6.6-stable review patch. If anyone has any objections, please let me know.
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From: Takamitsu Iwai takamitz@amazon.co.jp
[ Upstream commit d860d1faa6b2ce3becfdb8b0c2b048ad31800061 ]
The 'use' field in struct rose_neigh is used as a reference counter but lacks atomicity. This can lead to race conditions where a rose_neigh structure is freed while still being referenced by other code paths.
For example, when rose_neigh->use becomes zero during an ioctl operation via rose_rt_ioctl(), the structure may be removed while its timer is still active, potentially causing use-after-free issues.
This patch changes the type of 'use' from unsigned short to refcount_t and updates all code paths to use rose_neigh_hold() and rose_neigh_put() which operate reference counts atomically.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Takamitsu Iwai takamitz@amazon.co.jp Reviewed-by: Kuniyuki Iwashima kuniyu@google.com Link: https://patch.msgid.link/20250823085857.47674-3-takamitz@amazon.co.jp Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/rose.h | 18 +++++++++++++----- net/rose/af_rose.c | 13 +++++++------ net/rose/rose_in.c | 12 ++++++------ net/rose/rose_route.c | 33 ++++++++++++++++++--------------- net/rose/rose_timer.c | 2 +- 5 files changed, 45 insertions(+), 33 deletions(-)
diff --git a/include/net/rose.h b/include/net/rose.h index 174b4f605d849..2b5491bbf39ab 100644 --- a/include/net/rose.h +++ b/include/net/rose.h @@ -8,6 +8,7 @@ #ifndef _ROSE_H #define _ROSE_H
+#include <linux/refcount.h> #include <linux/rose.h> #include <net/ax25.h> #include <net/sock.h> @@ -96,7 +97,7 @@ struct rose_neigh { ax25_cb *ax25; struct net_device *dev; unsigned short count; - unsigned short use; + refcount_t use; unsigned int number; char restarted; char dce_mode; @@ -151,12 +152,19 @@ struct rose_sock {
#define rose_sk(sk) ((struct rose_sock *)(sk))
+static inline void rose_neigh_hold(struct rose_neigh *rose_neigh) +{ + refcount_inc(&rose_neigh->use); +} + static inline void rose_neigh_put(struct rose_neigh *rose_neigh) { - if (rose_neigh->ax25) - ax25_cb_put(rose_neigh->ax25); - kfree(rose_neigh->digipeat); - kfree(rose_neigh); + if (refcount_dec_and_test(&rose_neigh->use)) { + if (rose_neigh->ax25) + ax25_cb_put(rose_neigh->ax25); + kfree(rose_neigh->digipeat); + kfree(rose_neigh); + } }
/* af_rose.c */ diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index 66e9ceaaa43a1..614695444b6ac 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c @@ -170,7 +170,7 @@ void rose_kill_by_neigh(struct rose_neigh *neigh)
if (rose->neighbour == neigh) { rose_disconnect(s, ENETUNREACH, ROSE_OUT_OF_ORDER, 0); - rose->neighbour->use--; + rose_neigh_put(rose->neighbour); rose->neighbour = NULL; } } @@ -212,7 +212,7 @@ static void rose_kill_by_device(struct net_device *dev) if (rose->device == dev) { rose_disconnect(sk, ENETUNREACH, ROSE_OUT_OF_ORDER, 0); if (rose->neighbour) - rose->neighbour->use--; + rose_neigh_put(rose->neighbour); netdev_put(rose->device, &rose->dev_tracker); rose->device = NULL; } @@ -655,7 +655,7 @@ static int rose_release(struct socket *sock) break;
case ROSE_STATE_2: - rose->neighbour->use--; + rose_neigh_put(rose->neighbour); release_sock(sk); rose_disconnect(sk, 0, -1, -1); lock_sock(sk); @@ -823,6 +823,7 @@ static int rose_connect(struct socket *sock, struct sockaddr *uaddr, int addr_le rose->lci = rose_new_lci(rose->neighbour); if (!rose->lci) { err = -ENETUNREACH; + rose_neigh_put(rose->neighbour); goto out_release; }
@@ -834,12 +835,14 @@ static int rose_connect(struct socket *sock, struct sockaddr *uaddr, int addr_le dev = rose_dev_first(); if (!dev) { err = -ENETUNREACH; + rose_neigh_put(rose->neighbour); goto out_release; }
user = ax25_findbyuid(current_euid()); if (!user) { err = -EINVAL; + rose_neigh_put(rose->neighbour); dev_put(dev); goto out_release; } @@ -874,8 +877,6 @@ static int rose_connect(struct socket *sock, struct sockaddr *uaddr, int addr_le
rose->state = ROSE_STATE_1;
- rose->neighbour->use++; - rose_write_internal(sk, ROSE_CALL_REQUEST); rose_start_heartbeat(sk); rose_start_t1timer(sk); @@ -1077,7 +1078,7 @@ int rose_rx_call_request(struct sk_buff *skb, struct net_device *dev, struct ros GFP_ATOMIC); make_rose->facilities = facilities;
- make_rose->neighbour->use++; + rose_neigh_hold(make_rose->neighbour);
if (rose_sk(sk)->defer) { make_rose->state = ROSE_STATE_5; diff --git a/net/rose/rose_in.c b/net/rose/rose_in.c index 4d67f36dce1b4..7caae93937ee9 100644 --- a/net/rose/rose_in.c +++ b/net/rose/rose_in.c @@ -56,7 +56,7 @@ static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int framety case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]); - rose->neighbour->use--; + rose_neigh_put(rose->neighbour); break;
default: @@ -79,12 +79,12 @@ static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int framety case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); - rose->neighbour->use--; + rose_neigh_put(rose->neighbour); break;
case ROSE_CLEAR_CONFIRMATION: rose_disconnect(sk, 0, -1, -1); - rose->neighbour->use--; + rose_neigh_put(rose->neighbour); break;
default: @@ -120,7 +120,7 @@ static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int framety case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); - rose->neighbour->use--; + rose_neigh_put(rose->neighbour); break;
case ROSE_RR: @@ -233,7 +233,7 @@ static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int framety case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); - rose->neighbour->use--; + rose_neigh_put(rose->neighbour); break;
default: @@ -253,7 +253,7 @@ static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int framety if (frametype == ROSE_CLEAR_REQUEST) { rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); - rose_sk(sk)->neighbour->use--; + rose_neigh_put(rose_sk(sk)->neighbour); }
return 0; diff --git a/net/rose/rose_route.c b/net/rose/rose_route.c index b406b1e0fb1e7..42460da0854d5 100644 --- a/net/rose/rose_route.c +++ b/net/rose/rose_route.c @@ -93,11 +93,11 @@ static int __must_check rose_add_node(struct rose_route_struct *rose_route, rose_neigh->ax25 = NULL; rose_neigh->dev = dev; rose_neigh->count = 0; - rose_neigh->use = 0; rose_neigh->dce_mode = 0; rose_neigh->loopback = 0; rose_neigh->number = rose_neigh_no++; rose_neigh->restarted = 0; + refcount_set(&rose_neigh->use, 1);
skb_queue_head_init(&rose_neigh->queue);
@@ -255,10 +255,10 @@ static void rose_remove_route(struct rose_route *rose_route) struct rose_route *s;
if (rose_route->neigh1 != NULL) - rose_route->neigh1->use--; + rose_neigh_put(rose_route->neigh1);
if (rose_route->neigh2 != NULL) - rose_route->neigh2->use--; + rose_neigh_put(rose_route->neigh2);
if ((s = rose_route_list) == rose_route) { rose_route_list = rose_route->next; @@ -323,7 +323,7 @@ static int rose_del_node(struct rose_route_struct *rose_route, if (rose_node->neighbour[i] == rose_neigh) { rose_neigh->count--;
- if (rose_neigh->count == 0 && rose_neigh->use == 0) { + if (rose_neigh->count == 0) { rose_remove_neigh(rose_neigh); rose_neigh_put(rose_neigh); } @@ -375,11 +375,11 @@ void rose_add_loopback_neigh(void) sn->ax25 = NULL; sn->dev = NULL; sn->count = 0; - sn->use = 0; sn->dce_mode = 1; sn->loopback = 1; sn->number = rose_neigh_no++; sn->restarted = 1; + refcount_set(&sn->use, 1);
