[PATCH 4/5] hw/mem/cxl_type3: Change the CDAT allocation/free strategy

[Gregory Price]

The existing code allocates a subtable for SLBIS entries, uses a
local variable to avoid a g_autofree footgun, and the cleanup code
causes heap corruption.

Rather than allocate a table, explicitly allocate each individual entry
and make the sub-table size static.

Signed-off-by: Gregory Price <gregory.price@memverge.com>
---
 hw/mem/cxl_type3.c | 49 ++++++++++++++++++++++++----------------------
 1 file changed, 26 insertions(+), 23 deletions(-)

diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index 0e0ea70387..220b9f09a9 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -23,13 +23,14 @@ static int ct3_build_cdat_table(CDATSubHeader ***cdat_table,
                                 void *priv)
 {
     g_autofree CDATDsmas *dsmas_nonvolatile = NULL;
-    g_autofree CDATDslbis *dslbis_nonvolatile = NULL;
+    g_autofree CDATDslbis *dslbis_nonvolatile1 = NULL;
+    g_autofree CDATDslbis *dslbis_nonvolatile2 = NULL;
+    g_autofree CDATDslbis *dslbis_nonvolatile3 = NULL;
+    g_autofree CDATDslbis *dslbis_nonvolatile4 = NULL;
     g_autofree CDATDsemts *dsemts_nonvolatile = NULL;
     CXLType3Dev *ct3d = priv;
-    int i = 0;
     int next_dsmad_handle = 0;
     int nonvolatile_dsmad = -1;
-    int dslbis_nonvolatile_num = 4;
     MemoryRegion *mr;
 
     if (!ct3d->hostmem) {
@@ -48,10 +49,15 @@ static int ct3_build_cdat_table(CDATSubHeader ***cdat_table,
 
     /* Non volatile aspects */
     dsmas_nonvolatile = g_malloc(sizeof(*dsmas_nonvolatile));
-    dslbis_nonvolatile =
-        g_malloc(sizeof(*dslbis_nonvolatile) * dslbis_nonvolatile_num);
+    dslbis_nonvolatile1 = g_malloc(sizeof(*dslbis_nonvolatile1));
+    dslbis_nonvolatile2 = g_malloc(sizeof(*dslbis_nonvolatile2));
+    dslbis_nonvolatile3 = g_malloc(sizeof(*dslbis_nonvolatile3));
+    dslbis_nonvolatile4 = g_malloc(sizeof(*dslbis_nonvolatile4));
     dsemts_nonvolatile = g_malloc(sizeof(*dsemts_nonvolatile));
-    if (!dsmas_nonvolatile || !dslbis_nonvolatile || !dsemts_nonvolatile) {
+
+    if (!dsmas_nonvolatile || !dsemts_nonvolatile ||
+        !dslbis_nonvolatile1 || !dslbis_nonvolatile2 ||
+        !dslbis_nonvolatile3 || !dslbis_nonvolatile4) {
         g_free(*cdat_table);
         *cdat_table = NULL;
         return -ENOMEM;
@@ -70,10 +76,10 @@ static int ct3_build_cdat_table(CDATSubHeader ***cdat_table,
     };
 
     /* For now, no memory side cache, plausiblish numbers */
-    dslbis_nonvolatile[0] = (CDATDslbis) {
+    *dslbis_nonvolatile1 = (CDATDslbis) {
         .header = {
             .type = CDAT_TYPE_DSLBIS,
-            .length = sizeof(*dslbis_nonvolatile),
+            .length = sizeof(*dslbis_nonvolatile1),
         },
         .handle = nonvolatile_dsmad,
         .flags = HMAT_LB_MEM_MEMORY,
@@ -82,10 +88,10 @@ static int ct3_build_cdat_table(CDATSubHeader ***cdat_table,
         .entry[0] = 15, /* 150ns */
     };
 
-    dslbis_nonvolatile[1] = (CDATDslbis) {
+    *dslbis_nonvolatile2 = (CDATDslbis) {
         .header = {
             .type = CDAT_TYPE_DSLBIS,
-            .length = sizeof(*dslbis_nonvolatile),
+            .length = sizeof(*dslbis_nonvolatile2),
         },
         .handle = nonvolatile_dsmad,
         .flags = HMAT_LB_MEM_MEMORY,
@@ -94,10 +100,10 @@ static int ct3_build_cdat_table(CDATSubHeader 
***cdat_table,
         .entry[0] = 25, /* 250ns */
     };
 
-    dslbis_nonvolatile[2] = (CDATDslbis) {
+    *dslbis_nonvolatile3 = (CDATDslbis) {
         .header = {
             .type = CDAT_TYPE_DSLBIS,
-            .length = sizeof(*dslbis_nonvolatile),
+            .length = sizeof(*dslbis_nonvolatile3),
         },
         .handle = nonvolatile_dsmad,
         .flags = HMAT_LB_MEM_MEMORY,
@@ -106,10 +112,10 @@ static int ct3_build_cdat_table(CDATSubHeader 
***cdat_table,
         .entry[0] = 16,
     };
 
-    dslbis_nonvolatile[3] = (CDATDslbis) {
+    *dslbis_nonvolatile4 = (CDATDslbis) {
         .header = {
             .type = CDAT_TYPE_DSLBIS,
-            .length = sizeof(*dslbis_nonvolatile),
+            .length = sizeof(*dslbis_nonvolatile4),
         },
         .handle = nonvolatile_dsmad,
         .flags = HMAT_LB_MEM_MEMORY,
@@ -131,15 +137,12 @@ static int ct3_build_cdat_table(CDATSubHeader 
***cdat_table,
     };
 
     /* Header always at start of structure */
-    (*cdat_table)[i++] = g_steal_pointer(&dsmas_nonvolatile);
-
-    CDATDslbis *dslbis = g_steal_pointer(&dslbis_nonvolatile);
-    int j;
-    for (j = 0; j < dslbis_nonvolatile_num; j++) {
-        (*cdat_table)[i++] = (CDATSubHeader *)&dslbis[j];
-    }
-
-    (*cdat_table)[i++] = g_steal_pointer(&dsemts_nonvolatile);
+    (*cdat_table)[0] = g_steal_pointer(&dsmas_nonvolatile);
+    (*cdat_table)[1] = (CDATSubHeader *)g_steal_pointer(&dslbis_nonvolatile1);
+    (*cdat_table)[2] = (CDATSubHeader *)g_steal_pointer(&dslbis_nonvolatile2);
+    (*cdat_table)[3] = (CDATSubHeader *)g_steal_pointer(&dslbis_nonvolatile3);
+    (*cdat_table)[4] = (CDATSubHeader *)g_steal_pointer(&dslbis_nonvolatile4);
+    (*cdat_table)[5] = g_steal_pointer(&dsemts_nonvolatile);
 
     return CT3_CDAT_SUBTABLE_SIZE;
 }
-- 
2.37.3