From e6d3c97bac2566df51b64c4e07a02e3e18238c34 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 2 Nov 2020 16:14:45 +0000 Subject: [PATCH] UPSTREAM: xfrm/compat: Translate by copying XFRMA_UNSPEC attribute 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 Signed-off-by: Steffen Klassert (cherry picked from commit dbd7ae5154d5fff7e84a9f3010bb06499017ef29) Bug: 187129171 Signed-off-by: Connor O'Brien Change-Id: I11e05ca491155a1dd28f8820ded7ada096595075 --- 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 48cbece14430..aacbf250a25e 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: