Defer creation of ~/.ssh by ssh(1) until we attempt to write to it so we

don't leave an empty .ssh directory when it's not needed.  Use the same
function to replace the code in ssh-keygen that does the same thing.
bz#3156, ok djm@

4 files changed, 40 insertions, 31 deletions

diff --git a/usr.bin/ssh/hostfile.c b/usr.bin/ssh/hostfile.c
index 21917105ef3..2344b509c44 100644
--- a/usr.bin/ssh/hostfile.c
+++ b/usr.bin/ssh/hostfile.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: hostfile.c,v 1.80 2020/05/13 09:52:41 djm Exp $ */
+/* $OpenBSD: hostfile.c,v 1.81 2020/06/26 05:02:03 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -55,6 +55,7 @@
 #include "hostfile.h"
 #include "log.h"
 #include "misc.h"
+#include "pathnames.h"
 #include "ssherr.h"
 #include "digest.h"
 #include "hmac.h"
@@ -448,6 +449,34 @@ write_host_entry(FILE *f, const char *host, const char *ip,
 }
 
 /*
+ * Create user ~/.ssh directory if it doesn't exist and we want to write to it.
+ * If notify is set, a message will be emitted if the directory is created.
+ */
+void
+hostfile_create_user_ssh_dir(const char *filename, int notify)
+{
+	char *dotsshdir = NULL, *p;
+	size_t len;
+	struct stat st;
+
+	if ((p = strrchr(filename, '/')) == NULL)
+		return;
+	len = p - filename;
+	dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid());
+	if ((strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0
+	    || stat(dotsshdir, &st)) == 0)
+		; /* do nothing, path not in ~/.ssh or dir already exists */
+	else if (errno != ENOENT)
+		error("Could not stat %s: %s", dotsshdir, strerror(errno));
+	else if (mkdir(dotsshdir, 0700) == -1)
+		error("Could not create directory '%.200s' (%s).",
+		    dotsshdir, strerror(errno));
+	else if (notify)
+		logit("Created directory '%s'.", dotsshdir);
+	free(dotsshdir);
+}
+
+/*
  * Appends an entry to the host file.  Returns false if the entry could not
  * be appended.
  */
@@ -460,6 +489,7 @@ add_host_to_hostfile(const char *filename, const char *host,
 
 	if (key == NULL)
 		return 1;	/* XXX ? */
+	hostfile_create_user_ssh_dir(filename, 0);
 	f = fopen(filename, "a");
 	if (!f)
 		return 0;
diff --git a/usr.bin/ssh/hostfile.h b/usr.bin/ssh/hostfile.h
index 49fcbb7e883..de8b677e38c 100644
--- a/usr.bin/ssh/hostfile.h
+++ b/usr.bin/ssh/hostfile.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: hostfile.h,v 1.25 2020/05/13 09:52:41 djm Exp $ */
+/* $OpenBSD: hostfile.h,v 1.26 2020/06/26 05:02:03 dtucker Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -106,4 +106,6 @@ typedef int hostkeys_foreach_fn(struct hostkey_foreach_line *l, void *ctx);
 int hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
     const char *host, const char *ip, u_int options);
 
+void hostfile_create_user_ssh_dir(const char *, int);
+
 #endif
diff --git a/usr.bin/ssh/ssh-keygen.c b/usr.bin/ssh/ssh-keygen.c
index c1e307566e3..17866937eaf 100644
--- a/usr.bin/ssh/ssh-keygen.c
+++ b/usr.bin/ssh/ssh-keygen.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-keygen.c,v 1.412 2020/05/29 03:11:54 djm Exp $ */
+/* $OpenBSD: ssh-keygen.c,v 1.413 2020/06/26 05:02:03 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -3060,11 +3060,10 @@ usage(void)
 int
 main(int argc, char **argv)
 {
-	char dotsshdir[PATH_MAX], comment[1024], *passphrase;
+	char comment[1024], *passphrase;
 	char *rr_hostname = NULL, *ep, *fp, *ra;
 	struct sshkey *private, *public;
 	struct passwd *pw;
-	struct stat st;
 	int r, opt, type;
 	int change_passphrase = 0, change_comment = 0, show_cert = 0;
 	int find_host = 0, delete_host = 0, hash_hosts = 0;
@@ -3584,20 +3583,8 @@ main(int argc, char **argv)
 		ask_filename(pw, "Enter file in which to save the key");
 
 	/* Create ~/.ssh directory if it doesn't already exist. */
-	snprintf(dotsshdir, sizeof dotsshdir, "%s/%s",
-	    pw->pw_dir, _PATH_SSH_USER_DIR);
-	if (strstr(identity_file, dotsshdir) != NULL) {
-		if (stat(dotsshdir, &st) == -1) {
-			if (errno != ENOENT) {
-				error("Could not stat %s: %s", dotsshdir,
-				    strerror(errno));
-			} else if (mkdir(dotsshdir, 0700) == -1) {
-				error("Could not create directory '%s': %s",
-				    dotsshdir, strerror(errno));
-			} else if (!quiet)
-				printf("Created directory '%s'.\n", dotsshdir);
-		}
-	}
+	hostfile_create_user_ssh_dir(identity_file, !quiet);
+
 	/* If the file already exists, ask the user to confirm. */
 	if (!confirm_overwrite(identity_file))
 		exit(1);
diff --git a/usr.bin/ssh/ssh.c b/usr.bin/ssh/ssh.c
index c206e996125..3cd24df7600 100644
--- a/usr.bin/ssh/ssh.c
+++ b/usr.bin/ssh/ssh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.529 2020/06/05 03:15:26 dtucker Exp $ */
+/* $OpenBSD: ssh.c,v 1.530 2020/06/26 05:02:03 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -629,7 +629,7 @@ main(int ac, char **av)
 	struct ssh *ssh = NULL;
 	int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
 	int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
-	char *p, *cp, *line, *argv0, buf[PATH_MAX], *logfile;
+	char *p, *cp, *line, *argv0, *logfile;
 	char cname[NI_MAXHOST];
 	struct stat st;
 	struct passwd *pw;
@@ -1551,16 +1551,6 @@ main(int ac, char **av)
 		}
 	}
 
-	/* Create ~/.ssh * directory if it doesn't already exist. */
-	if (config == NULL) {
-		r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
-		    strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
-		if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) == -1)
-			if (mkdir(buf, 0700) == -1)
-				error("Could not create directory '%.200s'.",
-				    buf);
-	}
-
 	/* load options.identity_files */
 	load_public_identity_files(pw);