From 80847a71b270b172814dc7562f3eb59507fca61e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 26 Mar 2021 00:41:34 +0100 Subject: bpf: Undo ptr_to_map_key alu sanitation for now Remove PTR_TO_MAP_KEY for the time being from being sanitized on pointer ALU through sanitize_ptr_alu() mainly for 3 reasons: 1) It's currently unused and not available from unprivileged. However that by itself is not yet a strong reason to drop the code. 2) Commit 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper") implemented the sanitation not fully correct in that unlike stack or map_value pointer it doesn't probe whether the access to the map key /after/ the simulated ALU operation is still in bounds. This means that the generated mask can truncate the offset in the non-speculative domain whereas it should only truncate in the speculative domain. The verifier should instead reject such program as we do for other types. 3) Given the recent fixes from f232326f6966 ("bpf: Prohibit alu ops for pointer types not defining ptr_limit"), 10d2bb2e6b1d ("bpf: Fix off-by-one for area size in creating mask to left"), b5871dca250c ("bpf: Simplify alu_limit masking for pointer arithmetic") as well as 1b1597e64e1a ("bpf: Add sanity check for upper ptr_limit") the code changed quite a bit and the merge in efd13b71a3fa broke the PTR_TO_MAP_KEY case due to an incorrect merge conflict. Remove the relevant pieces for the time being and we can rework the PTR_TO_MAP_KEY case once everything settles. Fixes: efd13b71a3fa ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net") Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper") Signed-off-by: Daniel Borkmann --- kernel/bpf/verifier.c | 14 -------------- 1 file changed, 14 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 210169c25ead..85f9f842d15c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6062,19 +6062,6 @@ static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, else *ptr_limit = -off - 1; return *ptr_limit >= max ? -ERANGE : 0; - case PTR_TO_MAP_KEY: - /* Currently, this code is not exercised as the only use - * is bpf_for_each_map_elem() helper which requires - * bpf_capble. The code has been tested manually for - * future use. - */ - if (mask_to_left) { - *ptr_limit = ptr_reg->umax_value + ptr_reg->off; - } else { - off = ptr_reg->smin_value + ptr_reg->off; - *ptr_limit = ptr_reg->map_ptr->key_size - off; - } - return 0; case PTR_TO_MAP_VALUE: max = ptr_reg->map_ptr->value_size; if (mask_to_left) { @@ -6281,7 +6268,6 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, verbose(env, "R%d pointer arithmetic on %s prohibited\n", dst, reg_type_str[ptr_reg->type]); return -EACCES; - case PTR_TO_MAP_KEY: case PTR_TO_MAP_VALUE: if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) { verbose(env, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n", -- cgit v1.2.3 From b910eaaaa4b89976ef02e5d6448f3f73dc671d91 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Mon, 22 Mar 2021 22:51:46 -0700 Subject: bpf: Fix NULL pointer dereference in bpf_get_local_storage() helper Jiri Olsa reported a bug ([1]) in kernel where cgroup local storage pointer may be NULL in bpf_get_local_storage() helper. There are two issues uncovered by this bug: (1). kprobe or tracepoint prog incorrectly sets cgroup local storage before prog run, (2). due to change from preempt_disable to migrate_disable, preemption is possible and percpu storage might be overwritten by other tasks. This issue (1) is fixed in [2]. This patch tried to address issue (2). The following shows how things can go wrong: task 1: bpf_cgroup_storage_set() for percpu local storage preemption happens task 2: bpf_cgroup_storage_set() for percpu local storage preemption happens task 1: run bpf program task 1 will effectively use the percpu local storage setting by task 2 which will be either NULL or incorrect ones. Instead of just one common local storage per cpu, this patch fixed the issue by permitting 8 local storages per cpu and each local storage is identified by a task_struct pointer. This way, we allow at most 8 nested preemption between bpf_cgroup_storage_set() and bpf_cgroup_storage_unset(). The percpu local storage slot is released (calling bpf_cgroup_storage_unset()) by the same task after bpf program finished running. bpf_test_run() is also fixed to use the new bpf_cgroup_storage_set() interface. The patch is tested on top of [2] with reproducer in [1]. Without this patch, kernel will emit error in 2-3 minutes. With this patch, after one hour, still no error. [1] https://lore.kernel.org/bpf/CAKH8qBuXCfUz=w8L+Fj74OaUpbosO29niYwTki7e3Ag044_aww@mail.gmail.com/T [2] https://lore.kernel.org/bpf/20210309185028.3763817-1-yhs@fb.com Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Roman Gushchin Link: https://lore.kernel.org/bpf/20210323055146.3334476-1-yhs@fb.com --- include/linux/bpf-cgroup.h | 57 +++++++++++++++++++++++++++++++++++++++------- include/linux/bpf.h | 22 ++++++++++++++---- kernel/bpf/helpers.c | 15 ++++++++---- kernel/bpf/local_storage.c | 5 ++-- net/bpf/test_run.c | 6 ++++- 5 files changed, 86 insertions(+), 19 deletions(-) (limited to 'kernel') diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index c42e02b4d84b..6a29fe11485d 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -20,14 +20,25 @@ struct bpf_sock_ops_kern; struct bpf_cgroup_storage; struct ctl_table; struct ctl_table_header; +struct task_struct; #ifdef CONFIG_CGROUP_BPF extern struct static_key_false cgroup_bpf_enabled_key[MAX_BPF_ATTACH_TYPE]; #define cgroup_bpf_enabled(type) static_branch_unlikely(&cgroup_bpf_enabled_key[type]) -DECLARE_PER_CPU(struct bpf_cgroup_storage*, - bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]); +#define BPF_CGROUP_STORAGE_NEST_MAX 8 + +struct bpf_cgroup_storage_info { + struct task_struct *task; + struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE]; +}; + +/* For each cpu, permit maximum BPF_CGROUP_STORAGE_NEST_MAX number of tasks + * to use bpf cgroup storage simultaneously. + */ +DECLARE_PER_CPU(struct bpf_cgroup_storage_info, + bpf_cgroup_storage_info[BPF_CGROUP_STORAGE_NEST_MAX]); #define for_each_cgroup_storage_type(stype) \ for (stype = 0; stype < MAX_BPF_CGROUP_STORAGE_TYPE; stype++) @@ -161,13 +172,42 @@ static inline enum bpf_cgroup_storage_type cgroup_storage_type( return BPF_CGROUP_STORAGE_SHARED; } -static inline void bpf_cgroup_storage_set(struct bpf_cgroup_storage - *storage[MAX_BPF_CGROUP_STORAGE_TYPE]) +static inline int bpf_cgroup_storage_set(struct bpf_cgroup_storage + *storage[MAX_BPF_CGROUP_STORAGE_TYPE]) { enum bpf_cgroup_storage_type stype; + int i, err = 0; + + preempt_disable(); + for (i = 0; i < BPF_CGROUP_STORAGE_NEST_MAX; i++) { + if (unlikely(this_cpu_read(bpf_cgroup_storage_info[i].task) != NULL)) + continue; + + this_cpu_write(bpf_cgroup_storage_info[i].task, current); + for_each_cgroup_storage_type(stype) + this_cpu_write(bpf_cgroup_storage_info[i].storage[stype], + storage[stype]); + goto out; + } + err = -EBUSY; + WARN_ON_ONCE(1); + +out: + preempt_enable(); + return err; +} + +static inline void bpf_cgroup_storage_unset(void) +{ + int i; + + for (i = 0; i < BPF_CGROUP_STORAGE_NEST_MAX; i++) { + if (unlikely(this_cpu_read(bpf_cgroup_storage_info[i].task) != current)) + continue; - for_each_cgroup_storage_type(stype) - this_cpu_write(bpf_cgroup_storage[stype], storage[stype]); + this_cpu_write(bpf_cgroup_storage_info[i].task, NULL); + return; + } } struct bpf_cgroup_storage * @@ -448,8 +488,9 @@ static inline int cgroup_bpf_prog_query(const union bpf_attr *attr, return -EINVAL; } -static inline void bpf_cgroup_storage_set( - struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE]) {} +static inline int bpf_cgroup_storage_set( + struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE]) { return 0; } +static inline void bpf_cgroup_storage_unset(void) {} static inline int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *map) { return 0; } static inline struct bpf_cgroup_storage *bpf_cgroup_storage_alloc( diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 24678d6ecbcf..5a0801b420ca 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1106,6 +1106,13 @@ int bpf_prog_array_copy(struct bpf_prog_array *old_array, /* BPF program asks to set CN on the packet. */ #define BPF_RET_SET_CN (1 << 0) +/* For BPF_PROG_RUN_ARRAY_FLAGS and __BPF_PROG_RUN_ARRAY, + * if bpf_cgroup_storage_set() failed, the rest of programs + * will not execute. This should be a really rare scenario + * as it requires BPF_CGROUP_STORAGE_NEST_MAX number of + * preemptions all between bpf_cgroup_storage_set() and + * bpf_cgroup_storage_unset() on the same cpu. + */ #define BPF_PROG_RUN_ARRAY_FLAGS(array, ctx, func, ret_flags) \ ({ \ struct bpf_prog_array_item *_item; \ @@ -1118,10 +1125,12 @@ int bpf_prog_array_copy(struct bpf_prog_array *old_array, _array = rcu_dereference(array); \ _item = &_array->items[0]; \ while ((_prog = READ_ONCE(_item->prog))) { \ - bpf_cgroup_storage_set(_item->cgroup_storage); \ + if (unlikely(bpf_cgroup_storage_set(_item->cgroup_storage))) \ + break; \ func_ret = func(_prog, ctx); \ _ret &= (func_ret & 1); \ *(ret_flags) |= (func_ret >> 1); \ + bpf_cgroup_storage_unset(); \ _item++; \ } \ rcu_read_unlock(); \ @@ -1142,9 +1151,14 @@ int bpf_prog_array_copy(struct bpf_prog_array *old_array, goto _out; \ _item = &_array->items[0]; \ while ((_prog = READ_ONCE(_item->prog))) { \ - if (set_cg_storage) \ - bpf_cgroup_storage_set(_item->cgroup_storage); \ - _ret &= func(_prog, ctx); \ + if (!set_cg_storage) { \ + _ret &= func(_prog, ctx); \ + } else { \ + if (unlikely(bpf_cgroup_storage_set(_item->cgroup_storage))) \ + break; \ + _ret &= func(_prog, ctx); \ + bpf_cgroup_storage_unset(); \ + } \ _item++; \ } \ _out: \ diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 074800226327..f306611c4ddf 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -382,8 +382,8 @@ const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto = { }; #ifdef CONFIG_CGROUP_BPF -DECLARE_PER_CPU(struct bpf_cgroup_storage*, - bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]); +DECLARE_PER_CPU(struct bpf_cgroup_storage_info, + bpf_cgroup_storage_info[BPF_CGROUP_STORAGE_NEST_MAX]); BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags) { @@ -392,10 +392,17 @@ BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags) * verifier checks that its value is correct. */ enum bpf_cgroup_storage_type stype = cgroup_storage_type(map); - struct bpf_cgroup_storage *storage; + struct bpf_cgroup_storage *storage = NULL; void *ptr; + int i; - storage = this_cpu_read(bpf_cgroup_storage[stype]); + for (i = 0; i < BPF_CGROUP_STORAGE_NEST_MAX; i++) { + if (unlikely(this_cpu_read(bpf_cgroup_storage_info[i].task) != current)) + continue; + + storage = this_cpu_read(bpf_cgroup_storage_info[i].storage[stype]); + break; + } if (stype == BPF_CGROUP_STORAGE_SHARED) ptr = &READ_ONCE(storage->buf)->data[0]; diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c index 2d4f9ac12377..bd11db9774c3 100644 --- a/kernel/bpf/local_storage.c +++ b/kernel/bpf/local_storage.c @@ -9,10 +9,11 @@ #include #include -DEFINE_PER_CPU(struct bpf_cgroup_storage*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]); - #ifdef CONFIG_CGROUP_BPF +DEFINE_PER_CPU(struct bpf_cgroup_storage_info, + bpf_cgroup_storage_info[BPF_CGROUP_STORAGE_NEST_MAX]); + #include "../cgroup/cgroup-internal.h" #define LOCAL_STORAGE_CREATE_FLAG_MASK \ diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 0abdd67f44b1..4aabf71cd95d 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -106,12 +106,16 @@ static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, bpf_test_timer_enter(&t); do { - bpf_cgroup_storage_set(storage); + ret = bpf_cgroup_storage_set(storage); + if (ret) + break; if (xdp) *retval = bpf_prog_run_xdp(prog, ctx); else *retval = BPF_PROG_RUN(prog, ctx); + + bpf_cgroup_storage_unset(); } while (bpf_test_timer_continue(&t, repeat, &ret, time)); bpf_test_timer_leave(&t); -- cgit v1.2.3 From f56387c534cc54d2578b962692e574e3edd8c3f6 Mon Sep 17 00:00:00 2001 From: Pedro Tammela Date: Mon, 22 Mar 2021 23:50:53 -0300 Subject: bpf: Add support for batched ops in LPM trie maps Suggested-by: Jamal Hadi Salim Signed-off-by: Pedro Tammela Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210323025058.315763-2-pctammela@gmail.com --- kernel/bpf/lpm_trie.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c index cec792a17e5f..1b7b8a6f34ee 100644 --- a/kernel/bpf/lpm_trie.c +++ b/kernel/bpf/lpm_trie.c @@ -726,6 +726,9 @@ const struct bpf_map_ops trie_map_ops = { .map_lookup_elem = trie_lookup_elem, .map_update_elem = trie_update_elem, .map_delete_elem = trie_delete_elem, + .map_lookup_batch = generic_map_lookup_batch, + .map_update_batch = generic_map_update_batch, + .map_delete_batch = generic_map_delete_batch, .map_check_btf = trie_check_btf, .map_btf_name = "lpm_trie", .map_btf_id = &trie_map_btf_id, -- cgit v1.2.3 From e16301fbe1837c9594f9c1957c28fd1bb18fbd15 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 24 Mar 2021 18:51:30 -0700 Subject: bpf: Simplify freeing logic in linfo and jited_linfo This patch simplifies the linfo freeing logic by combining "bpf_prog_free_jited_linfo()" and "bpf_prog_free_unused_jited_linfo()" into the new "bpf_prog_jit_attempt_done()". It is a prep work for the kernel function call support. In a later patch, freeing the kernel function call descriptors will also be done in the "bpf_prog_jit_attempt_done()". "bpf_prog_free_linfo()" is removed since it is only called by "__bpf_prog_put_noref()". The kvfree() are directly called instead. It also takes this chance to s/kcalloc/kvcalloc/ for the jited_linfo allocation. Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210325015130.1544323-1-kafai@fb.com --- include/linux/filter.h | 3 +-- kernel/bpf/core.c | 35 ++++++++++++----------------------- kernel/bpf/syscall.c | 3 ++- kernel/bpf/verifier.c | 4 ++-- 4 files changed, 17 insertions(+), 28 deletions(-) (limited to 'kernel') diff --git a/include/linux/filter.h b/include/linux/filter.h index b2b85b2cad8e..0d9c710eb050 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -877,8 +877,7 @@ void bpf_prog_free_linfo(struct bpf_prog *prog); void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, const u32 *insn_to_jit_off); int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog); -void bpf_prog_free_jited_linfo(struct bpf_prog *prog); -void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog); +void bpf_prog_jit_attempt_done(struct bpf_prog *prog); struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags); struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 75244ecb2389..a35eb3d7b126 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -143,25 +143,22 @@ int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) if (!prog->aux->nr_linfo || !prog->jit_requested) return 0; - prog->aux->jited_linfo = kcalloc(prog->aux->nr_linfo, - sizeof(*prog->aux->jited_linfo), - GFP_KERNEL_ACCOUNT | __GFP_NOWARN); + prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, + sizeof(*prog->aux->jited_linfo), + GFP_KERNEL_ACCOUNT | __GFP_NOWARN); if (!prog->aux->jited_linfo) return -ENOMEM; return 0; } -void bpf_prog_free_jited_linfo(struct bpf_prog *prog) +void bpf_prog_jit_attempt_done(struct bpf_prog *prog) { - kfree(prog->aux->jited_linfo); - prog->aux->jited_linfo = NULL; -} - -void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog) -{ - if (prog->aux->jited_linfo && !prog->aux->jited_linfo[0]) - bpf_prog_free_jited_linfo(prog); + if (prog->aux->jited_linfo && + (!prog->jited || !prog->aux->jited_linfo[0])) { + kvfree(prog->aux->jited_linfo); + prog->aux->jited_linfo = NULL; + } } /* The jit engine is responsible to provide an array @@ -217,12 +214,6 @@ void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; } -void bpf_prog_free_linfo(struct bpf_prog *prog) -{ - bpf_prog_free_jited_linfo(prog); - kvfree(prog->aux->linfo); -} - struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, gfp_t gfp_extra_flags) { @@ -1866,15 +1857,13 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) return fp; fp = bpf_int_jit_compile(fp); - if (!fp->jited) { - bpf_prog_free_jited_linfo(fp); + bpf_prog_jit_attempt_done(fp); #ifdef CONFIG_BPF_JIT_ALWAYS_ON + if (!fp->jited) { *err = -ENOTSUPP; return fp; -#endif - } else { - bpf_prog_free_unused_jited_linfo(fp); } +#endif } else { *err = bpf_prog_offload_compile(fp); if (*err) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 250503482cda..eaf85bf51c5a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1694,7 +1694,8 @@ static void __bpf_prog_put_noref(struct bpf_prog *prog, bool deferred) { bpf_prog_kallsyms_del_all(prog); btf_put(prog->aux->btf); - bpf_prog_free_linfo(prog); + kvfree(prog->aux->jited_linfo); + kvfree(prog->aux->linfo); if (prog->aux->attach_btf) btf_put(prog->aux->attach_btf); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 85f9f842d15c..b7df3f06a279 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -11741,7 +11741,7 @@ static int jit_subprogs(struct bpf_verifier_env *env) prog->bpf_func = func[0]->bpf_func; prog->aux->func = func; prog->aux->func_cnt = env->subprog_cnt; - bpf_prog_free_unused_jited_linfo(prog); + bpf_prog_jit_attempt_done(prog); return 0; out_free: for (i = 0; i < env->subprog_cnt; i++) { @@ -11764,7 +11764,7 @@ out_undo_insn: insn->off = 0; insn->imm = env->insn_aux_data[i].call_imm; } - bpf_prog_free_jited_linfo(prog); + bpf_prog_jit_attempt_done(prog); return err; } -- cgit v1.2.3 From 34747c4120418143097d4343312a0ca96c986d86 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 24 Mar 2021 18:51:36 -0700 Subject: bpf: Refactor btf_check_func_arg_match This patch moved the subprog specific logic from btf_check_func_arg_match() to the new btf_check_subprog_arg_match(). The core logic is left in btf_check_func_arg_match() which will be reused later to check the kernel function call. The "if (!btf_type_is_ptr(t))" is checked first to improve the indentation which will be useful for a later patch. Some of the "btf_kind_str[]" usages is replaced with the shortcut "btf_type_str(t)". Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210325015136.1544504-1-kafai@fb.com --- include/linux/bpf.h | 4 +- include/linux/btf.h | 5 ++ kernel/bpf/btf.c | 159 +++++++++++++++++++++++++++----------------------- kernel/bpf/verifier.c | 4 +- 4 files changed, 95 insertions(+), 77 deletions(-) (limited to 'kernel') diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 5a0801b420ca..eaae618a90b5 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1545,8 +1545,8 @@ int btf_distill_func_proto(struct bpf_verifier_log *log, struct btf_func_model *m); struct bpf_reg_state; -int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, - struct bpf_reg_state *regs); +int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog, + struct bpf_reg_state *regs); 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/btf.h b/include/linux/btf.h index 9c1b52738bbe..8a05687a4ee2 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -141,6 +141,11 @@ static inline bool btf_type_is_enum(const struct btf_type *t) return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM; } +static inline bool btf_type_is_scalar(const struct btf_type *t) +{ + return btf_type_is_int(t) || btf_type_is_enum(t); +} + static inline bool btf_type_is_typedef(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF; diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 369faeddf1df..3c489adacf3b 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4377,7 +4377,7 @@ static u8 bpf_ctx_convert_map[] = { #undef BPF_LINK_TYPE static const struct btf_member * -btf_get_prog_ctx_type(struct bpf_verifier_log *log, struct btf *btf, +btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, enum bpf_prog_type prog_type, int arg) { @@ -5362,122 +5362,135 @@ int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *pr return btf_check_func_type_match(log, btf1, t1, btf2, t2); } -/* Compare BTF of a function 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. - */ -int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, - struct bpf_reg_state *regs) +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) { struct bpf_verifier_log *log = &env->log; - struct bpf_prog *prog = env->prog; - struct btf *btf = prog->aux->btf; - const struct btf_param *args; + const char *func_name, *ref_tname; const struct btf_type *t, *ref_t; - u32 i, nargs, btf_id, type_size; - const char *tname; - bool is_global; - - 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; + const struct btf_param *args; + u32 i, nargs; - t = btf_type_by_id(btf, btf_id); + t = btf_type_by_id(btf, func_id); if (!t || !btf_type_is_func(t)) { /* These checks were already done by the verifier while loading * struct bpf_func_info */ - bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n", - subprog); + bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n", + func_id); return -EFAULT; } - tname = btf_name_by_offset(btf, t->name_off); + func_name = btf_name_by_offset(btf, t->name_off); t = btf_type_by_id(btf, t->type); if (!t || !btf_type_is_func_proto(t)) { - bpf_log(log, "Invalid BTF of func %s\n", tname); + bpf_log(log, "Invalid BTF of func %s\n", func_name); return -EFAULT; } args = (const struct btf_param *)(t + 1); nargs = btf_type_vlen(t); if (nargs > MAX_BPF_FUNC_REG_ARGS) { - bpf_log(log, "Function %s has %d > %d args\n", tname, nargs, + bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs, MAX_BPF_FUNC_REG_ARGS); - goto out; + return -EINVAL; } - is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL; /* check that BTF function arguments match actual types that the * verifier sees. */ for (i = 0; i < nargs; i++) { - struct bpf_reg_state *reg = ®s[i + 1]; + u32 regno = i + 1; + struct bpf_reg_state *reg = ®s[regno]; - t = btf_type_by_id(btf, args[i].type); - while (btf_type_is_modifier(t)) - t = btf_type_by_id(btf, t->type); - if (btf_type_is_int(t) || btf_type_is_enum(t)) { + t = btf_type_skip_modifiers(btf, args[i].type, NULL); + if (btf_type_is_scalar(t)) { if (reg->type == SCALAR_VALUE) continue; - bpf_log(log, "R%d is not a scalar\n", i + 1); - goto out; + bpf_log(log, "R%d is not a scalar\n", regno); + return -EINVAL; } - if (btf_type_is_ptr(t)) { + + if (!btf_type_is_ptr(t)) { + bpf_log(log, "Unrecognized arg#%d type %s\n", + i, btf_type_str(t)); + return -EINVAL; + } + + ref_t = btf_type_skip_modifiers(btf, t->type, NULL); + ref_tname = btf_name_by_offset(btf, ref_t->name_off); + if (btf_get_prog_ctx_type(log, btf, t, env->prog->type, i)) { /* If function expects ctx type in BTF check that caller * is passing PTR_TO_CTX. */ - if (btf_get_prog_ctx_type(log, btf, t, prog->type, i)) { - if (reg->type != PTR_TO_CTX) { - bpf_log(log, - "arg#%d expected pointer to ctx, but got %s\n", - i, btf_kind_str[BTF_INFO_KIND(t->info)]); - goto out; - } - if (check_ctx_reg(env, reg, i + 1)) - goto out; - continue; + if (reg->type != PTR_TO_CTX) { + bpf_log(log, + "arg#%d expected pointer to ctx, but got %s\n", + i, btf_type_str(t)); + return -EINVAL; } + if (check_ctx_reg(env, reg, regno)) + return -EINVAL; + } else if (ptr_to_mem_ok) { + const struct btf_type *resolve_ret; + u32 type_size; - if (!is_global) - goto out; - - t = btf_type_skip_modifiers(btf, t->type, NULL); - - ref_t = btf_resolve_size(btf, t, &type_size); - if (IS_ERR(ref_t)) { + resolve_ret = btf_resolve_size(btf, ref_t, &type_size); + if (IS_ERR(resolve_ret)) { bpf_log(log, - "arg#%d reference type('%s %s') size cannot be determined: %ld\n", - i, btf_type_str(t), btf_name_by_offset(btf, t->name_off), - PTR_ERR(ref_t)); - goto out; + "arg#%d reference type('%s %s') size cannot be determined: %ld\n", + i, btf_type_str(ref_t), ref_tname, + PTR_ERR(resolve_ret)); + return -EINVAL; } - if (check_mem_reg(env, reg, i + 1, type_size)) - goto out; - - continue; + if (check_mem_reg(env, reg, regno, type_size)) + return -EINVAL; + } else { + return -EINVAL; } - bpf_log(log, "Unrecognized arg#%d type %s\n", - i, btf_kind_str[BTF_INFO_KIND(t->info)]); - goto out; } + return 0; -out: +} + +/* Compare BTF of a function 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. + */ +int btf_check_subprog_arg_match(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); + /* 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. */ - prog->aux->func_info_aux[subprog].unreliable = true; - return -EINVAL; + if (err) + prog->aux->func_info_aux[subprog].unreliable = true; + return err; } /* Convert