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bpf: Initialize storage pointers to NULL to prevent freeing garbage pointer 

commit 62039c30c1 upstream.

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_PERCPU storage type. Avoid this
by always initializing storage pointers to NULLs.

Fixes: 8bad74f984 ("bpf: extend cgroup bpf core to allow multiple cgroup storage types")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200309222756.1018737-1-andriin@fb.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andrii Nakryiko 2020-03-09 15:27:55 -07:00 committed by Greg Kroah-Hartman
parent c68e1117f4
commit 188aae1f3d
1 changed files with 2 additions and 2 deletions
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4
kernel/bpf/cgroup.c
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@ -303,8 +303,8 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
{
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] = {};
enum bpf_cgroup_storage_type stype;
struct bpf_prog_list *pl;
bool pl_was_allocated;