upstream: Add "-h" flag to sftp chown/chgrp/chmod commands to

request they do not follow symlinks. Requires recently-committed
lsetstat@openssh.com extension on the server side.

ok markus@ dtucker@

OpenBSD-Commit-ID: f93bb3f6f7eb2fb7ef1e59126e72714f1626d604

4 files changed, 103 insertions, 18 deletions

diff --git a/sftp-client.c b/sftp-client.c
index 4986d6d8d..d3f80e5a0 100644
--- a/sftp-client.c
+++ b/sftp-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-client.c,v 1.130 2018/07/31 03:07:24 djm Exp $ */
+/* $OpenBSD: sftp-client.c,v 1.131 2019/01/16 23:23:45 djm Exp $ */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -86,6 +86,7 @@ struct sftp_conn {
 #define SFTP_EXT_FSTATVFS       0x00000004
 #define SFTP_EXT_HARDLINK       0x00000008
 #define SFTP_EXT_FSYNC          0x00000010
+#define SFTP_EXT_LSETSTAT       0x00000020
         u_int exts;
         u_int64_t limit_kbps;
         struct bwlimit bwlimit_in, bwlimit_out;
@@ -463,6 +464,10 @@ do_init(int fd_in, int fd_out, u_int transfer_buflen, u_int num_requests,
                     strcmp((char *)value, "1") == 0) {
                         ret->exts |= SFTP_EXT_FSYNC;
                         known = 1;
+                } else if (strcmp(name, "lsetstat@openssh.com") == 0 &&
+                    strcmp((char *)value, "1") == 0) {
+                        ret->exts |= SFTP_EXT_LSETSTAT;
+                        known = 1;
                 }
                 if (known) {
                         debug2("Server supports extension \"%s\" revision %s",
@@ -1096,7 +1101,6 @@ do_statvfs(struct sftp_conn *conn, const char *path, struct sftp_statvfs *st,
 
         if ((msg = sshbuf_new()) == NULL)
                 fatal("%s: sshbuf_new failed", __func__);
-        sshbuf_reset(msg);
         if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED)) != 0 ||
             (r = sshbuf_put_u32(msg, id)) != 0 ||
             (r = sshbuf_put_cstring(msg, "statvfs@openssh.com")) != 0 ||
@@ -1125,7 +1129,6 @@ do_fstatvfs(struct sftp_conn *conn, const u_char *handle, u_int handle_len,
 
         if ((msg = sshbuf_new()) == NULL)
                 fatal("%s: sshbuf_new failed", __func__);
-        sshbuf_reset(msg);
         if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED)) != 0 ||
             (r = sshbuf_put_u32(msg, id)) != 0 ||
             (r = sshbuf_put_cstring(msg, "fstatvfs@openssh.com")) != 0 ||
@@ -1138,6 +1141,38 @@ do_fstatvfs(struct sftp_conn *conn, const u_char *handle, u_int handle_len,
 }
 #endif
 
+int
+do_lsetstat(struct sftp_conn *conn, const char *path, Attrib *a)
+{
+        struct sshbuf *msg;
+        u_int status, id;
+        int r;
+
+        if ((conn->exts & SFTP_EXT_LSETSTAT) == 0) {
+                error("Server does not support lsetstat@openssh.com extension");
+                return -1;
+        }
+
+        id = conn->msg_id++;
+        if ((msg = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
+        if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED)) != 0 ||
+            (r = sshbuf_put_u32(msg, id)) != 0 ||
+            (r = sshbuf_put_cstring(msg, "lsetstat@openssh.com")) != 0 ||
+            (r = sshbuf_put_cstring(msg, path)) != 0 ||
+            (r = encode_attrib(msg, a)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
+        send_msg(conn, msg);
+        sshbuf_free(msg);
+
+        status = get_status(conn, id);
+        if (status != SSH2_FX_OK)
+                error("Couldn't setstat on \"%s\": %s", path,
+                    fx2txt(status));
+
+        return status == SSH2_FX_OK ? 0 : -1;
+}
+
 static void
 send_read_request(struct sftp_conn *conn, u_int id, u_int64_t offset,
     u_int len, const u_char *handle, u_int handle_len)
@@ -1147,7 +1182,6 @@ send_read_request(struct sftp_conn *conn, u_int id, u_int64_t offset,
 
