From: Andrii Nakryiko <andriin@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
<daniel@iogearbox.net>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>,
Andrii Nakryiko <andriin@fb.com>
Subject: [PATCH bpf-next] bpf: initialize storage pointers to NULL to prevent freeing garbage pointer
Date: Mon, 9 Mar 2020 15:27:55 -0700 [thread overview]
Message-ID: <20200309222756.1018737-1-andriin@fb.com> (raw)
Local storage array isn't initialized, so if cgroup storage allocation fails
for BPF_CGROUP_STORAGE_SHARED, error handling code will attempt to free
uninitialized pointer for BPF_CGROUP_STORAGE_PERCPI storage type. Avoid this
by always initializing storage pointers to NULLs.
Fixes: 8bad74f9840f ("bpf: extend cgroup bpf core to allow multiple cgroup storage types")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
kernel/bpf/cgroup.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 9a500fadbef5..b2bc4c335bb1 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -302,8 +302,8 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
u32 saved_flags = (flags & (BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI));
struct list_head *progs = &cgrp->bpf.progs[type];
struct bpf_prog *old_prog = NULL;
- struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE],
- *old_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {NULL};
+ struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
+ struct bpf_cgroup_storage *old_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
struct bpf_prog_list *pl, *replace_pl = NULL;
enum bpf_cgroup_storage_type stype;
int err;
--
2.17.1
next reply other threads:[~2020-03-09 22:28 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 22:27 Andrii Nakryiko [this message]
2020-03-10 2:58 ` [PATCH bpf-next] bpf: initialize storage pointers to NULL to prevent freeing garbage pointer Alexei Starovoitov
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