diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 4d32f125f4af..79883f883ff3 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1944,13 +1944,22 @@ int btf_distill_func_proto(struct bpf_verifier_log *log, const char *func_name, struct btf_func_model *m); +struct bpf_kfunc_arg_meta { + u64 r0_size; + bool r0_rdonly; + int ref_obj_id; + u32 flags; +}; + struct bpf_reg_state; int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog, struct bpf_reg_state *regs); +int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog, + struct bpf_reg_state *regs); int btf_check_kfunc_arg_match(struct bpf_verifier_env *env, const struct btf *btf, u32 func_id, struct bpf_reg_state *regs, - u32 kfunc_flags); + struct bpf_kfunc_arg_meta *meta); int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog, struct bpf_reg_state *reg); int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog, diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 1fdddbf3546b..8fbc1d05281e 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -598,6 +598,8 @@ int bpf_check_attach_target(struct bpf_verifier_log *log, struct bpf_attach_target_info *tgt_info); void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab); +int mark_chain_precision(struct bpf_verifier_env *env, int regno); + #define BPF_BASE_TYPE_MASK GENMASK(BPF_BASE_TYPE_BITS - 1, 0) /* extract base type from bpf_{arg, return, reg}_type. */ diff --git a/include/linux/btf.h b/include/linux/btf.h index ad93c2d9cc1c..1fcc833a8690 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -441,4 +441,14 @@ static inline int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dt } #endif +static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t) +{ + if (!btf_type_is_ptr(t)) + return false; + + t = btf_type_skip_modifiers(btf, t->type, NULL); + + return btf_type_is_struct(t); +} + #endif diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index ea94527e5d70..9d12212fcd61 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -208,7 +208,7 @@ enum btf_kfunc_hook { }; enum { - BTF_KFUNC_SET_MAX_CNT = 32, + BTF_KFUNC_SET_MAX_CNT = 256, BTF_DTOR_KFUNC_MAX_CNT = 256, }; @@ -6199,11 +6199,37 @@ static bool is_kfunc_arg_mem_size(const struct btf *btf, return true; } +static bool btf_is_kfunc_arg_mem_size(const struct btf *btf, + const struct btf_param *arg, + const struct bpf_reg_state *reg, + const char *name) +{ + int len, target_len = strlen(name); + const struct btf_type *t; + const char *param_name; + + t = btf_type_skip_modifiers(btf, arg->type, NULL); + if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE) + return false; + + param_name = btf_name_by_offset(btf, arg->name_off); + if (str_is_empty(param_name)) + return false; + len = strlen(param_name); + if (len != target_len) + return false; + if (strcmp(param_name, name)) + return false; + + return true; +} + static int btf_check_func_arg_match(struct bpf_verifier_env *env, const struct btf *btf, u32 func_id, struct bpf_reg_state *regs, bool ptr_to_mem_ok, - u32 kfunc_flags) + struct bpf_kfunc_arg_meta *kfunc_meta, + bool processing_call) { enum bpf_prog_type prog_type = resolve_prog_type(env->prog); bool rel = false, kptr_get = false, trusted_arg = false; @@ -6240,12 +6266,12 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, return -EINVAL; } - if (is_kfunc) { + if (is_kfunc && kfunc_meta) { /* Only kfunc can be release func */ - rel = kfunc_flags & KF_RELEASE; - kptr_get = kfunc_flags & KF_KPTR_GET; - trusted_arg = kfunc_flags & KF_TRUSTED_ARGS; - sleepable = kfunc_flags & KF_SLEEPABLE; + rel = kfunc_meta->flags & KF_RELEASE; + kptr_get = kfunc_meta->flags & KF_KPTR_GET; + trusted_arg = kfunc_meta->flags & KF_TRUSTED_ARGS; + sleepable = kfunc_meta->flags & KF_SLEEPABLE; } /* check that BTF function