netdev - [PATCH bpf] libbpf: always NULL out pobj in bpf_prog_load

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Message-Id: <20190502154932.14698-1-lmb@cloudflare.com>
Date:   Thu,  2 May 2019 11:49:32 -0400
From:   Lorenz Bauer <lmb@...udflare.com>
To:     bpf@...r.kernel.org, netdev@...r.kernel.org, ast@...nel.org,
        daniel@...earbox.net
Cc:     Lorenz Bauer <lmb@...udflare.com>
Subject: [PATCH bpf] libbpf: always NULL out pobj in bpf_prog_load_xattr

Currently, code like the following segfaults if bpf_prog_load_xattr
returns an error:

    struct bpf_object *obj;

    err = bpf_prog_load_xattr(&attr, &obj, &prog_fd);
    bpf_object__close(obj);
    if (err)
        ...

Unconditionally reset pobj to NULL at the start of the function
to fix this.

Signed-off-by: Lorenz Bauer <lmb@...udflare.com>
---
 tools/lib/bpf/libbpf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 11a65db4b93f..2ddf3212b8f7 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -3363,6 +3363,8 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
 	struct bpf_map *map;
 	int err;
 
+	*pobj = NULL;
+
 	if (!attr)
 		return -EINVAL;
 	if (!attr->file)
-- 
2.19.1