[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>
This commit is contained in:
Ralf Baechle
David S. Miller
Родитель
53b924b31f
Коммит
01d7dd0e9f
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@ -139,11 +139,25 @@ enum {
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#define AX25_DEF_DS_TIMEOUT (3 * 60 * HZ) /* DAMA timeout 3 minutes */
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typedef struct ax25_uid_assoc {
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struct ax25_uid_assoc *next;
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struct hlist_node uid_node;
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atomic_t refcount;
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uid_t uid;
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ax25_address call;
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} ax25_uid_assoc;
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#define ax25_uid_for_each(__ax25, node, list) \
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hlist_for_each_entry(__ax25, node, list, uid_node)
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#define ax25_uid_hold(ax25) \
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atomic_inc(&((ax25)->refcount))
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static inline void ax25_uid_put(ax25_uid_assoc *assoc)
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{
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if (atomic_dec_and_test(&assoc->refcount)) {
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kfree(assoc);
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}
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}
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typedef struct {
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ax25_address calls[AX25_MAX_DIGIS];
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unsigned char repeated[AX25_MAX_DIGIS];
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@ -376,7 +390,7 @@ extern unsigned long ax25_display_timer(struct timer_list *);
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/* ax25_uid.c */
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extern int ax25_uid_policy;
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extern ax25_address *ax25_findbyuid(uid_t);
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extern ax25_uid_assoc *ax25_findbyuid(uid_t);
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extern int ax25_uid_ioctl(int, struct sockaddr_ax25 *);
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extern struct file_operations ax25_uid_fops;
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extern void ax25_uid_free(void);
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@ -1002,7 +1002,8 @@ static int ax25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
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struct sock *sk = sock->sk;
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struct full_sockaddr_ax25 *addr = (struct full_sockaddr_ax25 *)uaddr;
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ax25_dev *ax25_dev = NULL;
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ax25_address *call;
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ax25_uid_assoc *user;
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ax25_address call;
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ax25_cb *ax25;
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int err = 0;
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@ -1021,9 +1022,15 @@ static int ax25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
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if (addr->fsa_ax25.sax25_family != AF_AX25)
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return -EINVAL;
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call = ax25_findbyuid(current->euid);
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if (call == NULL && ax25_uid_policy && !capable(CAP_NET_ADMIN)) {
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return -EACCES;
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user = ax25_findbyuid(current->euid);
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if (user) {
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call = user->call;
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ax25_uid_put(user);
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} else {
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if (ax25_uid_policy && !capable(CAP_NET_ADMIN))
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return -EACCES;
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call = addr->fsa_ax25.sax25_call;
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}
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lock_sock(sk);
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@ -1034,10 +1041,7 @@ static int ax25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
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goto out;
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}
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if (call == NULL)
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ax25->source_addr = addr->fsa_ax25.sax25_call;
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else
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ax25->source_addr = *call;
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ax25->source_addr = call;
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/*
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* User already set interface with SO_BINDTODEVICE
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@ -422,8 +422,8 @@ static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
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*/
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int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
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{
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ax25_uid_assoc *user;
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ax25_route *ax25_rt;
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ax25_address *call;
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int err;
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if ((ax25_rt = ax25_get_route(addr, NULL)) == NULL)
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@ -434,16 +434,18 @@ int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
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goto put;
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}
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if ((call = ax25_findbyuid(current->euid)) == NULL) {
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user = ax25_findbyuid(current->euid);
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if (user) {
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ax25->source_addr = user->call;
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ax25_uid_put(user);
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} else {
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if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
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err = -EPERM;
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goto put;
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}
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call = (ax25_address *)ax25->ax25_dev->dev->dev_addr;
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ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
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}
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ax25->source_addr = *call;
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if (ax25_rt->digipeat != NULL) {
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if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
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err = -ENOMEM;
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@ -28,6 +28,7 @@
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#include <linux/fcntl.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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#include <linux/list.h>
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#include <linux/notifier.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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@ -41,38 +42,41 @@
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* Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
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*/
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static ax25_uid_assoc *ax25_uid_list;
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HLIST_HEAD(ax25_uid_list);
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static DEFINE_RWLOCK(ax25_uid_lock);
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int ax25_uid_policy = 0;
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ax25_address *ax25_findbyuid(uid_t uid)
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ax25_uid_assoc *ax25_findbyuid(uid_t uid)
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{
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ax25_uid_assoc *ax25_uid;
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ax25_address *res = NULL;
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ax25_uid_assoc *ax25_uid, *res = NULL;
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struct hlist_node *node;
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read_lock(&ax25_uid_lock);
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for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
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ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
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if (ax25_uid->uid == uid) {
