David Vernet 6c831c4684 bpf: Treat KF_RELEASE kfuncs as KF_TRUSTED_ARGS ... KF_RELEASE kfuncs are not currently treated as having KF_TRUSTED_ARGS, even though they have a superset of the requirements of KF_TRUSTED_ARGS. Like KF_TRUSTED_ARGS, KF_RELEASE kfuncs require a 0-offset argument, and don't allow NULL-able arguments. Unlike KF_TRUSTED_ARGS which require _either_ an argument with ref_obj_id > 0, _or_ (ref->type & BPF_REG_TRUSTED_MODIFIERS) (and no unsafe modifiers allowed), KF_RELEASE only allows for ref_obj_id > 0. Because KF_RELEASE today doesn't automatically imply KF_TRUSTED_ARGS, some of these requirements are enforced in different ways that can make the behavior of the verifier feel unpredictable. For example, a KF_RELEASE kfunc with a NULL-able argument will currently fail in the verifier with a message like, "arg#0 is ptr_or_null_ expected ptr_ or socket" rather than "Possibly NULL pointer passed to trusted arg0". Our intention is the same, but the semantics are different due to implemenetation details that kfunc authors and BPF program writers should not need to care about. Let's make the behavior of the verifier more consistent and intuitive by having KF_RELEASE kfuncs imply the presence of KF_TRUSTED_ARGS. Our eventual goal is to have all kfuncs assume KF_TRUSTED_ARGS by default anyways, so this takes us a step in that direction. Note that it does not make sense to assume KF_TRUSTED_ARGS for all KF_ACQUIRE kfuncs. KF_ACQUIRE kfuncs can have looser semantics than KF_RELEASE, with e.g. KF_RCU | KF_RET_NULL. We may want to have KF_ACQUIRE imply KF_TRUSTED_ARGS _unless_ KF_RCU is specified, but that can be left to another patch set, and there are no such subtleties to address for KF_RELEASE. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230325213144.486885-4-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>		2023-03-25 16:56:22 -07:00
..
libbpf	bpf, docs: Libbpf overview documentation	2023-03-18 10:17:39 -07:00
bpf_design_QA.rst	bpf: Rename __kptr_ref -> __kptr and __kptr -> __kptr_untrusted.	2023-03-03 17:42:20 +01:00
bpf_devel_QA.rst	bpf, docs: Use internal linking for link to netdev subsystem doc	2023-03-17 13:58:57 +01:00
bpf_iterators.rst	bpf, docs: BPF Iterator Document	2022-12-04 16:41:22 -08:00
bpf_licensing.rst	bpf: Document BPF licensing.	2021-09-22 23:13:13 +02:00
bpf_prog_run.rst	Documentation/bpf: Add documentation for BPF_PROG_RUN	2022-03-09 14:19:22 -08:00
btf.rst	docs/bpf: Update btf selftests program and add link	2022-11-25 00:00:15 +01:00
clang-notes.rst	bpf, docs: Explain helper functions	2023-03-10 13:02:00 -08:00
classic_vs_extended.rst	bpf, docs: Split the comparism to classic BPF from instruction-set.rst	2021-12-30 16:31:44 -08:00
cpumasks.rst	bpf,docs: Remove bpf_cpumask_kptr_get() from documentation	2023-03-16 12:28:30 -07:00
drgn.rst	bpf: Document bpf_inspect drgn tool	2020-03-26 00:08:36 +01:00
faq.rst	bpf, docs: Fix ordering of bpf documentation	2021-11-17 23:24:01 +01:00
