* [PATCH OLK-5.10 v2 1/2] net: tun_chr_open(): set sk_uid from current_fsuid()
[not found] <20230815135602.1014881-1-dongchenchen2@huawei.com>
@ 2023-08-15 13:56 ` Dong Chenchen
2023-08-15 15:14 ` Greg Kroah-Hartman
2023-08-15 13:56 ` [PATCH OLK-5.10 v2 2/2] net: tap_open(): " Dong Chenchen
1 sibling, 1 reply; 3+ messages in thread
From: Dong Chenchen @ 2023-08-15 13:56 UTC (permalink / raw)
To: kernel
Cc: duanzi, yuehaibing, weiyongjun1, liujian56, Laszlo Ersek,
Eric Dumazet, Lorenzo Colitti, Paolo Abeni, Pietro Borrello,
netdev, stable, David S . Miller, Greg Kroah-Hartman,
Dong Chenchen
From: Laszlo Ersek <lersek@redhat.com>
stable inclusion
from stable-v5.10.189
commit 5ea23f1cb67e4468db7ff651627892c9217fec24
category: bugfix
bugzilla: 189104, https://gitee.com/src-openeuler/kernel/issues/I7QXHX
CVE: CVE-2023-4194
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5ea23f1cb67e4468db7ff651627892c9217fec24
---------------------------
commit 9bc3047374d5bec163e83e743709e23753376f0c upstream.
Commit a096ccca6e50 initializes the "sk_uid" field in the protocol socket
(struct sock) from the "/dev/net/tun" device node's owner UID. Per
original commit 86741ec25462 ("net: core: Add a UID field to struct
sock.", 2016-11-04), that's wrong: the idea is to cache the UID of the
userspace process that creates the socket. Commit 86741ec25462 mentions
socket() and accept(); with "tun", the action that creates the socket is
open("/dev/net/tun").
Therefore the device node's owner UID is irrelevant. In most cases,
"/dev/net/tun" will be owned by root, so in practice, commit a096ccca6e50
has no observable effect:
- before, "sk_uid" would be zero, due to undefined behavior
(CVE-2023-1076),
- after, "sk_uid" would be zero, due to "/dev/net/tun" being owned by root.
What matters is the (fs)UID of the process performing the open(), so cache
that in "sk_uid".
Cc: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Pietro Borrello <borrello@diag.uniroma1.it>
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: a096ccca6e50 ("tun: tun_chr_open(): correctly initialize socket uid")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2173435
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com>
---
drivers/net/tun.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index f8feec522b32..50c2ce392cd1 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -3456,7 +3456,7 @@ static int tun_chr_open(struct inode *inode, struct file * file)
tfile->socket.file = file;
tfile->socket.ops = &tun_socket_ops;
- sock_init_data_uid(&tfile->socket, &tfile->sk, inode->i_uid);
+ sock_init_data_uid(&tfile->socket, &tfile->sk, current_fsuid());
tfile->sk.sk_write_space = tun_sock_write_space;
tfile->sk.sk_sndbuf = INT_MAX;
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH OLK-5.10 v2 2/2] net: tap_open(): set sk_uid from current_fsuid()
[not found] <20230815135602.1014881-1-dongchenchen2@huawei.com>
2023-08-15 13:56 ` [PATCH OLK-5.10 v2 1/2] net: tun_chr_open(): set sk_uid from current_fsuid() Dong Chenchen
@ 2023-08-15 13:56 ` Dong Chenchen
1 sibling, 0 replies; 3+ messages in thread
From: Dong Chenchen @ 2023-08-15 13:56 UTC (permalink / raw)
To: kernel
Cc: duanzi, yuehaibing, weiyongjun1, liujian56, Laszlo Ersek,
Eric Dumazet, Lorenzo Colitti, Paolo Abeni, Pietro Borrello,
netdev, stable, David S . Miller, Greg Kroah-Hartman,
Dong Chenchen
From: Laszlo Ersek <lersek@redhat.com>
stable inclusion
from stable-v5.10.189
commit 33a339e717be2c88b7ad11375165168d5b40e38e
category: bugfix
bugzilla: 189104, https://gitee.com/src-openeuler/kernel/issues/I7QXHX
CVE: CVE-2023-4194
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=33a339e717be2c88b7ad11375165168d5b40e38e
---------------------------
commit 5c9241f3ceab3257abe2923a59950db0dc8bb737 upstream.
Commit 66b2c338adce initializes the "sk_uid" field in the protocol socket
(struct sock) from the "/dev/tapX" device node's owner UID. Per original
commit 86741ec25462 ("net: core: Add a UID field to struct sock.",
2016-11-04), that's wrong: the idea is to cache the UID of the userspace
process that creates the socket. Commit 86741ec25462 mentions socket() and
accept(); with "tap", the action that creates the socket is
open("/dev/tapX").
Therefore the device node's owner UID is irrelevant. In most cases,
"/dev/tapX" will be owned by root, so in practice, commit 66b2c338adce has
no observable effect:
- before, "sk_uid" would be zero, due to undefined behavior
(CVE-2023-1076),
- after, "sk_uid" would be zero, due to "/dev/tapX" being owned by root.
What matters is the (fs)UID of the process performing the open(), so cache
that in "sk_uid".
Cc: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Pietro Borrello <borrello@diag.uniroma1.it>
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 66b2c338adce ("tap: tap_open(): correctly initialize socket uid")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2173435
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com>
---
drivers/net/tap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index d9018d9fe310..2c9ae02ada3e 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -523,7 +523,7 @@ static int tap_open(struct inode *inode, struct file *file)
q->sock.state = SS_CONNECTED;
q->sock.file = file;
q->sock.ops = &tap_socket_ops;
- sock_init_data_uid(&q->sock, &q->sk, inode->i_uid);
+ sock_init_data_uid(&q->sock, &q->sk, current_fsuid());
q->sk.sk_write_space = tap_sock_write_space;
q->sk.sk_destruct = tap_sock_destruct;
q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread