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Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/bpf_iter.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index b6715964b685..8faa2ce89396 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -67,6 +67,9 @@ static void bpf_iter_done_stop(struct seq_file *seq)
iter_priv->done_stop = true;
}
+/* maximum visited objects before bailing out */
+#define MAX_ITER_OBJECTS 1000000
+
/* bpf_seq_read, a customized and simpler version for bpf iterator.
* no_llseek is assumed for this file.
* The following are differences from seq_read():
@@ -79,7 +82,7 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
{
struct seq_file *seq = file->private_data;
size_t n, offs, copied = 0;
- int err = 0;
+ int err = 0, num_objs = 0;
void *p;
mutex_lock(&seq->lock);
@@ -135,6 +138,7 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
while (1) {
loff_t pos = seq->index;
+ num_objs++;
offs = seq->count;
p = seq->op->next(seq, p, &seq->index);
if (pos == seq->index) {
@@ -153,6 +157,15 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
if (seq->count >= size)
break;
+ if (num_objs >= MAX_ITER_OBJECTS) {
+ if (offs == 0) {
+ err = -EAGAIN;
+ seq->op->stop(seq, p);
+ goto done;
+ }
+ break;
+ }
+
err = seq->op->show(seq, p);
if (err > 0) {
bpf_iter_dec_seq_num(seq);