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926f38e974
KASAN reports out-of-bound access in proc_dostring() coming from
proc_tcp_available_ulp() because in case TCP ULP list is empty
the buffer allocated for the response will not have anything
printed into it. Set the first byte to zero to avoid strlen()
going out-of-bounds.
Fixes: 734942cc4e ("tcp: ULP infrastructure")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
136 lines
2.8 KiB
C
136 lines
2.8 KiB
C
/*
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* Pluggable TCP upper layer protocol support.
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*
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* Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved.
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* Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. All rights reserved.
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*
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*/
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#include<linux/module.h>
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#include <linux/mm.h>
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/gfp.h>
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#include <net/tcp.h>
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static DEFINE_SPINLOCK(tcp_ulp_list_lock);
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static LIST_HEAD(tcp_ulp_list);
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/* Simple linear search, don't expect many entries! */
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static struct tcp_ulp_ops *tcp_ulp_find(const char *name)
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{
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struct tcp_ulp_ops *e;
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list_for_each_entry_rcu(e, &tcp_ulp_list, list) {
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if (strcmp(e->name, name) == 0)
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return e;
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}
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return NULL;
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}
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static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name)
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{
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const struct tcp_ulp_ops *ulp = NULL;
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rcu_read_lock();
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ulp = tcp_ulp_find(name);
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#ifdef CONFIG_MODULES
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if (!ulp && capable(CAP_NET_ADMIN)) {
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rcu_read_unlock();
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request_module("%s", name);
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rcu_read_lock();
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ulp = tcp_ulp_find(name);
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}
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#endif
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if (!ulp || !try_module_get(ulp->owner))
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ulp = NULL;
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rcu_read_unlock();
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return ulp;
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}
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/* Attach new upper layer protocol to the list
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* of available protocols.
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*/
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int tcp_register_ulp(struct tcp_ulp_ops *ulp)
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{
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int ret = 0;
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spin_lock(&tcp_ulp_list_lock);
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if (tcp_ulp_find(ulp->name)) {
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pr_notice("%s already registered or non-unique name\n",
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ulp->name);
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ret = -EEXIST;
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} else {
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list_add_tail_rcu(&ulp->list, &tcp_ulp_list);
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}
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spin_unlock(&tcp_ulp_list_lock);
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return ret;
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}
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EXPORT_SYMBOL_GPL(tcp_register_ulp);
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void tcp_unregister_ulp(struct tcp_ulp_ops *ulp)
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{
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spin_lock(&tcp_ulp_list_lock);
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list_del_rcu(&ulp->list);
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spin_unlock(&tcp_ulp_list_lock);
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synchronize_rcu();
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}
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EXPORT_SYMBOL_GPL(tcp_unregister_ulp);
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/* Build string with list of available upper layer protocl values */
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void tcp_get_available_ulp(char *buf, size_t maxlen)
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{
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struct tcp_ulp_ops *ulp_ops;
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size_t offs = 0;
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*buf = '\0';
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rcu_read_lock();
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list_for_each_entry_rcu(ulp_ops, &tcp_ulp_list, list) {
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offs += snprintf(buf + offs, maxlen - offs,
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"%s%s",
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offs == 0 ? "" : " ", ulp_ops->name);
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}
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rcu_read_unlock();
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}
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void tcp_cleanup_ulp(struct sock *sk)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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if (!icsk->icsk_ulp_ops)
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return;
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if (icsk->icsk_ulp_ops->release)
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icsk->icsk_ulp_ops->release(sk);
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module_put(icsk->icsk_ulp_ops->owner);
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}
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/* Change upper layer protocol for socket */
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int tcp_set_ulp(struct sock *sk, const char *name)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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const struct tcp_ulp_ops *ulp_ops;
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int err = 0;
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if (icsk->icsk_ulp_ops)
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return -EEXIST;
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ulp_ops = __tcp_ulp_find_autoload(name);
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if (!ulp_ops)
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err = -ENOENT;
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else
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err = ulp_ops->init(sk);
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if (err)
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goto out;
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icsk->icsk_ulp_ops = ulp_ops;
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out:
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return err;
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}
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