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Commit a9915a1b authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv4: fix ip header ident selection in __ip_make_skb() 

Christian Casteyde reported a kmemcheck 32-bit read from uninitialized
memory in __ip_select_ident().

It turns out that __ip_make_skb() called ip_select_ident() before
properly initializing iph->daddr.

This is a bug uncovered by commit 1d861aa4 (inet: Minimize use of
cached route inetpeer.)

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=46131



Reported-by: default avatarChristian Casteyde <casteyde.christian@free.fr>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1a7b27c9

net/ipv4/ip_output.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -1338,10 +1338,10 @@ struct sk_buff *__ip_make_skb(struct sock *sk, 
	iph->ihl = 5;

	iph->ihl = 5;

	iph->tos = inet->tos;

	iph->tos = inet->tos;

	iph->frag_off = df;

	iph->frag_off = df;

	ip_select_ident(iph, &rt->dst, sk);

	iph->ttl = ttl;

	iph->ttl = ttl;

	iph->protocol = sk->sk_protocol;

	iph->protocol = sk->sk_protocol;

	ip_copy_addrs(iph, fl4);

	ip_copy_addrs(iph, fl4);

	ip_select_ident(iph, &rt->dst, sk);





	if (opt) {

	if (opt) {

		iph->ihl += opt->optlen>>2;

		iph->ihl += opt->optlen>>2;