Fix ex_data and session_dup issues

Code was added in commit b3c31a65 that overwrote the last ex_data value
using CRYPTO_dup_ex_data() causing a memory leak, and potentially
confusing the ex_data dup() callback.

In ssl_session_dup(), fix error handling (properly reference and up-ref
shared data) and new-up the ex_data before calling CRYPTO_dup_ex_data();
all other structures that dup ex_data have the destination ex_data new'd
before the dup.

Fix up some of the ex_data documentation.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3625)

1 files changed, 120 insertions, 11 deletions

diff --git a/test/exdatatest.c b/test/exdatatest.c
index e0eadd32dd..7998622de8 100644
--- a/test/exdatatest.c
+++ b/test/exdatatest.c
@@ -15,6 +15,12 @@
 static long saved_argl;
 static void *saved_argp;
 static int saved_idx;
+static int saved_idx2;
+
+/*
+ * SIMPLE EX_DATA IMPLEMENTATION
+ * Apps explicitly set/get ex_data as needed
+ */
 
 static void exnew(void *parent, void *ptr, CRYPTO_EX_DATA *ad,
           int idx, long argl, void *argp)
@@ -43,6 +49,75 @@ static void exfree(void *parent, void *ptr, CRYPTO_EX_DATA *ad,
     OPENSSL_assert(argp == saved_argp);
 }
 
+/*
+ * PRE-ALLOCATED EX_DATA IMPLEMENTATION
+ * Extended data structure is allocated in exnew2/freed in exfree2
+ * Data is stored inside extended data structure
+ */
+
+typedef struct myobj_ex_data_st {
+    char *hello;
+    int new;
+    int dup;
+} MYOBJ_EX_DATA;
+
+static void exnew2(void *parent, void *ptr, CRYPTO_EX_DATA *ad,
+          int idx, long argl, void *argp)
+{
+    int ret;
+    MYOBJ_EX_DATA *ex_data;
+
+    OPENSSL_assert(idx == saved_idx2);
+    OPENSSL_assert(argl == saved_argl);
+    OPENSSL_assert(argp == saved_argp);
+    OPENSSL_assert(ptr == NULL);
+
+    ex_data = OPENSSL_zalloc(sizeof(*ex_data));
+    OPENSSL_assert(ex_data != NULL);
+    ret = CRYPTO_set_ex_data(ad, saved_idx2, ex_data);
+    OPENSSL_assert(ret);
+
+    ex_data->new = 1;
+}
+
+static int exdup2(CRYPTO_EX_DATA *to, const CRYPTO_EX_DATA *from,
+          void *from_d, int idx, long argl, void *argp)
+{
+    MYOBJ_EX_DATA **update_ex_data = (MYOBJ_EX_DATA**)from_d;
+    MYOBJ_EX_DATA *ex_data = CRYPTO_get_ex_data(to, saved_idx2);
+
+    OPENSSL_assert(idx == saved_idx2);
+    OPENSSL_assert(argl == saved_argl);
+    OPENSSL_assert(argp == saved_argp);
+    OPENSSL_assert(from_d != NULL);
+    OPENSSL_assert(*update_ex_data != NULL);
+    OPENSSL_assert(ex_data != NULL);
+    OPENSSL_assert(ex_data->new);
+
+    /* Copy hello over */
+    ex_data->hello = (*update_ex_data)->hello;
+    /* indicate this is a dup */
+    ex_data->dup = 1;
+    /* Keep my original ex_data */
+    *update_ex_data = ex_data;
+    return 1;
+}
+
+static void exfree2(void *parent, void *ptr, CRYPTO_EX_DATA *ad,
+            int idx, long argl, void *argp)
+{
+    MYOBJ_EX_DATA *ex_data = CRYPTO_get_ex_data(ad, saved_idx2);
+    int ret;
+
+    OPENSSL_assert(ex_data != NULL);
+    OPENSSL_free(ex_data);
+    OPENSSL_assert(idx == saved_idx2);
+    OPENSSL_assert(argl == saved_argl);
+    OPENSSL_assert(argp == saved_argp);
+    ret = CRYPTO_set_ex_data(ad, saved_idx2, NULL);
+    OPENSSL_assert(ret);
+}
+
 typedef struct myobj_st {
     CRYPTO_EX_DATA ex_data;
     int id;
@@ -71,6 +146,25 @@ static char *MYOBJ_gethello(MYOBJ *obj)
     return CRYPTO_get_ex_data(&obj->ex_data, saved_idx);
 }
 
