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authorJakub Kicinski <kuba@kernel.org>2022-10-27 14:25:53 -0700
committerDavid S. Miller <davem@davemloft.net>2022-10-31 09:13:10 +0000
commit738136a0e3757a8534df3ad97d6ff6d7f429f6c1 (patch)
tree4ea24529d3600c1aa926aaa791f1085af6c111e6 /net/netlink
parenteca485d22165695587bed02d8b9d0f7f44246c4a (diff)
downloadlinux-738136a0e3757a8534df3ad97d6ff6d7f429f6c1.tar.bz2
netlink: split up copies in the ack construction
Clean up the use of unsafe_memcpy() by adding a flexible array at the end of netlink message header and splitting up the header and data copies. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink')
-rw-r--r--net/netlink/af_netlink.c29
1 files changed, 20 insertions, 9 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index f0c94d394ab1..b10d5e50b99d 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2499,19 +2499,24 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
flags |= NLM_F_ACK_TLVS;
skb = nlmsg_new(payload + tlvlen, GFP_KERNEL);
- if (!skb) {
- NETLINK_CB(in_skb).sk->sk_err = ENOBUFS;
- sk_error_report(NETLINK_CB(in_skb).sk);
- return;
- }
+ if (!skb)
+ goto err_bad_put;
rep = nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
- NLMSG_ERROR, payload, flags);
+ NLMSG_ERROR, sizeof(*errmsg), flags);
+ if (!rep)
+ goto err_bad_put;
errmsg = nlmsg_data(rep);
errmsg->error = err;
- unsafe_memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg)
- ? nlh->nlmsg_len : sizeof(*nlh),
- /* Bounds checked by the skb layer. */);
+ errmsg->msg = *nlh;
+
+ if (!(flags & NLM_F_CAPPED)) {
+ if (!nlmsg_append(skb, nlmsg_len(nlh)))
+ goto err_bad_put;
+
+ memcpy(errmsg->msg.nlmsg_data, nlh->nlmsg_data,
+ nlmsg_len(nlh));
+ }
if (tlvlen)
netlink_ack_tlv_fill(in_skb, skb, nlh, err, extack);
@@ -2519,6 +2524,12 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
nlmsg_end(skb, rep);
nlmsg_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid);
+
+ return;
+
+err_bad_put:
+ NETLINK_CB(in_skb).sk->sk_err = ENOBUFS;
+ sk_error_report(NETLINK_CB(in_skb).sk);
}
EXPORT_SYMBOL(netlink_ack);