hw/cxl: cdat: Fix failure to free buffer in erorr paths

The failure paths in CDAT file loading did not clear up properly.
Change to using g_auto_free and a local pointer for the buffer to
ensure this function has no side effects on error.
Also drop some unnecessary checks that can not fail.

Cleanup properly after a failure to load a CDAT file.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20230421132020.7408-3-Jonathan.Cameron@huawei.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/cxl/cxl-cdat.c

@@ -108,6 +108,7 @@ static void ct3_build_cdat(CDATObject *cdat, Error **errp)
 static void ct3_load_cdat(CDATObject *cdat, Error **errp)
 {
     g_autofree CDATEntry *cdat_st = NULL;
+    g_autofree char *buf = NULL;
     uint8_t sum = 0;
     int num_ent;
     int i = 0, ent = 1;
@@ -116,7 +117,7 @@ static void ct3_load_cdat(CDATObject *cdat, Error **errp)
     GError *error = NULL;
 
     /* Read CDAT file and create its cache */
-    if (!g_file_get_contents(cdat->filename, (gchar **)&cdat->buf,
+    if (!g_file_get_contents(cdat->filename, (gchar **)&buf,
                              &file_size, &error)) {
         error_setg(errp, "CDAT: File read failed: %s", error->message);
         g_error_free(error);
@@ -129,9 +130,17 @@ static void ct3_load_cdat(CDATObject *cdat, Error **errp)
     i = sizeof(CDATTableHeader);
     num_ent = 1;
     while (i < file_size) {
-        hdr = (CDATSubHeader *)(cdat->buf + i);
+        hdr = (CDATSubHeader *)(buf + i);
+        if (i + sizeof(CDATSubHeader) > file_size) {
+            error_setg(errp, "CDAT: Truncated table");
+            return;
+        }
         cdat_len_check(hdr, errp);
         i += hdr->length;
+        if (i > file_size) {
+            error_setg(errp, "CDAT: Truncated table");
+            return;
+        }
         num_ent++;
     }
     if (i != file_size) {
@@ -139,33 +148,26 @@ static void ct3_load_cdat(CDATObject *cdat, Error **errp)
         return;
     }
 
-    cdat_st = g_malloc0(sizeof(*cdat_st) * num_ent);
-    if (!cdat_st) {
-        error_setg(errp, "CDAT: Failed to allocate entry array");
-        return;
-    }
+    cdat_st = g_new0(CDATEntry, num_ent);
 
     /* Set CDAT header, Entry = 0 */
-    cdat_st[0].base = cdat->buf;
+    cdat_st[0].base = buf;
     cdat_st[0].length = sizeof(CDATTableHeader);
     i = 0;
 
     while (i < cdat_st[0].length) {
-        sum += cdat->buf[i++];
+        sum += buf[i++];
     }
 
     /* Read CDAT structures */
     while (i < file_size) {
-        hdr = (CDATSubHeader *)(cdat->buf + i);
-        cdat_len_check(hdr, errp);
-
+        hdr = (CDATSubHeader *)(buf + i);
         cdat_st[ent].base = hdr;
         cdat_st[ent].length = hdr->length;
 
-        while (cdat->buf + i <
-               (uint8_t *)cdat_st[ent].base + cdat_st[ent].length) {
+        while (buf + i < (char *)cdat_st[ent].base + cdat_st[ent].length) {
             assert(i < file_size);
-            sum += cdat->buf[i++];
+            sum += buf[i++];
         }
 
         ent++;
@@ -176,6 +178,7 @@ static void ct3_load_cdat(CDATObject *cdat, Error **errp)
     }
     cdat->entry_len = num_ent;
     cdat->entry = g_steal_pointer(&cdat_st);
+    cdat->buf = g_steal_pointer(&buf);
 }
 
 void cxl_doe_cdat_init(CXLComponentState *cxl_cstate, Error **errp)

hw/mem/cxl_type3.c

@@ -593,6 +593,9 @@ static void ct3_realize(PCIDevice *pci_dev, Error **errp)
     cxl_cstate->cdat.free_cdat_table = ct3_free_cdat_table;
     cxl_cstate->cdat.private = ct3d;
     cxl_doe_cdat_init(cxl_cstate, errp);
+    if (*errp) {
+        goto err_free_special_ops;
+    }
 
     pcie_cap_deverr_init(pci_dev);
     /* Leave a bit of room for expansion */
@@ -605,6 +608,7 @@ static void ct3_realize(PCIDevice *pci_dev, Error **errp)
 
 err_release_cdat:
     cxl_doe_cdat_release(cxl_cstate);
+err_free_special_ops:
     g_free(regs->special_ops);
 err_address_space_free:
     address_space_destroy(&ct3d->hostmem_as);

hw/pci-bridge/cxl_upstream.c

@@ -346,6 +346,9 @@ static void cxl_usp_realize(PCIDevice *d, Error **errp)
     cxl_cstate->cdat.free_cdat_table = free_default_cdat_table;
     cxl_cstate->cdat.private = d;
     cxl_doe_cdat_init(cxl_cstate, errp);
+    if (*errp) {
+        goto err_cap;
+    }
 
     return;