cregit-Linux how code gets into the kernel

Release 4.8 net/ipv4/ip_options.c

Directory: net/ipv4
/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              The options processing module for ip.c
 *
 * Authors:     A.N.Kuznetsov
 *
 */


#define pr_fmt(fmt) "IPv4: " fmt

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/icmp.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/route.h>
#include <net/cipso_ipv4.h>
#include <net/ip_fib.h>

/*
 * Write options to IP header, record destination address to
 * source route option, address of outgoing interface
 * (we should already know it, so that this  function is allowed be
 * called only after routing decision) and timestamp,
 * if we originate this datagram.
 *
 * daddr is real destination address, next hop is recorded in IP header.
 * saddr is address of outgoing interface.
 */


void ip_options_build(struct sk_buff *skb, struct ip_options *opt, __be32 daddr, struct rtable *rt, int is_frag) { unsigned char *iph = skb_network_header(skb); memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options)); memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen); opt = &(IPCB(skb)->opt); if (opt->srr) memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4); if (!is_frag) { if (opt->rr_needaddr) ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, skb, rt); if (opt->ts_needaddr) ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, skb, rt); if (opt->ts_needtime) { __be32 midtime; midtime = inet_current_timestamp(); memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4); } return; } if (opt->rr) { memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]); opt->rr = 0; opt->rr_needaddr = 0; } if (opt->ts) { memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]); opt->ts = 0; opt->ts_needaddr = opt->ts_needtime = 0; } }

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PersonTokensPropCommitsCommitProp
pre-gitpre-git30196.47%337.50%
david s. millerdavid s. miller41.28%112.50%
arnaldo carvalho de meloarnaldo carvalho de melo30.96%112.50%
al viroal viro20.64%225.00%
deepa dinamanideepa dinamani20.64%112.50%
Total312100.00%8100.00%

/* * Provided (sopt, skb) points to received options, * build in dopt compiled option set appropriate for answering. * i.e. invert SRR option, copy anothers, * and grab room in RR/TS options. * * NOTE: dopt cannot point to skb. */
int __ip_options_echo(struct ip_options *dopt, struct sk_buff *skb, const struct ip_options *sopt) { unsigned char *sptr, *dptr; int soffset, doffset; int optlen; memset(dopt, 0, sizeof(struct ip_options)); if (sopt->optlen == 0) return 0; sptr = skb_network_header(skb); dptr = dopt->__data; if (sopt->rr) { optlen = sptr[sopt->rr+1]; soffset = sptr[sopt->rr+2]; dopt->rr = dopt->optlen + sizeof(struct iphdr); memcpy(dptr, sptr+sopt->rr, optlen); if (sopt->rr_needaddr && soffset <= optlen) { if (soffset + 3 > optlen) return -EINVAL; dptr[2] = soffset + 4; dopt->rr_needaddr = 1; } dptr += optlen; dopt->optlen += optlen; } if (sopt->ts) { optlen = sptr[sopt->ts+1]; soffset = sptr[sopt->ts+2]; dopt->ts = dopt->optlen + sizeof(struct iphdr); memcpy(dptr, sptr+sopt->ts, optlen); if (soffset <= optlen) { if (sopt->ts_needaddr) { if (soffset + 3 > optlen) return -EINVAL; dopt->ts_needaddr = 1; soffset += 4; } if (sopt->ts_needtime) { if (soffset + 3 > optlen) return -EINVAL; if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) { dopt->ts_needtime = 1; soffset += 4; } else { dopt->ts_needtime = 0; if (soffset + 7 <= optlen) { __be32 addr; memcpy(&addr, dptr+soffset-1, 4); if (inet_addr_type(dev_net(skb_dst(skb)->dev), addr) != RTN_UNICAST) { dopt->ts_needtime = 1; soffset += 8; } } } } dptr[2] = soffset; } dptr += optlen; dopt->optlen += optlen; } if (sopt->srr) { unsigned char *start = sptr+sopt->srr; __be32 faddr; optlen = start[1]; soffset = start[2]; doffset = 0; if (soffset > optlen) soffset = optlen + 1; soffset -= 4; if (soffset > 3) { memcpy(&faddr, &start[soffset-1], 4); for (soffset -= 4, doffset = 4; soffset > 3; soffset -= 4, doffset += 4) memcpy(&dptr[doffset-1], &start[soffset-1], 4); /* * RFC1812 requires to fix illegal source routes. */ if (memcmp(&ip_hdr(skb)->saddr, &start[soffset + 3], 4) == 0) doffset -= 4; } if (doffset > 3) { __be32 daddr = fib_compute_spec_dst(skb); memcpy(&start[doffset-1], &daddr, 4); dopt->faddr = faddr; dptr[0] = start[0]; dptr[1] = doffset+3; dptr[2] = 4; dptr += doffset+3; dopt->srr = dopt->optlen + sizeof(struct iphdr); dopt->optlen += doffset+3; dopt->is_strictroute = sopt->is_strictroute; } } if (sopt->cipso) { optlen = sptr[sopt->cipso+1]; dopt->cipso = dopt->optlen+sizeof(struct iphdr); memcpy(dptr, sptr+sopt->cipso, optlen); dptr += optlen; dopt->optlen += optlen; } while (dopt->optlen & 3) { *dptr++ = IPOPT_END; dopt->optlen++; } return 0; }

