[ 157/184] inet: add RCU protection to inet->opt

From: Willy Tarreau
Date: Tue Jun 04 2013 - 18:44:50 EST

2.6.32-longterm review patch. If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <eric.dumazet@xxxxxxxxx>

commit f6d8bd051c391c1c0458a30b2a7abcd939329259 upstream.

We lack proper synchronization to manipulate inet->opt ip_options

Problem is ip_make_skb() calls ip_setup_cork() and
ip_setup_cork() possibly makes a copy of ipc->opt (struct ip_options),
without any protection against another thread manipulating inet->opt.

Another thread can change inet->opt pointer and free old one under us.

Use RCU to protect inet->opt (changed to inet->inet_opt).

Instead of handling atomic refcounts, just copy ip_options when
necessary, to avoid cache line dirtying.

We cant insert an rcu_head in struct ip_options since its included in
skb->cb[], so this patch is large because I had to introduce a new
ip_options_rcu structure.

Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[dannf/bwh: backported to Debian's 2.6.32]
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
include/net/inet_sock.h | 14 +++--
include/net/ip.h | 11 ++--
net/dccp/ipv4.c | 15 +++---
net/dccp/ipv6.c | 2 +-
net/ipv4/af_inet.c | 16 ++++--
net/ipv4/cipso_ipv4.c | 113 ++++++++++++++++++++++------------------
net/ipv4/icmp.c | 23 ++++----
net/ipv4/inet_connection_sock.c | 8 +--
net/ipv4/ip_options.c | 38 +++++++-------
net/ipv4/ip_output.c | 50 +++++++++---------
net/ipv4/ip_sockglue.c | 33 ++++++++----
net/ipv4/raw.c | 19 +++++--
net/ipv4/syncookies.c | 4 +-
net/ipv4/tcp_ipv4.c | 33 +++++++-----
net/ipv4/udp.c | 21 ++++++--
net/ipv6/tcp_ipv6.c | 2 +-
16 files changed, 235 insertions(+), 167 deletions(-)

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 47004f3..cf65e77 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -56,7 +56,15 @@ struct ip_options {
unsigned char __data[0];
};

-#define optlength(opt) (sizeof(struct ip_options) + opt->optlen)
+struct ip_options_rcu {
+ struct rcu_head rcu;
+ struct ip_options opt;
+};
+
+struct ip_options_data {
+ struct ip_options_rcu opt;
+ char data[40];
+};

struct inet_request_sock {
struct request_sock req;
@@ -77,7 +85,7 @@ struct inet_request_sock {
acked : 1,
no_srccheck: 1;
kmemcheck_bitfield_end(flags);
- struct ip_options *opt;
+ struct ip_options_rcu *opt;
};

static inline struct inet_request_sock *inet_rsk(const struct request_sock *sk)
@@ -122,7 +130,7 @@ struct inet_sock {
__be32 saddr;
__s16 uc_ttl;
__u16 cmsg_flags;
- struct ip_options *opt;
+ struct ip_options_rcu *inet_opt;
__be16 sport;
__u16 id;
__u8 tos;
diff --git a/include/net/ip.h b/include/net/ip.h
index 69db943..a7d4675 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -54,7 +54,7 @@ struct ipcm_cookie
{
__be32 addr;
int oif;
- struct ip_options *opt;
+ struct ip_options_rcu *opt;
union skb_shared_tx shtx;
};

@@ -92,7 +92,7 @@ extern int igmp_mc_proc_init(void);

extern int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
__be32 saddr, __be32 daddr,
- struct ip_options *opt);
+ struct ip_options_rcu *opt);
extern int ip_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev);
extern int ip_local_deliver(struct sk_buff *skb);
@@ -362,14 +362,15 @@ extern int ip_forward(struct sk_buff *skb);
* Functions provided by ip_options.c
*/

-extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, __be32 daddr, struct rtable *rt, int is_frag);
+extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
+ __be32 daddr, struct rtable *rt, int is_frag);
extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
extern void ip_options_fragment(struct sk_buff *skb);
extern int ip_options_compile(struct net *net,
struct ip_options *opt, struct sk_buff *skb);
-extern int ip_options_get(struct net *net, struct ip_options **optp,
+extern int ip_options_get(struct net *net, struct ip_options_rcu **optp,
unsigned char *data, int optlen);
-extern int ip_options_get_from_user(struct net *net, struct ip_options **optp,
+extern int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
unsigned char __user *data, int optlen);
extern void ip_options_undo(struct ip_options * opt);
extern void ip_forward_options(struct sk_buff *skb);
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index d14c0a3..cef3656 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -47,6 +47,7 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
__be32 daddr, nexthop;
int tmp;
int err;
+ struct ip_options_rcu *inet_opt;

dp->dccps_role = DCCP_ROLE_CLIENT;

