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a7f9a6f4cc
This patch fix the loop iteration by not walking over the last
iteration. The cmpri compressing value exempt the last segment. As the
code shows the last iteration will be overwritten by cmpre value
handling which is for the last segment.
I think this doesn't end in any bufferoverflows because we work on worst
case temporary buffer sizes but it ends in not best compression settings
in some cases.
Fixes: 8610c7c6e3 ("net: ipv6: add support for rpl sr exthdr")
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
124 lines
3.1 KiB
C
124 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/**
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* Authors:
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* (C) 2020 Alexander Aring <alex.aring@gmail.com>
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*/
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#include <net/ipv6.h>
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#include <net/rpl.h>
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#define IPV6_PFXTAIL_LEN(x) (sizeof(struct in6_addr) - (x))
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static void ipv6_rpl_addr_decompress(struct in6_addr *dst,
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const struct in6_addr *daddr,
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const void *post, unsigned char pfx)
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{
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memcpy(dst, daddr, pfx);
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memcpy(&dst->s6_addr[pfx], post, IPV6_PFXTAIL_LEN(pfx));
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}
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static void ipv6_rpl_addr_compress(void *dst, const struct in6_addr *addr,
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unsigned char pfx)
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{
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memcpy(dst, &addr->s6_addr[pfx], IPV6_PFXTAIL_LEN(pfx));
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}
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static void *ipv6_rpl_segdata_pos(const struct ipv6_rpl_sr_hdr *hdr, int i)
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{
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return (void *)&hdr->rpl_segdata[i * IPV6_PFXTAIL_LEN(hdr->cmpri)];
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}
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size_t ipv6_rpl_srh_size(unsigned char n, unsigned char cmpri,
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unsigned char cmpre)
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{
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return (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre);
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}
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void ipv6_rpl_srh_decompress(struct ipv6_rpl_sr_hdr *outhdr,
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const struct ipv6_rpl_sr_hdr *inhdr,
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const struct in6_addr *daddr, unsigned char n)
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{
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int i;
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outhdr->nexthdr = inhdr->nexthdr;
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outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3);
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outhdr->pad = 0;
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outhdr->type = inhdr->type;
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outhdr->segments_left = inhdr->segments_left;
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outhdr->cmpri = 0;
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outhdr->cmpre = 0;
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for (i = 0; i < n; i++)
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ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[i], daddr,
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ipv6_rpl_segdata_pos(inhdr, i),
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inhdr->cmpri);
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ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[n], daddr,
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ipv6_rpl_segdata_pos(inhdr, n),
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inhdr->cmpre);
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}
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static unsigned char ipv6_rpl_srh_calc_cmpri(const struct ipv6_rpl_sr_hdr *inhdr,
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const struct in6_addr *daddr,
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unsigned char n)
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{
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unsigned char plen;
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int i;
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for (plen = 0; plen < sizeof(*daddr); plen++) {
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for (i = 0; i < n; i++) {
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if (daddr->s6_addr[plen] !=
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inhdr->rpl_segaddr[i].s6_addr[plen])
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return plen;
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}
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}
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return plen;
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}
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static unsigned char ipv6_rpl_srh_calc_cmpre(const struct in6_addr *daddr,
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const struct in6_addr *last_segment)
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{
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unsigned int plen;
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for (plen = 0; plen < sizeof(*daddr); plen++) {
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if (daddr->s6_addr[plen] != last_segment->s6_addr[plen])
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break;
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}
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return plen;
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}
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void ipv6_rpl_srh_compress(struct ipv6_rpl_sr_hdr *outhdr,
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const struct ipv6_rpl_sr_hdr *inhdr,
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const struct in6_addr *daddr, unsigned char n)
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{
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unsigned char cmpri, cmpre;
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size_t seglen;
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int i;
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cmpri = ipv6_rpl_srh_calc_cmpri(inhdr, daddr, n);
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cmpre = ipv6_rpl_srh_calc_cmpre(daddr, &inhdr->rpl_segaddr[n]);
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outhdr->nexthdr = inhdr->nexthdr;
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seglen = (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre);
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outhdr->hdrlen = seglen >> 3;
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if (seglen & 0x7) {
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outhdr->hdrlen++;
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outhdr->pad = 8 - (seglen & 0x7);
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} else {
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outhdr->pad = 0;
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}
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outhdr->type = inhdr->type;
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outhdr->segments_left = inhdr->segments_left;
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outhdr->cmpri = cmpri;
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outhdr->cmpre = cmpre;
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for (i = 0; i < n; i++)
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ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, i),
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&inhdr->rpl_segaddr[i], cmpri);
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ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, n),
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&inhdr->rpl_segaddr[n], cmpre);
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}
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