This series adds unstable conntrack lookup helpers using BPF kfunc support. The patch adding the lookup helper is based off of Maxim's recent patch to aid in rebasing their series on top of this, all adjusted to work with module kfuncs [0]. [0]: https://lore.kernel.org/bpf/20211019144655.3483197-8-maximmi@xxxxxxxxxx To enable returning a reference to struct nf_conn, the verifier is extended to support reference tracking for PTR_TO_BTF_ID, and kfunc is extended with support for working as acquire/release functions, similar to existing BPF helpers. kfunc returning pointer (limited to PTR_TO_BTF_ID in the kernel) can also return a PTR_TO_BTF_ID_OR_NULL now, typically needed when acquiring a resource can fail. kfunc can also receive PTR_TO_CTX and PTR_TO_MEM (with some limitations) as arguments now. There is also support for passing a mem, len pair as argument to kfunc now. In such cases, passing pointer to unsized type (void) is also permitted. Please see individual commits for details. Changelog: ---------- v5 -> v6: v5: https://lore.kernel.org/bpf/20211230023705.3860970-1-memxor@xxxxxxxxx * Fix for a bug in btf_try_get_module leading to use-after-free * Drop *kallsyms_on_each_symbol loop, reinstate register_btf_kfunc_id_set (Alexei) * btf_free_kfunc_set_tab now takes struct btf, and handles resetting tab to NULL * Check return value btf_name_by_offset for param_name * Instead of using tmp_set, use btf->kfunc_set_tab directly, and simplify cleanup v4 -> v5: v4: https://lore.kernel.org/bpf/20211217015031.1278167-1-memxor@xxxxxxxxx * Move nf_conntrack helpers code to its own separate file (Toke, Pablo) * Remove verifier callbacks, put btf_id_sets in struct btf (Alexei) * Convert the in-kernel users away from the old API * Change len__ prefix convention to __sz suffix (Alexei) * Drop parent_ref_obj_id patch (Alexei) v3 -> v4: v3: https://lore.kernel.org/bpf/20211210130230.4128676-1-memxor@xxxxxxxxx * Guard unstable CT helpers with CONFIG_DEBUG_INFO_BTF_MODULES * Move addition of prog_test test kfuncs to selftest commit * Move negative kfunc tests to test_verifier suite * Limit struct nesting depth to 4, which should be enough for now v2 -> v3: v2: https://lore.kernel.org/bpf/20211209170929.3485242-1-memxor@xxxxxxxxx * Fix build error for !CONFIG_BPF_SYSCALL (Patchwork) RFC v1 -> v2: v1: https://lore.kernel.org/bpf/20211030144609.263572-1-memxor@xxxxxxxxx * Limit PTR_TO_MEM support to pointer to scalar, or struct with scalars (Alexei) * Use btf_id_set for checking acquire, release, ret type null (Alexei) * Introduce opts struct for CT helpers, move int err parameter to it * Add l4proto as parameter to CT helper's opts, remove separate tcp/udp helpers * Add support for mem, len argument pair to kfunc * Allow void * as pointer type for mem, len argument pair * Extend selftests to cover new additions to kfuncs * Copy ref_obj_id to PTR_TO_BTF_ID dst_reg on btf_struct_access, test it * Fix other misc nits, bugs, and expand commit messages Kumar Kartikeya Dwivedi (11): kernel: Implement try_module_get_live bpf: Fix UAF due to race between btf_try_get_module and load_module bpf: Populate kfunc BTF ID sets in struct btf bpf: Remove check_kfunc_call callback and old kfunc BTF ID API bpf: Introduce mem, size argument pair support for kfunc bpf: Add reference tracking support to kfunc net/netfilter: Add unstable CT lookup helpers for XDP and TC-BPF selftests/bpf: Add test for unstable CT lookup API selftests/bpf: Add test_verifier support to fixup kfunc call insns selftests/bpf: Extend kfunc selftests selftests/bpf: Add test for race in btf_try_get_module include/linux/bpf.h | 8 - include/linux/bpf_verifier.h | 7 + include/linux/btf.h | 82 ++--- include/linux/btf_ids.h | 13 +- include/linux/module.h | 26 +- include/net/netfilter/nf_conntrack_bpf.h | 23 ++ kernel/bpf/btf.c | 327 ++++++++++++++++-- kernel/bpf/verifier.c | 197 +++++++---- kernel/module.c | 20 +- net/bpf/test_run.c | 150 +++++++- net/core/filter.c | 1 - net/core/net_namespace.c | 1 + net/ipv4/bpf_tcp_ca.c | 22 +- net/ipv4/tcp_bbr.c | 18 +- net/ipv4/tcp_cubic.c | 17 +- net/ipv4/tcp_dctcp.c | 18 +- net/netfilter/Makefile | 5 + net/netfilter/nf_conntrack_bpf.c | 257 ++++++++++++++ net/netfilter/nf_conntrack_core.c | 8 + tools/testing/selftests/bpf/Makefile | 11 +- .../selftests/bpf/bpf_testmod/Makefile | 5 +- .../bpf/bpf_testmod/bpf_mod_kfunc_race.c | 50 +++ .../selftests/bpf/bpf_testmod/bpf_testmod.c | 17 +- tools/testing/selftests/bpf/config | 4 + .../selftests/bpf/prog_tests/bpf_mod_race.c | 221 ++++++++++++ .../testing/selftests/bpf/prog_tests/bpf_nf.c | 48 +++ .../selftests/bpf/prog_tests/kfunc_call.c | 6 + .../selftests/bpf/progs/bpf_mod_race.c | 100 ++++++ .../selftests/bpf/progs/kfunc_call_race.c | 14 + .../selftests/bpf/progs/kfunc_call_test.c | 52 ++- tools/testing/selftests/bpf/progs/ksym_race.c | 13 + .../testing/selftests/bpf/progs/test_bpf_nf.c | 105 ++++++ tools/testing/selftests/bpf/test_verifier.c | 28 ++ tools/testing/selftests/bpf/verifier/calls.c | 75 ++++ 34 files changed, 1713 insertions(+), 236 deletions(-) create mode 100644 include/net/netfilter/nf_conntrack_bpf.h create mode 100644 net/netfilter/nf_conntrack_bpf.c create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_mod_kfunc_race.c create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_mod_race.c create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_nf.c create mode 100644 tools/testing/selftests/bpf/progs/bpf_mod_race.c create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_race.c create mode 100644 tools/testing/selftests/bpf/progs/ksym_race.c create mode 100644 tools/testing/selftests/bpf/progs/test_bpf_nf.c -- 2.34.1