arguments match actual types that the @@ -6258,6 +6284,38 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, t = btf_type_skip_modifiers(btf, args[i].type, NULL); if (btf_type_is_scalar(t)) { + if (is_kfunc && kfunc_meta) { + bool is_buf_size = false; + + /* check for any const scalar parameter of name "rdonly_buf_size" + * or "rdwr_buf_size" + */ + if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg, + "rdonly_buf_size")) { + kfunc_meta->r0_rdonly = true; + is_buf_size = true; + } else if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg, + "rdwr_buf_size")) + is_buf_size = true; + + if (is_buf_size) { + if (kfunc_meta->r0_size) { + bpf_log(log, "2 or more rdonly/rdwr_buf_size parameters for kfunc"); + return -EINVAL; + } + + if (!tnum_is_const(reg->var_off)) { + bpf_log(log, "R%d is not a const\n", regno); + return -EINVAL; + } + + kfunc_meta->r0_size = reg->var_off.value; + ret = mark_chain_precision(env, regno); + if (ret) + return ret; + } + } + if (reg->type == SCALAR_VALUE) continue; bpf_log(log, "R%d is not a scalar\n", regno); @@ -6288,6 +6346,17 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, if (ret < 0) return ret; + if (is_kfunc && reg->ref_obj_id) { + /* Ensure only one argument is referenced PTR_TO_BTF_ID */ + if (ref_obj_id) { + bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", + regno, reg->ref_obj_id, ref_obj_id); + return -EFAULT; + } + ref_regno = regno; + ref_obj_id = reg->ref_obj_id; + } + /* kptr_get is only true for kfunc */ if (i == 0 && kptr_get) { struct bpf_map_value_off_desc *off_desc; @@ -6360,16 +6429,6 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, if (reg->type == PTR_TO_BTF_ID) { reg_btf = reg->btf; reg_ref_id = reg->btf_id; - /* Ensure only one argument is referenced PTR_TO_BTF_ID */ - if (reg->ref_obj_id) { - if (ref_obj_id) { - bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", - regno, reg->ref_obj_id, ref_obj_id); - return -EFAULT; - } - ref_regno = regno; - ref_obj_id = reg->ref_obj_id; - } } else { reg_btf = btf_vmlinux; reg_ref_id = *reg2btf_ids[base_type(reg->type)]; @@ -6389,7 +6448,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, reg_ref_tname); return -EINVAL; } - } else if (ptr_to_mem_ok) { + } else if (ptr_to_mem_ok && processing_call) { const struct btf_type *resolve_ret; u32 type_size; @@ -6460,11 +6519,14 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, return -EINVAL; } + if (kfunc_meta && ref_obj_id) + kfunc_meta->ref_obj_id = ref_obj_id; + /* returns argument register number > 0 in case of reference release kfunc */ return rel ? ref_regno : 0; } -/* Compare BTF of a function with given bpf_reg_state. +/* Compare BTF of a function declaration with given bpf_reg_state. * Returns: * EFAULT - there is a verifier bug. Abort verification. * EINVAL - there is a type mismatch or BTF is not available. @@ -6491,7 +6553,50 @@ int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog, return -EINVAL; is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL; - err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, 0); + err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, false); + + /* Compiler optimizations can remove arguments from static functions + * or mismatched type can be passed into a global function. + * In such cases mark the function as unreliable from BTF point of view. + */ + if (err) + prog->aux->func_info_aux[subprog].unreliable = true; + return err; +} + +/* Compare BTF of a function call with given bpf_reg_state. + * Returns: + * EFAULT - there is a verifier bug. Abort verification. + * EINVAL - there is a type mismatch or BTF is not available. + * 0 - BTF matches with what bpf_reg_state expects. + * Only PTR_TO_CTX and SCALAR_VALUE states are recognized. + * + * NOTE: