From d71621f64d850a53d8f2e4b3d51392b9f63654e9 Mon Sep 17 00:00:00 2001 From: djm Date: Fri, 12 Aug 2022 05:20:28 +0000 Subject: [PATCH] sftp-server: support home-directory request Add support to the sftp-server for the home-directory extension defined in draft-ietf-secsh-filexfer-extensions-00. This overlaps a bit with the existing expand-path@openssh.com, but uses a more official protocol name, and so is a bit more likely to be implemented by non-OpenSSH clients. From Mike Frysinger, ok dtucker@ --- usr.bin/ssh/PROTOCOL | 22 +++++++++++++++++++++- usr.bin/ssh/sftp-server.c | 31 ++++++++++++++++++++++++++++++- 2 files changed, 51 insertions(+), 2 deletions(-) diff --git a/usr.bin/ssh/PROTOCOL b/usr.bin/ssh/PROTOCOL index 424ae5c7e80..f27073d24dc 100644 --- a/usr.bin/ssh/PROTOCOL +++ b/usr.bin/ssh/PROTOCOL @@ -615,6 +615,26 @@ This request is identical to the "copy-data" request documented in: https://tools.ietf.org/html/draft-ietf-secsh-filexfer-extensions-00#section-7 +4.11. sftp: Extension request "home-directory" + +This request asks the server to expand the specified user's home directory. +An empty username implies the current user. This can be used by the client +to expand ~/ type paths locally. + + byte SSH_FXP_EXTENDED + uint32 id + string "home-directory" + string username + +This extension is advertised in the SSH_FXP_VERSION hello with version +"1". + +This provides similar information as the "expand-path@openssh.com" extension. + +This request is identical to the "home-directory" request documented in: + +https://datatracker.ietf.org/doc/html/draft-ietf-secsh-filexfer-extensions-00#section-5 + 5. Miscellaneous changes 5.1 Public key format @@ -651,4 +671,4 @@ master instance and later clients. OpenSSH extends the usual agent protocol. These changes are documented in the PROTOCOL.agent file. -$OpenBSD: PROTOCOL,v 1.45 2022/04/08 05:43:39 dtucker Exp $ +$OpenBSD: PROTOCOL,v 1.46 2022/08/12 05:20:28 djm Exp $ diff --git a/usr.bin/ssh/sftp-server.c b/usr.bin/ssh/sftp-server.c index b8cddb42acc..22f3e9964c4 100644 --- a/usr.bin/ssh/sftp-server.c +++ b/usr.bin/ssh/sftp-server.c @@ -1,4 +1,4 @@ -/* $OpenBSD: sftp-server.c,v 1.140 2022/03/31 03:05:49 djm Exp $ */ +/* $OpenBSD: sftp-server.c,v 1.141 2022/08/12 05:20:28 djm Exp $ */ /* * Copyright (c) 2000-2004 Markus Friedl. All rights reserved. * @@ -111,6 +111,7 @@ static void process_extended_lsetstat(u_int32_t id); static void process_extended_limits(u_int32_t id); static void process_extended_expand(u_int32_t id); static void process_extended_copy_data(u_int32_t id); +static void process_extended_home_directory(u_int32_t id); static void process_extended(u_int32_t id); struct sftp_handler { @@ -157,6 +158,8 @@ static const struct sftp_handler extended_handlers[] = { { "expand-path", "expand-path@openssh.com", 0, process_extended_expand, 0 }, { "copy-data", "copy-data", 0, process_extended_copy_data, 1 }, + { "home-directory", "home-directory", 0, + process_extended_home_directory, 0 }, { NULL, NULL, 0, NULL, 0 } }; @@ -714,6 +717,7 @@ process_init(void) compose_extension(msg, "limits@openssh.com", "1"); compose_extension(msg, "expand-path@openssh.com", "1"); compose_extension(msg, "copy-data", "1"); + compose_extension(msg, "home-directory", "1"); send_msg(msg); sshbuf_free(msg); @@ -1651,6 +1655,31 @@ process_extended_copy_data(u_int32_t id) send_status(id, status); } +static void +process_extended_home_directory(u_int32_t id) +{ + char *username; + struct passwd *user_pw; + int r; + Stat s; + + if ((r = sshbuf_get_cstring(iqueue, &username, NULL)) != 0) + fatal_fr(r, "parse"); + + debug3("request %u: home-directory \"%s\"", id, username); + if ((user_pw = getpwnam(username)) == NULL) { + send_status(id, errno_to_portable(errno)); + goto out; + } + + verbose("home-directory \"%s\"", pw->pw_dir); + attrib_clear(&s.attrib); + s.name = s.long_name = pw->pw_dir; + send_names(id, 1, &s); + out: + free(username); +} + static void process_extended(u_int32_t id) { -- 2.20.1