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PersonTokensPropCommitsCommitProp
pre-gitpre-git64787.79%631.58%
paul moorepaul moore567.60%15.26%
julian anastasovjulian anastasov81.09%15.26%
eric dumazeteric dumazet81.09%315.79%
arnaldo carvalho de meloarnaldo carvalho de melo60.81%210.53%
jan luebbejan luebbe30.41%15.26%
denis v. lunevdenis v. lunev30.41%15.26%
hideaki yoshifujihideaki yoshifuji30.41%15.26%
al viroal viro20.27%210.53%
eric w. biedermaneric w. biederman10.14%15.26%
Total737100.00%19100.00%

/* * Options "fragmenting", just fill options not * allowed in fragments with NOOPs. * Simple and stupid 8), but the most efficient way. */
void ip_options_fragment(struct sk_buff *skb) { unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr); struct ip_options *opt = &(IPCB(skb)->opt); int l = opt->optlen; int optlen; while (l > 0) { switch (*optptr) { case IPOPT_END: return; case IPOPT_NOOP: l--; optptr++; continue; } optlen = optptr[1]; if (optlen < 2 || optlen > l) return; if (!IPOPT_COPIED(*optptr)) memset(optptr, IPOPT_NOOP, optlen); l -= optlen; optptr += optlen; } opt->ts = 0; opt->rr = 0; opt->rr_needaddr = 0; opt->ts_needaddr = 0; opt->ts_needtime = 0; }

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pre-gitpre-git14594.16%360.00%
wei yongjunwei yongjun63.90%120.00%
arnaldo carvalho de meloarnaldo carvalho de melo31.95%120.00%
Total154100.00%5100.00%

/* helper used by ip_options_compile() to call fib_compute_spec_dst() * at most one time. */
static void spec_dst_fill(__be32 *spec_dst, struct sk_buff *skb) { if (*spec_dst == htonl(INADDR_ANY)) *spec_dst = fib_compute_spec_dst(skb); }

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eric dumazeteric dumazet33100.00%1100.00%
Total33100.00%1100.00%

