bpf: Fix memory leaks in generic update/delete batch ops

Generic update/delete batch ops functions were using __bpf_copy_key
without properly freeing the memory. Handle the memory allocation and
copy_from_user separately.

Fixes: aa2e93b8e58e ("bpf: Add generic support for update and delete batch ops")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200119194040.128369-1-brianvv@google.com

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c26a714..9a840c5 100644 (file)
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1239,12 +1239,15 @@ int generic_map_delete_batch(struct bpf_map *map,
        if (!max_count)
                return 0;
 
+       key = kmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
+       if (!key)
+               return -ENOMEM;
+
        for (cp = 0; cp < max_count; cp++) {
-               key = __bpf_copy_key(keys + cp * map->key_size, map->key_size);
-               if (IS_ERR(key)) {
-                       err = PTR_ERR(key);
+               err = -EFAULT;
+               if (copy_from_user(key, keys + cp * map->key_size,
+                                  map->key_size))
                        break;
-               }
 
                if (bpf_map_is_dev_bound(map)) {
                        err = bpf_map_offload_delete_elem(map, key);
@@ -1264,6 +1267,8 @@ int generic_map_delete_batch(struct bpf_map *map,
        }
        if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
                err = -EFAULT;
+
+       kfree(key);
        return err;
 }
 
@@ -1294,18 +1299,21 @@ int generic_map_update_batch(struct bpf_map *map,
        if (!max_count)
                return 0;
 
+       key = kmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
+       if (!key)
+               return -ENOMEM;
+
        value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
-       if (!value)
+       if (!value) {
+               kfree(key);
                return -ENOMEM;
+       }
 
        for (cp = 0; cp < max_count; cp++) {
-               key = __bpf_copy_key(keys + cp * map->key_size, map->key_size);
-               if (IS_ERR(key)) {
-                       err = PTR_ERR(key);
-                       break;
-               }
                err = -EFAULT;
-               if (copy_from_user(value, values + cp * value_size, value_size))
+               if (copy_from_user(key, keys + cp * map->key_size,
+                   map->key_size) ||
+                   copy_from_user(value, values + cp * value_size, value_size))
                        break;
 
                err = bpf_map_update_value(map, f, key, value,