+static void MYOBJ_sethello2(MYOBJ *obj, char *cp)
+{
+    MYOBJ_EX_DATA* ex_data = CRYPTO_get_ex_data(&obj->ex_data, saved_idx2);
+    if (ex_data != NULL)
+        ex_data->hello = cp;
+    else
+        obj->st = 0;
+}
+
+static char *MYOBJ_gethello2(MYOBJ *obj)
+{
+    MYOBJ_EX_DATA* ex_data = CRYPTO_get_ex_data(&obj->ex_data, saved_idx2);
+    if (ex_data != NULL)
+        return ex_data->hello;
+
+    obj->st = 0;
+    return NULL;
+}
+
 static void MYOBJ_free(MYOBJ *obj)
 {
     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_APP, obj, &obj->ex_data);
@@ -90,36 +184,51 @@ static MYOBJ *MYOBJ_dup(MYOBJ *in)
 int main()
 {
     MYOBJ *t1, *t2, *t3;
+    MYOBJ_EX_DATA *ex_data;
     const char *cp;
     char *p;
 
-    p = strdup("hello world");
+    p = OPENSSL_strdup("hello world");
     saved_argl = 21;
-    saved_argp = malloc(1);
+    saved_argp = OPENSSL_malloc(1);
     saved_idx = CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_APP,
                                         saved_argl, saved_argp,
                                         exnew, exdup, exfree);
+    saved_idx2 = CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_APP,
+                                         saved_argl, saved_argp,
+                                         exnew2, exdup2, exfree2);
     t1 = MYOBJ_new();
     t2 = MYOBJ_new();
+    OPENSSL_assert(t1->st && t2->st);
+    ex_data = CRYPTO_get_ex_data(&t1->ex_data, saved_idx2);
+    OPENSSL_assert(ex_data != NULL);
+    ex_data = CRYPTO_get_ex_data(&t2->ex_data, saved_idx2);
+    OPENSSL_assert(ex_data != NULL);
     MYOBJ_sethello(t1, p);
     cp = MYOBJ_gethello(t1);
     OPENSSL_assert(cp == p);
-    if (cp != p)
-        return 1;
     cp = MYOBJ_gethello(t2);
     OPENSSL_assert(cp == NULL);
-    if (cp != NULL)
-        return 1;
+    MYOBJ_sethello2(t1, p);
+    cp = MYOBJ_gethello2(t1);
+    OPENSSL_assert(cp == p);
+    OPENSSL_assert(t1->st);
+    cp = MYOBJ_gethello2(t2);
+    OPENSSL_assert(cp == NULL);
+    OPENSSL_assert(t2->st);
     t3 = MYOBJ_dup(t1);
+    ex_data = CRYPTO_get_ex_data(&t3->ex_data, saved_idx2);
+    OPENSSL_assert(ex_data != NULL);
+    OPENSSL_assert(ex_data->dup);
     cp = MYOBJ_gethello(t3);
     OPENSSL_assert(cp == p);
-    if (cp != p)
-        return 1;
-    cp = MYOBJ_gethello(t2);
+    cp = MYOBJ_gethello2(t3);
+    OPENSSL_assert(cp == p);
+    OPENSSL_assert(t3->st);
     MYOBJ_free(t1);
     MYOBJ_free(t2);
     MYOBJ_free(t3);
-    free(saved_argp);
-    free(p);
+    OPENSSL_free(saved_argp);
+    OPENSSL_free(p);
     return 0;
 }