lkml.org 
[lkml]   [2022]   [Sep]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] w1: Split memcpy() of struct cn_msg flexible array
Date
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: Kees Cook <keescook@chromium.org>
---
drivers/w1/w1_netlink.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c
index fa490aa4407c..db110cc442b1 100644
--- a/drivers/w1/w1_netlink.c
+++ b/drivers/w1/w1_netlink.c
@@ -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
--
2.34.1
\
 
 \ /
  Last update: 2022-09-27 02:39    [W:0.026 / U:0.264 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site