@@ -57,10 +58,12 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
return -EAFNOSUPPORT;

nexthop = daddr = usin->sin_addr.s_addr;
- if (inet->opt != NULL && inet->opt->srr) {
+
+ inet_opt = inet->inet_opt;
+ if (inet_opt != NULL && inet_opt->opt.srr) {
if (daddr == 0)
return -EINVAL;
- nexthop = inet->opt->faddr;
+ nexthop = inet_opt->opt.faddr;
}

tmp = ip_route_connect(&rt, nexthop, inet->saddr,
@@ -75,7 +78,7 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
return -ENETUNREACH;
}

- if (inet->opt == NULL || !inet->opt->srr)
+ if (inet_opt == NULL || !inet_opt->opt.srr)
daddr = rt->rt_dst;

if (inet->saddr == 0)
@@ -86,8 +89,8 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
inet->daddr = daddr;

inet_csk(sk)->icsk_ext_hdr_len = 0;
- if (inet->opt != NULL)
- inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
+ if (inet_opt)
+ inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
/*
* Socket identity is still unknown (sport may be zero).
* However we set state to DCCP_REQUESTING and not releasing socket
@@ -397,7 +400,7 @@ struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
newinet->daddr = ireq->rmt_addr;
newinet->rcv_saddr = ireq->loc_addr;
newinet->saddr = ireq->loc_addr;
- newinet->opt = ireq->opt;
+ newinet->inet_opt = ireq->opt;
ireq->opt = NULL;
newinet->mc_index = inet_iif(skb);
newinet->mc_ttl = ip_hdr(skb)->ttl;
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 9ed1962..2f11de7 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -600,7 +600,7 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,

First: no IPv4 options.
*/
- newinet->opt = NULL;
+ newinet->inet_opt = NULL;

/* Clone RX bits */
newnp->rxopt.all = np->rxopt.all;
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index a289878..d1992a4 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -152,7 +152,7 @@ void inet_sock_destruct(struct sock *sk)
WARN_ON(sk->sk_wmem_queued);
WARN_ON(sk->sk_forward_alloc);

- kfree(inet->opt);
+ kfree(inet->inet_opt);
dst_release(sk->sk_dst_cache);
sk_refcnt_debug_dec(sk);
}
@@ -1065,9 +1065,11 @@ static int inet_sk_reselect_saddr(struct sock *sk)
__be32 old_saddr = inet->saddr;
__be32 new_saddr;
__be32 daddr = inet->daddr;
+ struct ip_options_rcu *inet_opt;

- if (inet->opt && inet->opt->srr)
- daddr = inet->opt->faddr;
+ inet_opt = inet->inet_opt;
+ if (inet_opt && inet_opt->opt.srr)
+ daddr = inet_opt->opt.faddr;

/* Query new route. */
err = ip_route_connect(&rt, daddr, 0,
@@ -1109,6 +1111,7 @@ int inet_sk_rebuild_header(struct sock *sk)
struct inet_sock *inet = inet_sk(sk);
struct rtable *rt = (struct rtable *)__sk_dst_check(sk, 0);
__be32 daddr;
+ struct ip_options_rcu *inet_opt;
int err;

/* Route is OK, nothing to do. */
@@ -1116,9 +1119,12 @@ int inet_sk_rebuild_header(struct sock *sk)
return 0;

/* Reroute. */
+ rcu_read_lock();
+ inet_opt = rcu_dereference(inet->inet_opt);
daddr = inet->daddr;
- if (inet->opt && inet->opt->srr)
- daddr = inet->opt->faddr;
+ if (inet_opt && inet_opt->opt.srr)
+ daddr = inet_opt->opt.faddr;
+ rcu_read_unlock();
{
struct flowi fl = {
.oif = sk->sk_bound_dev_if,
diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 10f8f8d..b6d06d6 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -1860,6 +1860,11 @@ static int cipso_v4_genopt(unsigned char *buf, u32 buf_len,
return CIPSO_V4_HDR_LEN + ret_val;
}

+static void opt_kfree_rcu(struct rcu_head *head)
+{
+ kfree(container_of(head, struct ip_options_rcu, rcu));
+}
+
/**
* cipso_v4_sock_setattr - Add a CIPSO option to a socket
* @sk: the socket
@@ -1882,7 +1887,7 @@ int cipso_v4_sock_setattr(struct sock *sk,
unsigned char *buf = NULL;
u32 buf_len;
u32 opt_len;
- struct ip_options *opt = NULL;
+ struct ip_options_rcu *old, *opt = NULL;
struct inet_sock *sk_inet;
struct inet_connection_sock *sk_conn;

