[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <153867315418.10087.16314091028767268287.stgit@kernel>
Date: Thu, 04 Oct 2018 19:12:34 +0200
From: Mauricio Vasquez B <mauricio.vasquez@...ito.it>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>, netdev@...r.kernel.org
Subject: [RFC PATCH bpf-next v4 2/7] bpf/syscall: allow key to be null in
map functions
This commit adds the required logic to allow key being NULL
in case the key_size of the map is 0.
A new __bpf_copy_key function helper only copies the key from
userpsace when key_size != 0, otherwise it enforces that key must be
null.
Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@...ito.it>
---
kernel/bpf/syscall.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 5742df21598c..eb75e8af73ff 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -651,6 +651,17 @@ int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
return -ENOTSUPP;
}
+static void *__bpf_copy_key(void __user *ukey, u64 key_size)
+{
+ if (key_size)
+ return memdup_user(ukey, key_size);
+
+ if (ukey)
+ return ERR_PTR(-EINVAL);
+
+ return NULL;
+}
+
/* last field in 'union bpf_attr' used by this command */
#define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value
@@ -678,7 +689,7 @@ static int map_lookup_elem(union bpf_attr *attr)
goto err_put;
}
- key = memdup_user(ukey, map->key_size);
+ key = __bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
@@ -769,7 +780,7 @@ static int map_update_elem(union bpf_attr *attr)
goto err_put;
}
- key = memdup_user(ukey, map->key_size);
+ key = __bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
@@ -871,7 +882,7 @@ static int map_delete_elem(union bpf_attr *attr)
goto err_put;
}
- key = memdup_user(ukey, map->key_size);
+ key = __bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
@@ -923,7 +934,7 @@ static int map_get_next_key(union bpf_attr *attr)
}
if (ukey) {
- key = memdup_user(ukey, map->key_size);
+ key = __bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
Powered by blists - more mailing lists