[PATCH] ax25: fix reference count leaks of ax25_dev
From: Duoming Zhou
Date: Thu Feb 03 2022 - 10:09:25 EST
The previous commit d01ffb9eee4a ("ax25: add refcount in ax25_dev
to avoid UAF bugs") introduces refcount into ax25_dev, but there
are reference leak paths in ax25_ctl_ioctl(), ax25_fwd_ioctl(),
ax25_rt_add(), ax25_rt_del() and ax25_rt_opt().
This patch uses ax25_dev_put() and adjusts the position of
ax25_addr_ax25dev() to fix reference cout leaks of ax25_dev.
Fixes: d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Signed-off-by: Duoming Zhou <duoming@xxxxxxxxxx>
---
include/net/ax25.h | 8 +++++---
net/ax25/af_ax25.c | 12 ++++++++----
net/ax25/ax25_dev.c | 24 +++++++++++++++++-------
net/ax25/ax25_route.c | 16 +++++++++++-----
4 files changed, 41 insertions(+), 19 deletions(-)
diff --git a/include/net/ax25.h b/include/net/ax25.h
index 50b417df622..8221af1811d 100644
--- a/include/net/ax25.h
+++ b/include/net/ax25.h
@@ -294,10 +294,12 @@ static __inline__ void ax25_cb_put(ax25_cb *ax25)
}
}
-#define ax25_dev_hold(__ax25_dev) \
- refcount_inc(&((__ax25_dev)->refcount))
+static inline void ax25_dev_hold(ax25_dev *ax25_dev)
+{
+ refcount_inc(&ax25_dev->refcount);
+}
-static __inline__ void ax25_dev_put(ax25_dev *ax25_dev)
+static inline void ax25_dev_put(ax25_dev *ax25_dev)
{
if (refcount_dec_and_test(&ax25_dev->refcount)) {
kfree(ax25_dev);
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index 32f61978ff2..3e49d28824e 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -359,21 +359,25 @@ static int ax25_ctl_ioctl(const unsigned int cmd, void __user *arg)
if (copy_from_user(&ax25_ctl, arg, sizeof(ax25_ctl)))
return -EFAULT;
- if ((ax25_dev = ax25_addr_ax25dev(&ax25_ctl.port_addr)) == NULL)
- return -ENODEV;
-
if (ax25_ctl.digi_count > AX25_MAX_DIGIS)
return -EINVAL;
if (ax25_ctl.arg > ULONG_MAX / HZ && ax25_ctl.cmd != AX25_KILL)
return -EINVAL;
+ ax25_dev = ax25_addr_ax25dev(&ax25_ctl.port_addr);
+ if (!ax25_dev)
+ return -ENODEV;
+
digi.ndigi = ax25_ctl.digi_count;
for (k = 0; k < digi.ndigi; k++)
digi.calls[k] = ax25_ctl.digi_addr[k];
- if ((ax25 = ax25_find_cb(&ax25_ctl.source_addr, &ax25_ctl.dest_addr, &digi, ax25_dev->dev)) == NULL)
+ ax25 = ax25_find_cb(&ax25_ctl.source_addr, &ax25_ctl.dest_addr, &digi, ax25_dev->dev);
+ if (!ax25) {
+ ax25_dev_put(ax25_dev);
return -ENOTCONN;
+ }
switch (ax25_ctl.cmd) {
case AX25_KILL:
diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index 770b787fb7b..d2a244e1c26 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -85,8 +85,8 @@ void ax25_dev_device_up(struct net_device *dev)
spin_lock_bh(&ax25_dev_lock);
ax25_dev->next = ax25_dev_list;
ax25_dev_list = ax25_dev;
- ax25_dev_hold(ax25_dev);
spin_unlock_bh(&ax25_dev_lock);
+ ax25_dev_hold(ax25_dev);
ax25_register_dev_sysctl(ax25_dev);
}
@@ -115,8 +115,8 @@ void ax25_dev_device_down(struct net_device *dev)
if ((s = ax25_dev_list) == ax25_dev) {
ax25_dev_list = s->next;
- ax25_dev_put(ax25_dev);
spin_unlock_bh(&ax25_dev_lock);
+ ax25_dev_put(ax25_dev);
dev->ax25_ptr = NULL;
dev_put_track(dev, &ax25_dev->dev_tracker);
ax25_dev_put(ax25_dev);
@@ -126,8 +126,8 @@ void ax25_dev_device_down(struct net_device *dev)
