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, 14 insertions, 5 deletions

diff --git a/apps/ec.c b/apps/ec.c
index 341243ff28..e4f2db39e6 100644
--- a/apps/ec.c
+++ b/apps/ec.c
@@ -121,7 +121,7 @@ int ec_main(int argc, char **argv)
     OPTION_CHOICE o;
     int asn1_flag = OPENSSL_EC_NAMED_CURVE, new_form = 0, new_asn1_flag = 0;
     int informat = FORMAT_PEM, outformat = FORMAT_PEM, text = 0, noout = 0;
-    int pubin = 0, pubout = 0, param_out = 0, i, ret = 1;
+    int pubin = 0, pubout = 0, param_out = 0, i, ret = 1, private = 0;
 
     prog = opt_init(argc, argv, ec_options);
     while ((o = opt_next()) != OPT_EOF) {
@@ -193,6 +193,9 @@ int ec_main(int argc, char **argv)
     }
     argc = opt_num_rest();
     argv = opt_rest();
+    private = param_out || pubin || pubout ? 0 : 1;
+    if (text)
+        private = 1;
 
     if (!app_passwd(passinarg, passoutarg, &passin, &passout)) {
         BIO_printf(bio_err, "Error getting passwords\n");
@@ -224,7 +227,7 @@ int ec_main(int argc, char **argv)
         goto end;
     }
 
-    out = bio_open_default(outfile, WB(outformat));
+    out = bio_open_owner(outfile, WB(outformat), private);
     if (out == NULL)
         goto end;
 
@@ -236,12 +239,14 @@ int ec_main(int argc, char **argv)
     if (new_asn1_flag)
         EC_KEY_set_asn1_flag(eckey, asn1_flag);
 
-    if (text)
+    if (text) {
+        assert(private);
         if (!EC_KEY_print(out, eckey, 0)) {
             perror(outfile);
             ERR_print_errors(bio_err);
             goto end;
         }
+    }
 
     if (noout) {
         ret = 0;
@@ -254,16 +259,20 @@ int ec_main(int argc, char **argv)
             i = i2d_ECPKParameters_bio(out, group);
         else if (pubin || pubout)
             i = i2d_EC_PUBKEY_bio(out, eckey);
-        else
+        else {
+            assert(private);
             i = i2d_ECPrivateKey_bio(out, eckey);
+        }
     } else {
         if (param_out)
             i = PEM_write_bio_ECPKParameters(out, group);
         else if (pubin || pubout)
             i = PEM_write_bio_EC_PUBKEY(out, eckey);
-        else
+        else {
+            assert(private);
             i = PEM_write_bio_ECPrivateKey(out, eckey, enc,
                                            NULL, 0, NULL, passout);
+        }
     }
 
     if (!i) {