         if ((msg = sshbuf_new()) == NULL)
                 fatal("%s: sshbuf_new failed", __func__);
-        sshbuf_reset(msg);
         if ((r = sshbuf_put_u8(msg, SSH2_FXP_READ)) != 0 ||
             (r = sshbuf_put_u32(msg, id)) != 0 ||
             (r = sshbuf_put_string(msg, handle, handle_len)) != 0 ||
diff --git a/sftp-client.h b/sftp-client.h
index 14a3b8182..63a9b8b13 100644
--- a/sftp-client.h
+++ b/sftp-client.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-client.h,v 1.27 2015/05/08 06:45:13 djm Exp $ */
+/* $OpenBSD: sftp-client.h,v 1.28 2019/01/16 23:23:45 djm Exp $ */
 
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
@@ -91,6 +91,9 @@ int do_setstat(struct sftp_conn *, const char *, Attrib *);
 /* Set file attributes of open file 'handle' */
 int do_fsetstat(struct sftp_conn *, const u_char *, u_int, Attrib *);
 
+/* Set file attributes of 'path', not following symlinks */
+int do_lsetstat(struct sftp_conn *conn, const char *path, Attrib *a);
+
 /* Canonicalise 'path' - caller must free result */
 char *do_realpath(struct sftp_conn *, const char *);
 
diff --git a/sftp.1 b/sftp.1
index 7140bc19b..722a34419 100644
--- a/sftp.1
+++ b/sftp.1
@@ -1,4 +1,4 @@
-.\" $OpenBSD: sftp.1,v 1.122 2018/11/16 02:30:20 djm Exp $
+.\" $OpenBSD: sftp.1,v 1.123 2019/01/16 23:23:45 djm Exp $
 .\"
 .\" Copyright (c) 2001 Damien Miller.  All rights reserved.
 .\"
@@ -22,7 +22,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: November 16 2018 $
+.Dd $Mdocdate: January 16 2019 $
 .Dt SFTP 1
 .Os
 .Sh NAME
@@ -316,31 +316,52 @@ Change remote directory to
 If
 .Ar path
 is not specified, then change directory to the one the session started in.
-.It Ic chgrp Ar grp Ar path
+.It Xo Ic chgrp
+.Op Fl h
+.Ar grp
+.Ar path
+.Xc
 Change group of file
 .Ar path
 to
 .Ar grp .
+If the
+.Fl h
+flag is specified, then symlinks will not be followed.
 .Ar path
 may contain
 .Xr glob 7
 characters and may match multiple files.
 .Ar grp
 must be a numeric GID.
-.It Ic chmod Ar mode Ar path
+.It Xo Ic chmod
+.Op Fl h
+.Ar mode
+.Ar path
+.Xc
 Change permissions of file
 .Ar path
 to
 .Ar mode .
+If the
+.Fl h
+flag is specified, then symlinks will not be followed.
 .Ar path
 may contain
 .Xr glob 7
 characters and may match multiple files.
-.It Ic chown Ar own Ar path
+.It Xo Ic chown
+.Op Fl h
+.Ar own
+.Ar path
+.Xc
 Change owner of file
 .Ar path
 to
 .Ar own .
+If the
+.Fl h
+flag is specified, then symlinks will not be followed.
 .Ar path
 may contain
 .Xr glob 7
diff --git a/sftp.c b/sftp.c
index f886b330b..0f3f89d33 100644
--- a/sftp.c
+++ b/sftp.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp.c,v 1.188 2018/11/16 03:26:01 djm Exp $ */
+/* $OpenBSD: sftp.c,v 1.189 2019/01/16 23:23:45 djm Exp $ */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -278,9 +278,9 @@ help(void)
         printf("Available commands:\n"
             "bye                                Quit sftp\n"
             "cd path                            Change remote directory to 'path'\n"
-            "chgrp grp path                     Change group of file 'path' to 'grp'\n"
-            "chmod mode path                    Change permissions of file 'path' to 'mode'\n"
-            "chown own path                     Change owner of file 'path' to 'own'\n"
+            "chgrp [-h] grp path                Change group of file 'path' to 'grp'\n"
+            "chmod [-h] mode path               Change permissions of file 'path' to 'mode'\n"
+            "chown [-h] own path                Change owner of file 'path' to 'own'\n"
             "df [-hi] [path]                    Display statistics for current directory or\n"
             "                                   filesystem containing 'path'\n"
             "exit                               Quit sftp\n"
@@ -562,6 +562,30 @@ parse_df_flags(const char *cmd, char **argv, int argc, int *hflag, int *iflag)
 }
 
