From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: David Ahern <dsahern@kernel.org>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
Eric Dumazet <edumazet@google.com>,
Yu Watanabe <watanabe.yu@gmail.com>
Subject: [PATCH net] inet: fix inet_fill_ifaddr() flags truncation
Date: Fri, 10 May 2024 07:29:32 +0000 [thread overview]
Message-ID: <20240510072932.2678952-1-edumazet@google.com> (raw)
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: 3ddc2231c810 ("inet: annotate data-races around ifa->ifa_flags")
Reported-by: Yu Watanabe <watanabe.yu@gmail.com>
Dianosed-by: Yu Watanabe <watanabe.yu@gmail.com>
Closes: https://github.com/systemd/systemd/pull/32666#issuecomment-2103977928
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv4/devinet.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 7a437f0d41905e6acfdc35743afba3a7abfd0dd5..7e45c34c8340a6d2cf96b4485cd4249fd4da7009 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -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,
--
2.45.0.118.g7fe29c98d7-goog
next reply other threads:[~2024-05-10 7:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-10 7:29 Eric Dumazet [this message]
2024-05-10 8:29 ` [PATCH net] inet: fix inet_fill_ifaddr() flags truncation Larysa Zaremba
2024-05-11 1:47 ` David Ahern
2024-05-13 22:00 ` patchwork-bot+netdevbpf
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