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authorRalf Baechle <ralf@linux-mips.org>2005-08-23 10:11:45 -0700
committerDavid S. Miller <davem@davemloft.net>2005-08-23 10:11:45 -0700
commit01d7dd0e9f8c5f1888619d2649c7da389232b408 (patch)
treeee4f22a33557bae4883eb2f4fb1359e97ac74186 /net/ax25
parent53b924b31fa53ac3007df3fef6870d5074a9adf8 (diff)
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[AX25]: UID fixes
o Brown paperbag bug - ax25_findbyuid() was always returning a NULL pointer as the result. Breaks ROSE completly and AX.25 if UID policy set to deny. o While the list structure of AX.25's UID to callsign mapping table was properly protected by a spinlock, it's elements were not refcounted resulting in a race between removal and usage of an element. Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ax25')
-rw-r--r--net/ax25/af_ax25.c20
-rw-r--r--net/ax25/ax25_route.c12
-rw-r--r--net/ax25/ax25_uid.c83
3 files changed, 55 insertions, 60 deletions
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index 7d8ecadba66..a5c94f11547 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -1002,7 +1002,8 @@ static int ax25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
struct sock *sk = sock->sk;
struct full_sockaddr_ax25 *addr = (struct full_sockaddr_ax25 *)uaddr;
ax25_dev *ax25_dev = NULL;
- ax25_address *call;
+ ax25_uid_assoc *user;
+ ax25_address call;
ax25_cb *ax25;
int err = 0;
@@ -1021,9 +1022,15 @@ static int ax25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
if (addr->fsa_ax25.sax25_family != AF_AX25)
return -EINVAL;
- call = ax25_findbyuid(current->euid);
- if (call == NULL && ax25_uid_policy && !capable(CAP_NET_ADMIN)) {
- return -EACCES;
+ user = ax25_findbyuid(current->euid);
+ if (user) {
+ call = user->call;
+ ax25_uid_put(user);
+ } else {
+ if (ax25_uid_policy && !capable(CAP_NET_ADMIN))
+ return -EACCES;
+
+ call = addr->fsa_ax25.sax25_call;
}
lock_sock(sk);
@@ -1034,10 +1041,7 @@ static int ax25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
goto out;
}
- if (call == NULL)
- ax25->source_addr = addr->fsa_ax25.sax25_call;
- else
- ax25->source_addr = *call;
+ ax25->source_addr = call;
/*
* User already set interface with SO_BINDTODEVICE
diff --git a/net/ax25/ax25_route.c b/net/ax25/ax25_route.c
index 44b99b1ff9f..c288526da4c 100644
--- a/net/ax25/ax25_route.c
+++ b/net/ax25/ax25_route.c
@@ -422,8 +422,8 @@ static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
*/
int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
{
+ ax25_uid_assoc *user;
ax25_route *ax25_rt;
- ax25_address *call;
int err;
if ((ax25_rt = ax25_get_route(addr, NULL)) == NULL)
@@ -434,16 +434,18 @@ int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
goto put;
}
- if ((call = ax25_findbyuid(current->euid)) == NULL) {
+ user = ax25_findbyuid(current->euid);
+ if (user) {
+ ax25->source_addr = user->call;
+ ax25_uid_put(user);
+ } else {
if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
err = -EPERM;
goto put;
}
- call = (ax25_address *)ax25->ax25_dev->dev->dev_addr;
+ ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
}
- ax25->source_addr = *call;
-
if (ax25_rt->digipeat != NULL) {
if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
err = -ENOMEM;
diff --git a/net/ax25/ax25_uid.c b/net/ax25/ax25_uid.c
index cea6b7d1972..a8b3822f3ee 100644
--- a/net/ax25/ax25_uid.c
+++ b/net/ax25/ax25_uid.c
@@ -28,6 +28,7 @@
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
+#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
@@ -41,38 +42,41 @@
* Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
*/
-static ax25_uid_assoc *ax25_uid_list;
+HLIST_HEAD(ax25_uid_list);
static DEFINE_RWLOCK(ax25_uid_lock);
int ax25_uid_policy = 0;
-ax25_address *ax25_findbyuid(uid_t uid)
+ax25_uid_assoc *ax25_findbyuid(uid_t uid)
{
- ax25_uid_assoc *ax25_uid;
- ax25_address *res = NULL;