while (s != NULL && s->next != NULL) {
if (s->next == ax25_dev) {
s->next = ax25_dev->next;
- ax25_dev_put(ax25_dev);
spin_unlock_bh(&ax25_dev_lock);
+ ax25_dev_put(ax25_dev);
dev->ax25_ptr = NULL;
dev_put_track(dev, &ax25_dev->dev_tracker);
ax25_dev_put(ax25_dev);
@@ -150,25 +150,35 @@ int ax25_fwd_ioctl(unsigned int cmd, struct ax25_fwd_struct *fwd)
switch (cmd) {
case SIOCAX25ADDFWD:
- if ((fwd_dev = ax25_addr_ax25dev(&fwd->port_to)) == NULL)
+ fwd_dev = ax25_addr_ax25dev(&fwd->port_to);
+ if (!fwd_dev) {
+ ax25_dev_put(ax25_dev);
return -EINVAL;
- if (ax25_dev->forward != NULL)
+ }
+ if (ax25_dev->forward) {
+ ax25_dev_put(fwd_dev);
+ ax25_dev_put(ax25_dev);
return -EINVAL;
+ }
ax25_dev->forward = fwd_dev->dev;
ax25_dev_put(fwd_dev);
+ ax25_dev_put(ax25_dev);
break;
case SIOCAX25DELFWD:
- if (ax25_dev->forward == NULL)
+ if (!ax25_dev->forward) {
+ ax25_dev_put(ax25_dev);
return -EINVAL;
+ }
ax25_dev->forward = NULL;
+ ax25_dev_put(ax25_dev);
break;
default:
+ ax25_dev_put(ax25_dev);
return -EINVAL;
}
- ax25_dev_put(ax25_dev);
return 0;
}
diff --git a/net/ax25/ax25_route.c b/net/ax25/ax25_route.c
index 1e32693833e..9751207f775 100644
--- a/net/ax25/ax25_route.c
+++ b/net/ax25/ax25_route.c
@@ -75,11 +75,13 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
ax25_dev *ax25_dev;
int i;
- if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
- return -EINVAL;
if (route->digi_count > AX25_MAX_DIGIS)
return -EINVAL;
+ ax25_dev = ax25_addr_ax25dev(&route->port_addr);
+ if (!ax25_dev)
+ return -EINVAL;
+
write_lock_bh(&ax25_route_lock);
ax25_rt = ax25_route_list;
@@ -91,6 +93,7 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
if (route->digi_count != 0) {
if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
write_unlock_bh(&ax25_route_lock);
+ ax25_dev_put(ax25_dev);
return -ENOMEM;
}
ax25_rt->digipeat->lastrepeat = -1;
@@ -101,6 +104,7 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
}
}
write_unlock_bh(&ax25_route_lock);
+ ax25_dev_put(ax25_dev);
return 0;
}
ax25_rt = ax25_rt->next;
@@ -108,6 +112,7 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
write_unlock_bh(&ax25_route_lock);
+ ax25_dev_put(ax25_dev);
return -ENOMEM;
}
@@ -116,11 +121,11 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
ax25_rt->dev = ax25_dev->dev;
ax25_rt->digipeat = NULL;
ax25_rt->ip_mode = ' ';
- ax25_dev_put(ax25_dev);
if (route->digi_count != 0) {
if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
write_unlock_bh(&ax25_route_lock);
kfree(ax25_rt);
+ ax25_dev_put(ax25_dev);
return -ENOMEM;
}
ax25_rt->digipeat->lastrepeat = -1;
@@ -133,6 +138,7 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
ax25_rt->next = ax25_route_list;
ax25_route_list = ax25_rt;
write_unlock_bh(&ax25_route_lock);
+ ax25_dev_put(ax25_dev);
return 0;
}
@@ -173,8 +179,8 @@ static int ax25_rt_del(struct ax25_routes_struct *route)
}
}
}
- ax25_dev_put(ax25_dev);
write_unlock_bh(&ax25_route_lock);
+ ax25_dev_put(ax25_dev);
return 0;
}
@@ -216,8 +222,8 @@ static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
}
out:
- ax25_dev_put(ax25_dev);
write_unlock_bh(&ax25_route_lock);
+ ax25_dev_put(ax25_dev);
return err;
}
--
2.17.1