Commit 1af7f88a authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

inet: fix inet_fill_ifaddr() flags truncation 



I missed that (struct ifaddrmsg)->ifa_flags was only 8bits,
while (struct in_ifaddr)->ifa_flags is 32bits.

Use a temporary 32bit variable as I did in set_ifa_lifetime()
and check_lifetime().

Fixes: 3ddc2231 ("inet: annotate data-races around ifa->ifa_flags")
Reported-by: default avatarYu Watanabe <watanabe.yu@gmail.com>
Dianosed-by: default avatarYu Watanabe <watanabe.yu@gmail.com>
Closes: https://github.com/systemd/systemd/pull/32666#issuecomment-2103977928


Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarLarysa Zaremba <larysa.zaremba@intel.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240510072932.2678952-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c9f9df3f

net/ipv4/devinet.c

+10 −3
Original line number Diff line number Diff line
@@ -1683,6 +1683,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, const struct in_ifaddr *ifa, 
	struct nlmsghdr  *nlh;

	unsigned long tstamp;

	u32 preferred, valid;

	u32 flags;



	nlh = nlmsg_put(skb, args->portid, args->seq, args->event, sizeof(*ifm),

			args->flags);
@@ -1692,7 +1693,13 @@ static int inet_fill_ifaddr(struct sk_buff *skb, const struct in_ifaddr *ifa, 
	ifm = nlmsg_data(nlh);

	ifm->ifa_family = AF_INET;

	ifm->ifa_prefixlen = ifa->ifa_prefixlen;

	ifm->ifa_flags = READ_ONCE(ifa->ifa_flags);



	flags = READ_ONCE(ifa->ifa_flags);

	/* Warning : ifm->ifa_flags is an __u8, it holds only 8 bits.

	 * The 32bit value is given in IFA_FLAGS attribute.

	 */

	ifm->ifa_flags = (__u8)flags;



	ifm->ifa_scope = ifa->ifa_scope;

	ifm->ifa_index = ifa->ifa_dev->dev->ifindex;
@@ -1701,7 +1708,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, const struct in_ifaddr *ifa, 
		goto nla_put_failure;



	tstamp = READ_ONCE(ifa->ifa_tstamp);

	if (!(ifm->ifa_flags & IFA_F_PERMANENT)) {

	if (!(flags & IFA_F_PERMANENT)) {

		preferred = READ_ONCE(ifa->ifa_preferred_lft);

		valid = READ_ONCE(ifa->ifa_valid_lft);

		if (preferred != INFINITY_LIFE_TIME) {
@@ -1732,7 +1739,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, const struct in_ifaddr *ifa, 
	     nla_put_string(skb, IFA_LABEL, ifa->ifa_label)) ||

	    (ifa->ifa_proto &&

	     nla_put_u8(skb, IFA_PROTO, ifa->ifa_proto)) ||

	    nla_put_u32(skb, IFA_FLAGS, ifm->ifa_flags) ||

	    nla_put_u32(skb, IFA_FLAGS, flags) ||

	    (ifa->ifa_rt_priority &&

	     nla_put_u32(skb, IFA_RT_PRIORITY, ifa->ifa_rt_priority)) ||

	    put_cacheinfo(skb, READ_ONCE(ifa->ifa_cstamp), tstamp,