From: Andrii Nakryiko Date: Mon, 9 Mar 2020 22:27:55 +0000 (-0700) Subject: bpf: Initialize storage pointers to NULL to prevent freeing garbage pointer X-Git-Tag: v5.5.14~31 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=18ef53f1434e61808eaacdfe9a3835d7f49e86f4;p=thirdparty%2Fkernel%2Fstable.git bpf: Initialize storage pointers to NULL to prevent freeing garbage pointer commit 62039c30c19dcab96621e074aeeb90da7100def7 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: 8bad74f9840f ("bpf: extend cgroup bpf core to allow multiple cgroup storage types") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200309222756.1018737-1-andriin@fb.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index d68eb0ac1457b..bee1ecb399be7 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -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;