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Diffstat (limited to 'kernel/bpf/bpf_iter.c')
-rw-r--r--kernel/bpf/bpf_iter.c94
1 files changed, 80 insertions, 14 deletions
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index dd612b80b9fe..8faa2ce89396 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -14,11 +14,13 @@ struct bpf_iter_target_info {
struct bpf_iter_link {
struct bpf_link link;
+ struct bpf_iter_aux_info aux;
struct bpf_iter_target_info *tinfo;
};
struct bpf_iter_priv_data {
struct bpf_iter_target_info *tinfo;
+ const struct bpf_iter_seq_info *seq_info;
struct bpf_prog *prog;
u64 session_id;
u64 seq_num;
@@ -35,7 +37,8 @@ static DEFINE_MUTEX(link_mutex);
/* incremented on every opened seq_file */
static atomic64_t session_id;
-static int prepare_seq_file(struct file *file, struct bpf_iter_link *link);
+static int prepare_seq_file(struct file *file, struct bpf_iter_link *link,
+ const struct bpf_iter_seq_info *seq_info);
static void bpf_iter_inc_seq_num(struct seq_file *seq)
{
@@ -64,6 +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():
@@ -76,7 +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);
@@ -132,6 +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) {
@@ -150,6 +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);
@@ -199,11 +215,25 @@ done:
return copied;
}
+static const struct bpf_iter_seq_info *
+__get_seq_info(struct bpf_iter_link *link)
+{
+ const struct bpf_iter_seq_info *seq_info;
+
+ if (link->aux.map) {
+ seq_info = link->aux.map->ops->iter_seq_info;
+ if (seq_info)
+ return seq_info;
+ }
+
+ return link->tinfo->reg_info->seq_info;
+}
+
static int iter_open(struct inode *inode, struct file *file)
{
struct bpf_iter_link *link = inode->i_private;
- return prepare_seq_file(file, link);
+ return prepare_seq_file(file, link, __get_seq_info(link));
}
static int iter_release(struct inode *inode, struct file *file)
@@ -218,8 +248,8 @@ static int iter_release(struct inode *inode, struct file *file)
iter_priv = container_of(seq->private, struct bpf_iter_priv_data,
target_private);
- if (iter_priv->tinfo->reg_info->fini_seq_private)
- iter_priv->tinfo->reg_info->fini_seq_private(seq->private);
+ if (iter_priv->seq_info->fini_seq_private)
+ iter_priv->seq_info->fini_seq_private(seq->private);
bpf_prog_put(iter_priv->prog);
seq->private = iter_priv;
@@ -318,6 +348,11 @@ bool bpf_iter_prog_supported(struct bpf_prog *prog)
static void bpf_iter_link_release(struct bpf_link *link)
{
+ struct bpf_iter_link *iter_link =
+ container_of(link, struct bpf_iter_link, link);
+
+ if (iter_link->tinfo->reg_info->detach_target)
+ iter_link->tinfo->reg_info->detach_target(&iter_link->aux);
}
static void bpf_iter_link_dealloc(struct bpf_link *link)
@@ -368,16 +403,35 @@ bool bpf_link_is_iter(struct bpf_link *link)
int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
{
+ union bpf_iter_link_info __user *ulinfo;
struct bpf_link_primer link_primer;
struct bpf_iter_target_info *tinfo;
+ union bpf_iter_link_info linfo;
struct bpf_iter_link *link;
+ u32 prog_btf_id, linfo_len;
bool existed = false;
- u32 prog_btf_id;
int err;
if (attr->link_create.target_fd || attr->link_create.flags)
return -EINVAL;
+ memset(&linfo, 0, sizeof(union bpf_iter_link_info));
+
+ ulinfo = u64_to_user_ptr(attr->link_create.iter_info);
+ linfo_len = attr->link_create.iter_info_len;
+ if (!ulinfo ^ !linfo_len)
+ return -EINVAL;
+
+ if (ulinfo) {
+ err = bpf_check_uarg_tail_zero(ulinfo, sizeof(linfo),
+ linfo_len);
+ if (err)
+ return err;
+ linfo_len = min_t(u32, linfo_len, sizeof(linfo));
+ if (copy_from_user(&linfo, ulinfo, linfo_len))
+ return -EFAULT;
+ }
+
prog_btf_id = prog->aux->attach_btf_id;
mutex_lock(&targets_mutex);
list_for_each_entry(tinfo, &targets, list) {
@@ -403,21 +457,32 @@ int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
return err;
}
+ if (tinfo->reg_info->attach_target) {
+ err = tinfo->reg_info->attach_target(prog, &linfo, &link->aux);
+ if (err) {
+ bpf_link_cleanup(&link_primer);
+ return err;
+ }
+ }
+
return bpf_link_settle(&link_primer);
}
static void init_seq_meta(struct bpf_iter_priv_data *priv_data,
struct bpf_iter_target_info *tinfo,
+ const struct bpf_iter_seq_info *seq_info,
struct bpf_prog *prog)
{
priv_data->tinfo = tinfo;
+ priv_data->seq_info = seq_info;
priv_data->prog = prog;
priv_data->session_id = atomic64_inc_return(&session_id);
priv_data->seq_num = 0;
priv_data->done_stop = false;
}
-static int prepare_seq_file(struct file *file, struct bpf_iter_link *link)
+static int prepare_seq_file(struct file *file, struct bpf_iter_link *link,
+ const struct bpf_iter_seq_info *seq_info)
{
struct bpf_iter_priv_data *priv_data;
struct bpf_iter_target_info *tinfo;
@@ -433,21 +498,21 @@ static int prepare_seq_file(struct file *file, struct bpf_iter_link *link)
tinfo = link->tinfo;
total_priv_dsize = offsetof(struct bpf_iter_priv_data, target_private) +
- tinfo->reg_info->seq_priv_size;
- priv_data = __seq_open_private(file, tinfo->reg_info->seq_ops,
+ seq_info->seq_priv_size;
+ priv_data = __seq_open_private(file, seq_info->seq_ops,
total_priv_dsize);
if (!priv_data) {
err = -ENOMEM;
goto release_prog;
}
- if (tinfo->reg_info->init_seq_private) {
- err = tinfo->reg_info->init_seq_private(priv_data->target_private);
+ if (seq_info->init_seq_private) {
+ err = seq_info->init_seq_private(priv_data->target_private, &link->aux);
if (err)
goto release_seq_file;
}
- init_seq_meta(priv_data, tinfo, prog);
+ init_seq_meta(priv_data, tinfo, seq_info, prog);
seq = file->private_data;
seq->private = priv_data->target_private;
@@ -463,6 +528,7 @@ release_prog:
int bpf_iter_new_fd(struct bpf_link *link)
{
+ struct bpf_iter_link *iter_link;
struct file *file;
unsigned int flags;
int err, fd;
@@ -481,8 +547,8 @@ int bpf_iter_new_fd(struct bpf_link *link)
goto free_fd;
}
- err = prepare_seq_file(file,
- container_of(link, struct bpf_iter_link, link));
+ iter_link = container_of(link, struct bpf_iter_link, link);
+ err = prepare_seq_file(file, iter_link, __get_seq_info(iter_link));
if (err)
goto free_file;
generated by cgit v1.2.3 (git 2.46.0) at 2025-10-08 08:01:53 +0000