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Refactor ip6_getpcbopt() for better locking and memory management

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Created GET_PKTOPT_EXT_HDR() and GET_PKTOPT_SOCKADDR() macros to
handle safely fetching options from in6p_outputopts, including
properly dealing with in6p locking and preparing memory for
sooptcopyout().

Changed the function signature of ip6_getpcbopt() to allow the
function to acquire and release locks on in6p as needed.

Submitted by:	Jason Eggleston <jason@eggnet.com>
Sponsored by:	Limelight Networks
Differential Revision:	https://reviews.freebsd.org/D14619
This commit is contained in:
Sean Bruno 2018-03-22 23:34:48 +00:00
parent 2a499acf59
commit 06b479a6a7
1 changed files with 52 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

90
sys/netinet6/ip6_output.c
View File

@ -135,7 +135,7 @@ static int ip6_pcbopt(int, u_char *, int, struct ip6_pktopts **,
struct ucred *, int);
static int ip6_pcbopts(struct ip6_pktopts **, struct mbuf *,
struct socket *, struct sockopt *);
static int ip6_getpcbopt(struct ip6_pktopts *, int, struct sockopt *);
static int ip6_getpcbopt(struct inpcb *, int, struct sockopt *);
static int ip6_setpktopt(int, u_char *, int, struct ip6_pktopts *,
struct ucred *, int, int, int);
@ -2132,8 +2132,7 @@ do { \
case IPV6_DONTFRAG:
case IPV6_USE_MIN_MTU:
case IPV6_PREFER_TEMPADDR:
error = ip6_getpcbopt(in6p->in6p_outputopts,
optname, sopt);
error = ip6_getpcbopt(in6p, optname, sopt);
break;
case IPV6_MULTICAST_IF:
@ -2310,17 +2309,50 @@ ip6_pcbopt(int optname, u_char *buf, int len, struct ip6_pktopts **pktopt,
return (ip6_setpktopt(optname, buf, len, opt, cred, 1, 0, uproto));
}
#define GET_PKTOPT_VAR(field, lenexpr) do { \
if (pktopt && pktopt->field) { \
INP_RUNLOCK(in6p); \
optdata = malloc(sopt->sopt_valsize, M_TEMP, M_WAITOK); \
malloc_optdata = true; \
INP_RLOCK(in6p); \
if (in6p->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) { \
INP_RUNLOCK(in6p); \
free(optdata, M_TEMP); \
return (ECONNRESET); \
} \
pktopt = in6p->in6p_outputopts; \
if (pktopt && pktopt->field) { \
optdatalen = min(lenexpr, sopt->sopt_valsize); \
bcopy(&pktopt->field, optdata, optdatalen); \
} else { \
free(optdata, M_TEMP); \
optdata = NULL; \
malloc_optdata = false; \
} \
} \
} while(0)
#define GET_PKTOPT_EXT_HDR(field) GET_PKTOPT_VAR(field, \
(((struct ip6_ext *)pktopt->field)->ip6e_len + 1) << 3)
#define GET_PKTOPT_SOCKADDR(field) GET_PKTOPT_VAR(field, \
pktopt->field->sa_len)
static int
ip6_getpcbopt(struct ip6_pktopts *pktopt, int optname, struct sockopt *sopt)
ip6_getpcbopt(struct inpcb *in6p, int optname, struct sockopt *sopt)
{
void *optdata = NULL;
bool malloc_optdata = false;
int optdatalen = 0;
struct ip6_ext *ip6e;
int error = 0;
struct in6_pktinfo null_pktinfo;
int deftclass = 0, on;
int defminmtu = IP6PO_MINMTU_MCASTONLY;
int defpreftemp = IP6PO_TEMPADDR_SYSTEM;
struct ip6_pktopts *pktopt;
INP_RLOCK(in6p);
pktopt = in6p->in6p_outputopts;
switch (optname) {
case IPV6_PKTINFO:
@ -2337,50 +2369,29 @@ ip6_getpcbopt(struct ip6_pktopts *pktopt, int optname, struct sockopt *sopt)
break;
case IPV6_TCLASS:
if (pktopt && pktopt->ip6po_tclass >= 0)
optdata = (void *)&pktopt->ip6po_tclass;
else
optdata = (void *)&deftclass;
deftclass = pktopt->ip6po_tclass;
optdata = (void *)&deftclass;
optdatalen = sizeof(int);
break;
case IPV6_HOPOPTS:
if (pktopt && pktopt->ip6po_hbh) {
optdata = (void *)pktopt->ip6po_hbh;
ip6e = (struct ip6_ext *)pktopt->ip6po_hbh;
optdatalen = (ip6e->ip6e_len + 1) << 3;
}
GET_PKTOPT_EXT_HDR(ip6po_hbh);
break;
case IPV6_RTHDR:
if (pktopt && pktopt->ip6po_rthdr) {
optdata = (void *)pktopt->ip6po_rthdr;
ip6e = (struct ip6_ext *)pktopt->ip6po_rthdr;
optdatalen = (ip6e->ip6e_len + 1) << 3;
}
GET_PKTOPT_EXT_HDR(ip6po_rthdr);
break;
case IPV6_RTHDRDSTOPTS:
if (pktopt && pktopt->ip6po_dest1) {
optdata = (void *)pktopt->ip6po_dest1;
ip6e = (struct ip6_ext *)pktopt->ip6po_dest1;
optdatalen = (ip6e->ip6e_len + 1) << 3;
}
GET_PKTOPT_EXT_HDR(ip6po_dest1);
break;
case IPV6_DSTOPTS:
if (pktopt && pktopt->ip6po_dest2) {
optdata = (void *)pktopt->ip6po_dest2;
ip6e = (struct ip6_ext *)pktopt->ip6po_dest2;
optdatalen = (ip6e->ip6e_len + 1) << 3;
}
GET_PKTOPT_EXT_HDR(ip6po_dest2);
break;
case IPV6_NEXTHOP:
if (pktopt && pktopt->ip6po_nexthop) {
optdata = (void *)pktopt->ip6po_nexthop;
optdatalen = pktopt->ip6po_nexthop->sa_len;
}
GET_PKTOPT_SOCKADDR(ip6po_nexthop);
break;
case IPV6_USE_MIN_MTU:
if (pktopt)
optdata = (void *)&pktopt->ip6po_minmtu;
else
optdata = (void *)&defminmtu;
defminmtu = pktopt->ip6po_minmtu;
optdata = (void *)&defminmtu;
optdatalen = sizeof(int);
break;
case IPV6_DONTFRAG:
@ -2393,19 +2404,22 @@ ip6_getpcbopt(struct ip6_pktopts *pktopt, int optname, struct sockopt *sopt)
break;
case IPV6_PREFER_TEMPADDR:
if (pktopt)
optdata = (void *)&pktopt->ip6po_prefer_tempaddr;
else
optdata = (void *)&defpreftemp;
defpreftemp = pktopt->ip6po_prefer_tempaddr;
optdata = (void *)&defpreftemp;
optdatalen = sizeof(int);
break;
default: /* should not happen */
#ifdef DIAGNOSTIC
panic("ip6_getpcbopt: unexpected option\n");
#endif
INP_RUNLOCK(in6p);
return (ENOPROTOOPT);
}
INP_RUNLOCK(in6p);
error = sooptcopyout(sopt, optdata, optdatalen);
if (malloc_optdata)
free(optdata, M_TEMP);
return (error);
}