lkml.org 
[lkml]   [2020]   [Nov]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH bpf-next 2/3] bpf: Add a BPF helper for getting the IMA hash of an inode
On Fri, Nov 20, 2020 at 01:17:07PM +0000, KP Singh wrote:
> +
> +static bool bpf_ima_inode_hash_allowed(const struct bpf_prog *prog)
> +{
> + return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id);
> +}
> +
> +BTF_ID_LIST_SINGLE(bpf_ima_inode_hash_btf_ids, struct, inode)
> +
> +const static struct bpf_func_proto bpf_ima_inode_hash_proto = {
> + .func = bpf_ima_inode_hash,
> + .gpl_only = false,
> + .ret_type = RET_INTEGER,
> + .arg1_type = ARG_PTR_TO_BTF_ID,
> + .arg1_btf_id = &bpf_ima_inode_hash_btf_ids[0],
> + .arg2_type = ARG_PTR_TO_UNINIT_MEM,
> + .arg3_type = ARG_CONST_SIZE_OR_ZERO,
> + .allowed = bpf_ima_inode_hash_allowed,
> +};
> +
> static const struct bpf_func_proto *
> bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> {
> @@ -97,6 +121,8 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> return &bpf_task_storage_delete_proto;
> case BPF_FUNC_bprm_opts_set:
> return &bpf_bprm_opts_set_proto;
> + case BPF_FUNC_ima_inode_hash:
> + return &bpf_ima_inode_hash_proto;

That's not enough for correctness.
Not only hook has to sleepable, but the program has to be sleepable too.
The patch 3 should be causing all sort of kernel warnings
for calling mutex from preempt disabled.
There it calls bpf_ima_inode_hash() from SEC("lsm/file_mprotect") program.
"lsm/" is non-sleepable. "lsm.s/" is.
please enable CONFIG_DEBUG_ATOMIC_SLEEP=y in your config.

\
 
 \ /
  Last update: 2020-11-24 05:03    [W:0.184 / U:0.432 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site