Commit 2506a917 authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by David S. Miller
Browse files

tipc: Use size_add() in calls to struct_size() 



If, for any reason, the open-coded arithmetic causes a wraparound,
the protection that `struct_size()` adds against potential integer
overflows is defeated. Fix this by hardening call to `struct_size()`
with `size_add()`.

Fixes: e034c6d2 ("tipc: Use struct_size() helper")
Signed-off-by: default avatarGustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a2713257

net/tipc/link.c

+2 −2
Original line number Diff line number Diff line
@@ -1446,7 +1446,7 @@ u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l, 
		p = (struct tipc_gap_ack_blks *)msg_data(hdr);

		sz = ntohs(p->len);

		/* Sanity check */

		if (sz == struct_size(p, gacks, p->ugack_cnt + p->bgack_cnt)) {

		if (sz == struct_size(p, gacks, size_add(p->ugack_cnt, p->bgack_cnt))) {

			/* Good, check if the desired type exists */

			if ((uc && p->ugack_cnt) || (!uc && p->bgack_cnt))

				goto ok;
@@ -1533,7 +1533,7 @@ static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr) 
			__tipc_build_gap_ack_blks(ga, l, ga->bgack_cnt) : 0;



	/* Total len */

	len = struct_size(ga, gacks, ga->bgack_cnt + ga->ugack_cnt);

	len = struct_size(ga, gacks, size_add(ga->bgack_cnt, ga->ugack_cnt));

	ga->len = htons(len);

	return len;

}