | 5 +++++ 2 files changed, 24 insertions(+) (limited to 'libexec') diff --git a/libexec/tftpd/tests/functional.c b/libexec/tftpd/tests/functional.c index 3b70962854ba..d3d2f46ffdee 100644 --- a/libexec/tftpd/tests/functional.c +++ b/libexec/tftpd/tests/functional.c @@ -1219,6 +1219,22 @@ TFTPD_TC_DEFINE(wrq_window_rfc7440,) require_bufeq(contents, sizeof(contents), buffer, (size_t)r); } +/* + * Send less than four bytes + */ +TFTPD_TC_DEFINE(short_packet1, /* no head */, exitcode = 1) +{ + SEND_STR("\1"); +} +TFTPD_TC_DEFINE(short_packet2, /* no head */, exitcode = 1) +{ + SEND_STR("\1\2"); +} +TFTPD_TC_DEFINE(short_packet3, /* no head */, exitcode = 1) +{ + SEND_STR("\1\2\3"); +} + /* * Main @@ -1256,6 +1272,9 @@ ATF_TP_ADD_TCS(tp) TFTPD_TC_ADD(tp, wrq_small); TFTPD_TC_ADD(tp, wrq_truncate); TFTPD_TC_ADD(tp, wrq_window_rfc7440); + TFTPD_TC_ADD(tp, short_packet1); + TFTPD_TC_ADD(tp, short_packet2); + TFTPD_TC_ADD(tp, short_packet3); return (atf_no_error()); } diff --git a/libexec/tftpd/tftpd.c b/libexec/tftpd/tftpd.c index 45e7344c86ed..13f53024b147 100644 --- a/libexec/tftpd/tftpd.c +++ b/libexec/tftpd/tftpd.c @@ -228,6 +228,11 @@ main(int argc, char *argv[]) } getnameinfo((struct sockaddr *)&peer_sock, peer_sock.ss_len, peername, sizeof(peername), NULL, 0, NI_NUMERICHOST); + if ((size_t)n < 4 /* tftphdr */) { + tftp_log(LOG_ERR, "Rejecting %zd-byte request from %s", + n, peername); + exit(1); + } /* * Now that we have read the message out of the UDP -- cgit v1.2.3