6.1-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit a0002127cd746fcaa182ad3386ef6931c37f3bda ]
syzbot reported that udp->no_check6_tx can be read locklessly. Use one atomic bit from udp->udp_flags
Fixes: 1c19448c9ba6 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/udp.h | 10 +++++----- net/ipv4/udp.c | 4 ++-- net/ipv6/udp.c | 4 ++-- 3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/include/linux/udp.h b/include/linux/udp.h index 10b56b8231e3c..b5ca5760ae34b 100644 --- a/include/linux/udp.h +++ b/include/linux/udp.h @@ -32,6 +32,7 @@ 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? */ };
struct udp_sock { @@ -45,8 +46,7 @@ struct udp_sock {
int pending; /* Any pending frames ? */ __u8 encap_type; /* Is this an Encapsulation socket? */ - unsigned char no_check6_tx:1,/* Send zero UDP6 checksums on TX? */ - no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */ + unsigned char no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */ encap_enabled:1, /* This socket enabled encap * processing; UDP tunnels and * different encapsulation layer set @@ -112,7 +112,7 @@ static inline struct udp_sock *udp_sk(const struct sock *sk)
static inline void udp_set_no_check6_tx(struct sock *sk, bool val) { - udp_sk(sk)->no_check6_tx = val; + udp_assign_bit(NO_CHECK6_TX, sk, val); }
static inline void udp_set_no_check6_rx(struct sock *sk, bool val) @@ -120,9 +120,9 @@ static inline void udp_set_no_check6_rx(struct sock *sk, bool val) udp_sk(sk)->no_check6_rx = val; }
-static inline bool udp_get_no_check6_tx(struct sock *sk) +static inline bool udp_get_no_check6_tx(const struct sock *sk) { - return udp_sk(sk)->no_check6_tx; + return udp_test_bit(NO_CHECK6_TX, sk); }
static inline bool udp_get_no_check6_rx(struct sock *sk) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 60a754477efb2..513035e83a820 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2711,7 +2711,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, break;
case UDP_NO_CHECK6_TX: - up->no_check6_tx = valbool; + udp_set_no_check6_tx(sk, valbool); break;
case UDP_NO_CHECK6_RX: @@ -2808,7 +2808,7 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname, break;
case UDP_NO_CHECK6_TX: - val = up->no_check6_tx; + val = udp_get_no_check6_tx(sk); break;
case UDP_NO_CHECK6_RX: diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 85653e3a04fe8..c6e20293c521f 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1260,7 +1260,7 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6, kfree_skb(skb); return -EINVAL; } - if (udp_sk(sk)->no_check6_tx) { + if (udp_get_no_check6_tx(sk)) { kfree_skb(skb); return -EINVAL; } @@ -1281,7 +1281,7 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6,
if (is_udplite) csum = udplite_csum(skb); - else if (udp_sk(sk)->no_check6_tx) { /* UDP csum disabled */ + else if (udp_get_no_check6_tx(sk)) { /* UDP csum disabled */ skb->ip_summed = CHECKSUM_NONE; goto send; } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */