6.5-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit 882af43a0fc37e26d85fb0df0c9edd3bed928de4 ]
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@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 | 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 58156edec0096..d04188714dca1 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 299c14ce2bb94..dd60b51364837 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 be0370a64cc15..f712ff61beb8a 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2149,7 +2149,8 @@ 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 @@ -2162,7 +2163,7 @@ 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; @@ -2173,9 +2174,9 @@ 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; } } @@ -2754,8 +2755,8 @@ 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 @@ -2768,8 +2769,8 @@ 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: @@ -2833,11 +2834,11 @@ 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 9988160ca4a76..8d79642ae45dd 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -760,16 +760,17 @@ 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; } }