BTF of a function into bpf_reg_state if possible diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b7df3f06a279..b31e62daafbd 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5365,7 +5365,7 @@ 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_func_arg_match(env, subprog, caller->regs); + err = btf_check_subprog_arg_match(env, subprog, caller->regs); if (err == -EFAULT) return err; if (is_global) { @@ -12288,7 +12288,7 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) /* 1st arg to a function */ regs[BPF_REG_1].type = PTR_TO_CTX; mark_reg_known_zero(env, regs, BPF_REG_1); - ret = btf_check_func_arg_match(env, subprog, regs); + ret = btf_check_subprog_arg_match(env, subprog, regs); if (ret == -EFAULT) /* unlikely verifier bug. abort. * ret == 0 and ret < 0 are sadly acceptable for -- cgit v1.2.3 From e6ac2450d6dee3121cd8bbf2907b78a68a8a353d Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 24 Mar 2021 18:51:42 -0700 Subject: bpf: Support bpf program calling kernel function This patch adds support to BPF verifier to allow bpf program calling kernel function directly. The use case included in this set is to allow bpf-tcp-cc to directly call some tcp-cc helper functions (e.g. "tcp_cong_avoid_ai()"). Those functions have already been used by some kernel tcp-cc implementations. This set will also allow the bpf-tcp-cc program to directly call the kernel tcp-cc implementation, For example, a bpf_dctcp may only want to implement its own dctcp_cwnd_event() and reuse other dctcp_*() directly from the kernel tcp_dctcp.c instead of reimplementing (or copy-and-pasting) them. The tcp-cc kernel functions mentioned above will be white listed for the struct_ops bpf-tcp-cc programs to use in a later patch. The white listed functions are not bounded to a fixed ABI contract. Those functions have already been used by the existing kernel tcp-cc. If any of them has changed, both in-tree and out-of-tree kernel tcp-cc implementations have to be changed. The same goes for the struct_ops bpf-tcp-cc programs which have to be adjusted accordingly. This patch is to make the required changes in the bpf verifier. First change is in btf.c, it adds a case in "btf_check_func_arg_match()". When the passed in "btf->kernel_btf == true", it means matching the verifier regs' states with a kernel function. This will handle the PTR_TO_BTF_ID reg. It also maps PTR_TO_SOCK_COMMON, PTR_TO_SOCKET, and PTR_TO_TCP_SOCK to its kernel's btf_id. In the later libbpf patch, the insn calling a kernel function will look like: insn->code == (BPF_JMP | BPF_CALL) insn->src_reg == BPF_PSEUDO_KFUNC_CALL /* <- new in this patch */ insn->imm == func_btf_id /* btf_id of the running kernel */ [ For the future calling function-in-kernel-module support, an array of module btf_fds can be passed at the load time and insn->off can be used to index into this array. ] At the early stage of verifier, the verifier will collect all kernel function calls into "struct bpf_kfunc_desc". Those descriptors are stored in "prog->aux->kfunc_tab" and will be available to the JIT. Since this "add" operation is similar to the current "add_subprog()" and looking for the same insn->code, they are done together in the new "add_subprog_and_kfunc()". In the "do_check()" stage, the new "check_kfunc_call()" is added to verify the kernel function call instruction: 1. Ensure the kernel function can be used by a particular BPF_PROG_TYPE. A new bpf_verifier_ops "check_kfunc_call" is added to do that. The bpf-tcp-cc struct_ops program will implement this function in a later patch. 2. Call "btf_check_kfunc_args_match()" to ensure the regs can be used as the args of a kernel function. 3. Mark the regs' type, subreg_def, and zext_dst. At the later do_misc_fixups() stage, the new fixup_kfunc_call() will replace the insn->imm with the function address (relative to __bpf_call_base). If needed, the jit can find the btf_func_model by calling the new bpf_jit_find_kfunc_model(prog, insn). With the imm set to the function address, "bpftool prog dump xlated" will be able to display the kernel function calls the same way as it displays other bpf helper calls. gpl_compatible program is required to call kernel function. This feature currently requires JIT. The verifier selftests are adjusted because of the changes in the verbose log in add_subprog_and_kfunc(). Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210325015142.1544736-1-kafai@fb.com --- arch/x86/net/bpf_jit_comp.c | 5 + include/linux/bpf.h | 24 ++ include/linux/btf.h | 1 + include/linux/filter.h | 1 + include/uapi/linux/bpf.h | 4 + kernel/bpf/btf.c | 65 +++- kernel/bpf/core.c | 18 +- kernel/bpf/disasm.c | 13 +- kernel/bpf/syscall.c | 1 + kernel/bpf/verifier.c | 368 +++++++++++++++++++++-- tools/include/uapi/linux/bpf.h | 4 + tools/testing/selftests/bpf/verifier/calls.c | 12 +- tools/testing/selftests/bpf/verifier/dead_code.c | 10 +- 13 files changed, 480 insertions(+), 46 deletions(-) (limited to 'kernel') diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index b35fc8023884..9eead60f0301 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2346,3 +2346,8 @@ out: tmp : orig_prog); return prog; } + +bool bpf_jit_supports_kfunc_call(void) +{ + return true; +} diff --git a/include/linux/bpf.h b/include/linux/bpf.h index eaae618a90b5..b5b7967e3ff3 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -427,6 +427,7 @@ enum bpf_reg_type { PTR_TO_PERCPU_BTF_ID, /* reg points to a percpu kernel variable */ PTR_TO_FUNC, /* reg points to a bpf program function */ PTR_TO_MAP_KEY, /* reg points to a map element key */ + __BPF_REG_TYPE_MAX, }; /* The information passed from prog-specific *_is_valid_access @@ -480,6 +481,7 @@ struct bpf_verifier_ops { const struct btf_type *t, int off, int size, enum bpf_access_type atype, u32 *next_btf_id); + bool (*check_kfunc_call)(u32 kfunc_btf_id); }; struct bpf_prog_offload_ops { @@ -796,6 +798,8 @@ struct btf_mod_pair { struct module *module; }; +struct bpf_kfunc_desc_tab; + struct bpf_prog_aux { atomic64_t refcnt; u32 used_map_cnt; @@ -832,6 +836,7 @@ struct bpf_prog_aux { struct bpf_prog **func; void *jit_data; /* JIT specific data. arch dependent */ struct bpf_jit_poke_descriptor *poke_tab; + struct bpf_kfunc_desc_tab *kfunc_tab; u32 size_poke_tab; struct bpf_ksym ksym; const struct bpf_prog_ops *ops; @@ -1547,6 +1552,9 @@ int btf_distill_func_proto(struct bpf_verifier_log *log, 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_kfunc_arg_match(struct bpf_verifier_env *env, + const struct btf *btf, u32 func_id, + struct bpf_reg_state *regs); 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, @@ -1557,6 +1565,10 @@ struct bpf_link *bpf_link_by_id(u32 id); const struct bpf_func_proto *bpf_base_func_proto(enum bpf_func_id func_id); void bpf_task_storage_free(struct task_struct *task); +bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog); +const struct btf_func_model * +bpf_jit_find_kfunc_model(const struct bpf_prog *prog, + const struct bpf_insn *insn); #else /* !CONFIG_BPF_SYSCALL */ static inline struct bpf_prog *bpf_prog_get(u32 ufd) { @@ -1737,6 +1749,18 @@ bpf_base_func_proto(enum bpf_func_id func_id) static inline void bpf_task_storage_free(struct task_struct *task) { } + +static inline bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog) +{ + return false; +} + +static inline const struct btf_func_model * +bpf_jit_find_kfunc_model(const struct bpf_prog *prog, + const struct bpf_insn *insn) +{ + return NULL; +} #endif /* CONFIG_BPF_SYSCALL */ void __bpf_free_used_btfs(struct bpf_prog_aux *aux, diff --git a/include/linux/btf.h b/include/linux/btf.h index 8a05687a4ee2..3bac66e0183a 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -110,6 +110,7 @@ const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf, const struct btf_type * btf_resolve_size(const struct btf *btf, const struct btf_type *type, u32 *type_size); +const char *btf_type_str(const struct btf_type *t); #define for_each_member(i, struct_type, member) \ for (i = 0, member = btf_type_member(struct_type); \ diff --git a/include/linux/filter.h b/include/linux/filter.h index 0d9c710eb050..eecfd82db648 