Commit 7cd04013 authored by Kees Cook's avatar Kees Cook Committed by Greg Kroah-Hartman
Browse files

w1: Split memcpy() of struct cn_msg flexible array 

To work around a misbehavior of the compiler's ability to see into
composite flexible array structs (as detailed in the coming memcpy()
hardening series[1]), split the memcpy() of the header and the payload
so no false positive run-time overflow warning will be generated.

[1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org/



Cc: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarGustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20220927003927.1942170-1-keescook@chromium.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9c573cdc

drivers/w1/w1_netlink.c

+2 −1
Original line number Diff line number Diff line
@@ -611,7 +611,8 @@ static void w1_cn_callback(struct cn_msg *cn, struct netlink_skb_parms *nsp) 
		}

		atomic_set(&block->refcnt, 1);

		block->portid = nsp->portid;

		memcpy(&block->request_cn, cn, sizeof(*cn) + cn->len);

		block->request_cn = *cn;

		memcpy(block->request_cn.data, cn->data, cn->len);

		node = (struct w1_cb_node *)(block->request_cn.data + cn->len);



		/* Sneeky, when not bundling, reply_size is the allocated space