diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-01-18 17:33:50 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-01-18 17:33:50 -0800 |
commit | 736b5545d39ca59d4332a60e56cc8a1a5e264a8e (patch) | |
tree | 3200528110fab00e0f0d3a311b6e3ad2fcd86edd /tools/lib/bpf/libbpf.c | |
parent | ed8d84530ab0a3b7b370e8b28f12179314dcfcc3 (diff) | |
parent | 925781a471d8156011e8f8c1baf61bbe020dac55 (diff) | |
download | linux-736b5545d39ca59d4332a60e56cc8a1a5e264a8e.tar.gz linux-736b5545d39ca59d4332a60e56cc8a1a5e264a8e.tar.bz2 linux-736b5545d39ca59d4332a60e56cc8a1a5e264a8e.zip |
Merge tag 'net-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Including fixes from bpf and netfilter.
Previous releases - regressions:
- Revert "net: rtnetlink: Enslave device before bringing it up",
breaks the case inverse to the one it was trying to fix
- net: dsa: fix oob access in DSA's netdevice event handler
dereference netdev_priv() before check its a DSA port
- sched: track device in tcf_block_get/put_ext() only for clsact
binder types
- net: tls, fix WARNING in __sk_msg_free when record becomes full
during splice and MORE hint set
- sfp-bus: fix SFP mode detect from bitrate
- drv: stmmac: prevent DSA tags from breaking COE
Previous releases - always broken:
- bpf: fix no forward progress in in bpf_iter_udp if output buffer is
too small
- bpf: reject variable offset alu on registers with a type of
PTR_TO_FLOW_KEYS to prevent oob access
- netfilter: tighten input validation
- net: add more sanity check in virtio_net_hdr_to_skb()
- rxrpc: fix use of Don't Fragment flag on RESPONSE packets, avoid
infinite loop
- amt: do not use the portion of skb->cb area which may get clobbered
- mptcp: improve validation of the MPTCPOPT_MP_JOIN MCTCP option
Misc:
- spring cleanup of inactive maintainers"
* tag 'net-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (88 commits)
i40e: Include types.h to some headers
ipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work
selftests: mlxsw: qos_pfc: Adjust the test to support 8 lanes
selftests: mlxsw: qos_pfc: Remove wrong description
mlxsw: spectrum_router: Register netdevice notifier before nexthop
mlxsw: spectrum_acl_tcam: Fix stack corruption
mlxsw: spectrum_acl_tcam: Fix NULL pointer dereference in error path
mlxsw: spectrum_acl_erp: Fix error flow of pool allocation failure
ethtool: netlink: Add missing ethnl_ops_begin/complete
selftests: bonding: Add more missing config options
selftests: netdevsim: add a config file
libbpf: warn on unexpected __arg_ctx type when rewriting BTF
selftests/bpf: add tests confirming type logic in kernel for __arg_ctx
bpf: enforce types for __arg_ctx-tagged arguments in global subprogs
bpf: extract bpf_ctx_convert_map logic and make it more reusable
libbpf: feature-detect arg:ctx tag support in kernel
ipvs: avoid stat macros calls from preemptible context
netfilter: nf_tables: reject NFT_SET_CONCAT with not field length description
netfilter: nf_tables: skip dead set elements in netlink dump
netfilter: nf_tables: do not allow mismatch field size and set key length
...
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
-rw-r--r-- | tools/lib/bpf/libbpf.c | 142 |
1 files changed, 133 insertions, 9 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index c5a42ac309fd..afd09571c482 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6695,6 +6695,67 @@ static struct { /* all other program types don't have "named" context structs */ }; +static bool need_func_arg_type_fixup(const struct btf *btf, const struct bpf_program *prog, + const char *subprog_name, int arg_idx, + int arg_type_id, const char *ctx_name) +{ + const struct btf_type *t; + const char *tname; + + /* check if existing parameter already matches verifier expectations */ + t = skip_mods_and_typedefs(btf, arg_type_id, NULL); + if (!btf_is_ptr(t)) + goto out_warn; + + /* typedef bpf_user_pt_regs_t is a special PITA case, valid for kprobe + * and perf_event programs, so check this case early on and forget + * about it for subsequent checks + */ + while (btf_is_mod(t)) + t = btf__type_by_id(btf, t->type); + if (btf_is_typedef(t) && + (prog->type == BPF_PROG_TYPE_KPROBE || prog->type == BPF_PROG_TYPE_PERF_EVENT)) { + tname = btf__str_by_offset(btf, t->name_off) ?: "<anon>"; + if (strcmp(tname, "bpf_user_pt_regs_t") == 0) + return false; /* canonical type for kprobe/perf_event */ + } + + /* now we can ignore typedefs moving forward */ + t = skip_mods_and_typedefs(btf, t->type, NULL); + + /* if it's `void *`, definitely fix up BTF info */ + if (btf_is_void(t)) + return true; + + /* if it's already proper canonical type, no need to fix up */ + tname = btf__str_by_offset(btf, t->name_off) ?: "<anon>"; + if (btf_is_struct(t) && strcmp(tname, ctx_name) == 0) + return false; + + /* special cases */ + switch (prog->type) { + case BPF_PROG_TYPE_KPROBE: + case BPF_PROG_TYPE_PERF_EVENT: + /* `struct pt_regs *` is expected, but we need to fix up */ + if (btf_is_struct(t) && strcmp(tname, "pt_regs") == 0) + return true; + break; + case BPF_PROG_TYPE_RAW_TRACEPOINT: + case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE: + /* allow u64* as ctx */ + if (btf_is_int(t) && t->size == 8) + return true; + break; + default: + break; + } + +out_warn: + pr_warn("prog '%s': subprog '%s' arg#%d is expected to be of `struct %s *` type\n", + prog->name, subprog_name, arg_idx, ctx_name); + return false; +} + static int clone_func_btf_info(struct btf *btf, int orig_fn_id, struct bpf_program *prog) { int fn_id, fn_proto_id, ret_type_id, orig_proto_id; @@ -6757,6 +6818,69 @@ static int clone_func_btf_info(struct btf *btf, int orig_fn_id, struct bpf_progr return fn_id; } +static int probe_kern_arg_ctx_tag(void) +{ + /* To minimize merge conflicts with BPF token series that refactors + * feature detection code a lot, we don't integrate + * probe_kern_arg_ctx_tag() into kernel_supports() feature-detection + * framework yet, doing our own caching internally. + * This will be cleaned up a bit later when bpf/bpf-next trees settle. + */ + static int cached_result = -1; + static const char strs[] = "\0a\0b\0arg:ctx\0"; + const __u32 types[] = { + /* [1] INT */ + BTF_TYPE_INT_ENC(1 /* "a" */, BTF_INT_SIGNED, 0, 32, 4), + /* [2] PTR -> VOID */ + BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 0), + /* [3] FUNC_PROTO `int(void *a)` */ + BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 1), + BTF_PARAM_ENC(1 /* "a" */, 2), + /* [4] FUNC 'a' -> FUNC_PROTO (main prog) */ + BTF_TYPE_ENC(1 /* "a" */, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 3), + /* [5] FUNC_PROTO `int(void *b __arg_ctx)` */ + BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 1), + BTF_PARAM_ENC(3 /* "b" */, 2), + /* [6] FUNC 'b' -> FUNC_PROTO (subprog) */ + BTF_TYPE_ENC(3 /* "b" */, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 5), + /* [7] DECL_TAG 'arg:ctx' -> func 'b' arg 'b' */ + BTF_TYPE_DECL_TAG_ENC(5 /* "arg:ctx" */, 6, 0), + }; + const struct bpf_insn insns[] = { + /* main prog */ + BPF_CALL_REL(+1), + BPF_EXIT_INSN(), + /* global subprog */ + BPF_EMIT_CALL(BPF_FUNC_get_func_ip), /* needs PTR_TO_CTX */ + BPF_EXIT_INSN(), + }; + const struct bpf_func_info_min func_infos[] = { + { 0, 4 }, /* main prog -> FUNC 'a' */ + { 2, 6 }, /* subprog -> FUNC 'b' */ + }; + LIBBPF_OPTS(bpf_prog_load_opts, opts); + int prog_fd, btf_fd, insn_cnt = ARRAY_SIZE(insns); + + if (cached_result >= 0) + return cached_result; + + btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs)); + if (btf_fd < 0) + return 0; + + opts.prog_btf_fd = btf_fd; + opts.func_info = &func_infos; + opts.func_info_cnt = ARRAY_SIZE(func_infos); + opts.func_info_rec_size = sizeof(func_infos[0]); + + prog_fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, "det_arg_ctx", + "GPL", insns, insn_cnt, &opts); + close(btf_fd); + + cached_result = probe_fd(prog_fd); + return cached_result; +} + /* Check if main program or global subprog's function prototype has `arg:ctx` * argument tags, and, if necessary, substitute correct type to match what BPF * verifier would expect, taking into account specific program type. This @@ -6766,7 +6890,7 @@ static int clone_func_btf_info(struct btf *btf, int orig_fn_id, struct bpf_progr */ static int bpf_program_fixup_func_info(struct bpf_object *obj, struct bpf_program *prog) { - const char *ctx_name = NULL, *ctx_tag = "arg:ctx"; + const char *ctx_name = NULL, *ctx_tag = "arg:ctx", *fn_name; struct bpf_func_info_min *func_rec; struct btf_type *fn_t, *fn_proto_t; struct btf *btf = obj->btf; @@ -6780,6 +6904,10 @@ static int bpf_program_fixup_func_info(struct bpf_object *obj, struct bpf_progra if (!obj->btf_ext || !prog->func_info) return 0; + /* don't do any fix ups if kernel natively supports __arg_ctx */ + if (probe_kern_arg_ctx_tag() > 0) + return 0; + /* some BPF program types just don't have named context structs, so * this fallback mechanism doesn't work for them */ @@ -6842,15 +6970,11 @@ static int bpf_program_fixup_func_info(struct bpf_object *obj, struct bpf_progra if (arg_idx < 0 || arg_idx >= arg_cnt) continue; - /* check if existing parameter already matches verifier expectations */ + /* check if we should fix up argument type */ p = &btf_params(fn_proto_t)[arg_idx]; - t = skip_mods_and_typedefs(btf, p->type, NULL); - if (btf_is_ptr(t) && - (t = skip_mods_and_typedefs(btf, t->type, NULL)) && - btf_is_struct(t) && - strcmp(btf__str_by_offset(btf, t->name_off), ctx_name) == 0) { - continue; /* no need for fix up */ - } + fn_name = btf__str_by_offset(btf, fn_t->name_off) ?: "<anon>"; + if (!need_func_arg_type_fixup(btf, prog, fn_name, arg_idx, p->type, ctx_name)) + continue; /* clone fn/fn_proto, unless we already did it for another arg */ if (func_rec->type_id == orig_fn_id) { |