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| author | Mohamed Ghannam <simo.ghannam@gmail.com> | 2017-12-10 04:50:58 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-12-11 20:05:31 +0100 |
| commit | 8f659a03a0ba9289b9aeb9b4470e6fb263d6f483 (patch) | |
| tree | 2b962b0543f8306cadba7cd992f3f523834e87a9 /net/ipv4/raw.c | |
| parent | netlink: Add netns check on taps (diff) | |
| download | linux-8f659a03a0ba9289b9aeb9b4470e6fb263d6f483.tar.xz linux-8f659a03a0ba9289b9aeb9b4470e6fb263d6f483.zip | |
net: ipv4: fix for a race condition in raw_sendmsg
inet->hdrincl is racy, and could lead to uninitialized stack pointer
usage, so its value should be read only once.
Fixes: c008ba5bdc9f ("ipv4: Avoid reading user iov twice after raw_probe_proto_opt")
Signed-off-by: Mohamed Ghannam <simo.ghannam@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/raw.c')
| -rw-r--r-- | net/ipv4/raw.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c index 33b70bfd1122..125c1eab3eaa 100644 --- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -513,11 +513,16 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) int err; struct ip_options_data opt_copy; struct raw_frag_vec rfv; + int hdrincl; err = -EMSGSIZE; if (len > 0xFFFF) goto out; + /* hdrincl should be READ_ONCE(inet->hdrincl) + * but READ_ONCE() doesn't work with bit fields + */ + hdrincl = inet->hdrincl; /* * Check the flags. */ @@ -593,7 +598,7 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) /* Linux does not mangle headers on raw sockets, * so that IP options + IP_HDRINCL is non-sense. */ - if (inet->hdrincl) + if (hdrincl) goto done; if (ipc.opt->opt.srr) { if (!daddr) @@ -615,12 +620,12 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, - inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, + hdrincl ? IPPROTO_RAW : sk->sk_protocol, inet_sk_flowi_flags(sk) | - (inet->hdrincl ? FLOWI_FLAG_KNOWN_NH : 0), + (hdrincl ? FLOWI_FLAG_KNOWN_NH : 0), daddr, saddr, 0, 0, sk->sk_uid); - if (!inet->hdrincl) { + if (!hdrincl) { rfv.msg = msg; rfv.hlen = 0; @@ -645,7 +650,7 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) goto do_confirm; back_from_confirm: - if (inet->hdrincl) + if (hdrincl) err = raw_send_hdrinc(sk, &fl4, msg, len, &rt, msg->msg_flags, &ipc.sockc); |