skb_queue_head_init(&sn->queue);
@@ -561,8 +561,7 @@ static int rose_clear_routes(void) s = rose_neigh; rose_neigh = rose_neigh->next;
- if (s->use == 0 && !s->loopback) { - s->count = 0; + if (!s->loopback) { rose_remove_neigh(s); rose_neigh_put(s); } @@ -680,6 +679,7 @@ struct rose_neigh *rose_get_neigh(rose_address *addr, unsigned char *cause, for (i = 0; i < node->count; i++) { if (node->neighbour[i]->restarted) { res = node->neighbour[i]; + rose_neigh_hold(node->neighbour[i]); goto out; } } @@ -691,6 +691,7 @@ struct rose_neigh *rose_get_neigh(rose_address *addr, unsigned char *cause, for (i = 0; i < node->count; i++) { if (!rose_ftimer_running(node->neighbour[i])) { res = node->neighbour[i]; + rose_neigh_hold(node->neighbour[i]); goto out; } failed = 1; @@ -780,13 +781,13 @@ static void rose_del_route_by_neigh(struct rose_neigh *rose_neigh) }
if (rose_route->neigh1 == rose_neigh) { - rose_route->neigh1->use--; + rose_neigh_put(rose_route->neigh1); rose_route->neigh1 = NULL; rose_transmit_clear_request(rose_route->neigh2, rose_route->lci2, ROSE_OUT_OF_ORDER, 0); }
if (rose_route->neigh2 == rose_neigh) { - rose_route->neigh2->use--; + rose_neigh_put(rose_route->neigh2); rose_route->neigh2 = NULL; rose_transmit_clear_request(rose_route->neigh1, rose_route->lci1, ROSE_OUT_OF_ORDER, 0); } @@ -915,7 +916,7 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25) rose_clear_queues(sk); rose->cause = ROSE_NETWORK_CONGESTION; rose->diagnostic = 0; - rose->neighbour->use--; + rose_neigh_put(rose->neighbour); rose->neighbour = NULL; rose->lci = 0; rose->state = ROSE_STATE_0; @@ -1040,12 +1041,12 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25)
if ((new_lci = rose_new_lci(new_neigh)) == 0) { rose_transmit_clear_request(rose_neigh, lci, ROSE_NETWORK_CONGESTION, 71); - goto out; + goto put_neigh; }
if ((rose_route = kmalloc(sizeof(*rose_route), GFP_ATOMIC)) == NULL) { rose_transmit_clear_request(rose_neigh, lci, ROSE_NETWORK_CONGESTION, 120); - goto out; + goto put_neigh; }
rose_route->lci1 = lci; @@ -1058,8 +1059,8 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25) rose_route->lci2 = new_lci; rose_route->neigh2 = new_neigh;
- rose_route->neigh1->use++; - rose_route->neigh2->use++; + rose_neigh_hold(rose_route->neigh1); + rose_neigh_hold(rose_route->neigh2);
rose_route->next = rose_route_list; rose_route_list = rose_route; @@ -1071,6 +1072,8 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25) rose_transmit_link(skb, rose_route->neigh2); res = 1;
+put_neigh: + rose_neigh_put(new_neigh); out: spin_unlock_bh(&rose_route_list_lock); spin_unlock_bh(&rose_neigh_list_lock); @@ -1186,7 +1189,7 @@ static int rose_neigh_show(struct seq_file *seq, void *v) (rose_neigh->loopback) ? "RSLOOP-0" : ax2asc(buf, &rose_neigh->callsign), rose_neigh->dev ? rose_neigh->dev->name : "???", rose_neigh->count, - rose_neigh->use, + refcount_read(&rose_neigh->use) - 1, (rose_neigh->dce_mode) ? "DCE" : "DTE", (rose_neigh->restarted) ? "yes" : "no", ax25_display_timer(&rose_neigh->t0timer) / HZ, diff --git a/net/rose/rose_timer.c b/net/rose/rose_timer.c index 1525773e94aa1..c52d7d20c5199 100644 --- a/net/rose/rose_timer.c +++ b/net/rose/rose_timer.c @@ -180,7 +180,7 @@ static void rose_timer_expiry(struct timer_list *t) break;
case ROSE_STATE_2: /* T3 */ - rose->neighbour->use--; + rose_neigh_put(rose->neighbour); rose_disconnect(sk, ETIMEDOUT, -1, -1); break;