@@ -1918,22 +1923,25 @@ int cipso_v4_sock_setattr(struct sock *sk,
ret_val = -ENOMEM;
goto socket_setattr_failure;
}
- memcpy(opt->__data, buf, buf_len);
- opt->optlen = opt_len;
- opt->cipso = sizeof(struct iphdr);
+ memcpy(opt->opt.__data, buf, buf_len);
+ opt->opt.optlen = opt_len;
+ opt->opt.cipso = sizeof(struct iphdr);
kfree(buf);
buf = NULL;

sk_inet = inet_sk(sk);
+
+ old = sk_inet->inet_opt;
if (sk_inet->is_icsk) {
sk_conn = inet_csk(sk);
- if (sk_inet->opt)
- sk_conn->icsk_ext_hdr_len -= sk_inet->opt->optlen;
- sk_conn->icsk_ext_hdr_len += opt->optlen;
+ if (old)
+ sk_conn->icsk_ext_hdr_len -= old->opt.optlen;
+ sk_conn->icsk_ext_hdr_len += opt->opt.optlen;
sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
}
- opt = xchg(&sk_inet->opt, opt);
- kfree(opt);
+ rcu_assign_pointer(sk_inet->inet_opt, opt);
+ if (old)
+ call_rcu(&old->rcu, opt_kfree_rcu);

return 0;

@@ -1963,7 +1971,7 @@ int cipso_v4_req_setattr(struct request_sock *req,
unsigned char *buf = NULL;
u32 buf_len;
u32 opt_len;
- struct ip_options *opt = NULL;
+ struct ip_options_rcu *opt = NULL;
struct inet_request_sock *req_inet;

/* We allocate the maximum CIPSO option size here so we are probably
@@ -1991,15 +1999,16 @@ int cipso_v4_req_setattr(struct request_sock *req,
ret_val = -ENOMEM;
goto req_setattr_failure;
}
- memcpy(opt->__data, buf, buf_len);
- opt->optlen = opt_len;
- opt->cipso = sizeof(struct iphdr);
+ memcpy(opt->opt.__data, buf, buf_len);
+ opt->opt.optlen = opt_len;
+ opt->opt.cipso = sizeof(struct iphdr);
kfree(buf);
buf = NULL;

req_inet = inet_rsk(req);
opt = xchg(&req_inet->opt, opt);
- kfree(opt);
+ if (opt)
+ call_rcu(&opt->rcu, opt_kfree_rcu);

return 0;

@@ -2019,34 +2028,34 @@ req_setattr_failure:
* values on failure.
*
*/
-int cipso_v4_delopt(struct ip_options **opt_ptr)
+int cipso_v4_delopt(struct ip_options_rcu **opt_ptr)
{
int hdr_delta = 0;
- struct ip_options *opt = *opt_ptr;
+ struct ip_options_rcu *opt = *opt_ptr;

- if (opt->srr || opt->rr || opt->ts || opt->router_alert) {
+ if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) {
u8 cipso_len;
u8 cipso_off;
unsigned char *cipso_ptr;
int iter;
int optlen_new;

- cipso_off = opt->cipso - sizeof(struct iphdr);
- cipso_ptr = &opt->__data[cipso_off];
+ cipso_off = opt->opt.cipso - sizeof(struct iphdr);
+ cipso_ptr = &opt->opt.__data[cipso_off];
cipso_len = cipso_ptr[1];

- if (opt->srr > opt->cipso)
- opt->srr -= cipso_len;
- if (opt->rr > opt->cipso)
- opt->rr -= cipso_len;
- if (opt->ts > opt->cipso)
- opt->ts -= cipso_len;
- if (opt->router_alert > opt->cipso)
- opt->router_alert -= cipso_len;
- opt->cipso = 0;
+ if (opt->opt.srr > opt->opt.cipso)
+ opt->opt.srr -= cipso_len;
+ if (opt->opt.rr > opt->opt.cipso)
+ opt->opt.rr -= cipso_len;
+ if (opt->opt.ts > opt->opt.cipso)
+ opt->opt.ts -= cipso_len;
+ if (opt->opt.router_alert > opt->opt.cipso)
+ opt->opt.router_alert -= cipso_len;
+ opt->opt.cipso = 0;

memmove(cipso_ptr, cipso_ptr + cipso_len,
- opt->optlen - cipso_off - cipso_len);
+ opt->opt.optlen - cipso_off - cipso_len);

/* determining the new total option length is tricky because of
* the padding necessary, the only thing i can think to do at
@@ -2055,21 +2064,21 @@ int cipso_v4_delopt(struct ip_options **opt_ptr)
* from there we can determine the new total option length */
iter = 0;
optlen_new = 0;
- while (iter < opt->optlen)
- if (opt->__data[iter] != IPOPT_NOP) {
- iter += opt->__data[iter + 1];
+ while (iter < opt->opt.optlen)
+ if (opt->opt.__data[iter] != IPOPT_NOP) {
+ iter += opt->opt.__data[iter + 1];
optlen_new = iter;
} else
iter++;
- hdr_delta = opt->optlen;
- opt->optlen = (optlen_new + 3) & ~3;
- hdr_delta -= opt->optlen;
+ hdr_delta = opt->opt.optlen;
+ opt->opt.optlen = (optlen_new + 3) & ~3;
+ hdr_delta -= opt->opt.optlen;
} else {
/* only the cipso option was present on the socket so we can
* remove the entire option struct */
*opt_ptr = NULL;
- hdr_delta = opt->optlen;
- kfree(opt);
+ hdr_delta = opt->opt.optlen;
+ call_rcu(&opt->rcu, opt_kfree_rcu);
}

