Messages in this thread Patch in this message | | | From | Dmitry Safonov <> | Subject | [PATCH v2 1/3] xfrm/compat: Translate by copying XFRMA_UNSPEC attribute | Date | Mon, 2 Nov 2020 16:14:45 +0000 |
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xfrm_xlate32() translates 64-bit message provided by kernel to be sent for 32-bit listener (acknowledge or monitor). Translator code doesn't expect XFRMA_UNSPEC attribute as it doesn't know its payload. Kernel never attaches such attribute, but a user can.
I've searched if any opensource does it and the answer is no. Nothing on github and google finds only tfcproject that has such code commented-out.
What will happen if a user sends a netlink message with XFRMA_UNSPEC attribute? Ipsec code ignores this attribute. But if there is a monitor-process or 32-bit user requested ack - kernel will try to translate such message and will hit WARN_ONCE() in xfrm_xlate64_attr().
Deal with XFRMA_UNSPEC by copying the attribute payload with xfrm_nla_cpy(). In result, the default switch-case in xfrm_xlate64_attr() becomes an unused code. Leave those 3 lines in case a new xfrm attribute will be added.
Fixes: 5461fc0c8d9f ("xfrm/compat: Add 64=>32-bit messages translator") Reported-by: syzbot+a7e701c8385bd8543074@syzkaller.appspotmail.com Signed-off-by: Dmitry Safonov <dima@arista.com> --- net/xfrm/xfrm_compat.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/net/xfrm/xfrm_compat.c b/net/xfrm/xfrm_compat.c index e28f0c9ecd6a..17edbf935e35 100644 --- a/net/xfrm/xfrm_compat.c +++ b/net/xfrm/xfrm_compat.c @@ -234,6 +234,7 @@ static int xfrm_xlate64_attr(struct sk_buff *dst, const struct nlattr *src) case XFRMA_PAD: /* Ignore */ return 0; + case XFRMA_UNSPEC: case XFRMA_ALG_AUTH: case XFRMA_ALG_CRYPT: case XFRMA_ALG_COMP: -- 2.28.0
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