graph_ds_impl.rst	Documentation: bpf: Add missing line break separator in node_data struct code block	2023-02-15 08:43:51 -08:00
helpers.rst	bpf, docs: Fix ordering of bpf documentation	2021-11-17 23:24:01 +01:00
index.rst	bpf/docs: Document cpumask kfuncs in a new file	2023-01-25 07:57:50 -08:00
instruction-set.rst	bpf, docs: Add signed comparison example	2023-03-13 22:10:45 -07:00
kfuncs.rst	bpf: Treat KF_RELEASE kfuncs as KF_TRUSTED_ARGS	2023-03-25 16:56:22 -07:00
linux-notes.rst	bpf, docs: Explain helper functions	2023-03-10 13:02:00 -08:00
llvm_reloc.rst	bpf, docs: Add llvm_reloc.rst to explain llvm bpf relocations	2021-05-28 22:12:04 +02:00
map_array.rst	docs/bpf: Fix sphinx warnings in BPF map docs	2022-11-24 01:05:04 +01:00
map_bloom_filter.rst	docs/bpf: Document BPF_MAP_TYPE_BLOOM_FILTER	2022-11-23 22:47:32 +01:00
map_cgroup_storage.rst	Remove duplicate words inside documentation	2022-09-27 13:21:43 -06:00
map_cgrp_storage.rst	docs/bpf: Add documentation for new cgroup local storage	2022-10-25 23:19:20 -07:00
map_cpumap.rst	docs/bpf: Fix sphinx warnings for cpumap	2022-11-23 22:38:53 +01:00
map_devmap.rst	docs/bpf: Fix sphinx warnings for devmap	2022-11-23 22:40:27 +01:00
map_hash.rst	docs/bpf: Fix sphinx warnings in BPF map docs	2022-11-24 01:05:04 +01:00
map_lpm_trie.rst	docs/bpf: Fix sphinx warnings in BPF map docs	2022-11-24 01:05:04 +01:00
map_of_maps.rst	docs/bpf: Fix sphinx warnings in BPF map docs	2022-11-24 01:05:04 +01:00
map_queue_stack.rst	docs/bpf: Fix sphinx warnings in BPF map docs	2022-11-24 01:05:04 +01:00
map_sk_storage.rst	docs/bpf: Reword docs for BPF_MAP_TYPE_SK_STORAGE	2022-12-14 18:35:41 +01:00
map_sockmap.rst	docs: BPF_MAP_TYPE_SOCK[MAP|HASH]	2022-12-20 15:54:05 -08:00
map_xskmap.rst	Documentation: bpf: correct spelling	2023-01-28 12:22:20 -08:00
maps.rst	bpf, docs: Fix final bpf docs build failure	2023-03-02 22:36:10 -08:00
other.rst	bpf, documentation: Add graph documentation for non-owning refs	2023-02-13 19:40:53 -08:00
prog_cgroup_sockopt.rst	bpf: Document optval > PAGE_SIZE behavior for sockopt hooks	2020-06-17 10:54:05 -07:00
prog_cgroup_sysctl.rst	bpf: Document BPF_PROG_TYPE_CGROUP_SYSCTL	2019-04-18 16:05:36 -07:00
prog_flow_dissector.rst	bpf/flow_dissector: add mode to enforce global BPF flow dissector	2019-10-07 20:16:33 -07:00
prog_lsm.rst	bpf, docs: Rename bpf_lsm.rst to prog_lsm.rst	2021-11-17 23:23:58 +01:00
prog_sk_lookup.rst	bpf: sk_lookup: Add user documentation	2020-08-24 14:46:50 -07:00
programs.rst	docs/bpf: Add table of BPF program types to libbpf docs	2022-11-23 13:31:20 -08:00
redirect.rst	bpf, docs: DEVMAPs and XDP_REDIRECT	2022-11-18 23:16:31 +01:00
ringbuf.rst	Documentation: bpf: correct spelling	2023-01-28 12:22:20 -08:00
s390.rst	bpf: Add s390 testing documentation	2019-10-30 16:25:31 +01:00
syscall_api.rst	bpf, docs: Fix ordering of bpf documentation	2021-11-17 23:24:01 +01:00
test_debug.rst	bpf, docs: Fix ordering of bpf documentation	2021-11-17 23:24:01 +01:00
verifier.rst	docs/bpf: Add description of register liveness tracking algorithm	2023-02-02 20:21:59 -08:00