From: Kees Cook <keescook@chromium.org>
To: Jason@zx2c4.com
Cc: syzbot <syzbot+a448cda4dba2dac50de5@syzkaller.appspotmail.com>,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
linux-kernel@vger.kernel.org, linux-next@vger.kernel.org,
netdev@vger.kernel.org, pabeni@redhat.com, sfr@canb.auug.org.au,
syzkaller-bugs@googlegroups.com, wireguard@lists.zx2c4.com
Subject: Re: [syzbot] linux-next test error: WARNING in set_peer
Date: Tue, 13 Sep 2022 17:55:39 -0700 [thread overview]
Message-ID: <202209131753.D1BDA803@keescook> (raw)
In-Reply-To: <00000000000060a74405e8945759@google.com>
On Tue, Sep 13, 2022 at 12:51:42PM -0700, syzbot wrote:
> memcpy: detected field-spanning write (size 28) of single field "&endpoint.addr" at drivers/net/wireguard/netlink.c:446 (size 16)
This is one way to fix it:
diff --git a/drivers/net/wireguard/netlink.c b/drivers/net/wireguard/netlink.c
index 0c0644e762e5..dbbeba216530 100644
--- a/drivers/net/wireguard/netlink.c
+++ b/drivers/net/wireguard/netlink.c
@@ -434,16 +434,16 @@ static int set_peer(struct wg_device *wg, struct nlattr **attrs)
}
if (attrs[WGPEER_A_ENDPOINT]) {
- struct sockaddr *addr = nla_data(attrs[WGPEER_A_ENDPOINT]);
+ struct endpoint *raw = nla_data(attrs[WGPEER_A_ENDPOINT]);
size_t len = nla_len(attrs[WGPEER_A_ENDPOINT]);
if ((len == sizeof(struct sockaddr_in) &&
- addr->sa_family == AF_INET) ||
+ raw->addr.sa_family == AF_INET) ||
(len == sizeof(struct sockaddr_in6) &&
- addr->sa_family == AF_INET6)) {
+ raw->addr.sa_family == AF_INET6)) {
struct endpoint endpoint = { { { 0 } } };
- memcpy(&endpoint.addr, addr, len);
+ memcpy(&endpoint.addrs, &raw->addrs, len);
wg_socket_set_peer_endpoint(peer, &endpoint);
}
}
diff --git a/drivers/net/wireguard/peer.h b/drivers/net/wireguard/peer.h
index 76e4d3128ad4..4fbe7940828b 100644
--- a/drivers/net/wireguard/peer.h
+++ b/drivers/net/wireguard/peer.h
@@ -19,11 +19,13 @@
struct wg_device;
struct endpoint {
- union {
- struct sockaddr addr;
- struct sockaddr_in addr4;
- struct sockaddr_in6 addr6;
- };
+ struct_group(addrs,
+ union {
+ struct sockaddr addr;
+ struct sockaddr_in addr4;
+ struct sockaddr_in6 addr6;
+ };
+ );
union {
struct {
struct in_addr src4;
diffoscope shows the bounds check gets updated to the full union size:
│ - cmp $0x11,%edx
│ + cmp $0x1d,%edx
and the field name changes in the warning:
$ strings clang/drivers/net/wireguard/netlink.o.after | grep ^field
field "&endpoint.addrs" at drivers/net/wireguard/netlink.c:446
--
Kees Cook
next prev parent reply other threads:[~2022-09-14 0:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-13 19:51 syzbot
2022-09-14 0:55 ` Kees Cook [this message]
2022-09-14 17:48 ` Jason A. Donenfeld
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