From 1028ae4069991e26d1522e957939fb61d2da1d12 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Fri, 2 Oct 2020 17:25:44 -0700 Subject: [PATCH] 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: ef15314aa5de ("bpf: Add BPF_PROG_BIND_MAP syscall") Reported-by: Alexei Starovoitov Signed-off-by: Stanislav Fomichev Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20201003002544.3601440-1-sdf@google.com --- kernel/bpf/syscall.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index f1528c2a6927..1110ecd7d1f3 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -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]), -- 2.25.1