Fix encrypted keys and pw prompt retry w/OpenSSL 3

Stunnel has a ui_retry() function that inspects the topmost entry on the
OpenSSL error stack to decide whether it should re-try a certain
operation.

With OpenSSL 3, many of these error codes changed. For example, when
using an encrypted private key, stunnel will prompt for the password on
startup, but will not repeat the prompt with OpenSSL 3 when the password
is entered incorrectly, because the error code returned for this case
changed.

This problem becomes worse with OpenSSL 3.0.7 in RHEL 9.2: because of
the same root cause, stunnel no longer prompts for the password at all.

Fix this by backporting changes in the ui_retry() function from 5.66.

Resolves: rhbz#2151888
Signed-off-by: Clemens Lang <cllang@redhat.com>

stunnel-5.62-openssl3-error-handling.patch

@@ -0,0 +1,140 @@
+From 6baa5762ea5edb192ec003333d62b1d0e56509bf Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Micha=C5=82=20Trojnara?= <Michal.Trojnara@stunnel.org>
+Date: Sun, 11 Sep 2022 23:52:18 +0200
+Subject: [PATCH] stunnel-5.66
+
+---
+ src/common.h |  6 +++++-
+ src/ctx.c    | 58 +++++++++++++++++++++++++++++++++++++++++++---------
+ 2 files changed, 53 insertions(+), 11 deletions(-)
+
+diff --git a/src/common.h b/src/common.h
+index bc37eb5..997e66e 100644
+--- a/src/common.h
++++ b/src/common.h
+@@ -491,7 +491,7 @@ extern char *sys_errlist[];
+ #include <openssl/dh.h>
+ #if OPENSSL_VERSION_NUMBER<0x10100000L
+ int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g);
+-#endif /* OpenSSL older than 1.1.0 */
++#endif /* OPENSSL_VERSION_NUMBER<0x10100000L */
+ #endif /* !defined(OPENSSL_NO_DH) */
+ #ifndef OPENSSL_NO_ENGINE
+ #include <openssl/engine.h>
+@@ -503,8 +503,12 @@ int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g);
+ /* not defined in public headers before OpenSSL 0.9.8 */
+ STACK_OF(SSL_COMP) *SSL_COMP_get_compression_methods(void);
+ #endif /* !defined(OPENSSL_NO_COMP) */
++#if OPENSSL_VERSION_NUMBER>=0x10101000L
++#include <openssl/storeerr.h>
++#endif /* OPENSSL_VERSION_NUMBER>=0x10101000L */
+ #if OPENSSL_VERSION_NUMBER>=0x30000000L
+ #include <openssl/provider.h>
++#include <openssl/proverr.h>
+ #endif /* OPENSSL_VERSION_NUMBER>=0x30000000L */
+ 
+ #ifndef OPENSSL_VERSION
+diff --git a/src/ctx.c b/src/ctx.c
+index a2202b7..cc0806c 100644
+--- a/src/ctx.c
++++ b/src/ctx.c
+@@ -1001,30 +1001,41 @@ NOEXPORT int ui_retry() {
+     unsigned long err=ERR_peek_error();
+ 
+     switch(ERR_GET_LIB(err)) {
+-    case ERR_LIB_ASN1:
+-        return 1;
+-    case ERR_LIB_PKCS12:
++    case ERR_LIB_EVP: /* 6 */
+         switch(ERR_GET_REASON(err)) {
+-        case PKCS12_R_MAC_VERIFY_FAILURE:
++        case EVP_R_BAD_DECRYPT:
+             return 1;
+         default:
++            s_log(LOG_ERR, "Unhandled ERR_LIB_EVP error reason: %d",
++                ERR_GET_REASON(err));
+             return 0;
+         }
+-    case ERR_LIB_EVP:
++    case ERR_LIB_PEM: /* 9 */
+         switch(ERR_GET_REASON(err)) {
+-        case EVP_R_BAD_DECRYPT:
++        case PEM_R_BAD_PASSWORD_READ:
++        case PEM_R_BAD_DECRYPT:
+             return 1;
+         default:
++            s_log(LOG_ERR, "Unhandled ERR_LIB_PEM error reason: %d",
++                ERR_GET_REASON(err));
+             return 0;
+         }
+-    case ERR_LIB_PEM:
++    case ERR_LIB_ASN1: /* 13 */
++        return 1;
++    case ERR_LIB_PKCS12: /* 35 */
+         switch(ERR_GET_REASON(err)) {
+-        case PEM_R_BAD_PASSWORD_READ:
++        case PKCS12_R_MAC_VERIFY_FAILURE:
+             return 1;
+         default:
++            s_log(LOG_ERR, "Unhandled ERR_LIB_PKCS12 error reason: %d",
++                ERR_GET_REASON(err));
+             return 0;
+         }
+-    case ERR_LIB_UI:
++#ifdef ERR_LIB_DSO /* 37 */
++    case ERR_LIB_DSO:
++        return 1;
++#endif
++    case ERR_LIB_UI: /* 40 */
+         switch(ERR_GET_REASON(err)) {
+         case UI_R_RESULT_TOO_LARGE:
+         case UI_R_RESULT_TOO_SMALL:
+@@ -1033,17 +1044,44 @@ NOEXPORT int ui_retry() {
+ #endif
+             return 1;
+         default:
++            s_log(LOG_ERR, "Unhandled ERR_LIB_UI error reason: %d",
++                ERR_GET_REASON(err));
++            return 0;
++        }
++#ifdef ERR_LIB_OSSL_STORE
++    case ERR_LIB_OSSL_STORE: /* 44 - added in OpenSSL 1.1.1 */
++        switch(ERR_GET_REASON(err)) {
++        case OSSL_STORE_R_BAD_PASSWORD_READ:
++            return 1;
++        default:
++            s_log(LOG_ERR, "Unhandled ERR_LIB_OSSL_STORE error reason: %d",
++                ERR_GET_REASON(err));
++            return 0;
++        }
++#endif
++#ifdef ERR_LIB_PROV
++    case ERR_LIB_PROV: /* 57 - added in OpenSSL 3.0 */
++        switch(ERR_GET_REASON(err)) {
++        case PROV_R_BAD_DECRYPT:
++            return 1;
++        default:
++            s_log(LOG_ERR, "Unhandled ERR_LIB_PROV error reason: %d",
++                ERR_GET_REASON(err));
+             return 0;
+         }
+-    case ERR_LIB_USER: /* PKCS#11 hacks */
++#endif
++    case ERR_LIB_USER: /* 128 - PKCS#11 hacks */
+         switch(ERR_GET_REASON(err)) {
+         case 7UL: /* CKR_ARGUMENTS_BAD */
+         case 0xa0UL: /* CKR_PIN_INCORRECT */
+             return 1;
+         default:
++            s_log(LOG_ERR, "Unhandled ERR_LIB_USER error reason: %d",
++                ERR_GET_REASON(err));
+             return 0;
+         }
+     default:
++        s_log(LOG_ERR, "Unhandled error library: %d", ERR_GET_LIB(err));
+         return 0;
+     }
+ }
+-- 
+2.38.1
+

