bpf: Change inode_storage's lookup_elem return value from NULL to -EBADF

bpf_fd_inode_storage_lookup_elem() returned NULL when getting a bad FD,
which caused -ENOENT in bpf_map_copy_value. -EBADF error is better than
-ENOENT for a bad FD behaviour.

The patch was partially contributed by CyberArk Software, Inc.

Fixes: 8ea636848aca ("bpf: Implement bpf_local_storage for inodes")
Signed-off-by: Tal Lossos <tallossos@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210307120948.61414-1-tallossos@gmail.com

diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c
index 6639640523c0bb1afb6a51d9e3e141fc30d8be8a..b58b2efb9b431db68121e7c5cdaf6dedbfa3c517 100644 (file)
--- a/kernel/bpf/bpf_inode_storage.c
+++ b/kernel/bpf/bpf_inode_storage.c
@@ -109,7 +109,7 @@ static void *bpf_fd_inode_storage_lookup_elem(struct bpf_map *map, void *key)
        fd = *(int *)key;
        f = fget_raw(fd);
        if (!f)
-               return NULL;
+               return ERR_PTR(-EBADF);
 
        sdata = inode_storage_lookup(f->f_inode, map, true);
        fput(f);