commit 2e3a94aa2bfc6de95a0700f0a868c6f5db3a9592
author Brian Vazquez <brianvv@google.com> Sun Jan 19 11:40:40 2020 -0800
committer Daniel Borkmann <daniel@iogearbox.net> Mon Jan 20 22:27:51 2020 +0100
tree 18ee2f84509602f1383c1dcf8a55d49130bb342e
parent a6ed02cac690b635dbb938690e795812ce1e14ca

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

kernel/bpf/syscall.c

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c26a714..9a840c5 100644
--- 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;
 
-	value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
-	if (!value)
+	key = kmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
+	if (!key)
 		return -ENOMEM;
 
+	value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
+	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,