libbpf: Potential NULL dereference in usdt_manager_attach_usdt()

link could be null but still dereference bpf_link__destroy(&link->link)
and it will lead to a null pointer access.

Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1649299098-2069-1-git-send-email-baihaowen@meizu.com

diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index c5acf28..bb1e886 100644 (file)
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -1071,8 +1071,8 @@ struct bpf_link *usdt_manager_attach_usdt(struct usdt_manager *man, const struct
        return &link->link;
 
 err_out:
-       bpf_link__destroy(&link->link);
-
+       if (link)
+               bpf_link__destroy(&link->link);
        free(targets);
        hashmap__free(specs_hash);
        if (elf)