return hdr_delta;
@@ -2086,15 +2095,15 @@ int cipso_v4_delopt(struct ip_options **opt_ptr)
void cipso_v4_sock_delattr(struct sock *sk)
{
int hdr_delta;
- struct ip_options *opt;
+ struct ip_options_rcu *opt;
struct inet_sock *sk_inet;

sk_inet = inet_sk(sk);
- opt = sk_inet->opt;
- if (opt == NULL || opt->cipso == 0)
+ opt = sk_inet->inet_opt;
+ if (opt == NULL || opt->opt.cipso == 0)
return;

- hdr_delta = cipso_v4_delopt(&sk_inet->opt);
+ hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt);
if (sk_inet->is_icsk && hdr_delta > 0) {
struct inet_connection_sock *sk_conn = inet_csk(sk);
sk_conn->icsk_ext_hdr_len -= hdr_delta;
@@ -2112,12 +2121,12 @@ void cipso_v4_sock_delattr(struct sock *sk)
*/
void cipso_v4_req_delattr(struct request_sock *req)
{
- struct ip_options *opt;
+ struct ip_options_rcu *opt;
struct inet_request_sock *req_inet;

req_inet = inet_rsk(req);
opt = req_inet->opt;
- if (opt == NULL || opt->cipso == 0)
+ if (opt == NULL || opt->opt.cipso == 0)
return;

cipso_v4_delopt(&req_inet->opt);
@@ -2187,14 +2196,18 @@ getattr_return:
*/
int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
{
- struct ip_options *opt;
+ struct ip_options_rcu *opt;
+ int res = -ENOMSG;

- opt = inet_sk(sk)->opt;
- if (opt == NULL || opt->cipso == 0)
- return -ENOMSG;
-
- return cipso_v4_getattr(opt->__data + opt->cipso - sizeof(struct iphdr),
- secattr);
+ rcu_read_lock();
+ opt = rcu_dereference(inet_sk(sk)->inet_opt);
+ if (opt && opt->opt.cipso)
+ res = cipso_v4_getattr(opt->opt.__data +
+ opt->opt.cipso -
+ sizeof(struct iphdr),
+ secattr);
+ rcu_read_unlock();
+ return res;
}

/**
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 5bc13fe..859d781 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -107,8 +107,7 @@ struct icmp_bxm {
__be32 times[3];
} data;
int head_len;
- struct ip_options replyopts;
- unsigned char optbuf[40];
+ struct ip_options_data replyopts;
};

/* An array of errno for error messages from dest unreach. */
@@ -362,7 +361,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
struct inet_sock *inet;
__be32 daddr;

- if (ip_options_echo(&icmp_param->replyopts, skb))
+ if (ip_options_echo(&icmp_param->replyopts.opt.opt, skb))
return;

sk = icmp_xmit_lock(net);
@@ -376,10 +375,10 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
daddr = ipc.addr = rt->rt_src;
ipc.opt = NULL;
ipc.shtx.flags = 0;
- if (icmp_param->replyopts.optlen) {
- ipc.opt = &icmp_param->replyopts;
- if (ipc.opt->srr)
- daddr = icmp_param->replyopts.faddr;
+ if (icmp_param->replyopts.opt.opt.optlen) {
+ ipc.opt = &icmp_param->replyopts.opt;
+ if (ipc.opt->opt.srr)
+ daddr = icmp_param->replyopts.opt.opt.faddr;
}
{
struct flowi fl = { .nl_u = { .ip4_u =
@@ -516,7 +515,7 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
IPTOS_PREC_INTERNETCONTROL) :
iph->tos;

- if (ip_options_echo(&icmp_param.replyopts, skb_in))
+ if (ip_options_echo(&icmp_param.replyopts.opt.opt, skb_in))
goto out_unlock;


@@ -532,15 +531,15 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
icmp_param.offset = skb_network_offset(skb_in);
inet_sk(sk)->tos = tos;
ipc.addr = iph->saddr;
- ipc.opt = &icmp_param.replyopts;
+ ipc.opt = &icmp_param.replyopts.opt;
ipc.shtx.flags = 0;

