From cb078a3968e000ed876c29d2f1abe74d0ddbbff9 Mon Sep 17 00:00:00 2001
From: Sergey Kandaurov <pluknet@nginx.com>
Date: Thu, 29 May 2025 17:49:48 +0400
Subject: [PATCH] SSL: fixed "key values mismatch" with object cache
 inheritance.

In rare cases, it was possible to get into this error state on reload
with improperly updated file timestamps for certificate and key pairs.

The fix is to retry on X509_R_KEY_VALUES_MISMATCH, similar to 5d5d9adcc.
---
 src/event/ngx_event_openssl.c       | 28 +++++++++++++++++++++++++---
 src/event/ngx_event_openssl_cache.c | 13 +++++++++++--
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index a7b389444..00bab4c57 100644
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -444,10 +444,17 @@ ngx_ssl_certificate(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *cert,
 {
     char            *err;
     X509            *x509, **elm;
+    u_long           n;
     EVP_PKEY        *pkey;
+    ngx_uint_t       mask;
     STACK_OF(X509)  *chain;
 
-    chain = ngx_ssl_cache_fetch(cf, NGX_SSL_CACHE_CERT, &err, cert, NULL);
+    mask = 0;
+
+retry:
+
+    chain = ngx_ssl_cache_fetch(cf, NGX_SSL_CACHE_CERT | mask,
+                                &err, cert, NULL);
     if (chain == NULL) {
         if (err != NULL) {
             ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
@@ -537,7 +544,8 @@ ngx_ssl_certificate(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *cert,
     }
 #endif
 
-    pkey = ngx_ssl_cache_fetch(cf, NGX_SSL_CACHE_PKEY, &err, key, passwords);
+    pkey = ngx_ssl_cache_fetch(cf, NGX_SSL_CACHE_PKEY | mask,
+                               &err, key, passwords);
     if (pkey == NULL) {
         if (err != NULL) {
             ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
@@ -549,9 +557,23 @@ ngx_ssl_certificate(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *cert,
     }
 
     if (SSL_CTX_use_PrivateKey(ssl->ctx, pkey) == 0) {
+        EVP_PKEY_free(pkey);
+
+        /* there can be mismatched pairs on uneven cache update */
+
+        n = ERR_peek_last_error();
+
+        if (ERR_GET_LIB(n) == ERR_LIB_X509
+            && ERR_GET_REASON(n) == X509_R_KEY_VALUES_MISMATCH
+            && mask == 0)
+        {
+            ERR_clear_error();
+            mask = NGX_SSL_CACHE_INVALIDATE;
+            goto retry;
+        }
+
         ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
                       "SSL_CTX_use_PrivateKey(\"%s\") failed", key->data);
-        EVP_PKEY_free(pkey);
         return NGX_ERROR;
     }
 
diff --git a/src/event/ngx_event_openssl_cache.c b/src/event/ngx_event_openssl_cache.c
index 18efc73d0..277464609 100644
--- a/src/event/ngx_event_openssl_cache.c
+++ b/src/event/ngx_event_openssl_cache.c
@@ -193,6 +193,7 @@ ngx_ssl_cache_fetch(ngx_conf_t *cf, ngx_uint_t index, char **err,
     time_t                 mtime;
     uint32_t               hash;
     ngx_int_t              rc;
+    ngx_uint_t             invalidate;
     ngx_file_uniq_t        uniq;
     ngx_file_info_t        fi;
     ngx_ssl_cache_t       *cache, *old_cache;
@@ -202,6 +203,9 @@ ngx_ssl_cache_fetch(ngx_conf_t *cf, ngx_uint_t index, char **err,
 
     *err = NULL;
 
+    invalidate = index & NGX_SSL_CACHE_INVALIDATE;
+    index &= ~NGX_SSL_CACHE_INVALIDATE;
+
     if (ngx_ssl_cache_init_key(cf->pool, index, path, &id) != NGX_OK) {
         return NULL;
     }
@@ -215,7 +219,12 @@ ngx_ssl_cache_fetch(ngx_conf_t *cf, ngx_uint_t index, char **err,
     cn = ngx_ssl_cache_lookup(cache, type, &id, hash);
 
     if (cn != NULL) {
-        return type->ref(err, cn->value);
+        if (!invalidate || id.type != NGX_SSL_CACHE_PATH) {
+            return type->ref(err, cn->value);
+        }
+
+        type->free(cn->value);
+        ngx_rbtree_delete(&cache->rbtree, &cn->node);
     }
 
     value = NULL;
@@ -236,7 +245,7 @@ ngx_ssl_cache_fetch(ngx_conf_t *cf, ngx_uint_t index, char **err,
 
     old_cache = ngx_ssl_cache_get_old_conf(cf->cycle);
 
-    if (old_cache && old_cache->inheritable) {
+    if (old_cache && old_cache->inheritable && !invalidate) {
         cn = ngx_ssl_cache_lookup(old_cache, type, &id, hash);
 
         if (cn != NULL) {