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sctp: improve handling of address changes

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Identify interfaces consistenly by the pair of the ifn pointer
and the index.
This avoids a use after free when the ifn and or index was reused.

Reported by:	bz, pho, and others
MFC after:	3 days
This commit is contained in:
Michael Tuexen 2024-11-03 10:20:08 +01:00
parent 0f5116d7ef
commit 523913c943
3 changed files with 15 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
sys/netinet/sctp_bsd_addr.c
View File

@ -338,6 +338,7 @@ sctp_addr_change(struct ifaddr *ifa, int cmd)
(void *)ifa, ifa->ifa_addr, ifa_flags, 1);
} else {
sctp_del_addr_from_vrf(SCTP_DEFAULT_VRFID, ifa->ifa_addr,
(void *)ifa->ifa_ifp,
ifa->ifa_ifp->if_index);
/*

23
sys/netinet/sctp_pcb.c
View File

@ -193,12 +193,11 @@ sctp_find_ifn(void *ifn, uint32_t ifn_index)
struct sctp_ifnlist *hash_ifn_head;
SCTP_IPI_ADDR_LOCK_ASSERT();
KASSERT(ifn != NULL, ("sctp_find_ifn(NULL, %u) called", ifn_index));
hash_ifn_head = &SCTP_BASE_INFO(vrf_ifn_hash)[(ifn_index & SCTP_BASE_INFO(vrf_ifn_hashmark))];
LIST_FOREACH(sctp_ifnp, hash_ifn_head, next_bucket) {
if (sctp_ifnp->ifn_index == ifn_index) {
break;
}
if (ifn != NULL && sctp_ifnp->ifn_p == ifn) {
if (sctp_ifnp->ifn_index == ifn_index &&
sctp_ifnp->ifn_p == ifn) {
break;
}
}
@ -439,7 +438,8 @@ sctp_add_addr_to_vrf(uint32_t vrf_id, void *ifn, uint32_t ifn_index,
if (sctp_ifap != NULL) {
/* The address being added is already or still known. */
if (sctp_ifap->ifn_p != NULL) {
if (sctp_ifap->ifn_p->ifn_index == ifn_index) {
if (sctp_ifap->ifn_p->ifn_index == ifn_index &&
sctp_ifap->ifn_p->ifn_p == ifn) {
SCTPDBG(SCTP_DEBUG_PCB4,
"Using existing ifn %s (0x%x) for ifa %p\n",
sctp_ifap->ifn_p->ifn_name, ifn_index,
@ -578,7 +578,7 @@ sctp_add_addr_to_vrf(uint32_t vrf_id, void *ifn, uint32_t ifn_index,
*/
SCTPDBG(SCTP_DEBUG_PCB4, "Lost an address change?\n");
/* Opps, must decrement the count */
sctp_del_addr_from_vrf(vrf_id, addr, ifn_index);
sctp_del_addr_from_vrf(vrf_id, addr, ifn, ifn_index);
return (NULL);
}
SCTP_INCR_LADDR_COUNT();
@ -603,7 +603,7 @@ sctp_add_addr_to_vrf(uint32_t vrf_id, void *ifn, uint32_t ifn_index,
void
sctp_del_addr_from_vrf(uint32_t vrf_id, struct sockaddr *addr,
uint32_t ifn_index)
void *ifn, uint32_t ifn_index)
{
struct sctp_vrf *vrf;
struct sctp_ifa *sctp_ifap;
@ -624,9 +624,12 @@ sctp_del_addr_from_vrf(uint32_t vrf_id, struct sockaddr *addr,
if (sctp_ifap != NULL) {
/* Validate the delete */
if (sctp_ifap->ifn_p) {
if (ifn_index != sctp_ifap->ifn_p->ifn_index) {
SCTPDBG(SCTP_DEBUG_PCB4, "ifn:%d ifname:%s - ignoring delete\n",
sctp_ifap->ifn_p->ifn_index, sctp_ifap->ifn_p->ifn_name);
if (ifn_index != sctp_ifap->ifn_p->ifn_index ||
ifn != sctp_ifap->ifn_p->ifn_p) {
SCTPDBG(SCTP_DEBUG_PCB4, "ifn:%d (p) ifname:%s - ignoring delete\n",
sctp_ifap->ifn_p->ifn_index,
sctp_ifap->ifn_p->ifn_p,
sctp_ifap->ifn_p->ifn_name);
SCTP_IPI_ADDR_WUNLOCK();
return;
}

2
sys/netinet/sctp_pcb.h
View File

@ -498,7 +498,7 @@ void sctp_free_ifa(struct sctp_ifa *sctp_ifap);
void
sctp_del_addr_from_vrf(uint32_t vrfid, struct sockaddr *addr,
uint32_t ifn_index);
void *ifn, uint32_t ifn_index);
struct sctp_nets *sctp_findnet(struct sctp_tcb *, struct sockaddr *);