/* * Verify options and fill pointers in struct options. * Caller should clear *opt, and set opt->data. * If opt == NULL, then skb->data should point to IP header. */
int ip_options_compile(struct net *net, struct ip_options *opt, struct sk_buff *skb) { __be32 spec_dst = htonl(INADDR_ANY); unsigned char *pp_ptr = NULL; struct rtable *rt = NULL; unsigned char *optptr; unsigned char *iph; int optlen, l; if (skb) { rt = skb_rtable(skb); optptr = (unsigned char *)&(ip_hdr(skb)[1]); } else optptr = opt->__data; iph = optptr - sizeof(struct iphdr); for (l = opt->optlen; l > 0; ) { switch (*optptr) { case IPOPT_END: for (optptr++, l--; l > 0; optptr++, l--) { if (*optptr != IPOPT_END) { *optptr = IPOPT_END; opt->is_changed = 1; } } goto eol; case IPOPT_NOOP: l--; optptr++; continue; } if (unlikely(l < 2)) { pp_ptr = optptr; goto error; } optlen = optptr[1]; if (optlen < 2 || optlen > l) { pp_ptr = optptr; goto error; } switch (*optptr) { case IPOPT_SSRR: case IPOPT_LSRR: if (optlen < 3) { pp_ptr = optptr + 1; goto error; } if (optptr[2] < 4) { pp_ptr = optptr + 2; goto error; } /* NB: cf RFC-1812 5.2.4.1 */ if (opt->srr) { pp_ptr = optptr; goto error; } if (!skb) { if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) { pp_ptr = optptr + 1; goto error; } memcpy(&opt->faddr, &optptr[3], 4); if (optlen > 7) memmove(&optptr[3], &optptr[7], optlen-7); } opt->is_strictroute = (optptr[0] == IPOPT_SSRR); opt->srr = optptr - iph; break; case IPOPT_RR: if (opt->rr) { pp_ptr = optptr; goto error; } if (optlen < 3) { pp_ptr = optptr + 1; goto error; } if (optptr[2] < 4) { pp_ptr = optptr + 2; goto error; } if (optptr[2] <= optlen) { if (optptr[2]+3 > optlen) { pp_ptr = optptr + 2; goto error; } if (rt) { spec_dst_fill(&spec_dst, skb); memcpy(&optptr[optptr[2]-1], &spec_dst, 4); opt->is_changed = 1; } optptr[2] += 4; opt->rr_needaddr = 1; } opt->rr = optptr - iph; break; case IPOPT_TIMESTAMP: if (opt->ts) { pp_ptr = optptr; goto error; } if (optlen < 4) { pp_ptr = optptr + 1; goto error; } if (optptr[2] < 5) { pp_ptr = optptr + 2; goto error; } if (optptr[2] <= optlen) { unsigned char *timeptr = NULL; if (optptr[2]+3 > optlen) { pp_ptr = optptr + 2; goto error; } switch (optptr[3]&0xF) { case IPOPT_TS_TSONLY: if (skb) timeptr = &optptr[optptr[2]-1]; opt->ts_needtime = 1; optptr[2] += 4; break; case IPOPT_TS_TSANDADDR: if (optptr[2]+7 > optlen) { pp_ptr = optptr + 2; goto error; } if (rt) { spec_dst_fill(&spec_dst, skb); memcpy(&optptr[optptr[2]-1], &spec_dst, 4); timeptr = &optptr[optptr[2]+3]; } opt->ts_needaddr = 1; opt->ts_needtime = 1; optptr[2] += 8; break; case IPOPT_TS_PRESPEC: if (optptr[2]+7 > optlen) { pp_ptr = optptr + 2; goto error; } { __be32 addr; memcpy(&addr, &optptr[optptr[2]-1], 4); if (inet_addr_type(net, addr) == RTN_UNICAST) break; if (skb) timeptr = &optptr[optptr[2]+3]; } opt->ts_needtime = 1; optptr[2] += 8; break; default: if (!skb && !ns_capable(net->user_ns, CAP_NET_RAW)) { pp_ptr = optptr + 3; goto error; } break; } if (timeptr) { __be32 midtime; midtime = inet_current_timestamp(); memcpy(timeptr, &midtime, 4); opt->is_changed = 1; } } else if ((optptr[3]&0xF) != IPOPT_TS_PRESPEC) { unsigned int overflow = optptr[3]>>4; if (overflow == 15) { pp_ptr = optptr + 3; goto error; } if (skb) { optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4); opt->is_changed = 1; } } opt->ts = optptr - iph; break; case IPOPT_RA: if (optlen < 4) { pp_ptr = optptr + 1; goto error; } if (optptr[2] == 0 && optptr[3] == 0) opt->router_alert = optptr - iph; break; case IPOPT_CIPSO: if ((!skb && !ns_capable(net->user_ns, CAP_NET_RAW)) || opt->cipso) { pp_ptr = optptr; goto error; } opt->cipso = optptr - iph; if (cipso_v4_validate(skb, &optptr)) { pp_ptr = optptr; goto error; } break; case IPOPT_SEC: case IPOPT_SID: default: if (!skb && !ns_capable(net->user_ns, CAP_NET_RAW)) { pp_ptr = optptr; goto error; } break; } l -= optlen; optptr += optlen; } eol: if (!pp_ptr) return 0; error: if (skb) { icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24)); } return -EINVAL; }

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PersonTokensPropCommitsCommitProp
pre-gitpre-git100783.64%829.63%
paul moorepaul moore564.65%311.11%
eric dumazeteric dumazet393.24%311.11%
david s. millerdavid s. miller292.41%27.41%
david warddavid ward221.83%27.41%
denis v. lunevdenis v. lunev181.50%27.41%
eric w. biedermaneric w. biederman161.33%27.41%
deepa dinamanideepa dinamani80.66%13.70%
jeff defouwjeff defouw30.25%13.70%
hisao tanabehisao tanabe30.25%13.70%
chris metcalfchris metcalf20.17%13.70%
al viroal viro10.08%13.70%
Total1204100.00%27100.00%

