upstream commit
When generating all hostkeys (ssh-keygen -A), clobber
existing keys if they exist but are zero length. zero-length keys could
previously be made if ssh-keygen failed part way through generating them, so
avoid that case too. bz#2561 reported by Krzysztof Cieplucha; ok dtucker@
Upstream-ID: f662201c28ab8e1f086b5d43c59cddab5ade4044
diff --git a/ssh-keygen.c b/ssh-keygen.c
index d8f942f..835f7d0 100644
--- a/ssh-keygen.c
+++ b/ssh-keygen.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-keygen.c,v 1.306 2017/07/01 13:50:45 djm Exp $ */
+/* $OpenBSD: ssh-keygen.c,v 1.307 2017/07/07 03:53:12 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -997,20 +997,38 @@
int first = 0;
struct stat st;
struct sshkey *private, *public;
- char comment[1024];
+ char comment[1024], *prv_tmp, *pub_tmp, *prv_file, *pub_file;
int i, type, fd, r;
FILE *f;
for (i = 0; key_types[i].key_type; i++) {
- if (stat(key_types[i].path, &st) == 0)
- continue;
- if (errno != ENOENT) {
+ public = private = NULL;
+ prv_tmp = pub_tmp = prv_file = pub_file = NULL;
+
+ xasprintf(&prv_file, "%s%s",
+ identity_file, key_types[i].path);
+
+ /* Check whether private key exists and is not zero-length */
+ if (stat(prv_file, &st) == 0) {
+ if (st.st_size != 0)
+ goto next;
+ } else if (errno != ENOENT) {
error("Could not stat %s: %s", key_types[i].path,
strerror(errno));
- first = 0;
- continue;
+ goto failnext;
}
+ /*
+ * Private key doesn't exist or is invalid; proceed with
+ * key generation.
+ */
+ xasprintf(&prv_tmp, "%s%s.XXXXXXXXXX",
+ identity_file, key_types[i].path);
+ xasprintf(&pub_tmp, "%s%s.pub.XXXXXXXXXX",
+ identity_file, key_types[i].path);
+ xasprintf(&pub_file, "%s%s.pub",
+ identity_file, key_types[i].path);
+
if (first == 0) {
first = 1;
printf("%s: generating new host keys: ", __progname);
@@ -1018,56 +1036,76 @@
printf("%s ", key_types[i].key_type_display);
fflush(stdout);
type = sshkey_type_from_name(key_types[i].key_type);
- strlcpy(identity_file, key_types[i].path, sizeof(identity_file));
+ if ((fd = mkstemp(prv_tmp)) == -1) {
+ error("Could not save your public key in %s: %s",
+ prv_tmp, strerror(errno));
+ goto failnext;
+ }
+ close(fd); /* just using mkstemp() to generate/reserve a name */
bits = 0;
type_bits_valid(type, NULL, &bits);
if ((r = sshkey_generate(type, bits, &private)) != 0) {
error("sshkey_generate failed: %s", ssh_err(r));
- first = 0;
- continue;
+ goto failnext;
}
if ((r = sshkey_from_private(private, &public)) != 0)
fatal("sshkey_from_private failed: %s", ssh_err(r));
snprintf(comment, sizeof comment, "%s@%s", pw->pw_name,
hostname);
- if ((r = sshkey_save_private(private, identity_file, "",
+ if ((r = sshkey_save_private(private, prv_tmp, "",
comment, use_new_format, new_format_cipher, rounds)) != 0) {
error("Saving key \"%s\" failed: %s",
- identity_file, ssh_err(r));
- sshkey_free(private);
- sshkey_free(public);
- first = 0;
- continue;
+ prv_tmp, ssh_err(r));
+ goto failnext;
}
- sshkey_free(private);
- strlcat(identity_file, ".pub", sizeof(identity_file));
- fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
- if (fd == -1) {
- error("Could not save your public key in %s",
- identity_file);
- sshkey_free(public);
- first = 0;
- continue;
+ if ((fd = mkstemp(pub_tmp)) == -1) {
+ error("Could not save your public key in %s: %s",
+ pub_tmp, strerror(errno));
+ goto failnext;
}
+ (void)fchmod(fd, 0644);
f = fdopen(fd, "w");
if (f == NULL) {
- error("fdopen %s failed", identity_file);
+ error("fdopen %s failed: %s", pub_tmp, strerror(errno));
close(fd);
- sshkey_free(public);
- first = 0;
- continue;
+ goto failnext;
}
if ((r = sshkey_write(public, f)) != 0) {
error("write key failed: %s", ssh_err(r));
fclose(f);
- sshkey_free(public);
- first = 0;
- continue;
+ goto failnext;
}
fprintf(f, " %s\n", comment);
- fclose(f);
- sshkey_free(public);
+ if (ferror(f) != 0) {
+ error("write key failed: %s", strerror(errno));
+ fclose(f);
+ goto failnext;
+ }
+ if (fclose(f) != 0) {
+ error("key close failed: %s", strerror(errno));
+ goto failnext;
+ }
+ /* Rename temporary files to their permanent locations. */
+ if (rename(pub_tmp, pub_file) != 0) {
+ error("Unable to move %s into position: %s",
+ pub_file, strerror(errno));
+ goto failnext;
+ }
+ if (rename(prv_tmp, prv_file) != 0) {
+ error("Unable to move %s into position: %s",
+ key_types[i].path, strerror(errno));
+ failnext:
+ first = 0;
+ goto next;
+ }
+ next:
+ sshkey_free(private);
+ sshkey_free(public);
+ free(prv_tmp);
+ free(pub_tmp);
+ free(prv_file);
+ free(pub_file);
}
if (first != 0)
printf("\n");