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15f35d49c9
Since UDP-Lite is always using checksum, the following path is
triggered when calculating pseudo header for it:
udp4_csum_init() or udp6_csum_init()
skb_checksum_init_zero_check()
__skb_checksum_validate_complete()
The problem can appear if skb->len is less than CHECKSUM_BREAK. In
this particular case __skb_checksum_validate_complete() also invokes
__skb_checksum_complete(skb). If UDP-Lite is using partial checksum
that covers only part of a packet, the function will return bad
checksum and the packet will be dropped.
It can be fixed if we skip skb_checksum_init_zero_check() and only
set the required pseudo header checksum for UDP-Lite with partial
checksum before udp4_csum_init()/udp6_csum_init() functions return.
Fixes: ed70fcfcee ("net: Call skb_checksum_init in IPv4")
Fixes: e4f45b7f40 ("net: Call skb_checksum_init in IPv6")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
122 lines
3.1 KiB
C
122 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <net/ip.h>
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#include <net/udp.h>
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#include <net/udplite.h>
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#include <asm/checksum.h>
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#ifndef _HAVE_ARCH_IPV6_CSUM
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__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
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const struct in6_addr *daddr,
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__u32 len, __u8 proto, __wsum csum)
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{
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int carry;
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__u32 ulen;
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__u32 uproto;
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__u32 sum = (__force u32)csum;
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sum += (__force u32)saddr->s6_addr32[0];
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carry = (sum < (__force u32)saddr->s6_addr32[0]);
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sum += carry;
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sum += (__force u32)saddr->s6_addr32[1];
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carry = (sum < (__force u32)saddr->s6_addr32[1]);
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sum += carry;
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sum += (__force u32)saddr->s6_addr32[2];
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carry = (sum < (__force u32)saddr->s6_addr32[2]);
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sum += carry;
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sum += (__force u32)saddr->s6_addr32[3];
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carry = (sum < (__force u32)saddr->s6_addr32[3]);
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sum += carry;
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sum += (__force u32)daddr->s6_addr32[0];
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carry = (sum < (__force u32)daddr->s6_addr32[0]);
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sum += carry;
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sum += (__force u32)daddr->s6_addr32[1];
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carry = (sum < (__force u32)daddr->s6_addr32[1]);
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sum += carry;
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sum += (__force u32)daddr->s6_addr32[2];
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carry = (sum < (__force u32)daddr->s6_addr32[2]);
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sum += carry;
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sum += (__force u32)daddr->s6_addr32[3];
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carry = (sum < (__force u32)daddr->s6_addr32[3]);
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sum += carry;
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ulen = (__force u32)htonl((__u32) len);
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sum += ulen;
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carry = (sum < ulen);
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sum += carry;
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uproto = (__force u32)htonl(proto);
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sum += uproto;
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carry = (sum < uproto);
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sum += carry;
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return csum_fold((__force __wsum)sum);
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}
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EXPORT_SYMBOL(csum_ipv6_magic);
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#endif
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int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
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{
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int err;
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UDP_SKB_CB(skb)->partial_cov = 0;
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UDP_SKB_CB(skb)->cscov = skb->len;
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if (proto == IPPROTO_UDPLITE) {
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err = udplite_checksum_init(skb, uh);
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if (err)
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return err;
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if (UDP_SKB_CB(skb)->partial_cov) {
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skb->csum = ip6_compute_pseudo(skb, proto);
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return 0;
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}
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}
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/* To support RFC 6936 (allow zero checksum in UDP/IPV6 for tunnels)
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* we accept a checksum of zero here. When we find the socket
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* for the UDP packet we'll check if that socket allows zero checksum
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* for IPv6 (set by socket option).
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*
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* Note, we are only interested in != 0 or == 0, thus the
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* force to int.
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*/
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return (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
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ip6_compute_pseudo);
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}
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EXPORT_SYMBOL(udp6_csum_init);
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/* Function to set UDP checksum for an IPv6 UDP packet. This is intended
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* for the simple case like when setting the checksum for a UDP tunnel.
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*/
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void udp6_set_csum(bool nocheck, struct sk_buff *skb,
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const struct in6_addr *saddr,
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const struct in6_addr *daddr, int len)
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{
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struct udphdr *uh = udp_hdr(skb);
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if (nocheck)
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uh->check = 0;
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else if (skb_is_gso(skb))
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uh->check = ~udp_v6_check(len, saddr, daddr, 0);
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else if (skb->ip_summed == CHECKSUM_PARTIAL) {
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uh->check = 0;
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uh->check = udp_v6_check(len, saddr, daddr, lco_csum(skb));
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if (uh->check == 0)
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uh->check = CSUM_MANGLED_0;
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} else {
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skb->ip_summed = CHECKSUM_PARTIAL;
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skb->csum_start = skb_transport_header(skb) - skb->head;
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skb->csum_offset = offsetof(struct udphdr, check);
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uh->check = ~udp_v6_check(len, saddr, daddr, 0);
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}
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}
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EXPORT_SYMBOL(udp6_set_csum);
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