EXPORT_SYMBOL(ip_options_compile); /* * Undo all the changes done by ip_options_compile(). */
void ip_options_undo(struct ip_options *opt) { if (opt->srr) { unsigned char *optptr = opt->__data+opt->srr-sizeof(struct iphdr); memmove(optptr+7, optptr+3, optptr[1]-7); memcpy(optptr+3, &opt->faddr, 4); } if (opt->rr_needaddr) { unsigned char *optptr = opt->__data+opt->rr-sizeof(struct iphdr); optptr[2] -= 4; memset(&optptr[optptr[2]-1], 0, 4); } if (opt->ts) { unsigned char *optptr = opt->__data+opt->ts-sizeof(struct iphdr); if (opt->ts_needtime) { optptr[2] -= 4; memset(&optptr[optptr[2]-1], 0, 4); if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC) optptr[2] -= 4; } if (opt->ts_needaddr) { optptr[2] -= 4; memset(&optptr[optptr[2]-1], 0, 4); } } }

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pre-gitpre-git234100.00%2100.00%
Total234100.00%2100.00%


static struct ip_options_rcu *ip_options_get_alloc(const int optlen) { return kzalloc(sizeof(struct ip_options_rcu) + ((optlen + 3) & ~3), GFP_KERNEL); }

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pre-gitpre-git2674.29%240.00%
arnaldo carvalho de meloarnaldo carvalho de melo411.43%120.00%
mariusz kozlowskimariusz kozlowski38.57%120.00%
eric dumazeteric dumazet25.71%120.00%
Total35100.00%5100.00%


static int ip_options_get_finish(struct net *net, struct ip_options_rcu **optp, struct ip_options_rcu *opt, int optlen) { while (optlen & 3) opt->opt.__data[optlen++] = IPOPT_END; opt->opt.optlen = optlen; if (optlen && ip_options_compile(net, &opt->opt, NULL)) { kfree(opt); return -EINVAL; } kfree(*optp); *optp = opt; return 0; }

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pre-gitpre-git5559.78%337.50%
arnaldo carvalho de meloarnaldo carvalho de melo1516.30%112.50%
eric dumazeteric dumazet99.78%112.50%
denis v. lunevdenis v. lunev77.61%225.00%
david s. millerdavid s. miller66.52%112.50%
Total92100.00%8100.00%


int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp, unsigned char __user *data, int optlen) { struct ip_options_rcu *opt = ip_options_get_alloc(optlen); if (!opt) return -ENOMEM; if (optlen && copy_from_user(opt->opt.__data, data, optlen)) { kfree(opt); return -EFAULT; } return ip_options_get_finish(net, optp, opt, optlen); }

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arnaldo carvalho de meloarnaldo carvalho de melo7386.90%133.33%
denis v. lunevdenis v. lunev78.33%133.33%
eric dumazeteric dumazet44.76%133.33%
Total84100.00%3100.00%


int ip_options_get(struct net *net, struct ip_options_rcu **optp, unsigned char *data, int optlen) { struct ip_options_rcu *opt = ip_options_get_alloc(optlen); if (!opt) return -ENOMEM; if (optlen) memcpy(opt->opt.__data, data, optlen); return ip_options_get_finish(net, optp, opt, optlen); }

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arnaldo carvalho de meloarnaldo carvalho de melo6184.72%133.33%
denis v. lunevdenis v. lunev79.72%133.33%
eric dumazeteric dumazet45.56%133.33%
Total72100.00%3100.00%


void ip_forward_options(struct sk_buff *skb) { struct ip_options *opt = &(IPCB(skb)->opt); unsigned char *optptr; struct rtable *rt = skb_rtable(skb); unsigned char *raw = skb_network_header(skb); if (opt->rr_needaddr) { optptr = (unsigned char *)raw + opt->rr; ip_rt_get_source(&optptr[optptr[2]-5], skb, rt); opt->is_changed = 1; } if (opt->srr_is_hit) { int srrptr, srrspace; optptr = raw + opt->srr; for ( srrptr = optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4 ) { if (srrptr + 3 > srrspace) break; if (memcmp(&opt->nexthop, &optptr[srrptr-1], 4) == 0) break; } if (srrptr + 3 <= srrspace) { opt->is_changed = 1; ip_hdr(skb)->daddr = opt->nexthop; ip_rt_get_source(&optptr[srrptr-