https://github.com/torvalds/linux
Revision e76018cb604ace486de9cf85898c14bb2b47faff authored by Gustavo A. R. Silva on 23 March 2020, 21:48:10 UTC, committed by Gustavo A. R. Silva on 18 April 2020, 20:44:54 UTC
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
1 parent 5a58ec8
Tip revision: e76018cb604ace486de9cf85898c14bb2b47faff authored by Gustavo A. R. Silva on 23 March 2020, 21:48:10 UTC
can: dev: peak_canfd.h: Replace zero-length array with flexible-array member
can: dev: peak_canfd.h: Replace zero-length array with flexible-array member
Tip revision: e76018c
nf_sockopt.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <linux/mutex.h>
#include <net/sock.h>
#include "nf_internals.h"
/* Sockopts only registered and called from user context, so
net locking would be overkill. Also, [gs]etsockopt calls may
sleep. */
static DEFINE_MUTEX(nf_sockopt_mutex);
static LIST_HEAD(nf_sockopts);
/* Do exclusive ranges overlap? */
static inline int overlap(int min1, int max1, int min2, int max2)
{
return max1 > min2 && min1 < max2;
}
/* Functions to register sockopt ranges (exclusive). */
int nf_register_sockopt(struct nf_sockopt_ops *reg)
{
struct nf_sockopt_ops *ops;
int ret = 0;
mutex_lock(&nf_sockopt_mutex);
list_for_each_entry(ops, &nf_sockopts, list) {
if (ops->pf == reg->pf
&& (overlap(ops->set_optmin, ops->set_optmax,
reg->set_optmin, reg->set_optmax)
|| overlap(ops->get_optmin, ops->get_optmax,
reg->get_optmin, reg->get_optmax))) {
pr_debug("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n",
ops->set_optmin, ops->set_optmax,
ops->get_optmin, ops->get_optmax,
reg->set_optmin, reg->set_optmax,
reg->get_optmin, reg->get_optmax);
ret = -EBUSY;
goto out;
}
}
list_add(®->list, &nf_sockopts);
out:
mutex_unlock(&nf_sockopt_mutex);
return ret;
}
EXPORT_SYMBOL(nf_register_sockopt);
void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
{
mutex_lock(&nf_sockopt_mutex);
list_del(®->list);
mutex_unlock(&nf_sockopt_mutex);
}
EXPORT_SYMBOL(nf_unregister_sockopt);
static struct nf_sockopt_ops *nf_sockopt_find(struct sock *sk, u_int8_t pf,
int val, int get)
{
struct nf_sockopt_ops *ops;
mutex_lock(&nf_sockopt_mutex);
list_for_each_entry(ops, &nf_sockopts, list) {
if (ops->pf == pf) {
if (!try_module_get(ops->owner))
goto out_nosup;
if (get) {
if (val >= ops->get_optmin &&
val < ops->get_optmax)
goto out;
} else {
if (val >= ops->set_optmin &&
val < ops->set_optmax)
goto out;
}
module_put(ops->owner);
}
}
out_nosup:
ops = ERR_PTR(-ENOPROTOOPT);
out:
mutex_unlock(&nf_sockopt_mutex);
return ops;
}
/* Call get/setsockopt() */
static int nf_sockopt(struct sock *sk, u_int8_t pf, int val,
char __user *opt, int *len, int get)
{
struct nf_sockopt_ops *ops;
int ret;
ops = nf_sockopt_find(sk, pf, val, get);
if (IS_ERR(ops))
return PTR_ERR(ops);
if (get)
ret = ops->get(sk, val, opt, len);
else
ret = ops->set(sk, val, opt, *len);
module_put(ops->owner);
return ret;
}
int nf_setsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
unsigned int len)
{
return nf_sockopt(sk, pf, val, opt, &len, 0);
}
EXPORT_SYMBOL(nf_setsockopt);
int nf_getsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
int *len)
{
return nf_sockopt(sk, pf, val, opt, len, 1);
}
EXPORT_SYMBOL(nf_getsockopt);
#ifdef CONFIG_COMPAT
static int compat_nf_sockopt(struct sock *sk, u_int8_t pf, int val,
char __user *opt, int *len, int get)
{
struct nf_sockopt_ops *ops;
int ret;
ops = nf_sockopt_find(sk, pf, val, get);
if (IS_ERR(ops))
return PTR_ERR(ops);
if (get) {
if (ops->compat_get)
ret = ops->compat_get(sk, val, opt, len);
else
ret = ops->get(sk, val, opt, len);
} else {
if (ops->compat_set)
ret = ops->compat_set(sk, val, opt, *len);
else
ret = ops->set(sk, val, opt, *len);
}
module_put(ops->owner);
return ret;
}
int compat_nf_setsockopt(struct sock *sk, u_int8_t pf,
int val, char __user *opt, unsigned int len)
{
return compat_nf_sockopt(sk, pf, val, opt, &len, 0);
}
EXPORT_SYMBOL(compat_nf_setsockopt);
int compat_nf_getsockopt(struct sock *sk, u_int8_t pf,
int val, char __user *opt, int *len)
{
return compat_nf_sockopt(sk, pf, val, opt, len, 1);
}
EXPORT_SYMBOL(compat_nf_getsockopt);
#endif
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