{
struct flowi fl = {
.nl_u = {
.ip4_u = {
- .daddr = icmp_param.replyopts.srr ?
- icmp_param.replyopts.faddr :
+ .daddr = icmp_param.replyopts.opt.opt.srr ?
+ icmp_param.replyopts.opt.opt.faddr :
iph->saddr,
.saddr = saddr,
.tos = RT_TOS(tos)
@@ -629,7 +628,7 @@ route_done:
room = dst_mtu(&rt->u.dst);
if (room > 576)
room = 576;
- room -= sizeof(struct iphdr) + icmp_param.replyopts.optlen;
+ room -= sizeof(struct iphdr) + icmp_param.replyopts.opt.opt.optlen;
room -= sizeof(struct icmphdr);

icmp_param.data_len = skb_in->len - icmp_param.offset;
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 537731b..a3bf986 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -356,11 +356,11 @@ struct dst_entry *inet_csk_route_req(struct sock *sk,
{
struct rtable *rt;
const struct inet_request_sock *ireq = inet_rsk(req);
- struct ip_options *opt = inet_rsk(req)->opt;
+ struct ip_options_rcu *opt = inet_rsk(req)->opt;
struct flowi fl = { .oif = sk->sk_bound_dev_if,
.nl_u = { .ip4_u =
- { .daddr = ((opt && opt->srr) ?
- opt->faddr :
+ { .daddr = ((opt && opt->opt.srr) ?
+ opt->opt.faddr :
ireq->rmt_addr),
.saddr = ireq->loc_addr,
.tos = RT_CONN_FLAGS(sk) } },
@@ -374,7 +374,7 @@ struct dst_entry *inet_csk_route_req(struct sock *sk,
security_req_classify_flow(req, &fl);
if (ip_route_output_flow(net, &rt, &fl, sk, 0))
goto no_route;
- if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
+ if (opt && opt->opt.is_strictroute && rt->rt_dst != rt->rt_gateway)
goto route_err;
return &rt->u.dst;

diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
index 94bf105..8a95972 100644
--- a/net/ipv4/ip_options.c
+++ b/net/ipv4/ip_options.c
@@ -35,7 +35,7 @@
* saddr is address of outgoing interface.
*/

-void ip_options_build(struct sk_buff * skb, struct ip_options * opt,
+void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
__be32 daddr, struct rtable *rt, int is_frag)
{
unsigned char *iph = skb_network_header(skb);
@@ -82,9 +82,9 @@ void ip_options_build(struct sk_buff * skb, struct ip_options * opt,
* NOTE: dopt cannot point to skb.
*/

-int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)
+int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb)
{
- struct ip_options *sopt;
+ const struct ip_options *sopt;
unsigned char *sptr, *dptr;
int soffset, doffset;
int optlen;
@@ -94,10 +94,8 @@ int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)

sopt = &(IPCB(skb)->opt);

- if (sopt->optlen == 0) {
- dopt->optlen = 0;
+ if (sopt->optlen == 0)
return 0;
- }

sptr = skb_network_header(skb);
dptr = dopt->__data;
@@ -156,7 +154,7 @@ int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)
dopt->optlen += optlen;
}
if (sopt->srr) {
- unsigned char * start = sptr+sopt->srr;
+ unsigned char *start = sptr+sopt->srr;
__be32 faddr;

optlen = start[1];
@@ -499,19 +497,19 @@ void ip_options_undo(struct ip_options * opt)
}
}

-static struct ip_options *ip_options_get_alloc(const int optlen)
+static struct ip_options_rcu *ip_options_get_alloc(const int optlen)
{
- return kzalloc(sizeof(struct ip_options) + ((optlen + 3) & ~3),
+ return kzalloc(sizeof(struct ip_options_rcu) + ((optlen + 3) & ~3),
GFP_KERNEL);
}

-static int ip_options_get_finish(struct net *net, struct ip_options **optp,
- struct ip_options *opt, int optlen)
+static int ip_options_get_finish(struct net *net, struct ip_options_rcu **optp,
+ struct ip_options_rcu *opt, int optlen)
{
while (optlen & 3)
- opt->__data[optlen++] = IPOPT_END;
- opt->optlen = optlen;
- if (optlen && ip_options_compile(net, opt, NULL)) {
+ opt->opt.__data[optlen++] = IPOPT_END;
+ opt->opt.optlen = optlen;
+ if (optlen && ip_options_compile(net, &opt->opt, NULL)) {
kfree(opt);
return -EINVAL;
}
@@ -520,29 +518,29 @@ static int ip_options_get_finish(struct net *net, struct ip_options **optp,
return 0;
}

-int ip_options_get_from_user(struct net *net, struct ip_options **optp,
+int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
unsigned char __user *data, int optlen)
{
- struct ip_options *opt = ip_options_get_alloc(optlen);
+ struct ip_options_rcu *opt = ip_options_get_alloc(optlen);

if (!opt)
return -ENOMEM;
- if (optlen && copy_from_user(opt->__data, data, optlen)) {
+ if (optlen && copy_from_user(opt->opt.__data, data, optlen)) {
kfree(opt);
return -EFAULT;
}
return ip_options_get_finish(net, optp, opt, optlen);
}

-int ip_options_get(struct net *net, struct ip_options **optp,
+int ip_options_get(struct net *net, struct ip_options_rcu **optp,
unsigned char *data, int optlen)
{
- struct ip_options *opt = ip_options_get_alloc(optlen);
+ struct ip_options_rcu *opt = ip_options_get_alloc(optlen);

if (!opt)
return -ENOMEM;
if (optlen)
- memcpy(opt->__data, data, optlen);
+ memcpy(opt->opt.__data, data, optlen);
return ip_options_get_finish(net, optp, opt, optlen);
}

