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udplite: fix various data-races

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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: ba4e58eca8 ("[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>
This commit is contained in:
Eric Dumazet 2023-09-12 09:17:30 +00:00 committed by Paolo Abeni
parent 729549aa35
commit 882af43a0f
4 changed files with 27 additions and 23 deletions
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6
include/linux/udp.h
View File

@ -40,6 +40,8 @@ enum {
UDP_FLAGS_ACCEPT_FRAGLIST, UDP_FLAGS_ACCEPT_FRAGLIST,
UDP_FLAGS_ACCEPT_L4, UDP_FLAGS_ACCEPT_L4,
UDP_FLAGS_ENCAP_ENABLED, /* This socket enabled encap */ 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 { struct udp_sock {
@ -54,10 +56,6 @@ struct udp_sock {
int pending; /* Any pending frames ? */ int pending; /* Any pending frames ? */
__u8 encap_type; /* Is this an Encapsulation socket? */ __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 * Following member retains the information to create a UDP header
* when the socket is uncorked. * when the socket is uncorked.

14
include/net/udplite.h
View File

@ -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. */ /* Fast-path computation of checksum. Socket may not be locked. */
static inline __wsum udplite_csum(struct sk_buff *skb) 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 int off = skb_transport_offset(skb);
const struct sock *sk = skb->sk;
int len = skb->len - off; int len = skb->len - off;
if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) { if (udp_test_bit(UDPLITE_SEND_CC, sk)) {
if (0 < up->pcslen) u16 pcslen = READ_ONCE(udp_sk(sk)->pcslen);
len = up->pcslen;
udp_hdr(skb)->len = htons(up->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 */ skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */

21
net/ipv4/udp.c
View File

@ -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 * 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 * 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 * delivery of packets with coverage values less than a value
* provided by the application." * 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", net_dbg_ratelimited("UDPLite: partial coverage %d while full coverage %d requested\n",
UDP_SKB_CB(skb)->cscov, skb->len); UDP_SKB_CB(skb)->cscov, skb->len);
goto drop; 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. * that it wants x while sender emits packets of smaller size y.
* Therefore the above ...()->partial_cov statement is essential. * 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", 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; goto drop;
} }
} }
@ -2729,8 +2730,8 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
val = 8; val = 8;
else if (val > USHRT_MAX) else if (val > USHRT_MAX)
val = USHRT_MAX; val = USHRT_MAX;
up->pcslen = val; WRITE_ONCE(up->pcslen, val);
up->pcflag |= UDPLITE_SEND_CC; udp_set_bit(UDPLITE_SEND_CC, sk);
break; break;
/* The receiver specifies a minimum checksum coverage value. To make /* 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; val = 8;
else if (val > USHRT_MAX) else if (val > USHRT_MAX)
val = USHRT_MAX; val = USHRT_MAX;
up->pcrlen = val; WRITE_ONCE(up->pcrlen, val);
up->pcflag |= UDPLITE_RECV_CC; udp_set_bit(UDPLITE_RECV_CC, sk);
break; break;
default: 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 /* The following two cannot be changed on UDP sockets, the return is
* always 0 (which corresponds to the full checksum coverage of UDP). */ * always 0 (which corresponds to the full checksum coverage of UDP). */
case UDPLITE_SEND_CSCOV: case UDPLITE_SEND_CSCOV:
val = up->pcslen; val = READ_ONCE(up->pcslen);
break; break;
case UDPLITE_RECV_CSCOV: case UDPLITE_RECV_CSCOV:
val = up->pcrlen; val = READ_ONCE(up->pcrlen);
break; break;
default: default:

9
net/ipv6/udp.c
View File

@ -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). * 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", net_dbg_ratelimited("UDPLITE6: partial coverage %d while full coverage %d requested\n",
UDP_SKB_CB(skb)->cscov, skb->len); UDP_SKB_CB(skb)->cscov, skb->len);
goto drop; 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", 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; goto drop;
} }
} }