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[UDP6]: Fix flowi clobbering
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The udp6_sendmsg function uses a shared buffer to store the
flow without taking any locks.  This leads to races with SMP.
This patch moves the flowi object onto the stack.

Signed-off-by: Herbert Xu <[email protected]>
Acked-by: James Morris <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@herbertx
herbertx authored and David S. Miller committed Oct 4, 2006
1 parent 81771b3 commit 132a55f
Showing 1 changed file with 31 additions and 31 deletions.
62 changes: 31 additions & 31 deletions net/ipv6/udp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -546,7 +546,7 @@ static int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
struct in6_addr *daddr, *final_p = NULL, final;
struct ipv6_txoptions *opt = NULL;
struct ip6_flowlabel *flowlabel = NULL;
struct flowi *fl = &inet->cork.fl;
struct flowi fl;
struct dst_entry *dst;
int addr_len = msg->msg_namelen;
int ulen = len;
Expand Down Expand Up @@ -626,19 +626,19 @@ static int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
}
ulen += sizeof(struct udphdr);

memset(fl, 0, sizeof(*fl));
memset(&fl, 0, sizeof(fl));

if (sin6) {
if (sin6->sin6_port == 0)
return -EINVAL;

fl->fl_ip_dport = sin6->sin6_port;
fl.fl_ip_dport = sin6->sin6_port;
daddr = &sin6->sin6_addr;

if (np->sndflow) {
fl->fl6_flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
if (fl->fl6_flowlabel&IPV6_FLOWLABEL_MASK) {
flowlabel = fl6_sock_lookup(sk, fl->fl6_flowlabel);
fl.fl6_flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
if (fl.fl6_flowlabel&IPV6_FLOWLABEL_MASK) {
flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
if (flowlabel == NULL)
return -EINVAL;
daddr = &flowlabel->dst;
Expand All @@ -656,32 +656,32 @@ static int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
if (addr_len >= sizeof(struct sockaddr_in6) &&
sin6->sin6_scope_id &&
ipv6_addr_type(daddr)&IPV6_ADDR_LINKLOCAL)
fl->oif = sin6->sin6_scope_id;
fl.oif = sin6->sin6_scope_id;
} else {
if (sk->sk_state != TCP_ESTABLISHED)
return -EDESTADDRREQ;

fl->fl_ip_dport = inet->dport;
fl.fl_ip_dport = inet->dport;
daddr = &np->daddr;
fl->fl6_flowlabel = np->flow_label;
fl.fl6_flowlabel = np->flow_label;
connected = 1;
}

if (!fl->oif)
fl->oif = sk->sk_bound_dev_if;
if (!fl.oif)
fl.oif = sk->sk_bound_dev_if;

if (msg->msg_controllen) {
opt = &opt_space;
memset(opt, 0, sizeof(struct ipv6_txoptions));
opt->tot_len = sizeof(*opt);

err = datagram_send_ctl(msg, fl, opt, &hlimit, &tclass);
err = datagram_send_ctl(msg, &fl, opt, &hlimit, &tclass);
if (err < 0) {
fl6_sock_release(flowlabel);
return err;
}
if ((fl->fl6_flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
flowlabel = fl6_sock_lookup(sk, fl->fl6_flowlabel);
if ((fl.fl6_flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
if (flowlabel == NULL)
return -EINVAL;
}
Expand All @@ -695,39 +695,39 @@ static int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
opt = fl6_merge_options(&opt_space, flowlabel, opt);
opt = ipv6_fixup_options(&opt_space, opt);

fl->proto = IPPROTO_UDP;
ipv6_addr_copy(&fl->fl6_dst, daddr);
if (ipv6_addr_any(&fl->fl6_src) && !ipv6_addr_any(&np->saddr))
ipv6_addr_copy(&fl->fl6_src, &np->saddr);
fl->fl_ip_sport = inet->sport;
fl.proto = IPPROTO_UDP;
ipv6_addr_copy(&fl.fl6_dst, daddr);
if (ipv6_addr_any(&fl.fl6_src) && !ipv6_addr_any(&np->saddr))
ipv6_addr_copy(&fl.fl6_src, &np->saddr);
fl.fl_ip_sport = inet->sport;

/* merge ip6_build_xmit from ip6_output */
if (opt && opt->srcrt) {
struct rt0_hdr *rt0 = (struct rt0_hdr *) opt->srcrt;
ipv6_addr_copy(&final, &fl->fl6_dst);
ipv6_addr_copy(&fl->fl6_dst, rt0->addr);
ipv6_addr_copy(&final, &fl.fl6_dst);
ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
final_p = &final;
connected = 0;
}

if (!fl->oif && ipv6_addr_is_multicast(&fl->fl6_dst)) {
fl->oif = np->mcast_oif;
if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst)) {
fl.oif = np->mcast_oif;
connected = 0;
}

security_sk_classify_flow(sk, fl);
security_sk_classify_flow(sk, &fl);

err = ip6_sk_dst_lookup(sk, &dst, fl);
err = ip6_sk_dst_lookup(sk, &dst, &fl);
if (err)
goto out;
if (final_p)
ipv6_addr_copy(&fl->fl6_dst, final_p);
ipv6_addr_copy(&fl.fl6_dst, final_p);

if ((err = xfrm_lookup(&dst, fl, sk, 0)) < 0)
if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
goto out;

if (hlimit < 0) {
if (ipv6_addr_is_multicast(&fl->fl6_dst))
if (ipv6_addr_is_multicast(&fl.fl6_dst))
hlimit = np->mcast_hops;
else
hlimit = np->hop_limit;
Expand Down Expand Up @@ -763,7 +763,7 @@ static int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
do_append_data:
up->len += ulen;
err = ip6_append_data(sk, ip_generic_getfrag, msg->msg_iov, ulen,
sizeof(struct udphdr), hlimit, tclass, opt, fl,
sizeof(struct udphdr), hlimit, tclass, opt, &fl,
(struct rt6_info*)dst,
corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
if (err)
Expand All @@ -774,10 +774,10 @@ static int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
if (dst) {
if (connected) {
ip6_dst_store(sk, dst,
ipv6_addr_equal(&fl->fl6_dst, &np->daddr) ?
ipv6_addr_equal(&fl.fl6_dst, &np->daddr) ?
&np->daddr : NULL,
#ifdef CONFIG_IPV6_SUBTREES
ipv6_addr_equal(&fl->fl6_src, &np->saddr) ?
ipv6_addr_equal(&fl.fl6_src, &np->saddr) ?
&np->saddr :
#endif
NULL);
Expand Down

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