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 44b7910..7dde039 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -137,14 +137,14 @@ static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst)
*
*/
int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
- __be32 saddr, __be32 daddr, struct ip_options *opt)
+ __be32 saddr, __be32 daddr, struct ip_options_rcu *opt)
{
struct inet_sock *inet = inet_sk(sk);
struct rtable *rt = skb_rtable(skb);
struct iphdr *iph;

/* Build the IP header. */
- skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0));
+ skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0));
skb_reset_network_header(skb);
iph = ip_hdr(skb);
iph->version = 4;
@@ -160,9 +160,9 @@ int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
iph->protocol = sk->sk_protocol;
ip_select_ident(iph, &rt->u.dst, sk);

- if (opt && opt->optlen) {
- iph->ihl += opt->optlen>>2;
- ip_options_build(skb, opt, daddr, rt, 0);
+ if (opt && opt->opt.optlen) {
+ iph->ihl += opt->opt.optlen>>2;
+ ip_options_build(skb, &opt->opt, daddr, rt, 0);
}

skb->priority = sk->sk_priority;
@@ -312,9 +312,10 @@ int ip_queue_xmit(struct sk_buff *skb, int ipfragok)
{
struct sock *sk = skb->sk;
struct inet_sock *inet = inet_sk(sk);
- struct ip_options *opt = inet->opt;
+ struct ip_options_rcu *inet_opt = NULL;
struct rtable *rt;
struct iphdr *iph;
+ int res;

/* Skip all of this if the packet is already routed,
* f.e. by something like SCTP.
@@ -325,13 +326,15 @@ int ip_queue_xmit(struct sk_buff *skb, int ipfragok)

/* Make sure we can route this packet. */
rt = (struct rtable *)__sk_dst_check(sk, 0);
+ rcu_read_lock();
+ inet_opt = rcu_dereference(inet->inet_opt);
if (rt == NULL) {
__be32 daddr;

/* Use correct destination address if we have options. */
daddr = inet->daddr;
- if(opt && opt->srr)
- daddr = opt->faddr;
+ if (inet_opt && inet_opt->opt.srr)
+ daddr = inet_opt->opt.faddr;

{
struct flowi fl = { .oif = sk->sk_bound_dev_if,
@@ -359,11 +362,11 @@ int ip_queue_xmit(struct sk_buff *skb, int ipfragok)
skb_dst_set(skb, dst_clone(&rt->u.dst));

packet_routed:
- if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
+ if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_dst != rt->rt_gateway)
goto no_route;

/* OK, we know where to send it, allocate and build IP header. */
- skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0));
+ skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0));
skb_reset_network_header(skb);
iph = ip_hdr(skb);
*((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff));
@@ -377,9 +380,9 @@ packet_routed:
iph->daddr = rt->rt_dst;
/* Transport layer set skb->h.foo itself. */

- if (opt && opt->optlen) {
- iph->ihl += opt->optlen >> 2;
- ip_options_build(skb, opt, inet->daddr, rt, 0);
+ if (inet_opt && inet_opt->opt.optlen) {
+ iph->ihl += inet_opt->opt.optlen >> 2;
+ ip_options_build(skb, &inet_opt->opt, inet->daddr, rt, 0);
}

ip_select_ident_more(iph, &rt->u.dst, sk,
@@ -387,10 +390,12 @@ packet_routed:

skb->priority = sk->sk_priority;
skb->mark = sk->sk_mark;
-
- return ip_local_out(skb);
+ res = ip_local_out(skb);
+ rcu_read_unlock();
+ return res;

no_route:
+ rcu_read_unlock();
IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
kfree_skb(skb);
return -EHOSTUNREACH;
@@ -809,7 +814,7 @@ int ip_append_data(struct sock *sk,
/*
* setup for corking.
*/
- opt = ipc->opt;
+ opt = ipc->opt ? &ipc->opt->opt : NULL;
if (opt) {
if (inet->cork.opt == NULL) {
inet->cork.opt = kmalloc(sizeof(struct ip_options) + 40, sk->sk_allocation);
@@ -1367,26 +1372,23 @@ void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *ar
unsigned int len)
{
struct inet_sock *inet = inet_sk(sk);
- struct {
- struct ip_options opt;
- char data[40];
- } replyopts;
+ struct ip_options_data replyopts;
struct ipcm_cookie ipc;
__be32 daddr;
struct rtable *rt = skb_rtable(skb);

- if (ip_options_echo(&replyopts.opt, skb))
+ if (ip_options_echo(&replyopts.opt.opt, skb))
return;

daddr = ipc.addr = rt->rt_src;
ipc.opt = NULL;
ipc.shtx.flags = 0;

- if (replyopts.opt.optlen) {
+ if (replyopts.opt.opt.optlen) {
ipc.opt = &replyopts.opt;