the code is duplicated from btf_check_subprog_arg_match() + * because btf_check_func_arg_match() is still doing both. Once that + * function is split in 2, we can call from here btf_check_subprog_arg_match() + * first, and then treat the calling part in a new code path. + */ +int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog, + struct bpf_reg_state *regs) +{ + struct bpf_prog *prog = env->prog; + struct btf *btf = prog->aux->btf; + bool is_global; + u32 btf_id; + int err; + + if (!prog->aux->func_info) + return -EINVAL; + + btf_id = prog->aux->func_info[subprog].type_id; + if (!btf_id) + return -EFAULT; + + if (prog->aux->func_info_aux[subprog].unreliable) + return -EINVAL; + + is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL; + err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, true); /* Compiler optimizations can remove arguments from static functions * or mismatched type can be passed into a global function. @@ -6505,9 +6610,9 @@ int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog, int btf_check_kfunc_arg_match(struct bpf_verifier_env *env, const struct btf *btf, u32 func_id, struct bpf_reg_state *regs, - u32 kfunc_flags) + struct bpf_kfunc_arg_meta *meta) { - return btf_check_func_arg_match(env, btf, func_id, regs, true, kfunc_flags); + return btf_check_func_arg_match(env, btf, func_id, regs, true, meta, true); } /* Convert BTF of a function into bpf_reg_state if possible diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 003f7ba19558..f3344a86d88d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2908,7 +2908,7 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno, return 0; } -static int mark_chain_precision(struct bpf_verifier_env *env, int regno) +int mark_chain_precision(struct bpf_verifier_env *env, int regno) { return __mark_chain_precision(env, regno, -1); } @@ -5233,6 +5233,25 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, env, regno, reg->off, access_size, zero_size_allowed, ACCESS_HELPER, meta); + case PTR_TO_CTX: + /* in case the function doesn't know how to access the context, + * (because we are in a program of type SYSCALL for example), we + * can not statically check its size. + * Dynamically check it now. + */ + if (!env->ops->convert_ctx_access) { + enum bpf_access_type atype = meta && meta->raw_mode ? BPF_WRITE : BPF_READ; + int offset = access_size - 1; + + /* Allow zero-byte read from PTR_TO_CTX */ + if (access_size == 0) + return zero_size_allowed ? 0 : -EACCES; + + return check_mem_access(env, env->insn_idx, regno, offset, BPF_B, + atype, -1, false); + } + + fallthrough; default: /* scalar_value or invalid ptr */ /* Allow zero-byte read from NULL, regardless of pointer type */ if (zero_size_allowed && access_size == 0 && @@ -6629,7 +6648,7 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn func_info_aux = env->prog->aux->func_info_aux; if (func_info_aux) is_global = func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL; - err = btf_check_subprog_arg_match(env, subprog, caller->regs); + err = btf_check_subprog_call(env, subprog, caller->regs); if (err == -EFAULT) return err; if (is_global) { @@ -7576,6 +7595,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, { const struct btf_type *t, *func, *func_proto, *ptr_type; struct bpf_reg_state *regs = cur_regs(env); + struct bpf_kfunc_arg_meta meta = { 0 }; const char *func_name, *ptr_type_name; u32 i, nargs, func_id, ptr_type_id; int err, insn_idx = *insn_idx_p; @@ -7610,8 +7630,10 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, acq = *kfunc_flags & KF_ACQUIRE; + meta.flags = *kfunc_flags; + /* Check the arguments */ - err = btf_check_kfunc_arg_match(env, desc_btf, func_id, regs, *kfunc_flags); + err = btf_check_kfunc_arg_match(env, desc_btf, func_id, regs, &meta); if (err < 0) return err; /* In case of release function, we get register number of refcounted @@ -7632,7 +7654,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, /* Check return type */ t = btf_type_skip_modifiers(desc_btf, func_proto->type, NULL); - if (acq && !btf_type_is_ptr(t)) { + if (acq && !btf_type_is_struct_ptr(desc_btf, t)) { verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n"); return -EINVAL; } @@ -7644,17 +7666,33 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, ptr_type = btf_type_skip_modifiers(desc_btf, t->type, &ptr_type_id); if (!btf_type_is_struct(ptr_type)) { - ptr_type_name = btf_name_by_offset(desc_btf, - ptr_type->name_off); - verbose(env, "kernel function %s returns pointer type %s %s is not supported\n", - func_name, btf_type_str(ptr_type), - ptr_type_name); - return -EINVAL; + if (!meta.r0_size) { + ptr_type_name = btf_name_by_offset(desc_btf, + ptr_type->name_off); + verbose(env, + "kernel function %s returns pointer type %s %s is not supported\n", + func_name, + btf_type_str(ptr_type), + ptr_type_name); + return -EINVAL; + } + + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_MEM; + regs[BPF_REG_0].mem_size = meta.r0_size; + + if (meta.r0_rdonly) + regs[BPF_REG_0].type |= MEM_RDONLY; + + /* Ensures we don't access the memory after a release_reference() */ + if (meta.ref_obj_id) + regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id; + } else { + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].btf = desc_btf; + regs[BPF_REG_0].type = PTR_TO_BTF_ID; + regs[BPF_REG_0].btf_id = ptr_type_id; } - mark_reg_known_zero(env, regs, BPF_REG_0); - regs[BPF_REG_0].btf = desc_btf; - regs[BPF_REG_0].type = PTR_TO_BTF_ID; - regs[BPF_REG_0].btf_id = ptr_type_id; if (*kfunc_flags & KF_RET_NULL) { regs[BPF_REG_0].type |= PTR_MAYBE_NULL; /* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */ diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 25d8ecf105aa..13d578ce2a09 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -606,6 +606,38 @@ noinline void bpf_kfunc_call_memb1_release(struct prog_test_member1 *p) WARN_ON_ONCE(1); } +static int *__bpf_kfunc_call_test_get_mem(struct prog_test_ref_kfunc *p, const int size) +{ + if (size > 2 * sizeof(int)) + return NULL; + + return (int *)p; +} + +noinline int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) +{ + return __bpf_kfunc_call_test_get_mem(p, rdwr_buf_size); +} + +noinline int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) +{ + return __bpf_kfunc_call_test_get_mem(p, rdonly_buf_size); +} + +/* the next 2 ones can't be really used for testing expect to ensure + * that the verifier rejects the call. + * Acquire functions must return struct pointers, so these ones are + * failing. + */ +noinline int *bpf_kfunc_call_test_acq_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) +{ + return __bpf_kfunc_call_test_get_mem(p, rdonly_buf_size); +} + +noinline void bpf_kfunc_call_int_mem_release(int *p) +{ +} + noinline struct prog_test_ref_kfunc * bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **pp, int a, int b) { @@ -712,6 +744,10 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_memb_acquire, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_kfunc_call_test_release, KF_RELEASE) BTF_ID_FLAGS(func, bpf_kfunc_call_memb_release, KF_RELEASE) BTF_ID_FLAGS(func, bpf_kfunc_call_memb1_release, KF_RELEASE) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_get_rdwr_mem, KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_get_rdonly_mem, KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_acq_rdonly_mem, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_kfunc_call_int_mem_release, KF_RELEASE) BTF_ID_FLAGS(func, bpf_kfunc_call_test_kptr_get, KF_ACQUIRE | KF_RET_NULL | KF_KPTR_GET) BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass_ctx) BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass1) @@ -1634,6 +1670,7 @@ static int __init bpf_prog_test_run_init(void) ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_prog_test_kfunc_set); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_prog_test_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &bpf_prog_test_kfunc_set); return ret ?: register_btf_id_dtor_kfuncs(bpf_prog_test_dtor_kfunc, ARRAY_SIZE(bpf_prog_test_dtor_kfunc), THIS_MODULE); diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index c10adecb5a73..6cd327f1f216 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -351,11 +351,12 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h \ test_subskeleton.skel.h test_subskeleton_lib.skel.h \ test_usdt.skel.h -LSKELS := kfunc_call_test.c fentry_test.c fexit_test.c fexit_sleep.c \ +LSKELS := fentry_test.c fexit_test.c fexit_sleep.c \ test_ringbuf.c atomics.c trace_printk.c trace_vprintk.c \ map_ptr_kern.c core_kern.c core_kern_overflow.c # Generate both light skeleton and libbpf skeleton for these -LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test_subprog.c +LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test.c \ + kfunc_call_test_subprog.c SKEL_BLACKLIST += $$(LSKELS) test_static_linked.skel.h-deps := test_static_linked1.bpf.o test_static_linked2.bpf.o diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c index eede7c304f86..5af1ee8f0e6e 100644 --- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c @@ -2,6 +2,8 @@ /* Copyright (c) 2021 Facebook */ #include #include +#include "kfunc_call_fail.skel.h" +#include "kfunc_call_test.skel.h" #include "kfunc_call_test.lskel.h" #include "kfunc_call_test_subprog.skel.h" #include "kfunc_call_test_subprog.lskel.h" @@ -9,36 +11,220 @@ #include "cap_helpers.h" -static void test_main(void) -{ - struct kfunc_call_test_lskel *skel; - int prog_fd, err; - LIBBPF_OPTS(bpf_test_run_opts, topts, - .data_in = &pkt_v4, - .data_size_in = sizeof(pkt_v4), - .repeat = 1, - ); +static size_t log_buf_sz = 1048576; /* 1 MB */ +static char obj_log_buf[1048576]; - skel = kfunc_call_test_lskel__open_and_load(); +enum kfunc_test_type { + tc_test = 0, + syscall_test, + syscall_null_ctx_test, +}; + +struct kfunc_test_params { + const char *prog_name; + unsigned long lskel_prog_desc_offset; + int retval; + enum kfunc_test_type test_type; + const char *expected_err_msg; +}; + +#define __BPF_TEST_SUCCESS(name, __retval, type) \ + { \ + .prog_name = #name, \ + .lskel_prog_desc_offset = offsetof(struct kfunc_call_test_lskel, progs.name), \ + .retval = __retval, \ + .test_type = type, \ + .expected_err_msg = NULL, \ + } + +#define __BPF_TEST_FAIL(name, __retval, type, error_msg) \ + { \ + .prog_name = #name, \ + .lskel_prog_desc_offset = 0 /* unused when test is failing */, \ + .retval = __retval, \ + .test_type = type, \ + .expected_err_msg = error_msg, \ + } + +#define TC_TEST(name, retval) __BPF_TEST_SUCCESS(name, retval, tc_test) +#define SYSCALL_TEST(name, retval) __BPF_TEST_SUCCESS(name, retval, syscall_test) +#define SYSCALL_NULL_CTX_TEST(name, retval) __BPF_TEST_SUCCESS(name, retval, syscall_null_ctx_test) + +#define TC_FAIL(name, retval, error_msg) __BPF_TEST_FAIL(name, retval, tc_test, error_msg) +#define SYSCALL_NULL_CTX_FAIL(name, retval, error_msg) \ + __BPF_TEST_FAIL(name, retval, syscall_null_ctx_test, error_msg) + +static struct kfunc_test_params kfunc_tests[] = { + /* failure cases: + * if retval is 0 -> the program will fail to load and the error message is an error + * if retval is not 0 -> the program can be loaded but running it will gives the + * provided return value. The error message is thus the one + * from