Replace WARN_ONCE() that can be triggered from userspace with pr_warn_once(). Those still give user a hint what's the issue.

I've left WARN()s that are not possible to trigger with current code-base and that would mean that the code has issues: - relying on current compat_msg_min[type] <= xfrm_msg_min[type] - expected 4-byte padding size difference between compat_msg_min[type] and xfrm_msg_min[type] - compat_policy[type].len <= xfrma_policy[type].len (for every type)

Reported-by: syzbot+834ffd1afc7212eb8147@syzkaller.appspotmail.com Fixes: 5f3eea6b7e8f ("xfrm/compat: Attach xfrm dumps to 64=>32 bit translator") Cc: "David S. Miller" davem@davemloft.net Cc: Eric Dumazet eric.dumazet@gmail.com Cc: Herbert Xu herbert@gondor.apana.org.au Cc: Jakub Kicinski kuba@kernel.org Cc: Steffen Klassert steffen.klassert@secunet.com Cc: netdev@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Dmitry Safonov dima@arista.com --- net/xfrm/xfrm_compat.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/net/xfrm/xfrm_compat.c b/net/xfrm/xfrm_compat.c index d8e8a11ca845..a20aec9d7393 100644 --- a/net/xfrm/xfrm_compat.c +++ b/net/xfrm/xfrm_compat.c @@ -216,7 +216,7 @@ static struct nlmsghdr *xfrm_nlmsg_put_compat(struct sk_buff *skb, case XFRM_MSG_GETSADINFO: case XFRM_MSG_GETSPDINFO: default: - WARN_ONCE(1, "unsupported nlmsg_type %d", nlh_src->nlmsg_type); + pr_warn_once("unsupported nlmsg_type %d\n", nlh_src->nlmsg_type); return ERR_PTR(-EOPNOTSUPP); }

@@ -277,7 +277,7 @@ static int xfrm_xlate64_attr(struct sk_buff *dst, const struct nlattr *src) return xfrm_nla_cpy(dst, src, nla_len(src)); default: BUILD_BUG_ON(XFRMA_MAX != XFRMA_IF_ID); - WARN_ONCE(1, "unsupported nla_type %d", src->nla_type); + pr_warn_once("unsupported nla_type %d\n", src->nla_type); return -EOPNOTSUPP; } } @@ -315,8 +315,10 @@ static int xfrm_alloc_compat(struct sk_buff *skb, const struct nlmsghdr *nlh_src struct sk_buff *new = NULL; int err;

- if (WARN_ON_ONCE(type >= ARRAY_SIZE(xfrm_msg_min))) + if (type >= ARRAY_SIZE(xfrm_msg_min)) { + pr_warn_once("unsupported nlmsg_type %d\n", nlh_src->nlmsg_type); return -EOPNOTSUPP; + }

if (skb_shinfo(skb)->frag_list == NULL) { new = alloc_skb(skb->len + skb_tailroom(skb), GFP_ATOMIC); @@ -378,6 +380,10 @@ static int xfrm_attr_cpy32(void *dst, size_t *pos, const struct nlattr *src, struct nlmsghdr *nlmsg = dst; struct nlattr *nla;

+ /* xfrm_user_rcv_msg_compat() relies on fact that 32-bit messages + * have the same len or shorted than 64-bit ones. + * 32-bit translation that is bigger than 64-bit original is unexpected. + */ if (WARN_ON_ONCE(copy_len > payload)) copy_len = payload;