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -918,6 +918,7 @@ u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog); void bpf_jit_compile(struct bpf_prog *prog); bool bpf_jit_needs_zext(void); +bool bpf_jit_supports_kfunc_call(void); bool bpf_helper_changes_pkt_data(void *func); static inline bool bpf_dump_raw_ok(const struct cred *cred) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 008edc1dc8c1..598716742593 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1117,6 +1117,10 @@ enum bpf_link_type { * offset to another bpf function */ #define BPF_PSEUDO_CALL 1 +/* when bpf_call->src_reg == BPF_PSEUDO_KFUNC_CALL, + * bpf_call->imm == btf_id of a BTF_KIND_FUNC in the running kernel + */ +#define BPF_PSEUDO_KFUNC_CALL 2 /* flags for BPF_MAP_UPDATE_ELEM command */ enum { diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 3c489adacf3b..ec8afc4bc560 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -283,7 +283,7 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = { [BTF_KIND_FLOAT] = "FLOAT", }; -static const char *btf_type_str(const struct btf_type *t) +const char *btf_type_str(const struct btf_type *t) { return btf_kind_str[BTF_INFO_KIND(t->info)]; } @@ -5362,6 +5362,14 @@ int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *pr return btf_check_func_type_match(log, btf1, t1, btf2, t2); } +static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = { +#ifdef CONFIG_NET + [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK], + [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], + [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP], +#endif +}; + static int btf_check_func_arg_match(struct bpf_verifier_env *env, const struct btf *btf, u32 func_id, struct bpf_reg_state *regs, @@ -5371,12 +5379,12 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, const char *func_name, *ref_tname; const struct btf_type *t, *ref_t; const struct btf_param *args; - u32 i, nargs; + u32 i, nargs, ref_id; t = btf_type_by_id(btf, func_id); if (!t || !btf_type_is_func(t)) { /* These checks were already done by the verifier while loading - * struct bpf_func_info + * struct bpf_func_info or in add_kfunc_call(). */ bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n", func_id); @@ -5418,9 +5426,49 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, return -EINVAL; } - ref_t = btf_type_skip_modifiers(btf, t->type, NULL); + ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id); ref_tname = btf_name_by_offset(btf, ref_t->name_off); - if (btf_get_prog_ctx_type(log, btf, t, env->prog->type, i)) { + if (btf_is_kernel(btf)) { + const struct btf_type *reg_ref_t; + const struct btf *reg_btf; + const char *reg_ref_tname; + u32 reg_ref_id; + + if (!btf_type_is_struct(ref_t)) { + bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n", + func_name, i, btf_type_str(ref_t), + ref_tname); + return -EINVAL; + } + + if (reg->type == PTR_TO_BTF_ID) { + reg_btf = reg->btf; + reg_ref_id = reg->btf_id; + } else if (reg2btf_ids[reg->type]) { + reg_btf = btf_vmlinux; + reg_ref_id = *reg2btf_ids[reg->type]; + } else { + bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d is not a pointer to btf_id\n", + func_name, i, + btf_type_str(ref_t), ref_tname, regno); + return -EINVAL; + } + + reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id, + ®_ref_id); + reg_ref_tname = btf_name_by_offset(reg_btf, + reg_ref_t->name_off); + if (!btf_struct_ids_match(log, reg_btf, reg_ref_id, + reg->off, btf, ref_id)) { + bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n", + func_name, i, + btf_type_str(ref_t), ref_tname, + regno, btf_type_str(reg_ref_t), + reg_ref_tname); + return -EINVAL; + } + } else if (btf_get_prog_ctx_type(log, btf, t, + env->prog->type, i)) { /* If function expects ctx type in BTF check that caller * is passing PTR_TO_CTX. */ @@ -5493,6 +5541,13 @@ int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog, return err; } +int btf_check_kfunc_arg_match(struct bpf_verifier_env *env, + const struct btf *btf, u32 func_id, + struct bpf_reg_state *regs) +{ + return btf_check_func_arg_match(env, btf, func_id, regs, false); +} + /* Convert BTF of a function into bpf_reg_state if possible * Returns: * EFAULT - there is a verifier bug. Abort verification. diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index a35eb3d7b126..f5423251c118 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -159,6 +159,9 @@ void bpf_prog_jit_attempt_done(struct bpf_prog *prog) kvfree(prog->aux->jited_linfo); prog->aux->jited_linfo = NULL; } + + kfree(prog->aux->kfunc_tab); + prog->aux->kfunc_tab = NULL; } /* The jit engine is responsible to provide an array @@ -1840,9 +1843,15 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) /* In case of BPF to BPF calls, verifier did all the prep * work with regards to JITing, etc. */ + bool jit_needed = false; + if (fp->bpf_func) goto finalize; + if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || + bpf_prog_has_kfunc_call(fp)) + jit_needed = true; + bpf_prog_select_func(fp); /* eBPF JITs can rewrite the program in case constant @@ -1858,12 +1867,10 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) fp = bpf_int_jit_compile(fp); bpf_prog_jit_attempt_done(fp); -#ifdef CONFIG_BPF_JIT_ALWAYS_ON - if (!fp->jited) { + if (!fp->jited && jit_needed) { *err = -ENOTSUPP; return fp; } -#endif } else { *err = bpf_prog_offload_compile(fp); if (*err) @@ -2343,6 +2350,11 @@ bool __weak bpf_jit_needs_zext(void) return false; } +bool __weak bpf_jit_supports_kfunc_call(void) +{ + return false; +} + /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call * skb_copy_bits(), so provide a weak definition of it for NET-less config. */ diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c index 3acc7e0b6916..dad821c8ecd0 100644 --- a/kernel/bpf/disasm.c +++ b/kernel/bpf/disasm.c @@ -19,16 +19,23 @@ static const char *__func_get_name(const struct bpf_insn_cbs *cbs, { BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID); - if (insn->src_reg != BPF_PSEUDO_CALL && + if (!insn->src_reg && insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID && func_id_str[insn->imm]) return func_id_str[insn->imm]; - if (cbs && cbs->cb_call) - return cbs->cb_call(cbs->private_data, insn); + if (cbs && cbs->cb_call) { + const char *res; + + res = cbs->cb_call(cbs->private_data, insn); + if (res) + return res; + } if (insn->src_reg == BPF_PSEUDO_CALL) snprintf(buff, len, "%+d", insn->imm); + else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) + snprintf(buff, len, "kernel-function"); return buff; } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index eaf85bf51c5a..9603de81811a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1696,6 +1696,7 @@ static void __bpf_prog_put_noref(struct bpf_prog *prog, bool deferred) btf_put(prog->aux->btf); kvfree(prog->aux->jited_linfo); kvfree(prog->aux->linfo); + kfree(prog->aux->kfunc_tab); if (prog->aux->attach_btf) btf_put(prog->aux->attach_btf); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b31e62daafbd..852541a435ef 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -234,6 +234,12 @@ static bool bpf_pseudo_call(const struct bpf_insn *insn) insn->src_reg == BPF_PSEUDO_CALL; } +static bool bpf_pseudo_kfunc_call(const struct bpf_insn *insn) +{ + return insn->code == (BPF_JMP | BPF_CALL) && + insn->src_reg == BPF_PSEUDO_KFUNC_CALL; +} + static bool bpf_pseudo_func(const struct bpf_insn *insn) { return insn->code == (BPF_LD | BPF_IMM | BPF_DW) && @@ -1554,47 +1560,205 @@ static int add_subprog(struct bpf_verifier_env *env, int off) verbose(env, "too many subprograms\n"); return -E2BIG; } + /* determine subprog starts. The end is one before the next starts */ env->subprog_info[env->subprog_cnt++].start = off; sort(env->subprog_info, env->subprog_cnt, sizeof(env->subprog_info[0]), cmp_subprogs, NULL); return env->subprog_cnt - 1; } -static int check_subprogs(struct bpf_verifier_env *env) +struct bpf_kfunc_desc { + struct btf_func_model func_model; + u32 func_id; + s32 imm; +}; + +#define MAX_KFUNC_DESCS 256 +struct bpf_kfunc_desc_tab { + struct bpf_kfunc_desc descs[MAX_KFUNC_DESCS]; + u32 nr_descs; +}; + +static int kfunc_desc_cmp_by_id(const void *a, const void *b) +{ + const struct bpf_kfunc_desc *d0 = a; + const struct bpf_kfunc_desc *d1 = b; + + /* func_id is not greater than BTF_MAX_TYPE */ + return d0->func_id - d1->func_id; +} + +static const struct bpf_kfunc_desc * +find_kfunc_desc(const struct bpf_prog *prog, u32 func_id) +{ + struct bpf_kfunc_desc desc = { + .func_id = func_id, + }; + struct bpf_kfunc_desc_tab *tab; + + tab = prog->aux->kfunc_tab; + return bsearch(&desc, tab->descs, tab->nr_descs, + sizeof(tab->descs[0]), kfunc_desc_cmp_by_id); +} + +static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id) +{ + const struct btf_type *func, *func_proto; + struct bpf_kfunc_desc_tab *tab; + struct bpf_prog_aux *prog_aux; + struct bpf_kfunc_desc *desc; + const char *func_name; + unsigned long addr; + int err; + + prog_aux = env->prog->aux; + tab = prog_aux->kfunc_tab; + if (!tab) { + if (!btf_vmlinux) { + verbose(env, "calling kernel function is not supported without CONFIG_DEBUG_INFO_BTF\n"); + return -ENOTSUPP; + } + + if (!env->prog->jit_requested) { + verbose(env, "JIT is required for calling kernel function\n"); + return -ENOTSUPP; + } + + if (!bpf_jit_supports_kfunc_call()) { + verbose(env, "JIT does not support calling kernel function\n"); + return -ENOTSUPP; + } + + if (!env->prog->gpl_compatible) { + verbose(env, "cannot call kernel function from non-GPL compatible program\n"); + return -EINVAL; + } + + tab = kzalloc(sizeof(*tab), GFP_KERNEL); + if (!tab) + return -ENOMEM; + prog_aux->kfunc_tab = tab; + } + + if (find_kfunc_desc(env->prog, func_id)) + return 0; + + if (tab->nr_descs == MAX_KFUNC_DESCS) { + verbose(env, "too many different kernel function calls\n"); + return -E2BIG; + } + + func = btf_type_by_id(btf_vmlinux, func_id); + if (!func || !btf_type_is_func(func)) { + verbose(env, "kernel btf_id %u is not a function\n", + func_id); + return -EINVAL; + } + func_proto = btf_type_by_id(btf_vmlinux, func->type); + if (!func_proto || !btf_type_is_func_proto(func_proto)) { + verbose(env, "kernel function btf_id %u does not have a valid func_proto\n", + func_id); + return -EINVAL; + } + + func_name = btf_name_by_offset(btf_vmlinux, func->name_off); + addr = kallsyms_lookup_name(func_name); + if (!addr) { + verbose(env, "cannot find address for kernel function %s\n", + func_name); + return -EINVAL; + } + + desc = &tab->descs[tab->nr_descs++]; + desc->func_id = func_id; + desc->imm = BPF_CAST_CALL(addr) - __bpf_call_base; + err = btf_distill_func_proto(&env->log, btf_vmlinux, + func_proto, func_name, + &desc->func_model); + if (!err) + sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]), + kfunc_desc_cmp_by_id, NULL); + return err; +} + +static int kfunc_desc_cmp_by_imm(const void *a, const void *b) +{ + const struct bpf_kfunc_desc *d0 = a; + const struct bpf_kfunc_desc *d1 = b; + + if (d0->imm > d1->imm) + return 1; + else if (d0->imm < d1->imm) + return -1; + return 0; +} + +static void sort_kfunc_descs_by_imm(struct bpf_prog *prog) +{ + struct bpf_kfunc_desc_tab *tab; + + tab = prog->aux->kfunc_tab; + if (!tab) + return; + + sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]), + kfunc_desc_cmp_by_imm, NULL); +} + +bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog) +{ + return !!prog->aux->kfunc_tab; +} + +const struct btf_func_model * +bpf_jit_find_kfunc_model(const struct bpf_prog *prog, + const struct bpf_insn *insn) +{ + const struct bpf_kfunc_desc desc = { + .imm = insn->imm, + }; + const struct bpf_kfunc_desc *res; + struct bpf_kfunc_desc_tab *tab; + + tab = prog->aux->kfunc_tab; + res = bsearch(&desc, tab->descs, tab->nr_descs, + sizeof(tab->descs[0]), kfunc_desc_cmp_by_imm); + + return res ? &res->func_model : NULL; +} + +static int add_subprog_and_kfunc(struct bpf_verifier_env *env) { - int i, ret, subprog_start, subprog_end, off, cur_subprog = 0; struct bpf_subprog_info *subprog = env->subprog_info; struct bpf_insn *insn = env->prog->insnsi; - int insn_cnt = env->prog->len; + int i, ret, insn_cnt = env->prog->len; /* Add entry function. */ ret = add_subprog(env, 0); - if (ret < 0) + if (ret) return ret; - /* determine subprog starts. The end is one before the next starts */ - for (i = 0; i < insn_cnt; i++) { - if (bpf_pseudo_func(insn + i)) { - if (!env->bpf_capable) { - verbose(env, - "function pointers are allowed for CAP_BPF and CAP_SYS_ADMIN\n"); - return -EPERM; - } - ret = add_subprog(env, i + insn[i].imm + 1); - if (ret < 0) - return ret; - /* remember subprog */ - insn[i + 1].imm = ret; - continue; - } - if (!bpf_pseudo_call(insn + i)) + for (i = 0; i < insn_cnt; i++, insn++) { + if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn) && + !bpf_pseudo_kfunc_call(insn)) continue; + if (!env->bpf_capable) { - verbose(env, - "function calls to other bpf functions are allowed for CAP_BPF and CAP_SYS_ADMIN\n"); + verbose(env, "loading/calling other bpf or kernel functions are allowed for CAP_BPF and CAP_SYS_ADMIN\n"); return -EPERM; } - ret = add_subprog(env, i + insn[i].imm + 1); + + if (bpf_pseudo_func(insn)) { + ret = add_subprog(env, i + insn->imm + 1); + if (ret >= 0) + /* remember subprog */ + insn[1].imm = ret; + } else if (bpf_pseudo_call(insn)) { + ret = add_subprog(env, i + insn->imm + 1); + } else { + ret = add_kfunc_call(env, insn->imm); + } + if (ret < 0) return ret; } @@ -1608,6 +1772,16 @@ static int check_subprogs(struct bpf_verifier_env *env) for (i = 0; i < env->subprog_cnt; i++) verbose(env, "func#%d @%d\n", i, subprog[i].start); + return 0; +} + +static int check_subprogs(struct bpf_verifier_env *env) +{ + int i, subprog_start, subprog_end, off, cur_subprog = 0; + struct bpf_subprog_info *subprog = env->subprog_info; + struct bpf_insn *insn = env->prog->insnsi; + int insn_cnt = env->prog->len; + /* now check that all jumps are within the same subprog */ subprog_start = subprog[cur_subprog].start; subprog_end = subprog[cur_subprog + 1].start; @@ -1916,6 +2090,17 @@ static int get_prev_insn_idx(struct bpf_verifier_state *st, int i, return i; } +static const char *disasm_kfunc_name(void *data, const struct bpf_insn *insn) +{ + const struct btf_type *func; + + if (insn->src_reg != BPF_PSEUDO_KFUNC_CALL) + return NULL; + + func = btf_type_by_id(btf_vmlinux, insn->imm); + return btf_name_by_offset(btf_vmlinux, func->name_off); +} + /* For given verifier state backtrack_insn() is called from the last insn to * the first insn. Its purpose is to compute a bitmask of registers and * stack slots that needs precision in the parent verifier state. @@ -1924,6 +2109,7 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, u32 *reg_mask, u64 *stack_mask) { const struct bpf_insn_cbs cbs = { + .cb_call = disasm_kfunc_name, .cb_print = verbose, .private_data = env, }; @@ -5960,6 +6146,98 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn return 0; } +/* mark_btf_func_reg_size() is used when the reg size is determined by + * the BTF func_proto's return value size and argument. + */ +static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno, + size_t reg_size) +{ + struct bpf_reg_state *reg = &cur_regs(env)[regno]; + + if (regno == BPF_REG_0) { + /* Function return value */ + reg->live |= REG_LIVE_WRITTEN; + reg->subreg_def = reg_size == sizeof(u64) ? + DEF_NOT_SUBREG : env->insn_idx + 1; + } else { + /* Function argument */ + if (reg_size == sizeof(u64)) { + mark_insn_zext(env, reg); + mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64); + } else { + mark_reg_read(env, reg, reg->parent, REG_LIVE_READ32); + } + } +} + +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); + const char *func_name, *ptr_type_name; + u32 i, nargs, func_id, ptr_type_id; + const struct btf_param *args; + int err; + + func_id = insn->imm; + func = btf_type_by_id(btf_vmlinux, func_id); + func_name = btf_name_by_offset(btf_vmlinux, func->name_off); + func_proto = btf_type_by_id(btf_vmlinux, func->type); + + if (!env->ops->check_kfunc_call || + !env->ops->check_kfunc_call(func_id)) { + verbose(env, "calling kernel function %s is not allowed\n", + func_name); + return -EACCES; + } + + /* Check the arguments */ + err = btf_check_kfunc_arg_match(env, btf_vmlinux, func_id, regs); + if (err) + return err; + + for (i = 0; i < CALLER_SAVED_REGS; i++) + mark_reg_not_init(env, regs, caller_saved[i]); + + /* Check return type */ + t = btf_type_skip_modifiers(btf_vmlinux, func_proto->type, NULL); + if (btf_type_is_scalar(t)) { + mark_reg_unknown(env, regs, BPF_REG_0); + mark_btf_func_reg_size(env, BPF_REG_0, t->size); + } else if (btf_type_is_ptr(t)) { + ptr_type = btf_type_skip_modifiers(btf_vmlinux, t->type, + &ptr_type_id); + if (!btf_type_is_struct(ptr_type)) { + ptr_type_name = btf_name_by_offset(btf_vmlinux, + 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].btf = btf_vmlinux; + regs[BPF_REG_0].type = PTR_TO_BTF_ID; + regs[BPF_REG_0].btf_id = ptr_type_id; + mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *)); + } /* else { add_kfunc_call() ensures it is btf_type_is_void(t) } */ + + nargs = btf_type_vlen(func_proto); + args = (const struct btf_param *)(func_proto + 1); + for (i = 0; i < nargs; i++) { + u32 regno = i + 1; + + t = btf_type_skip_modifiers(btf_vmlinux, args[i].type, NULL); + if (btf_type_is_ptr(t)) + mark_btf_func_reg_size(env, regno, sizeof(void *)); + else + /* scalar. ensured by btf_check_kfunc_arg_match() */ + mark_btf_func_reg_size(env, regno, t->size); + } + + return 0; +} + static bool signed_add_overflows(s64 a, s64 b) { /* Do the add in u64, where overflow is well-defined */ @@ -10162,6 +10440,7 @@ static int do_check(struct bpf_verifier_env *env) if (env->log.level & BPF_LOG_LEVEL) { const struct bpf_insn_cbs cbs = { + .cb_call = disasm_kfunc_name, .cb_print = verbose, .private_data = env, }; @@ -10309,7 +10588,8 @@ static int do_check(struct bpf_verifier_env *env) if (BPF_SRC(insn->code) != BPF_K || insn->off != 0 || (insn->src_reg != BPF_REG_0 && - insn->src_reg != BPF_PSEUDO_CALL) || + insn->src_reg != BPF_PSEUDO_CALL && + insn->src_reg != BPF_PSEUDO_KFUNC_CALL) || insn->dst_reg != BPF_REG_0 || class == BPF_JMP32) { verbose(env, "BPF_CALL uses reserved fields\n"); @@ -10324,6 +10604,8 @@ static int do_check(struct bpf_verifier_env *env) } if (insn->src_reg == BPF_PSEUDO_CALL) err = check_func_call(env, insn, &env->insn_idx); + else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) + err = check_kfunc_call(env, insn); else err = check_helper_call(env, insn, &env->insn_idx); if (err) @@ -11634,6 +11916,7 @@ static int jit_subprogs(struct bpf_verifier_env *env) func[i]->aux->name[0] = 'F'; func[i]->aux->stack_depth = env->subprog_info[i].stack_depth; func[i]->jit_requested = 1; + func[i]->aux->kfunc_tab = prog->aux->kfunc_tab; func[i]->aux->linfo = prog->aux->linfo; func[i]->aux->nr_linfo = prog->aux->nr_linfo; func[i]->aux->jited_linfo = prog->aux->jited_linfo; @@ -11773,6 +12056,7 @@ static int fixup_call_args(struct bpf_verifier_env *env) #ifndef CONFIG_BPF_JIT_ALWAYS_ON struct bpf_prog *prog = env->prog; struct bpf_insn *insn = prog->insnsi; + bool has_kfunc_call = bpf_prog_has_kfunc_call(prog); int i, depth; #endif int err = 0; @@ -11786,6 +12070,10 @@ static int fixup_call_args(struct bpf_verifier_env *env) return err; } #ifndef CONFIG_BPF_JIT_ALWAYS_ON + if (has_kfunc_call) { + verbose(env, "calling kernel functions are not allowed in non-JITed programs\n"); + return -EINVAL; + } if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) { /* When JIT fails the progs with bpf2bpf calls and tail_calls * have to be rejected, since interpreter doesn't support them yet. @@ -11814,6 +12102,26 @@ static int fixup_call_args(struct bpf_verifier_env *env) return err; } +static int fixup_kfunc_call(struct bpf_verifier_env *env, + struct bpf_insn *insn) +{ + const struct bpf_kfunc_desc *desc; + + /* insn->imm has the btf func_id. Replace it with + * an address (relative to __bpf_base_call). + */ + desc = find_kfunc_desc(env->prog, insn->imm); + if (!desc) { + verbose(env, "verifier internal error: kernel function descriptor not found for func_id %u\n", + insn->imm); + return -EFAULT; + } + + insn->imm = desc->imm; + + return 0; +} + /* Do various post-verification rewrites in a single program pass. * These rewrites simplify JIT and interpreter implementations. */ @@ -11949,6 +12257,12 @@ static int do_misc_fixups(struct bpf_verifier_env *env) continue; if (insn->src_reg == BPF_PSEUDO_CALL) continue; + if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) { + ret = fixup_kfunc_call(env, insn); + if (ret) + return ret; + continue; + } if (insn->imm == BPF_FUNC_get_route_realm) prog->dst_needed = 1; @@ -12178,6 +12492,8 @@ patch_call_imm: } } + sort_kfunc_descs_by_imm(env->prog); + return 0; } @@ -12883,6 +13199,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, if (!env->explored_states) goto skip_full_check; + ret = add_subprog_and_kfunc(env); + if (ret < 0) + goto skip_full_check; + ret = check_subprogs(env); if (ret < 0) goto skip_full_check; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 2d3036e292a9..ab9f2233607c 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1117,6 +1117,10 @@ enum bpf_link_type { * offset to another bpf function */ #define BPF_PSEUDO_CALL 1 +/* when bpf_call->src_reg == BPF_PSEUDO_KFUNC_CALL, + * bpf_call->imm == btf_id of a BTF_KIND_FUNC in the running kernel + */ +#define BPF_PSEUDO_KFUNC_CALL 2 /* flags for BPF_MAP_UPDATE_ELEM command */ enum { diff --git a/tools/testing/selftests/bpf/verifier/calls.c b/tools/testing/selftests/bpf/verifier/calls.c index eb888c8479c3..336a749673d1 100644 --- a/tools/testing/selftests/bpf/verifier/calls.c +++ b/tools/testing/selftests/bpf/verifier/calls.c @@ -19,7 +19,7 @@ BPF_MOV64_IMM(BPF_REG_0, 2), BPF_EXIT_INSN(), }, - .errstr_unpriv = "function calls to other bpf functions are allowed for", + .errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for", .result_unpriv = REJECT, .result = ACCEPT, .retval = 1, @@ -136,7 +136,7 @@ { "calls: wrong src reg", .insns = { - BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 2, 0, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 3, 0, 0), BPF_MOV64_IMM(BPF_REG_0, 1), BPF_EXIT_INSN(), }, @@ -397,7 +397,7 @@ BPF_MOV64_IMM(BPF_REG_0, 1), BPF_EXIT_INSN(), }, - .errstr_unpriv = "function calls to other bpf functions are allowed for", + .errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for", .fixup_map_hash_48b = { 3 }, .result_unpriv = REJECT, .result = ACCEPT, @@ -1977,7 +1977,7 @@ BPF_EXIT_INSN(), }, .prog_type = BPF_PROG_TYPE_SOCKET_FILTER, - .errstr_unpriv = "function calls to other bpf functions are allowed for", + .errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for", .result_unpriv = REJECT, .result = ACCEPT, }, @@ -2003,7 +2003,7 @@ BPF_EXIT_INSN(), }, .prog_type = BPF_PROG_TYPE_SOCKET_FILTER, - .errstr_unpriv = "function calls to other bpf functions are allowed for", + .errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for", .errstr = "!read_ok", .result = REJECT, }, @@ -2028,7 +2028,7 @@ BPF_EXIT_INSN(), }, .prog_type = BPF_PROG_TYPE_SOCKET_FILTER, - .errstr_unpriv = "function calls to other bpf functions are allowed for", + .errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for", .errstr = "!read_ok", .result = REJECT, }, diff --git a/tools/testing/selftests/bpf/verifier/dead_code.c b/tools/testing/selftests/bpf/verifier/dead_code.c index 5cf361d8eb1c..17fe33a75034 100644 --- a/tools/testing/selftests/bpf/verifier/dead_code.c +++ b/tools/testing/selftests/bpf/verifier/dead_code.c @@ -85,7 +85,7 @@ BPF_MOV64_IMM(BPF_REG_0, 12), BPF_EXIT_INSN(), }, - .errstr_unpriv = "function calls to other bpf functions are allowed for", + .errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for", .result_unpriv = REJECT, .result = ACCEPT, .retval = 7, @@ -103,7 +103,7 @@ BPF_MOV64_IMM(BPF_REG_0, 12), BPF_EXIT_INSN(), }, - .errstr_unpriv = "function calls to other bpf functions are allowed for", + .errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for", .result_unpriv = REJECT, .result = ACCEPT, .retval = 7, @@ -121,7 +121,7 @@ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -5), BPF_EXIT_INSN(), }, - .errstr_unpriv = "function calls to other bpf functions are allowed for", + .errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for", .result_unpriv = REJECT, .result = ACCEPT, .retval = 7, @@ -137,7 +137,7 @@ BPF_MOV64_REG(BPF_REG_0, BPF_REG_1), BPF_EXIT_INSN(), }, - .errstr_unpriv = "function calls to other bpf functions are allowed for", + .errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for", .result_unpriv = REJECT, .result = ACCEPT, .retval = 2, @@ -152,7 +152,7 @@ BPF_MOV64_REG(BPF_REG_0, BPF_REG_1), BPF_EXIT_INSN(), }, - .errstr_unpriv = "function calls to other bpf functions are allowed for", + .errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for", .result_unpriv = REJECT, .result = ACCEPT, .retval = 2, -- cgit v1.2.3 From 235fc0e36d35270e1ff426f26bbea6154b8863a5 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Fri, 26 Mar 2021 19:43:48 +0000 Subject: bpf: Remove redundant assignment of variable id The variable id is being assigned a value that is never read, the assignment is redundant and can be removed. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King Signed-off-by: Daniel Borkmann Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20210326194348.623782-1-colin.king@canonical.com --- kernel/bpf/btf.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index ec8afc4bc560..0600ed325fa0 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -789,7 +789,6 @@ static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf, while (btf_type_is_modifier(t) && BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) { - id = t->type; t = btf_type_by_id(btf, t->type); } -- cgit v1.2.3 From a7ba4558e69a3c2ae4ca521f015832ef44799538 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Tue, 30 Mar 2021 19:32:30 -0700 Subject: sock_map: Introduce BPF_SK_SKB_VERDICT Reusing BPF_SK_SKB_STREAM_VERDICT is possible but its name is confusing and more importantly we still want to distinguish them from user-space. So we can just reuse the stream verdict code but introduce a new type of eBPF program, skb_verdict. Users are not allowed to attach stream_verdict and skb_verdict programs to the same map. Signed-off-by: Cong Wang Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20210331023237.41094-10-xiyou.wangcong@gmail.com --- include/linux/skmsg.h | 2 ++ include/uapi/linux/bpf.h | 1 + kernel/bpf/syscall.c | 1 + net/core/skmsg.c | 4 +++- net/core/sock_map.c | 28 ++++++++++++++++++++++++++++ tools/bpf/bpftool/common.c | 1 + tools/bpf/bpftool/prog.c | 1 + tools/include/uapi/linux/bpf.h | 1 + 8 files changed, 38 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h index e7aba150539d..c83dbc2d81d9 100644 --- a/include/linux/skmsg.h +++ b/include/linux/skmsg.h @@ -58,6 +58,7 @@ struct sk_psock_progs { struct bpf_prog *msg_parser; struct bpf_prog *stream_parser; struct bpf_prog *stream_verdict; + struct bpf_prog *skb_verdict; }; enum sk_psock_state_bits { @@ -487,6 +488,7 @@ static inline void psock_progs_drop(struct sk_psock_progs *progs) psock_set_prog(&progs->msg_parser, NULL); psock_set_prog(&progs->stream_parser, NULL); psock_set_prog(&progs->stream_verdict, NULL); + psock_set_prog(&progs->skb_verdict, NULL); } int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 598716742593..49371eba98ba 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -957,6 +957,7 @@ enum bpf_attach_type { BPF_XDP_CPUMAP, BPF_SK_LOOKUP, BPF_XDP, + BPF_SK_SKB_VERDICT, __MAX_BPF_ATTACH_TYPE }; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 9603de81811a..6428634da57e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2948,6 +2948,7 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type) return BPF_PROG_TYPE_SK_MSG; case BPF_SK_SKB_STREAM_PARSER: case BPF_SK_SKB_STREAM_VERDICT: + case BPF_SK_SKB_VERDICT: return BPF_PROG_TYPE_SK_SKB; case BPF_LIRC_MODE2: return BPF_PROG_TYPE_LIRC_MODE2; diff --git a/net/core/skmsg.c b/net/core/skmsg.c index 656eceab73bc..a045812d7c78 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -697,7 +697,7 @@ void sk_psock_drop(struct sock *sk, struct sk_psock *psock) rcu_assign_sk_user_data(sk, NULL); if (psock->progs.stream_parser) sk_psock_stop_strp(sk, psock); - else if (psock->progs.stream_verdict) + else if (psock->progs.stream_verdict || psock->progs.skb_verdict) sk_psock_stop_verdict(sk, psock); write_unlock_bh(&sk->sk_callback_lock); @@ -1024,6 +1024,8 @@ static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb, } skb_set_owner_r(skb, sk); prog = READ_ONCE(psock->progs.stream_verdict); + if (!prog) + prog = READ_ONCE(psock->progs.skb_verdict); if (likely(prog)) { skb_dst_drop(skb); skb_bpf_redirect_clear(skb); diff --git a/net/core/sock_map.c b/net/core/sock_map.c index 42d797291d34..c2a0411e08a8 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -156,6 +156,8 @@ static void sock_map_del_link(struct sock *sk, strp_stop = true; if (psock->saved_data_ready && stab->progs.stream_verdict) verdict_stop = true; + if (psock->saved_data_ready && stab->progs.skb_verdict) + verdict_stop = true; list_del(&link->list); sk_psock_free_link(link); } @@ -232,6 +234,7 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk) struct sk_psock_progs *progs = sock_map_progs(map); struct bpf_prog *stream_verdict = NULL; struct bpf_prog *stream_parser = NULL; + struct bpf_prog *skb_verdict = NULL; struct bpf_prog *msg_parser = NULL; struct sk_psock *psock; int ret; @@ -268,6 +271,15 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk) } } + skb_verdict = READ_ONCE(progs->skb_verdict); + if (skb_verdict) { + skb_verdict = bpf_prog_inc_not_zero(skb_verdict); + if (IS_ERR(skb_verdict)) { + ret = PTR_ERR(skb_verdict); + goto out_put_msg_parser; + } + } + no_progs: psock = sock_map_psock_get_checked(sk); if (IS_ERR(psock)) { @@ -278,6 +290,9 @@ no_progs: if (psock) { if ((msg_parser && READ_ONCE(psock->progs.msg_parser)) || (stream_parser && READ_ONCE(psock->progs.stream_parser)) || + (skb_verdict && READ_ONCE(psock->progs.skb_verdict)) || + (skb_verdict && READ_ONCE(psock->progs.stream_verdict)) || + (stream_verdict && READ_ONCE(psock->progs.skb_verdict)) || (stream_verdict && READ_ONCE(psock->progs.stream_verdict))) { sk_psock_put(sk, psock); ret = -EBUSY; @@ -309,6 +324,9 @@ no_progs: } else if (!stream_parser && stream_verdict && !psock->saved_data_ready) { psock_set_prog(&psock->progs.stream_verdict, stream_verdict); sk_psock_start_verdict(sk,psock); + } else if (!stream_verdict && skb_verdict && !psock->saved_data_ready) { + psock_set_prog(&psock->progs.skb_verdict, skb_verdict); + sk_psock_start_verdict(sk, psock); } write_unlock_bh(&sk->sk_callback_lock); return 0; @@ -317,6 +335,9 @@ out_unlock_drop: out_drop: sk_psock_put(sk, psock); out_progs: + if (skb_verdict) + bpf_prog_put(skb_verdict); +out_put_msg_parser: if (msg_parser) bpf_prog_put(msg_parser); out_put_stream_parser: @@ -1442,8 +1463,15 @@ static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog, break; #endif case BPF_SK_SKB_STREAM_VERDICT: + if (progs->skb_verdict) + return -EBUSY; pprog = &progs->stream_verdict; break; + case BPF_SK_SKB_VERDICT: + if (progs->stream_verdict) + return -EBUSY; + pprog = &progs->skb_verdict; + break; default: return -EOPNOTSUPP; } diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index 65303664417e..1828bba19020 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -57,6 +57,7 @@ const char * const attach_type_name[__MAX_BPF_ATTACH_TYPE] = { [BPF_SK_SKB_STREAM_PARSER] = "sk_skb_stream_parser", [BPF_SK_SKB_STREAM_VERDICT] = "sk_skb_stream_verdict", + [BPF_SK_SKB_VERDICT] = "sk_skb_verdict", [BPF_SK_MSG_VERDICT] = "sk_msg_verdict", [BPF_LIRC_MODE2] = "lirc_mode2", [BPF_FLOW_DISSECTOR] = "flow_dissector", diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index f2b915b20546..3f067d2d7584 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -76,6 +76,7 @@ enum dump_mode { static const char * const attach_type_strings[] = { [BPF_SK_SKB_STREAM_PARSER] = "stream_parser", [BPF_SK_SKB_STREAM_VERDICT] = "stream_verdict", + [BPF_SK_SKB_VERDICT] = "skb_verdict", [BPF_SK_MSG_VERDICT] = "msg_verdict", [BPF_FLOW_DISSECTOR] = "flow_dissector", [__MAX_BPF_ATTACH_TYPE] = NULL, diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index ab9f2233607c..69902603012c 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -957,6 +957,7 @@ enum bpf_attach_type { BPF_XDP_CPUMAP, BPF_SK_LOOKUP, BPF_XDP, + BPF_SK_SKB_VERDICT, __MAX_BPF_ATTACH_TYPE }; -- cgit v1.2.3