1 files changed, 106 insertions, 0 deletions
diff --git a/net/core/skb_fault_injection.c b/net/core/skb_fault_injection.c
new file mode 100644
index 000000000000..4235db6bdfad
--- /dev/null
+++ b/net/core/skb_fault_injection.c
@@ -0,0 +1,106 @@
+// 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);