+ ax25_uid_assoc *ax25_uid, *res = NULL;
+ struct hlist_node *node;
read_lock(&ax25_uid_lock);
- for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
+ ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
if (ax25_uid->uid == uid) {
- res = &ax25_uid->call;
+ ax25_uid_hold(ax25_uid);
+ res = ax25_uid;
break;
}
}
read_unlock(&ax25_uid_lock);
- return NULL;
+ return res;
}
int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
{
- ax25_uid_assoc *s, *ax25_uid;
+ ax25_uid_assoc *ax25_uid;
+ struct hlist_node *node;
+ ax25_uid_assoc *user;
unsigned long res;
switch (cmd) {
case SIOCAX25GETUID:
res = -ENOENT;
read_lock(&ax25_uid_lock);
- for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
+ ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
res = ax25_uid->uid;
break;
@@ -85,19 +89,22 @@ int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
case SIOCAX25ADDUID:
if (!capable(CAP_NET_ADMIN))
return -EPERM;
- if (ax25_findbyuid(sax->sax25_uid))
+ user = ax25_findbyuid(sax->sax25_uid);
+ if (user) {
+ ax25_uid_put(user);
return -EEXIST;
+ }
if (sax->sax25_uid == 0)
return -EINVAL;
if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
return -ENOMEM;
+ atomic_set(&ax25_uid->refcount, 1);
ax25_uid->uid = sax->sax25_uid;
ax25_uid->call = sax->sax25_call;
write_lock(&ax25_uid_lock);
- ax25_uid->next = ax25_uid_list;
- ax25_uid_list = ax25_uid;
+ hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
write_unlock(&ax25_uid_lock);
return 0;
@@ -106,34 +113,21 @@ int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
if (!capable(CAP_NET_ADMIN))
return -EPERM;
+ ax25_uid = NULL;
write_lock(&ax25_uid_lock);
- for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
- if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
+ ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
+ if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
break;
- }
}
if (ax25_uid == NULL) {
write_unlock(&ax25_uid_lock);
return -ENOENT;
}
- if ((s = ax25_uid_list) == ax25_uid) {
- ax25_uid_list = s->next;
- write_unlock(&ax25_uid_lock);
- kfree(ax25_uid);
- return 0;
- }
- while (s != NULL && s->next != NULL) {
- if (s->next == ax25_uid) {
- s->next = ax25_uid->next;
- write_unlock(&ax25_uid_lock);
- kfree(ax25_uid);
- return 0;
- }
- s = s->next;
- }
+ hlist_del_init(&ax25_uid->uid_node);
+ ax25_uid_put(ax25_uid);
write_unlock(&ax25_uid_lock);
- return -ENOENT;
+ return 0;
default:
return -EINVAL;
@@ -147,13 +141,11 @@ int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
{
struct ax25_uid_assoc *pt;
- int i = 1;
+ struct hlist_node *node;
+ int i = 0;
read_lock(&ax25_uid_lock);
- if (*pos == 0)
- return SEQ_START_TOKEN;
-
- for (pt = ax25_uid_list; pt != NULL; pt = pt->next) {
+ ax25_uid_for_each(pt, node, &ax25_uid_list) {
if (i == *pos)
return pt;
++i;
@@ -164,8 +156,9 @@ static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
++*pos;
- return (v == SEQ_START_TOKEN) ? ax25_uid_list :
- ((struct ax25_uid_assoc *) v)->next;
+
+ return hlist_entry(((ax25_uid_assoc *)v)->uid_node.next,
+ ax25_uid_assoc, uid_node);
}
static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
@@ -179,7 +172,6 @@ static int ax25_uid_seq_show(struct seq_file *seq, void *v)
seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
else {
struct ax25_uid_assoc *pt = v;
-
seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(&pt->call));
}
@@ -213,16 +205,13 @@ struct file_operations ax25_uid_fops = {
*/
void __exit ax25_uid_free(void)
{
- ax25_uid_assoc *s, *ax25_uid;
+ ax25_uid_assoc *ax25_uid;
+ struct hlist_node *node;
write_lock(&ax25_uid_lock);
- ax25_uid = ax25_uid_list;
- while (ax25_uid != NULL) {
- s = ax25_uid;
- ax25_uid = ax25_uid->next;
-
- kfree(s);
+ ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
+ hlist_del_init(&ax25_uid->uid_node);
+ ax25_uid_put(ax25_uid);
}
- ax25_uid_list = NULL;
write_unlock(&ax25_uid_lock);
}