From: Larysa Zaremba <larysa.zaremba@intel.com>
To: Eric Dumazet <edumazet@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
David Ahern <dsahern@kernel.org>, <netdev@vger.kernel.org>,
<eric.dumazet@gmail.com>, "Yu Watanabe" <watanabe.yu@gmail.com>
Subject: Re: [PATCH net] inet: fix inet_fill_ifaddr() flags truncation
Date: Fri, 10 May 2024 10:29:42 +0200 [thread overview]
Message-ID: <Zj3a9h/VdgwboRZJ@lzaremba-mobl.ger.corp.intel.com> (raw)
In-Reply-To: <20240510072932.2678952-1-edumazet@google.com>
On Fri, May 10, 2024 at 07:29:32AM +0000, Eric Dumazet wrote:
> 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
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
> 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 prev parent reply other threads:[~2024-05-10 8:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-10 7:29 [PATCH net] inet: fix inet_fill_ifaddr() flags truncation Eric Dumazet
2024-05-10 8:29 ` Larysa Zaremba [this message]
2024-05-11 1:47 ` David Ahern
2024-05-13 22:00 ` patchwork-bot+netdevbpf
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