upstream commit
Have sftp print a warning about shell cleanliness when
decoding the first packet fails, which is usually caused by shells polluting
stdout of non-interactive starups. bz#2800, ok markus@ deraadt@.
OpenBSD-Commit-ID: 88d6a9bf3470f9324b76ba1cbd53e50120f685b5
diff --git a/sftp-client.c b/sftp-client.c
index 6263302..0b53a2e 100644
--- a/sftp-client.c
+++ b/sftp-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-client.c,v 1.127 2017/08/11 04:41:08 djm Exp $ */
+/* $OpenBSD: sftp-client.c,v 1.128 2017/11/28 21:10:22 dtucker Exp $ */
/*
* Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
*
@@ -130,7 +130,7 @@
}
static void
-get_msg(struct sftp_conn *conn, struct sshbuf *m)
+get_msg_extended(struct sftp_conn *conn, struct sshbuf *m, int initial)
{
u_int msg_len;
u_char *p;
@@ -148,8 +148,12 @@
if ((r = sshbuf_get_u32(m, &msg_len)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
- if (msg_len > SFTP_MAX_MSG_LENGTH)
- fatal("Received message too long %u", msg_len);
+ if (msg_len > SFTP_MAX_MSG_LENGTH) {
+ do_log2(initial ? SYSLOG_LEVEL_ERROR : SYSLOG_LEVEL_FATAL,
+ "Received message too long %u", msg_len);
+ fatal("Ensure the remote shell produces no output "
+ "for non-interactive sessions.");
+ }
if ((r = sshbuf_reserve(m, msg_len, &p)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
@@ -164,6 +168,12 @@
}
static void
+get_msg(struct sftp_conn *conn, struct sshbuf *m)
+{
+ get_msg_extended(conn, m, 0);
+}
+
+static void
send_string_request(struct sftp_conn *conn, u_int id, u_int code, const char *s,
u_int len)
{
@@ -406,7 +416,7 @@
sshbuf_reset(msg);
- get_msg(ret, msg);
+ get_msg_extended(ret, msg, 1);
/* Expecting a VERSION reply */
if ((r = sshbuf_get_u8(msg, &type)) != 0)