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res = &ax25_uid->call;
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ax25_uid_hold(ax25_uid);
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res = ax25_uid;
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break;
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}
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}
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read_unlock(&ax25_uid_lock);
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return NULL;
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return res;
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}
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int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
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{
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ax25_uid_assoc *s, *ax25_uid;
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ax25_uid_assoc *ax25_uid;
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struct hlist_node *node;
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ax25_uid_assoc *user;
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unsigned long res;
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switch (cmd) {
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case SIOCAX25GETUID:
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res = -ENOENT;
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read_lock(&ax25_uid_lock);
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for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
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ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
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if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
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res = ax25_uid->uid;
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break;
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@ -85,19 +89,22 @@ int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
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case SIOCAX25ADDUID:
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if (!capable(CAP_NET_ADMIN))
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return -EPERM;
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if (ax25_findbyuid(sax->sax25_uid))
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user = ax25_findbyuid(sax->sax25_uid);
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if (user) {
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ax25_uid_put(user);
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return -EEXIST;
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}
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if (sax->sax25_uid == 0)
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return -EINVAL;
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if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
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return -ENOMEM;
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atomic_set(&ax25_uid->refcount, 1);
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ax25_uid->uid = sax->sax25_uid;
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ax25_uid->call = sax->sax25_call;
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write_lock(&ax25_uid_lock);
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ax25_uid->next = ax25_uid_list;
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ax25_uid_list = ax25_uid;
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hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
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write_unlock(&ax25_uid_lock);
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return 0;
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@ -106,34 +113,21 @@ int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
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if (!capable(CAP_NET_ADMIN))
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return -EPERM;
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ax25_uid = NULL;
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write_lock(&ax25_uid_lock);
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for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
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if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
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ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
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if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
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break;
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}
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}
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if (ax25_uid == NULL) {
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write_unlock(&ax25_uid_lock);
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return -ENOENT;
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}
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if ((s = ax25_uid_list) == ax25_uid) {
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ax25_uid_list = s->next;
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write_unlock(&ax25_uid_lock);
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kfree(ax25_uid);
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return 0;
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}
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while (s != NULL && s->next != NULL) {
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if (s->next == ax25_uid) {
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s->next = ax25_uid->next;
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write_unlock(&ax25_uid_lock);
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kfree(ax25_uid);
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return 0;
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}
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s = s->next;
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}
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hlist_del_init(&ax25_uid->uid_node);
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ax25_uid_put(ax25_uid);
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write_unlock(&ax25_uid_lock);
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return -ENOENT;
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return 0;
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default:
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return -EINVAL;
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@ -147,13 +141,11 @@ int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
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static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
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{
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struct ax25_uid_assoc *pt;
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int i = 1;
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struct hlist_node *node;
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int i = 0;
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read_lock(&ax25_uid_lock);
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if (*pos == 0)
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return SEQ_START_TOKEN;
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for (pt = ax25_uid_list; pt != NULL; pt = pt->next) {
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ax25_uid_for_each(pt, node, &ax25_uid_list) {
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if (i == *pos)
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return pt;
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++i;
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@ -164,8 +156,9 @@ static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
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static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
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{
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++*pos;
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return (v == SEQ_START_TOKEN) ? ax25_uid_list :
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((struct ax25_uid_assoc *) v)->next;
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return hlist_entry(((ax25_uid_assoc *)v)->uid_node.next,
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ax25_uid_assoc, uid_node);
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}
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static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
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@ -179,7 +172,6 @@ static int ax25_uid_seq_show(struct seq_file *seq, void *v)
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seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
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else {
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struct ax25_uid_assoc *pt = v;
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seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(&pt->call));
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}
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@ -213,16 +205,13 @@ struct file_operations ax25_uid_fops = {
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*/
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void __exit ax25_uid_free(void)
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{
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ax25_uid_assoc *s, *ax25_uid;
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ax25_uid_assoc *ax25_uid;
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struct hlist_node *node;