 static int
+parse_ch_flags(const char *cmd, char **argv, int argc, int *hflag)
+{
+        extern int opterr, optind, optopt, optreset;
+        int ch;
+
+        optind = optreset = 1;
+        opterr = 0;
+
+        *hflag = 0;
+        while ((ch = getopt(argc, argv, "h")) != -1) {
+                switch (ch) {
+                case 'h':
+                        *hflag = 1;
+                        break;
+                default:
+                        error("%s: Invalid flag -%c", cmd, optopt);
+                        return -1;
+                }
+        }
+
+        return optind;
+}
+
+static int
 parse_no_flags(const char *cmd, char **argv, int argc)
 {
         extern int opterr, optind, optopt, optreset;
@@ -1456,7 +1480,7 @@ parse_args(const char **cpp, int *ignore_errors, int *disable_echo, int *aflag,
                 /* FALLTHROUGH */
         case I_CHOWN:
         case I_CHGRP:
-                if ((optidx = parse_no_flags(cmd, argv, argc)) == -1)
+                if ((optidx = parse_ch_flags(cmd, argv, argc, hflag)) == -1)
                         return -1;
                 /* Get numeric arg (mandatory) */
                 if (argc - optidx < 1)
@@ -1675,7 +1699,8 @@ parse_dispatch_command(struct sftp_conn *conn, const char *cmd, char **pwd,
                         if (!quiet)
                                 mprintf("Changing mode on %s\n",
                                     g.gl_pathv[i]);
-                        err = do_setstat(conn, g.gl_pathv[i], &a);
+                        err = (hflag ? do_lsetstat : do_setstat)(conn,
+                            g.gl_pathv[i], &a);
                         if (err != 0 && err_abort)
                                 break;
                 }
@@ -1685,7 +1710,8 @@ parse_dispatch_command(struct sftp_conn *conn, const char *cmd, char **pwd,
                 path1 = make_absolute(path1, *pwd);
                 remote_glob(conn, path1, GLOB_NOCHECK, NULL, &g);
                 for (i = 0; g.gl_pathv[i] && !interrupted; i++) {
-                        if (!(aa = do_stat(conn, g.gl_pathv[i], 0))) {
+                        if (!(aa = (hflag ? do_lstat : do_stat)(conn,
+                            g.gl_pathv[i], 0))) {
                                 if (err_abort) {
                                         err = -1;
                                         break;
@@ -1713,7 +1739,8 @@ parse_dispatch_command(struct sftp_conn *conn, const char *cmd, char **pwd,
                                             g.gl_pathv[i]);
                                 aa->gid = n_arg;
                         }
-                        err = do_setstat(conn, g.gl_pathv[i], aa);
+                        err = (hflag ? do_lsetstat : do_setstat)(conn,
+                            g.gl_pathv[i], aa);
                         if (err != 0 && err_abort)
                                 break;
                 }