- if (ipc.opt->srr)
- daddr = replyopts.opt.faddr;
+ if (replyopts.opt.opt.srr)
+ daddr = replyopts.opt.opt.faddr;
}

{
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 184a7ad..099e6c3 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -434,6 +434,11 @@ out:
}


+static void opt_kfree_rcu(struct rcu_head *head)
+{
+ kfree(container_of(head, struct ip_options_rcu, rcu));
+}
+
/*
* Socket option code for IP. This is the end of the line after any
* TCP,UDP etc options on an IP socket.
@@ -479,13 +484,15 @@ static int do_ip_setsockopt(struct sock *sk, int level,
switch (optname) {
case IP_OPTIONS:
{
- struct ip_options *opt = NULL;
+ struct ip_options_rcu *old, *opt = NULL;
+
if (optlen > 40 || optlen < 0)
goto e_inval;
err = ip_options_get_from_user(sock_net(sk), &opt,
optval, optlen);
if (err)
break;
+ old = inet->inet_opt;
if (inet->is_icsk) {
struct inet_connection_sock *icsk = inet_csk(sk);
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
@@ -494,17 +501,18 @@ static int do_ip_setsockopt(struct sock *sk, int level,
(TCPF_LISTEN | TCPF_CLOSE)) &&
inet->daddr != LOOPBACK4_IPV6)) {
#endif
- if (inet->opt)
- icsk->icsk_ext_hdr_len -= inet->opt->optlen;
+ if (old)
+ icsk->icsk_ext_hdr_len -= old->opt.optlen;
if (opt)
- icsk->icsk_ext_hdr_len += opt->optlen;
+ icsk->icsk_ext_hdr_len += opt->opt.optlen;
icsk->icsk_sync_mss(sk, icsk->icsk_pmtu_cookie);
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
}
#endif
}
- opt = xchg(&inet->opt, opt);
- kfree(opt);
+ rcu_assign_pointer(inet->inet_opt, opt);
+ if (old)
+ call_rcu(&old->rcu, opt_kfree_rcu);
break;
}
case IP_PKTINFO:
@@ -1032,12 +1040,15 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
case IP_OPTIONS:
{
unsigned char optbuf[sizeof(struct ip_options)+40];
- struct ip_options * opt = (struct ip_options *)optbuf;
+ struct ip_options *opt = (struct ip_options *)optbuf;
+ struct ip_options_rcu *inet_opt;
+
+ inet_opt = inet->inet_opt;
opt->optlen = 0;
- if (inet->opt)
- memcpy(optbuf, inet->opt,
- sizeof(struct ip_options)+
- inet->opt->optlen);
+ if (inet_opt)
+ memcpy(optbuf, &inet_opt->opt,
+ sizeof(struct ip_options) +
+ inet_opt->opt.optlen);
release_sock(sk);

if (opt->optlen == 0)
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index ab996f9..07ab583 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -459,6 +459,7 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
__be32 saddr;
u8 tos;
int err;
+ struct ip_options_data opt_copy;

err = -EMSGSIZE;
if (len > 0xFFFF)
@@ -519,8 +520,18 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
saddr = ipc.addr;
ipc.addr = daddr;

- if (!ipc.opt)
- ipc.opt = inet->opt;
+ if (!ipc.opt) {
+ struct ip_options_rcu *inet_opt;
+
+ rcu_read_lock();
+ inet_opt = rcu_dereference(inet->inet_opt);
+ if (inet_opt) {
+ memcpy(&opt_copy, inet_opt,
+ sizeof(*inet_opt) + inet_opt->opt.optlen);
+ ipc.opt = &opt_copy.opt;
+ }
+ rcu_read_unlock();
+ }

if (ipc.opt) {
err = -EINVAL;
@@ -529,10 +540,10 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
*/
if (inet->hdrincl)
goto done;
- if (ipc.opt->srr) {
+ if (ipc.opt->opt.srr) {
if (!daddr)
goto done;
- daddr = ipc.opt->faddr;
+ daddr = ipc.opt->opt.faddr;
}
}
tos = RT_CONN_FLAGS(sk);
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index a6e0e07..0a94b64 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -309,10 +309,10 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
* the ACK carries the same options again (see RFC1122 4.2.3.8)
*/
if (opt && opt->optlen) {
- int opt_size = sizeof(struct ip_options) + opt->optlen;
+ int opt_size = sizeof(struct ip_options_rcu) + opt->optlen;

ireq->opt = kmalloc(opt_size, GFP_ATOMIC);
- if (ireq->opt != NULL && ip_options_echo(ireq->opt, skb)) {
+ if (ireq->opt != NULL && ip_options_echo(&ireq->opt->opt, skb)) {
kfree(ireq->opt);
ireq->opt = NULL;
}
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 6a4e832..d746d3b3 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -152,6 +152,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
__be32 daddr, nexthop;
int tmp;
int err;
+ struct ip_options_rcu *inet_opt;

if (addr_len < sizeof(struct sockaddr_in))
return -EINVAL;
@@ -160,10 +161,11 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
return -EAFNOSUPPORT;

nexthop = daddr = usin->sin_addr.s_addr;
- if (inet->opt && inet->opt->srr) {
+ inet_opt = inet->inet_opt;
+ if (inet_opt && inet_opt->opt.srr) {
if (!daddr)
return -EINVAL;
- nexthop = inet->opt->faddr;
+ nexthop = inet_opt->opt.faddr;
}

tmp = ip_route_connect(&rt, nexthop, inet->saddr,
@@ -181,7 +183,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
return -ENETUNREACH;
}

