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Date: Tue, 12 Sep 2023 09:17:30 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org, Willem de Bruijn <willemdebruijn.kernel@...il.com>,
eric.dumazet@...il.com, Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next 10/10] udplite: fix various data-races
udp->pcflag, udp->pcslen and udp->pcrlen reads/writes are racy.
Move udp->pcflag to udp->udp_flags for atomicity,
and add READ_ONCE()/WRITE_ONCE() annotations for pcslen and pcrlen.
Fixes: ba4e58eca8aa ("[NET]: Supporting UDP-Lite (RFC 3828) in Linux")
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
include/linux/udp.h | 6 ++----
include/net/udplite.h | 14 +++++++++-----
net/ipv4/udp.c | 21 +++++++++++----------
net/ipv6/udp.c | 9 +++++----
4 files changed, 27 insertions(+), 23 deletions(-)
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 58156edec009636f2616b8a735945658d2982054..d04188714dca14da25aa57083488cd28c34c41ba 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -40,6 +40,8 @@ enum {
UDP_FLAGS_ACCEPT_FRAGLIST,
UDP_FLAGS_ACCEPT_L4,
UDP_FLAGS_ENCAP_ENABLED, /* This socket enabled encap */
+ UDP_FLAGS_UDPLITE_SEND_CC, /* set via udplite setsockopt */
+ UDP_FLAGS_UDPLITE_RECV_CC, /* set via udplite setsockopt */
};
struct udp_sock {
@@ -54,10 +56,6 @@ struct udp_sock {
int pending; /* Any pending frames ? */
__u8 encap_type; /* Is this an Encapsulation socket? */
-/* indicator bits used by pcflag: */
-#define UDPLITE_SEND_CC 0x1 /* set via udplite setsockopt */
-#define UDPLITE_RECV_CC 0x2 /* set via udplite setsocktopt */
- __u8 pcflag; /* marks socket as UDP-Lite if > 0 */
/*
* Following member retains the information to create a UDP header
* when the socket is uncorked.
diff --git a/include/net/udplite.h b/include/net/udplite.h
index bd33ff2b8f426de24640cb7e821a28873a813260..786919d29f8de7664b5e8cabab00692ecf4b9089 100644
--- a/include/net/udplite.h
+++ b/include/net/udplite.h
@@ -66,14 +66,18 @@ static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
/* Fast-path computation of checksum. Socket may not be locked. */
static inline __wsum udplite_csum(struct sk_buff *skb)
{
- const struct udp_sock *up = udp_sk(skb->sk);
const int off = skb_transport_offset(skb);
+ const struct sock *sk = skb->sk;
int len = skb->len - off;
- if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
- if (0 < up->pcslen)
- len = up->pcslen;
- udp_hdr(skb)->len = htons(up->pcslen);
+ if (udp_test_bit(UDPLITE_SEND_CC, sk)) {
+ u16 pcslen = READ_ONCE(udp_sk(sk)->pcslen);
+
+ if (pcslen < len) {
+ if (pcslen > 0)
+ len = pcslen;
+ udp_hdr(skb)->len = htons(pcslen);
+ }
}
skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 2eeab4af17a13de5a25a2da64259b8dc2fe3d047..c3ff984b63547daf0ecfb4ab96956aee2f8d589d 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2120,7 +2120,8 @@ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
/*
* UDP-Lite specific tests, ignored on UDP sockets
*/
- if ((up->pcflag & UDPLITE_RECV_CC) && UDP_SKB_CB(skb)->partial_cov) {
+ if (udp_test_bit(UDPLITE_RECV_CC, sk) && UDP_SKB_CB(skb)->partial_cov) {
+ u16 pcrlen = READ_ONCE(up->pcrlen);
/*
* MIB statistics other than incrementing the error count are
@@ -2133,7 +2134,7 @@ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
* delivery of packets with coverage values less than a value
* provided by the application."
*/
- if (up->pcrlen == 0) { /* full coverage was set */
+ if (pcrlen == 0) { /* full coverage was set */
net_dbg_ratelimited("UDPLite: partial coverage %d while full coverage %d requested\n",
UDP_SKB_CB(skb)->cscov, skb->len);
goto drop;
@@ -2144,9 +2145,9 @@ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
* that it wants x while sender emits packets of smaller size y.
* Therefore the above ...()->partial_cov statement is essential.
*/
- if (UDP_SKB_CB(skb)->cscov < up->pcrlen) {
+ if (UDP_SKB_CB(skb)->cscov < pcrlen) {
net_dbg_ratelimited("UDPLite: coverage %d too small, need min %d\n",
- UDP_SKB_CB(skb)->cscov, up->pcrlen);
+ UDP_SKB_CB(skb)->cscov, pcrlen);
goto drop;
}
}
@@ -2729,8 +2730,8 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
val = 8;
else if (val > USHRT_MAX)
val = USHRT_MAX;
- up->pcslen = val;
- up->pcflag |= UDPLITE_SEND_CC;
+ WRITE_ONCE(up->pcslen, val);
+ udp_set_bit(UDPLITE_SEND_CC, sk);
break;
/* The receiver specifies a minimum checksum coverage value. To make
@@ -2743,8 +2744,8 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
val = 8;
else if (val > USHRT_MAX)
val = USHRT_MAX;
- up->pcrlen = val;
- up->pcflag |= UDPLITE_RECV_CC;
+ WRITE_ONCE(up->pcrlen, val);
+ udp_set_bit(UDPLITE_RECV_CC, sk);
break;
default:
@@ -2808,11 +2809,11 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname,
/* The following two cannot be changed on UDP sockets, the return is
* always 0 (which corresponds to the full checksum coverage of UDP). */
case UDPLITE_SEND_CSCOV:
- val = up->pcslen;
+ val = READ_ONCE(up->pcslen);
break;
case UDPLITE_RECV_CSCOV:
- val = up->pcrlen;
+ val = READ_ONCE(up->pcrlen);
break;
default:
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 0e79d189613bef41e3ba39c463b19761d2fa3d34..f60ba429543526b7ade2666c36dd51828ffe54a9 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -727,16 +727,17 @@ static int udpv6_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
/*
* UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
*/
- if ((up->pcflag & UDPLITE_RECV_CC) && UDP_SKB_CB(skb)->partial_cov) {
+ if (udp_test_bit(UDPLITE_RECV_CC, sk) && UDP_SKB_CB(skb)->partial_cov) {
+ u16 pcrlen = READ_ONCE(up->pcrlen);
- if (up->pcrlen == 0) { /* full coverage was set */
+ if (pcrlen == 0) { /* full coverage was set */
net_dbg_ratelimited("UDPLITE6: partial coverage %d while full coverage %d requested\n",
UDP_SKB_CB(skb)->cscov, skb->len);
goto drop;
}
- if (UDP_SKB_CB(skb)->cscov < up->pcrlen) {
+ if (UDP_SKB_CB(skb)->cscov < pcrlen) {
net_dbg_ratelimited("UDPLITE6: coverage %d too small, need min %d\n",
- UDP_SKB_CB(skb)->cscov, up->pcrlen);
+ UDP_SKB_CB(skb)->cscov, pcrlen);
goto drop;
}
}
--
2.42.0.283.g2d96d420d3-goog
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