stunnel.spec

@@ -10,7 +10,7 @@
 Summary: A TLS-encrypting socket wrapper
 Name: stunnel
 Version: 5.62
-Release: 2%{?dist}
+Release: 3%{?dist}
 License: GPLv2
 URL: https://www.stunnel.org/
 Source0: https://www.stunnel.org/downloads/stunnel-%{version}.tar.gz
@@ -29,6 +29,7 @@ Patch5: stunnel-5.61-default-tls-version.patch
 Patch6: stunnel-5.56-curves-doc-update.patch
 Patch7: stunnel-5.61-openssl30-fips.patch
 Patch8: stunnel-5.62-disabled-curves.patch
+Patch9: stunnel-5.62-openssl3-error-handling.patch
 # util-linux is needed for rename
 BuildRequires: make
 BuildRequires: gcc
@@ -61,6 +62,7 @@ conjunction with imapd to create a TLS secure IMAP server.
 %patch6 -p1 -b .curves-doc-update
 %patch7 -p1 -b .openssl30-fips
 %patch8 -p1 -b .disabled-curves
+%patch9 -p1 -b .openssl3-error-handling
 
 # Fix the stack protector flag
 sed -i 's/-fstack-protector/-fstack-protector-strong/' configure
@@ -142,6 +144,10 @@ fi
 %systemd_postun_with_restart %{name}.service
 
 %changelog
+* Thu Dec 08 2022 Clemens Lang <cllang@redhat.com> - 5.62-3
+- Fix use of encrypted key files and password retry with OpenSSL 3
+  Resolves: rhbz#2151888
+
 * Fri Feb 04 2022 Clemens Lang <cllang@redhat.com> - 5.62-2
 - Fix stunnel in FIPS mode
   Resolves: rhbz#2050617