Commit 63ec72bd authored by Kees Cook's avatar Kees Cook Committed by Jakub Kicinski
Browse files

mptcp: Use struct_group() to avoid cross-field memset() 



In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.

Use struct_group() to capture the fields to be reset, so that memset()
can be appropriately bounds-checked by the compiler.

Cc: Matthieu Baerts <matthieu.baerts@tessares.net>
Cc: mptcp@lists.linux.dev
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Link: https://lore.kernel.org/r/20220121073935.1154263-1-keescook@chromium.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 2c13c05c

net/mptcp/protocol.h

+3 −3
Original line number Diff line number Diff line
@@ -408,7 +408,7 @@ DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions); 
struct mptcp_subflow_context {

	struct	list_head node;/* conn_list of subflows */



	char	reset_start[0];

	struct_group(reset,



	unsigned long avg_pacing_rate; /* protected by msk socket lock */

	u64	local_key;
@@ -458,7 +458,7 @@ struct mptcp_subflow_context { 


	long	delegated_status;



	char	reset_end[0];

	);



	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
@@ -494,7 +494,7 @@ mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow) 
static inline void

mptcp_subflow_ctx_reset(struct mptcp_subflow_context *subflow)

{

	memset(subflow->reset_start, 0, subflow->reset_end - subflow->reset_start);

	memset(&subflow->reset, 0, sizeof(subflow->reset));

	subflow->request_mptcp = 1;

}