a successful load + */ + SYSCALL_NULL_CTX_FAIL(kfunc_syscall_test_fail, -EINVAL, "processed 4 insns"), + SYSCALL_NULL_CTX_FAIL(kfunc_syscall_test_null_fail, -EINVAL, "processed 4 insns"), + TC_FAIL(kfunc_call_test_get_mem_fail_rdonly, 0, "R0 cannot write into rdonly_mem"), + TC_FAIL(kfunc_call_test_get_mem_fail_use_after_free, 0, "invalid mem access 'scalar'"), + TC_FAIL(kfunc_call_test_get_mem_fail_oob, 0, "min value is outside of the allowed memory range"), + TC_FAIL(kfunc_call_test_get_mem_fail_not_const, 0, "is not a const"), + TC_FAIL(kfunc_call_test_mem_acquire_fail, 0, "acquire kernel function does not return PTR_TO_BTF_ID"), + + /* success cases */ + TC_TEST(kfunc_call_test1, 12), + TC_TEST(kfunc_call_test2, 3), + TC_TEST(kfunc_call_test_ref_btf_id, 0), + TC_TEST(kfunc_call_test_get_mem, 42), + SYSCALL_TEST(kfunc_syscall_test, 0), + SYSCALL_NULL_CTX_TEST(kfunc_syscall_test_null, 0), +}; + +struct syscall_test_args { + __u8 data[16]; + size_t size; +}; + +static void verify_success(struct kfunc_test_params *param) +{ + struct kfunc_call_test_lskel *lskel = NULL; + LIBBPF_OPTS(bpf_test_run_opts, topts); + struct bpf_prog_desc *lskel_prog; + struct kfunc_call_test *skel; + struct bpf_program *prog; + int prog_fd, err; + struct syscall_test_args args = { + .size = 10, + }; + + switch (param->test_type) { + case syscall_test: + topts.ctx_in = &args; + topts.ctx_size_in = sizeof(args); + /* fallthrough */ + case syscall_null_ctx_test: + break; + case tc_test: + topts.data_in = &pkt_v4; + topts.data_size_in = sizeof(pkt_v4); + topts.repeat = 1; + break; + } + + /* first test with normal libbpf */ + skel = kfunc_call_test__open_and_load(); if (!ASSERT_OK_PTR(skel, "skel")) return; - prog_fd = skel->progs.kfunc_call_test1.prog_fd; - err = bpf_prog_test_run_opts(prog_fd, &topts); - ASSERT_OK(err, "bpf_prog_test_run(test1)"); - ASSERT_EQ(topts.retval, 12, "test1-retval"); + prog = bpf_object__find_program_by_name(skel->obj, param->prog_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto cleanup; - prog_fd = skel->progs.kfunc_call_test2.prog_fd; + prog_fd = bpf_program__fd(prog); err = bpf_prog_test_run_opts(prog_fd, &topts); - ASSERT_OK(err, "bpf_prog_test_run(test2)"); - ASSERT_EQ(topts.retval, 3, "test2-retval"); + if (!ASSERT_OK(err, param->prog_name)) + goto cleanup; - prog_fd = skel->progs.kfunc_call_test_ref_btf_id.prog_fd; + if (!ASSERT_EQ(topts.retval, param->retval, "retval")) + goto cleanup; + + /* second test with light skeletons */ + lskel = kfunc_call_test_lskel__open_and_load(); + if (!ASSERT_OK_PTR(lskel, "lskel")) + goto cleanup; + + lskel_prog = (struct bpf_prog_desc *)((char *)lskel + param->lskel_prog_desc_offset); + + prog_fd = lskel_prog->prog_fd; err = bpf_prog_test_run_opts(prog_fd, &topts); - ASSERT_OK(err, "bpf_prog_test_run(test_ref_btf_id)"); - ASSERT_EQ(topts.retval, 0, "test_ref_btf_id-retval"); + if (!ASSERT_OK(err, param->prog_name)) + goto cleanup; - kfunc_call_test_lskel__destroy(skel); + ASSERT_EQ(topts.retval, param->retval, "retval"); + +cleanup: + kfunc_call_test__destroy(skel); + if (lskel) + kfunc_call_test_lskel__destroy(lskel); +} + +static void verify_fail(struct kfunc_test_params *param) +{ + LIBBPF_OPTS(bpf_object_open_opts, opts); + LIBBPF_OPTS(bpf_test_run_opts, topts); + struct bpf_program *prog; + struct kfunc_call_fail *skel; + int prog_fd, err; + struct syscall_test_args args = { + .size = 10, + }; + + opts.kernel_log_buf = obj_log_buf; + opts.kernel_log_size = log_buf_sz; + opts.kernel_log_level = 1; + + switch (param->test_type) { + case syscall_test: + topts.ctx_in = &args; + topts.ctx_size_in = sizeof(args); + /* fallthrough */ + case syscall_null_ctx_test: + break; + case tc_test: + topts.data_in = &pkt_v4; + topts.data_size_in = sizeof(pkt_v4); + break; + topts.repeat = 1; + } + + skel = kfunc_call_fail__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "kfunc_call_fail__open_opts")) + goto cleanup; + + prog = bpf_object__find_program_by_name(skel->obj, param->prog_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto cleanup; + + bpf_program__set_autoload(prog, true); + + err = kfunc_call_fail__load(skel); + if (!param->retval) { + /* the verifier is supposed to complain and refuses to load */ + if (!ASSERT_ERR(err, "unexpected load success")) + goto out_err; + + } else { + /* the program is loaded but must dynamically fail */ + if (!ASSERT_OK(err, "unexpected load error")) + goto out_err; + + prog_fd = bpf_program__fd(prog); + err = bpf_prog_test_run_opts(prog_fd, &topts); + if (!ASSERT_EQ(err, param->retval, param->prog_name)) + goto out_err; + } + +out_err: + if (!ASSERT_OK_PTR(strstr(obj_log_buf, param->expected_err_msg), "expected_err_msg")) { + fprintf(stderr, "Expected err_msg: %s\n", param->expected_err_msg); + fprintf(stderr, "Verifier output: %s\n", obj_log_buf); + } + +cleanup: + kfunc_call_fail__destroy(skel); +} + +static void test_main(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(kfunc_tests); i++) { + if (!test__start_subtest(kfunc_tests[i].prog_name)) + continue; + + if (!kfunc_tests[i].expected_err_msg) + verify_success(&kfunc_tests[i]); + else + verify_fail(&kfunc_tests[i]); + } } static void test_subprog(void) @@ -121,8 +307,7 @@ static void test_destructive(void) void test_kfunc_call(void) { - if (test__start_subtest("main")) - test_main(); + test_main(); if (test__start_subtest("subprog")) test_subprog(); diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c new file mode 100644 index 000000000000..b98313d391c6 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c @@ -0,0 +1,160 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include +#include + +extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym; +extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym; +extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym; +extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym; +extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym; +extern int *bpf_kfunc_call_test_acq_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym; +extern void bpf_kfunc_call_int_mem_release(int *p) __ksym; + +struct syscall_test_args { + __u8 data[16]; + size_t size; +}; + +SEC("?syscall") +int kfunc_syscall_test_fail(struct syscall_test_args *args) +{ + bpf_kfunc_call_test_mem_len_pass1(&args->data, sizeof(*args) + 1); + + return 0; +} + +SEC("?syscall") +int kfunc_syscall_test_null_fail(struct syscall_test_args *args) +{ + /* Must be called with args as a NULL pointer + * we do not check for it to have the verifier consider that + * the pointer might not be null, and so we can load it. + * + * So the following can not be added: + * + * if (args) + * return -22; + */ + + bpf_kfunc_call_test_mem_len_pass1(args, sizeof(*args)); + + return 0; +} + +SEC("?tc") +int kfunc_call_test_get_mem_fail_rdonly(struct __sk_buff *skb) +{ + struct prog_test_ref_kfunc *pt; + unsigned long s = 0; + int *p = NULL; + int ret = 0; + + pt = bpf_kfunc_call_test_acquire(&s); + if (pt) { + p = bpf_kfunc_call_test_get_rdonly_mem(pt, 2 * sizeof(int)); + if (p) + p[0] = 42; /* this is a read-only buffer, so -EACCES */ + else + ret = -1; + + bpf_kfunc_call_test_release(pt); + } + return ret; +} + +SEC("?tc") +int kfunc_call_test_get_mem_fail_use_after_free(struct __sk_buff *skb) +{ + struct prog_test_ref_kfunc *pt; + unsigned long s = 0; + int *p = NULL; + int ret = 0; + + pt = bpf_kfunc_call_test_acquire(&s); + if (pt) { + p = bpf_kfunc_call_test_get_rdwr_mem(pt, 2 * sizeof(int)); + if (p) { + p[0] = 42; + ret = p[1]; /* 108 */ + } else { + ret = -1; + } + + bpf_kfunc_call_test_release(pt); + } + if (p) + ret = p[0]; /* p is not valid anymore */ + + return ret; +} + +SEC("?tc") +int kfunc_call_test_get_mem_fail_oob(struct __sk_buff *skb) +{ + struct prog_test_ref_kfunc *pt; + unsigned long s = 0; + int *p = NULL; + int ret = 0; + + pt = bpf_kfunc_call_test_acquire(&s); + if (pt) { + p = bpf_kfunc_call_test_get_rdonly_mem(pt, 2 * sizeof(int)); + if (p) + ret = p[2 * sizeof(int)]; /* oob access, so -EACCES */ + else + ret = -1; + + bpf_kfunc_call_test_release(pt); + } + return ret; +} + +int not_const_size = 2 * sizeof(int); + +SEC("?tc") +int kfunc_call_test_get_mem_fail_not_const(struct __sk_buff *skb) +{ + struct prog_test_ref_kfunc *pt; + unsigned long s = 0; + int *p = NULL; + int ret = 0; + + pt = bpf_kfunc_call_test_acquire(&s); + if (pt) { + p = bpf_kfunc_call_test_get_rdonly_mem(pt, not_const_size); /* non const size, -EINVAL */ + if (p) + ret = p[0]; + else + ret = -1; + + bpf_kfunc_call_test_release(pt); + } + return ret; +} + +SEC("?tc") +int kfunc_call_test_mem_acquire_fail(struct __sk_buff *skb) +{ + struct prog_test_ref_kfunc *pt; + unsigned long s = 0; + int *p = NULL; + int ret = 0; + + pt = bpf_kfunc_call_test_acquire(&s); + if (pt) { + /* we are failing on this one, because we are not acquiring a PTR_TO_BTF_ID (a struct ptr) */ + p = bpf_kfunc_call_test_acq_rdonly_mem(pt, 2 * sizeof(int)); + if (p) + ret = p[0]; + else + ret = -1; + + bpf_kfunc_call_int_mem_release(p); + + bpf_kfunc_call_test_release(pt); + } + return ret; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c index 5aecbb9fdc68..f636e50be259 100644 --- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c +++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c @@ -14,6 +14,8 @@ extern void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p) __ksym; extern void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p) __ksym; extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym; extern void bpf_kfunc_call_test_mem_len_fail2(__u64 *mem, int len) __ksym; +extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym; +extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym; SEC("tc") int kfunc_call_test2(struct __sk_buff *skb) @@ -92,4 +94,73 @@ int kfunc_call_test_pass(struct __sk_buff *skb) return 0; } +struct syscall_test_args { + __u8 data[16]; + size_t size; +}; + +SEC("syscall") +int kfunc_syscall_test(struct syscall_test_args *args) +{ + const long size = args->size; + + if (size > sizeof(args->data)) + return -7; /* -E2BIG */ + + bpf_kfunc_call_test_mem_len_pass1(&args->data, sizeof(args->data)); + bpf_kfunc_call_test_mem_len_pass1(&args->data, sizeof(*args)); + bpf_kfunc_call_test_mem_len_pass1(&args->data, size); + + return 0; +} + +SEC("syscall") +int kfunc_syscall_test_null(struct syscall_test_args *args) +{ + /* Must be called with args as a NULL pointer + * we do not check for it to have the verifier consider that + * the pointer might not be null, and so we can load it. + * + * So the following can not be added: + * + * if (args) + * return -22; + */ + + bpf_kfunc_call_test_mem_len_pass1(args, 0); + + return 0; +} + +SEC("tc") +int kfunc_call_test_get_mem(struct __sk_buff *skb) +{ + struct prog_test_ref_kfunc *pt; + unsigned long s = 0; + int *p = NULL; + int ret = 0; + + pt = bpf_kfunc_call_test_acquire(&s); + if (pt) { + p = bpf_kfunc_call_test_get_rdwr_mem(pt, 2 * sizeof(int)); + if (p) { + p[0] = 42; + ret = p[1]; /* 108 */ + } else { + ret = -1; + } + + if (ret >= 0) { + p = bpf_kfunc_call_test_get_rdonly_mem(pt, 2 * sizeof(int)); + if (p) + ret = p[0]; /* 42 */ + else + ret = -1; + } + + bpf_kfunc_call_test_release(pt); + } + return ret; +} + char _license[] SEC("license") = "GPL";