RT2547: Tighten perms on generated privkey files

When generating a private key, try to make the output file be readable
only by the owner.  Put it in CHANGES file since it might be noticeable.

Add "int private" flag to apps that write private keys, and check that it's
set whenever we do write a private key.  Checked via assert so that this
bug (security-related) gets fixed.  Thanks to Viktor for help in tracing
the code-paths where private keys are written.

Reviewed-by: Viktor Dukhovni <viktor@openssl.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/apps/pkey.c b/apps/pkey.c
index 875087fd18..80c2e154dd 100644
--- a/apps/pkey.c
+++ b/apps/pkey.c
@@ -101,6 +101,7 @@ int pkey_main(int argc, char **argv)
     OPTION_CHOICE o;
     int informat = FORMAT_PEM, outformat = FORMAT_PEM;
     int pubin = 0, pubout = 0, pubtext = 0, text = 0, noout = 0, ret = 1;
+    int private = 0;
 
     prog = opt_init(argc, argv, pkey_options);
     while ((o = opt_next()) != OPT_EOF) {
@@ -159,6 +160,9 @@ int pkey_main(int argc, char **argv)
     }
     argc = opt_num_rest();
     argv = opt_rest();
+    private = !noout && !pubout ? 1 : 0;
+    if (text && !pubtext)
+        private = 1;
 
     if (!app_passwd(passinarg, passoutarg, &passin, &passout)) {
         BIO_printf(bio_err, "Error getting passwords\n");
@@ -168,7 +172,7 @@ int pkey_main(int argc, char **argv)
     if (!app_load_modules(NULL))
         goto end;
 
-    out = bio_open_default(outfile, "wb");
+    out = bio_open_owner(outfile, "wb", private);
     if (out == NULL)
         goto end;
 
@@ -181,12 +185,14 @@ int pkey_main(int argc, char **argv)
 
     if (!noout) {
         if (outformat == FORMAT_PEM) {
+            assert(private);
             if (pubout)
                 PEM_write_bio_PUBKEY(out, pkey);
             else
                 PEM_write_bio_PrivateKey(out, pkey, cipher,
                                          NULL, 0, NULL, passout);
         } else if (outformat == FORMAT_ASN1) {
+            assert(private);
             if (pubout)
                 i2d_PUBKEY_bio(out, pkey);
             else
@@ -201,8 +207,10 @@ int pkey_main(int argc, char **argv)
     if (text) {
         if (pubtext)
             EVP_PKEY_print_public(out, pkey, 0, NULL);
-        else
+        else {
+            assert(private);
             EVP_PKEY_print_private(out, pkey, 0, NULL);
+        }
     }
 
     ret = 0;