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Fix synchronization of LB group access.

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Lookups are protected by an epoch section, so the LB group linkage must
be a CK_LIST rather than a plain LIST.  Furthermore, we were not
deferring LB group frees, so in_pcbremlbgrouphash() could race with
readers and cause a use-after-free.

Reviewed by:	sbruno, Johannes Lundberg <johalun0@gmail.com>
Tested by:	gallatin
Approved by:	re (gjb)
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D17031
This commit is contained in:
Mark Johnston 2018-09-10 19:00:29 +00:00
parent 7a364d458a
commit 54af3d0dac
3 changed files with 20 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
sys/netinet/in_pcb.c
View File

@ -235,16 +235,26 @@ in_pcblbgroup_alloc(struct inpcblbgrouphead *hdr, u_char vflag,
grp->il_lport = port; grp->il_lport = port;
grp->il_dependladdr = *addr; grp->il_dependladdr = *addr;
grp->il_inpsiz = size; grp->il_inpsiz = size;
LIST_INSERT_HEAD(hdr, grp, il_list); CK_LIST_INSERT_HEAD(hdr, grp, il_list);
return (grp); return (grp);
} }
static void
in_pcblbgroup_free_deferred(epoch_context_t ctx)
{
struct inpcblbgroup *grp;
grp = __containerof(ctx, struct inpcblbgroup, il_epoch_ctx);
free(grp, M_PCB);
}
static void static void
in_pcblbgroup_free(struct inpcblbgroup *grp) in_pcblbgroup_free(struct inpcblbgroup *grp)
{ {
LIST_REMOVE(grp, il_list); CK_LIST_REMOVE(grp, il_list);
free(grp, M_PCB); epoch_call(net_epoch_preempt, &grp->il_epoch_ctx,
in_pcblbgroup_free_deferred);
} }
static struct inpcblbgroup * static struct inpcblbgroup *
@ -347,7 +357,7 @@ in_pcbinslbgrouphash(struct inpcb *inp)
hdr = &pcbinfo->ipi_lbgrouphashbase[ hdr = &pcbinfo->ipi_lbgrouphashbase[
INP_PCBLBGROUP_PORTHASH(inp->inp_lport, INP_PCBLBGROUP_PORTHASH(inp->inp_lport,
pcbinfo->ipi_lbgrouphashmask)]; pcbinfo->ipi_lbgrouphashmask)];
LIST_FOREACH(grp, hdr, il_list) { CK_LIST_FOREACH(grp, hdr, il_list) {
if (grp->il_vflag == inp->inp_vflag && if (grp->il_vflag == inp->inp_vflag &&
grp->il_lport == inp->inp_lport && grp->il_lport == inp->inp_lport &&
memcmp(&grp->il_dependladdr, memcmp(&grp->il_dependladdr,
@ -409,7 +419,7 @@ in_pcbremlbgrouphash(struct inpcb *inp)
INP_PCBLBGROUP_PORTHASH(inp->inp_lport, INP_PCBLBGROUP_PORTHASH(inp->inp_lport,
pcbinfo->ipi_lbgrouphashmask)]; pcbinfo->ipi_lbgrouphashmask)];
LIST_FOREACH(grp, hdr, il_list) { CK_LIST_FOREACH(grp, hdr, il_list) {
for (i = 0; i < grp->il_inpcnt; ++i) { for (i = 0; i < grp->il_inpcnt; ++i) {
if (grp->il_inp[i] != inp) if (grp->il_inp[i] != inp)
continue; continue;
@ -1972,7 +1982,7 @@ in_pcblookup_lbgroup(const struct inpcbinfo *pcbinfo,
* - Load balanced group does not contain IPv4 mapped INET6 wild sockets * - Load balanced group does not contain IPv4 mapped INET6 wild sockets
*/ */
local_wild = NULL; local_wild = NULL;
LIST_FOREACH(grp, hdr, il_list) { CK_LIST_FOREACH(grp, hdr, il_list) {
#ifdef INET6 #ifdef INET6
if (!(grp->il_vflag & INP_IPV4)) if (!(grp->il_vflag & INP_IPV4))
continue; continue;

5
sys/netinet/in_pcb.h
View File

@ -70,6 +70,7 @@
*/ */
CK_LIST_HEAD(inpcbhead, inpcb); CK_LIST_HEAD(inpcbhead, inpcb);
CK_LIST_HEAD(inpcbporthead, inpcbport); CK_LIST_HEAD(inpcbporthead, inpcbport);
CK_LIST_HEAD(inpcblbgrouphead, inpcblbgroup);
typedef uint64_t inp_gen_t; typedef uint64_t inp_gen_t;
/* /*
@ -566,7 +567,8 @@ struct inpcbgroup {
* is dynamically resized as processes bind/unbind to that specific group. * is dynamically resized as processes bind/unbind to that specific group.
*/ */
struct inpcblbgroup { struct inpcblbgroup {
LIST_ENTRY(inpcblbgroup) il_list; CK_LIST_ENTRY(inpcblbgroup) il_list;
struct epoch_context il_epoch_ctx;
uint16_t il_lport; /* (c) */ uint16_t il_lport; /* (c) */
u_char il_vflag; /* (c) */ u_char il_vflag; /* (c) */
u_char il_pad; u_char il_pad;
@ -578,7 +580,6 @@ struct inpcblbgroup {
uint32_t il_inpcnt; /* cur count in il_inp[] (h) */ uint32_t il_inpcnt; /* cur count in il_inp[] (h) */
struct inpcb *il_inp[]; /* (h) */ struct inpcb *il_inp[]; /* (h) */
}; };
LIST_HEAD(inpcblbgrouphead, inpcblbgroup);
#define INP_LOCK_INIT(inp, d, t) \ #define INP_LOCK_INIT(inp, d, t) \
rw_init_flags(&(inp)->inp_lock, (t), RW_RECURSE | RW_DUPOK) rw_init_flags(&(inp)->inp_lock, (t), RW_RECURSE | RW_DUPOK)

2
sys/netinet6/in6_pcb.c
View File

@ -889,7 +889,7 @@ in6_pcblookup_lbgroup(const struct inpcbinfo *pcbinfo,
* - Load balanced group does not contain jailed sockets. * - Load balanced group does not contain jailed sockets.
* - Load balanced does not contain IPv4 mapped INET6 wild sockets. * - Load balanced does not contain IPv4 mapped INET6 wild sockets.
*/ */
LIST_FOREACH(grp, hdr, il_list) { CK_LIST_FOREACH(grp, hdr, il_list) {
#ifdef INET #ifdef INET
if (!(grp->il_vflag & INP_IPV6)) if (!(grp->il_vflag & INP_IPV6))
continue; continue;