From b8fe36fee000970dcb7cd363f31445969cfbf677 Mon Sep 17 00:00:00 2001
From: Matt Caswell <matt@openssl.org>
Date: Tue, 30 Apr 2019 15:15:48 +0100
Subject: [PATCH] Add support for openssl_ctx_run_once and openssl_ctx_onfree

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8857)
---
 crypto/context.c            | 73 ++++++++++++++++++++++++++++++++++++-
 include/internal/cryptlib.h |  8 ++++
 2 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/crypto/context.c b/crypto/context.c
index 752711b9a4..a1a5d0cbd1 100644
--- a/crypto/context.c
+++ b/crypto/context.c
@@ -10,9 +10,17 @@
 #include "internal/cryptlib.h"
 #include "internal/thread_once.h"
 
+struct openssl_ctx_onfree_list_st {
+    openssl_ctx_onfree_fn fn;
+    struct openssl_ctx_onfree_list_st *next;
+};
+
 struct openssl_ctx_st {
     CRYPTO_RWLOCK *lock;
     CRYPTO_EX_DATA data;
+    int run_once_done[MAX_OPENSSL_CTX_RUN_ONCE];
+    int run_once_ret[MAX_OPENSSL_CTX_RUN_ONCE];
+    struct openssl_ctx_onfree_list_st *onfreelist;
 };
 
 static OPENSSL_CTX default_context;
@@ -26,6 +34,14 @@ static int context_init(OPENSSL_CTX *ctx)
 
 static int context_deinit(OPENSSL_CTX *ctx)
 {
+    struct openssl_ctx_onfree_list_st *tmp, *onfree = ctx->onfreelist;
+
+    while (onfree != NULL) {
+        onfree->fn(ctx);
+        tmp = onfree;
+        onfree = onfree->next;
+        OPENSSL_free(tmp);
+    }
     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_OPENSSL_CTX, NULL, &ctx->data);
     CRYPTO_THREAD_lock_free(ctx->lock);
     return 1;
@@ -92,9 +108,11 @@ void *openssl_ctx_get_data(OPENSSL_CTX *ctx, int index)
 
     if (ctx == NULL) {
         if (!RUN_ONCE(&default_context_init, do_default_context_init))
-            return 0;
+            return NULL;
         ctx = &default_context;
     }
+    if (ctx == NULL)
+        return NULL;
 
     CRYPTO_THREAD_read_lock(ctx->lock);
 
@@ -108,3 +126,56 @@ void *openssl_ctx_get_data(OPENSSL_CTX *ctx, int index)
     return data;
 }
 
+int openssl_ctx_run_once(OPENSSL_CTX *ctx, unsigned int idx,
+                         openssl_ctx_run_once_fn run_once_fn)
+{
+    int done = 0, ret = 0;
+
+#ifndef FIPS_MODE
+    if (ctx == NULL) {
+        if (!RUN_ONCE(&default_context_init, do_default_context_init))
+            return 0;
+        ctx = &default_context;
+    }
+#endif
+    if (ctx == NULL)
+        return 0;
+
+    CRYPTO_THREAD_read_lock(ctx->lock);
+    done = ctx->run_once_done[idx];
+    if (done)
+        ret = ctx->run_once_ret[idx];
+    CRYPTO_THREAD_unlock(ctx->lock);
+
+    if (done)
+        return ret;
+
+    CRYPTO_THREAD_write_lock(ctx->lock);
+    if (ctx->run_once_done[idx]) {
+        ret = ctx->run_once_ret[idx];
+        CRYPTO_THREAD_unlock(ctx->lock);
+        return ret;
+    }
+
+    ret = run_once_fn(ctx);
+    ctx->run_once_done[idx] = 1;
+    ctx->run_once_ret[idx] = ret;
+    CRYPTO_THREAD_unlock(ctx->lock);
+
+    return ret;
+}
+
+int openssl_ctx_onfree(OPENSSL_CTX *ctx, openssl_ctx_onfree_fn onfreefn)
+{
+    struct openssl_ctx_onfree_list_st *newonfree
+        = OPENSSL_malloc(sizeof(*newonfree));
+
+    if (newonfree == NULL)
+        return 0;
+
+    newonfree->fn = onfreefn;
+    newonfree->next = ctx->onfreelist;
+    ctx->onfreelist = newonfree;
+
+    return 1;
+}
diff --git a/include/internal/cryptlib.h b/include/internal/cryptlib.h
index e791245ada..dae10e2bd2 100644
--- a/include/internal/cryptlib.h
+++ b/include/internal/cryptlib.h
@@ -105,6 +105,8 @@ uint32_t OPENSSL_rdtsc(void);
 size_t OPENSSL_instrument_bus(unsigned int *, size_t);
 size_t OPENSSL_instrument_bus2(unsigned int *, size_t, size_t);
 
+# define MAX_OPENSSL_CTX_RUN_ONCE           1
+
 typedef struct openssl_ctx_method {
     void *(*new_func)(void);
     void (*free_func)(void *);
@@ -114,4 +116,10 @@ int openssl_ctx_new_index(const OPENSSL_CTX_METHOD *);
 /* Functions to retrieve pointers to data by index */
 void *openssl_ctx_get_data(OPENSSL_CTX *, int /* index */);
 
+typedef int (*openssl_ctx_run_once_fn)(OPENSSL_CTX *ctx);
+typedef void (*openssl_ctx_onfree_fn)(OPENSSL_CTX *ctx);
+
+int openssl_ctx_run_once(OPENSSL_CTX *ctx, unsigned int idx,
+                         openssl_ctx_run_once_fn run_once_fn);
+int openssl_ctx_onfree(OPENSSL_CTX *ctx, openssl_ctx_onfree_fn onfreefn);
 #endif
-- 
2.25.1