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write_lock(&ax25_uid_lock);
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ax25_uid = ax25_uid_list;
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while (ax25_uid != NULL) {
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s = ax25_uid;
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ax25_uid = ax25_uid->next;
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kfree(s);
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ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
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hlist_del_init(&ax25_uid->uid_node);
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ax25_uid_put(ax25_uid);
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}
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ax25_uid_list = NULL;
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write_unlock(&ax25_uid_lock);
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}
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@ -536,7 +536,8 @@ static int nr_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
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struct nr_sock *nr = nr_sk(sk);
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struct full_sockaddr_ax25 *addr = (struct full_sockaddr_ax25 *)uaddr;
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struct net_device *dev;
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ax25_address *user, *source;
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ax25_uid_assoc *user;
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ax25_address *source;
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lock_sock(sk);
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if (!sock_flag(sk, SOCK_ZAPPED)) {
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@ -575,16 +576,19 @@ static int nr_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
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} else {
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source = &addr->fsa_ax25.sax25_call;
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if ((user = ax25_findbyuid(current->euid)) == NULL) {
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user = ax25_findbyuid(current->euid);
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if (user) {
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nr->user_addr = user->call;
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ax25_uid_put(user);
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} else {
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if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
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release_sock(sk);
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dev_put(dev);
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return -EPERM;
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}
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user = source;
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nr->user_addr = *source;
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}
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nr->user_addr = *user;
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nr->source_addr = *source;
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}
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@ -604,7 +608,8 @@ static int nr_connect(struct socket *sock, struct sockaddr *uaddr,
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struct sock *sk = sock->sk;
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struct nr_sock *nr = nr_sk(sk);
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struct sockaddr_ax25 *addr = (struct sockaddr_ax25 *)uaddr;
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ax25_address *user, *source = NULL;
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ax25_address *source = NULL;
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ax25_uid_assoc *user;
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struct net_device *dev;
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lock_sock(sk);
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@ -645,16 +650,19 @@ static int nr_connect(struct socket *sock, struct sockaddr *uaddr,
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}
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source = (ax25_address *)dev->dev_addr;
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if ((user = ax25_findbyuid(current->euid)) == NULL) {
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user = ax25_findbyuid(current->euid);
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if (user) {
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nr->user_addr = user->call;
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ax25_uid_put(user);
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} else {
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if (ax25_uid_policy && !capable(CAP_NET_ADMIN)) {
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dev_put(dev);
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release_sock(sk);
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return -EPERM;
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}
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user = source;
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nr->user_addr = *source;
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}
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nr->user_addr = *user;
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nr->source_addr = *source;
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nr->device = dev;
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@ -626,7 +626,8 @@ static int rose_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
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struct rose_sock *rose = rose_sk(sk);
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struct sockaddr_rose *addr = (struct sockaddr_rose *)uaddr;
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struct net_device *dev;
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ax25_address *user, *source;
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ax25_address *source;
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ax25_uid_assoc *user;
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int n;
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if (!sock_flag(sk, SOCK_ZAPPED))
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@ -651,14 +652,17 @@ static int rose_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
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source = &addr->srose_call;
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if ((user = ax25_findbyuid(current->euid)) == NULL) {
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user = ax25_findbyuid(current->euid);
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if (user) {
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rose->source_call = user->call;
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ax25_uid_put(user);
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} else {
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if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE))
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return -EACCES;
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user = source;
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rose->source_call = *source;
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}
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rose->source_addr = addr->srose_addr;
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rose->source_call = *user;
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rose->device = dev;
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rose->source_ndigis = addr->srose_ndigis;
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@ -685,8 +689,8 @@ static int rose_connect(struct socket *sock, struct sockaddr *uaddr, int addr_le
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struct rose_sock *rose = rose_sk(sk);
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struct sockaddr_rose *addr = (struct sockaddr_rose *)uaddr;
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unsigned char cause, diagnostic;
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ax25_address *user;
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struct net_device *dev;
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ax25_uid_assoc *user;
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int n;
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if (sk->sk_state == TCP_ESTABLISHED && sock->state == SS_CONNECTING) {
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|
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@ -736,12 +740,14 @@ static int rose_connect(struct socket *sock, struct sockaddr *uaddr, int addr_le
|
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if ((dev = rose_dev_first()) == NULL)
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return -ENETUNREACH;
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|
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if ((user = ax25_findbyuid(current->euid)) == NULL)
|
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user = ax25_findbyuid(current->euid);
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if (!user)
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return -EINVAL;
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memcpy(&rose->source_addr, dev->dev_addr, ROSE_ADDR_LEN);
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rose->source_call = *user;
|
||||
rose->source_call = user->call;
|
||||
rose->device = dev;
|
||||
ax25_uid_put(user);
|
||||
|
||||
rose_insert_socket(sk); /* Finish the bind */
|
||||
}
|
||||
|
|
|
|||
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