Commit 1028ae40 authored Oct 02, 2020 by Stanislav Fomichev Committed by Alexei Starovoitov Oct 02, 2020

bpf: Deref map in BPF_PROG_BIND_MAP when it's already used



We are missing a deref for the case when we are doing BPF_PROG_BIND_MAP
on a map that's being already held by the program.
There is 'if (ret) bpf_map_put(map)' below which doesn't trigger
because we don't consider this an error.
Let's add missing bpf_map_put() for this specific condition.

Fixes: ef15314a ("bpf: Add BPF_PROG_BIND_MAP syscall")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20201003002544.3601440-1-sdf@google.com

parent fb91db01

kernel/bpf/syscall.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -4323,8 +4323,10 @@ static int bpf_prog_bind_map(union bpf_attr *attr)
		used_maps_old = prog->aux->used_maps;

		for (i = 0; i < prog->aux->used_map_cnt; i++)
		if (used_maps_old[i] == map)
		if (used_maps_old[i] == map) {
		bpf_map_put(map);
		goto out_unlock;
		}

		used_maps_new = kmalloc_array(prog->aux->used_map_cnt + 1,
		sizeof(used_maps_new[0]),

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