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ipsec: fix race condition in key.c

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Small patch that fixes a race condition in sys/netipsec/key.c

Obtained from:		Stormshield
Differential revision:	https://reviews.freebsd.org/D31271
This commit is contained in:
Wojciech Macek 2021-08-13 12:52:38 +02:00
parent c9f833abf1
commit 4920e38fec
1 changed files with 37 additions and 16 deletions
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53
sys/netipsec/key.c
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@ -616,6 +616,7 @@ static struct callout key_timer;
#endif
static void key_unlink(struct secpolicy *);
static void key_detach(struct secpolicy *);
static struct secpolicy *key_do_allocsp(struct secpolicyindex *spidx, u_int dir);
static struct secpolicy *key_getsp(struct secpolicyindex *);
static struct secpolicy *key_getspbyid(u_int32_t);
@ -1200,18 +1201,26 @@ key_freesp(struct secpolicy **spp)
static void
key_unlink(struct secpolicy *sp)
{
SPTREE_WLOCK();
key_detach(sp);
SPTREE_WUNLOCK();
if (SPDCACHE_ENABLED())
spdcache_clear();
key_freesp(&sp);
}
static void
key_detach(struct secpolicy *sp)
{
IPSEC_ASSERT(sp->spidx.dir == IPSEC_DIR_INBOUND ||
sp->spidx.dir == IPSEC_DIR_OUTBOUND,
("invalid direction %u", sp->spidx.dir));
SPTREE_UNLOCK_ASSERT();
SPTREE_WLOCK_ASSERT();
KEYDBG(KEY_STAMP,
printf("%s: SP(%p)\n", __func__, sp));
SPTREE_WLOCK();
if (sp->state != IPSEC_SPSTATE_ALIVE) {
/* SP is already unlinked */
SPTREE_WUNLOCK();
return;
}
sp->state = IPSEC_SPSTATE_DEAD;
@ -1219,10 +1228,6 @@ key_unlink(struct secpolicy *sp)
V_spd_size--;
LIST_REMOVE(sp, idhash);
V_sp_genid++;
SPTREE_WUNLOCK();
if (SPDCACHE_ENABLED())
spdcache_clear();
key_freesp(&sp);
}
/*
@ -1941,7 +1946,7 @@ key_spdadd(struct socket *so, struct mbuf *m, const struct sadb_msghdr *mhp)
struct sadb_address *src0, *dst0;
struct sadb_x_policy *xpl0, *xpl;
struct sadb_lifetime *lft = NULL;
struct secpolicy *newsp;
struct secpolicy *newsp, *oldsp;
int error;
IPSEC_ASSERT(so != NULL, ("null socket"));
@ -2019,15 +2024,13 @@ key_spdadd(struct socket *so, struct mbuf *m, const struct sadb_msghdr *mhp)
src0->sadb_address_proto,
&spidx);
/* Checking there is SP already or not. */
newsp = key_getsp(&spidx);
if (newsp != NULL) {
oldsp = key_getsp(&spidx);
if (oldsp != NULL) {
if (mhp->msg->sadb_msg_type == SADB_X_SPDUPDATE) {
KEYDBG(KEY_STAMP,
printf("%s: unlink SP(%p) for SPDUPDATE\n",
__func__, newsp));
KEYDBG(KEY_DATA, kdebug_secpolicy(newsp));
key_unlink(newsp);
key_freesp(&newsp);
__func__, oldsp));
KEYDBG(KEY_DATA, kdebug_secpolicy(oldsp));
} else {
key_freesp(&newsp);
ipseclog((LOG_DEBUG,
@ -2038,6 +2041,10 @@ key_spdadd(struct socket *so, struct mbuf *m, const struct sadb_msghdr *mhp)
/* allocate new SP entry */
if ((newsp = key_msg2sp(xpl0, PFKEY_EXTLEN(xpl0), &error)) == NULL) {
if (oldsp != NULL) {
key_unlink(oldsp);
key_freesp(&oldsp); /* second for our reference */
}
return key_senderror(so, m, error);
}
@ -2046,18 +2053,32 @@ key_spdadd(struct socket *so, struct mbuf *m, const struct sadb_msghdr *mhp)
newsp->validtime = lft ? lft->sadb_lifetime_usetime : 0;
bcopy(&spidx, &newsp->spidx, sizeof(spidx));
/* XXXAE: there is race between key_getsp() and key_insertsp() */
SPTREE_WLOCK();
if ((newsp->id = key_getnewspid()) == 0) {
if (oldsp != NULL)
key_detach(oldsp);
SPTREE_WUNLOCK();
if (oldsp != NULL) {
key_freesp(&oldsp); /* first for key_detach */
IPSEC_ASSERT(oldsp != NULL, ("null oldsp: refcount bug"));
key_freesp(&oldsp); /* second for our reference */
if (SPDCACHE_ENABLED()) /* refresh cache because of key_detach */
spdcache_clear();
}
key_freesp(&newsp);
return key_senderror(so, m, ENOBUFS);
}
if (oldsp != NULL)
key_detach(oldsp);
key_insertsp(newsp);
SPTREE_WUNLOCK();
if (oldsp != NULL) {
key_freesp(&oldsp); /* first for key_detach */
IPSEC_ASSERT(oldsp != NULL, ("null oldsp: refcount bug"));
key_freesp(&oldsp); /* second for our reference */
}
if (SPDCACHE_ENABLED())
spdcache_clear();
KEYDBG(KEY_STAMP,
printf("%s: SP(%p)\n", __func__, newsp));
KEYDBG(KEY_DATA, kdebug_secpolicy(newsp));