[PATCH 63/64] iwlwifi: dbg_ini: Split memcpy() to avoid multi-field write

Kees Cook
2021-07-27T21:07:25Z

To avoid a run-time false positive in the stricter FORTIFY_SOURCE
memcpy() checks, split the memcpy() into the struct and the data.
Additionally switch the data member to a flexible array to follow
modern language conventions.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/net/wireless/intel/iwlwifi/fw/file.h | 2 +-
drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/fw/file.h b/drivers/net/wireless/intel/iwlwifi/fw/file.h
index 9a8c7b7a0816..226ccd3a6612 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/file.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/file.h
@@ -116,7 +116,7 @@ enum iwl_ucode_tlv_type {
struct iwl_ucode_tlv {
__le32 type; /* see above */
__le32 length; /* not including type/length fields */
- u8 data[0];
+ u8 data[];
};

#define IWL_TLV_UCODE_MAGIC 0x0a4c5749
diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c b/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
index 0ddd255a8cc1..f4efddf3e3c3 100644
--- a/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
@@ -71,7 +71,8 @@ static int iwl_dbg_tlv_add(const struct iwl_ucode_tlv *tlv,
if (!node)
return -ENOMEM;

- memcpy(&node->tlv, tlv, sizeof(node->tlv) + len);
+ memcpy(&node->tlv, tlv, sizeof(node->tlv));
+ memcpy(node->tlv.data, tlv->data, len);
list_add_tail(&node->list, list);

return 0;
--
2.30.2