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// SPDX-License-Identifier: GPL-2.0-only
#include <linux/debugfs.h>
#include <linux/fault-inject.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
static struct {
struct fault_attr attr;
char devname[IFNAMSIZ];
bool filtered;
} skb_realloc = {
.attr = FAULT_ATTR_INITIALIZER,
.filtered = false,
};
static bool should_fail_net_realloc_skb(struct sk_buff *skb)
{
struct net_device *net = skb->dev;
if (skb_realloc.filtered &&
strncmp(net->name, skb_realloc.devname, IFNAMSIZ))
/* device name filter set, but names do not match */
return false;
if (!should_fail(&skb_realloc.attr, 1))
return false;
return true;
}
ALLOW_ERROR_INJECTION(should_fail_net_realloc_skb, TRUE);
void skb_might_realloc(struct sk_buff *skb)
{
if (!should_fail_net_realloc_skb(skb))
return;
pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
}
EXPORT_SYMBOL(skb_might_realloc);
static int __init fail_skb_realloc_setup(char *str)
{
return setup_fault_attr(&skb_realloc.attr, str);
}
__setup("fail_skb_realloc=", fail_skb_realloc_setup);
static void reset_settings(void)
{
skb_realloc.filtered = false;
memset(&skb_realloc.devname, 0, IFNAMSIZ);
}
static ssize_t devname_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
ssize_t ret;
reset_settings();
ret = simple_write_to_buffer(&skb_realloc.devname, IFNAMSIZ,
ppos, buffer, count);
if (ret < 0)
return ret;
skb_realloc.devname[IFNAMSIZ - 1] = '\0';
/* Remove a possible \n at the end of devname */
strim(skb_realloc.devname);
if (strnlen(skb_realloc.devname, IFNAMSIZ))
skb_realloc.filtered = true;
return count;
}
static ssize_t devname_read(struct file *file,
char __user *buffer,
size_t size, loff_t *ppos)
{
if (!skb_realloc.filtered)
return 0;
return simple_read_from_buffer(buffer, size, ppos, &skb_realloc.devname,
strlen(skb_realloc.devname));
}
static const struct file_operations devname_ops = {
.write = devname_write,
.read = devname_read,
};
static int __init fail_skb_realloc_debugfs(void)
{
umode_t mode = S_IFREG | 0600;
struct dentry *dir;
dir = fault_create_debugfs_attr("fail_skb_realloc", NULL,
&skb_realloc.attr);
if (IS_ERR(dir))
return PTR_ERR(dir);
debugfs_create_file("devname", mode, dir, NULL, &devname_ops);
return 0;
}
late_initcall(fail_skb_realloc_debugfs);
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