- if (!inet->opt || !inet->opt->srr)
+ if (!inet_opt || !inet_opt->opt.srr)
daddr = rt->rt_dst;

if (!inet->saddr)
@@ -215,8 +217,8 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
inet->daddr = daddr;

inet_csk(sk)->icsk_ext_hdr_len = 0;
- if (inet->opt)
- inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
+ if (inet_opt)
+ inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;

tp->rx_opt.mss_clamp = 536;

@@ -802,17 +804,18 @@ static void syn_flood_warning(struct sk_buff *skb)
/*
* Save and compile IPv4 options into the request_sock if needed.
*/
-static struct ip_options *tcp_v4_save_options(struct sock *sk,
- struct sk_buff *skb)
+static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk,
+ struct sk_buff *skb)
{
- struct ip_options *opt = &(IPCB(skb)->opt);
- struct ip_options *dopt = NULL;
+ const struct ip_options *opt = &(IPCB(skb)->opt);
+ struct ip_options_rcu *dopt = NULL;

if (opt && opt->optlen) {
- int opt_size = optlength(opt);
+ int opt_size = sizeof(*dopt) + opt->optlen;
+
dopt = kmalloc(opt_size, GFP_ATOMIC);
if (dopt) {
- if (ip_options_echo(dopt, skb)) {
+ if (ip_options_echo(&dopt->opt, skb)) {
kfree(dopt);
dopt = NULL;
}
@@ -1362,6 +1365,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
#ifdef CONFIG_TCP_MD5SIG
struct tcp_md5sig_key *key;
#endif
+ struct ip_options_rcu *inet_opt;

if (sk_acceptq_is_full(sk))
goto exit_overflow;
@@ -1382,13 +1386,14 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
newinet->daddr = ireq->rmt_addr;
newinet->rcv_saddr = ireq->loc_addr;
newinet->saddr = ireq->loc_addr;
- newinet->opt = ireq->opt;
+ inet_opt = ireq->opt;
+ rcu_assign_pointer(newinet->inet_opt, inet_opt);
ireq->opt = NULL;
newinet->mc_index = inet_iif(skb);
newinet->mc_ttl = ip_hdr(skb)->ttl;
inet_csk(newsk)->icsk_ext_hdr_len = 0;
- if (newinet->opt)
- inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
+ if (inet_opt)
+ inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
newinet->id = newtp->write_seq ^ jiffies;

tcp_mtup_init(newsk);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 8e28770..af559e0 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -592,6 +592,7 @@ int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
int err, is_udplite = IS_UDPLITE(sk);
int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
+ struct ip_options_data opt_copy;

if (len > 0xFFFF)
return -EMSGSIZE;
@@ -663,22 +664,32 @@ int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
free = 1;
connected = 0;
}
- if (!ipc.opt)
- ipc.opt = inet->opt;
+ if (!ipc.opt) {
+ struct ip_options_rcu *inet_opt;
+
+ rcu_read_lock();
+ inet_opt = rcu_dereference(inet->inet_opt);
+ if (inet_opt) {
+ memcpy(&opt_copy, inet_opt,
+ sizeof(*inet_opt) + inet_opt->opt.optlen);
+ ipc.opt = &opt_copy.opt;
+ }
+ rcu_read_unlock();
+ }

saddr = ipc.addr;
ipc.addr = faddr = daddr;

- if (ipc.opt && ipc.opt->srr) {
+ if (ipc.opt && ipc.opt->opt.srr) {
if (!daddr)
return -EINVAL;
- faddr = ipc.opt->faddr;
+ faddr = ipc.opt->opt.faddr;
connected = 0;
}
tos = RT_TOS(inet->tos);
if (sock_flag(sk, SOCK_LOCALROUTE) ||
(msg->msg_flags & MSG_DONTROUTE) ||
- (ipc.opt && ipc.opt->is_strictroute)) {
+ (ipc.opt && ipc.opt->opt.is_strictroute)) {
tos |= RTO_ONLINK;
connected = 0;
}
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index faae6df..1b25191 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1391,7 +1391,7 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,

First: no IPv4 options.
*/
- newinet->opt = NULL;
+ newinet->inet_opt = NULL;
newnp->ipv6_fl_list = NULL;

/* Clone RX bits */
--
1.7.12.2.21.g234cd45.dirty



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