[14/28] hw/nvram/fw_cfg: Replace g_memdup() by g_memdup2_qemu()

Commit Message

Philippe Mathieu-Daudé Sept. 3, 2021, 11:06 a.m. UTC

Per https://discourse.gnome.org/t/port-your-module-from-g-memdup-to-g-memdup2-now/5538

  The old API took the size of the memory to duplicate as a guint,
  whereas most memory functions take memory sizes as a gsize. This
  made it easy to accidentally pass a gsize to g_memdup(). For large
  values, that would lead to a silent truncation of the size from 64
  to 32 bits, and result in a heap area being returned which is
  significantly smaller than what the caller expects. This can likely
  be exploited in various modules to cause a heap buffer overflow.

Replace g_memdup() by the safer g_memdup2_qemu() wrapper.

Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
---
 hw/nvram/fw_cfg.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Patch

diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 9b8dcca4ead..fefcdeb8241 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -205,7 +205,8 @@  static void fw_cfg_bootsplash(FWCfgState *s)
         /* use little endian format */
         bst_le16 = cpu_to_le16(bst_val);
         fw_cfg_add_file(s, "etc/boot-menu-wait",
-                        g_memdup(&bst_le16, sizeof bst_le16), sizeof bst_le16);
+                        g_memdup2_qemu(&bst_le16, sizeof bst_le16),
+                        sizeof bst_le16);
     }
 
     /* insert splash file if user configurated */
@@ -260,7 +261,7 @@  static void fw_cfg_reboot(FWCfgState *s)
     }
 
     rt_le32 = cpu_to_le32(rt_val);
-    fw_cfg_add_file(s, "etc/boot-fail-wait", g_memdup(&rt_le32, 4), 4);
+    fw_cfg_add_file(s, "etc/boot-fail-wait", g_memdup2_qemu(&rt_le32, 4), 4);
 }
 
 static void fw_cfg_write(FWCfgState *s, uint8_t value)
@@ -755,7 +756,7 @@  void fw_cfg_add_string(FWCfgState *s, uint16_t key, const char *value)
     size_t sz = strlen(value) + 1;
 
     trace_fw_cfg_add_string(key, trace_key_name(key), value);
-    fw_cfg_add_bytes(s, key, g_memdup(value, sz), sz);
+    fw_cfg_add_bytes(s, key, g_memdup2_qemu(value, sz), sz);
 }
 
 void fw_cfg_modify_string(FWCfgState *s, uint16_t key, const char *value)
@@ -763,7 +764,7 @@  void fw_cfg_modify_string(FWCfgState *s, uint16_t key, const char *value)
     size_t sz = strlen(value) + 1;
     char *old;
 
-    old = fw_cfg_modify_bytes_read(s, key, g_memdup(value, sz), sz);
+    old = fw_cfg_modify_bytes_read(s, key, g_memdup2_qemu(value, sz), sz);
     g_free(old);
 }