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udp: move udp->no_check6_rx to udp->udp_flags

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syzbot reported that udp->no_check6_rx can be read locklessly.
Use one atomic bit from udp->udp_flags.

Fixes: 1c19448c9b ("net: Make enabling of zero UDP6 csums more restrictive")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Eric Dumazet 2023-09-12 09:17:23 +00:00 committed by Paolo Abeni
parent a0002127cd
commit bcbc1b1de8
3 changed files with 10 additions and 10 deletions
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10
include/linux/udp.h
View file

@ -35,6 +35,7 @@ static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask)
enum {
UDP_FLAGS_CORK, /* Cork is required */
UDP_FLAGS_NO_CHECK6_TX, /* Send zero UDP6 checksums on TX? */
UDP_FLAGS_NO_CHECK6_RX, /* Allow zero UDP6 checksums on RX? */
};
struct udp_sock {
@ -48,8 +49,7 @@ struct udp_sock {
int pending; /* Any pending frames ? */
__u8 encap_type; /* Is this an Encapsulation socket? */
unsigned char no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */
encap_enabled:1, /* This socket enabled encap
unsigned char encap_enabled:1, /* This socket enabled encap
* processing; UDP tunnels and
* different encapsulation layer set
* this
@ -120,7 +120,7 @@ static inline void udp_set_no_check6_tx(struct sock *sk, bool val)
static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
{
udp_sk(sk)->no_check6_rx = val;
udp_assign_bit(NO_CHECK6_RX, sk, val);
}
static inline bool udp_get_no_check6_tx(const struct sock *sk)
@ -128,9 +128,9 @@ static inline bool udp_get_no_check6_tx(const struct sock *sk)
return udp_test_bit(NO_CHECK6_TX, sk);
}
static inline bool udp_get_no_check6_rx(struct sock *sk)
static inline bool udp_get_no_check6_rx(const struct sock *sk)
{
return udp_sk(sk)->no_check6_rx;
return udp_test_bit(NO_CHECK6_RX, sk);
}
static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk,

4
net/ipv4/udp.c
View file

@ -2698,7 +2698,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
break;
case UDP_NO_CHECK6_RX:
up->no_check6_rx = valbool;
udp_set_no_check6_rx(sk, valbool);
break;
case UDP_SEGMENT:
@ -2795,7 +2795,7 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname,
break;
case UDP_NO_CHECK6_RX:
val = up->no_check6_rx;
val = udp_get_no_check6_rx(sk);
break;
case UDP_SEGMENT:

6
net/ipv6/udp.c
View file

@ -858,7 +858,7 @@ start_lookup:
/* If zero checksum and no_check is not on for
* the socket then skip it.
*/
if (!uh->check && !udp_sk(sk)->no_check6_rx)
if (!uh->check && !udp_get_no_check6_rx(sk))
continue;
if (!first) {
first = sk;
@ -980,7 +980,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
if (unlikely(rcu_dereference(sk->sk_rx_dst) != dst))
udp6_sk_rx_dst_set(sk, dst);
if (!uh->check && !udp_sk(sk)->no_check6_rx) {
if (!uh->check && !udp_get_no_check6_rx(sk)) {
if (refcounted)
sock_put(sk);
goto report_csum_error;
@ -1002,7 +1002,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
/* Unicast */
sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
if (sk) {
if (!uh->check && !udp_sk(sk)->no_check6_rx)
if (!uh->check && !udp_get_no_check6_rx(sk))
goto report_csum_error;
return udp6_unicast_rcv_skb(sk, skb, uh);
}