diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 5d93fd82e764..9f33e95d5741 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -8749,6 +8749,7 @@ BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = { .func = bpf_btf_find_by_name_kind, .gpl_only = false, + .might_sleep = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY, .arg2_type = ARG_MEM_SIZE, diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index a839041e0d00..d09d4c3fe547 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -875,6 +875,7 @@ BPF_CALL_4(bpf_get_stack_sleepable, struct pt_regs *, regs, void *, buf, u32, si const struct bpf_func_proto bpf_get_stack_sleepable_proto = { .func = bpf_get_stack_sleepable, .gpl_only = true, + .might_sleep = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_PTR_TO_UNINIT_MEM, @@ -928,6 +929,7 @@ BPF_CALL_4(bpf_get_task_stack_sleepable, struct task_struct *, task, void *, buf const struct bpf_func_proto bpf_get_task_stack_sleepable_proto = { .func = bpf_get_task_stack_sleepable, .gpl_only = false, + .might_sleep = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_BTF_ID, .arg1_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 2ed17edf77f2..d7dd0befbd10 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5302,6 +5302,15 @@ static int check_max_stack_depth_subprog(struct bpf_verifier_env *env, int idx, if (!priv_stack_supported) subprog[idx].priv_stack_mode = NO_PRIV_STACK; process_func: + if (subprog[idx].has_ld_abs) { + for (tmp = idx; tmp >= 0; tmp = dinfo[tmp].caller) { + if (subprog[tmp].is_cb) { + verbose(env, "cannot use BPF_LD_[ABS|IND] within callback\n"); + return -EINVAL; + } + } + } + /* protect against potential stack overflow that might happen when * bpf2bpf calls get combined with tailcalls. Limit the caller's stack * depth for such case down to 256 so that the worst case scenario @@ -10235,9 +10244,10 @@ static void account_current_path(struct bpf_verifier_env *env) frame ? state->frame[frame - 1] : NULL); } -/* Are we currently verifying the callback for a rbtree helper that must - * be called with lock held? If so, no need to complain about unreleased - * lock +/* + * Are we currently verifying the callback for an rbtree kfunc that must + * be called with a lock held, or one of that callback's subprogs? If so, + * no need to complain about an unreleased lock. */ static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env) { @@ -10245,17 +10255,19 @@ static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env) struct bpf_insn *insn = env->prog->insnsi; struct bpf_func_state *callee; int kfunc_btf_id; + u32 frame; - if (!state->curframe) - return false; + for (frame = state->curframe; frame; frame--) { + callee = state->frame[frame]; + if (!callee->in_callback_fn) + continue; - callee = state->frame[state->curframe]; + kfunc_btf_id = insn[callee->callsite].imm; + if (is_rbtree_lock_required_kfunc(kfunc_btf_id)) + return true; + } - if (!callee->in_callback_fn) - return false; - - kfunc_btf_id = insn[callee->callsite].imm; - return is_rbtree_lock_required_kfunc(kfunc_btf_id); + return false; } static bool retval_range_within(struct bpf_retval_range range, const struct bpf_reg_state *reg) @@ -17179,6 +17191,7 @@ static bool may_access_skb(enum bpf_prog_type type) */ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) { + struct bpf_verifier_state *state = env->cur_state; struct bpf_reg_state *regs = cur_regs(env); static const int ctx_reg = BPF_REG_6; u8 mode = BPF_MODE(insn->code); @@ -17189,6 +17202,13 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) return -EINVAL; } + for (i = state->curframe; i; i--) { + if (state->frame[i]->in_callback_fn) { + verbose(env, "cannot use BPF_LD_[ABS|IND] within callback\n"); + return -EINVAL; + } + } + if (!env->ops->gen_ld_abs) { verifier_bug(env, "gen_ld_abs is null"); return -EFAULT; diff --git a/tools/testing/selftests/bpf/progs/preempt_lock.c b/tools/testing/selftests/bpf/progs/preempt_lock.c index 6d5fce7e6ffc..81c459435680 100644 --- a/tools/testing/selftests/bpf/progs/preempt_lock.c +++ b/tools/testing/selftests/bpf/progs/preempt_lock.c @@ -115,6 +115,58 @@ int preempt_sleepable_helper(void *ctx) return 0; } +SEC("?uprobe.s") +__failure __msg("sleepable helper bpf_get_stack#") +int preempt_sleepable_get_stack(struct pt_regs *ctx) +{ + struct bpf_stack_build_id stack; + + bpf_preempt_disable(); + bpf_get_stack(ctx, &stack, sizeof(stack), + BPF_F_USER_STACK | BPF_F_USER_BUILD_ID); + bpf_preempt_enable(); + return 0; +} + +SEC("?uprobe.s") +__failure __msg("sleepable helper bpf_get_task_stack#") +int preempt_sleepable_get_task_stack(void *ctx) +{ + struct bpf_stack_build_id stack; + struct task_struct *task; + + task = bpf_get_current_task_btf(); + bpf_preempt_disable(); + bpf_get_task_stack(task, &stack, sizeof(stack), + BPF_F_USER_STACK | BPF_F_USER_BUILD_ID); + bpf_preempt_enable(); + return 0; +} + +SEC("?uprobe.s") +__success +int sleepable_get_stack(struct pt_regs *ctx) +{ + struct bpf_stack_build_id stack; + + bpf_get_stack(ctx, &stack, sizeof(stack), + BPF_F_USER_STACK | BPF_F_USER_BUILD_ID); + return 0; +} + +SEC("?uprobe.s") +__success +int sleepable_get_task_stack(void *ctx) +{ + struct bpf_stack_build_id stack; + struct task_struct *task; + + task = bpf_get_current_task_btf(); + bpf_get_task_stack(task, &stack, sizeof(stack), + BPF_F_USER_STACK | BPF_F_USER_BUILD_ID); + return 0; +} + SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") __failure __msg("kernel func bpf_copy_from_user_str is sleepable within non-preemptible region") int preempt_sleepable_kfunc(void *ctx) diff --git a/tools/testing/selftests/bpf/progs/rbtree_fail.c b/tools/testing/selftests/bpf/progs/rbtree_fail.c index 803419a47c62..4504608196ab 100644 --- a/tools/testing/selftests/bpf/progs/rbtree_fail.c +++ b/tools/testing/selftests/bpf/progs/rbtree_fail.c @@ -272,6 +272,47 @@ static bool less__bad_res_spin_unlock(struct bpf_rb_node *a, const struct bpf_rb return false; } +static __noinline void rbtree_cb_unlock_relock(void) +{ + bpf_spin_unlock(&glock); + bpf_spin_lock(&glock); +} + +static __noinline void rbtree_cb_nested_unlock(void) +{ + rbtree_cb_unlock_relock(); + asm volatile (""); +} + +static bool less__bad_subprog_unlock(struct bpf_rb_node *a, const struct bpf_rb_node *b) +{ + struct node_data *node_a; + struct node_data *node_b; + + node_a = container_of(a, struct node_data, node); + node_b = container_of(b, struct node_data, node); + rbtree_cb_nested_unlock(); + + return node_a->key < node_b->key; +} + +static __noinline void rbtree_cb_noop(void) +{ + asm volatile (""); +} + +static bool less__subprog_allowed(struct bpf_rb_node *a, const struct bpf_rb_node *b) +{ + struct node_data *node_a; + struct node_data *node_b; + + node_a = container_of(a, struct node_data, node); + node_b = container_of(b, struct node_data, node); + rbtree_cb_noop(); + + return node_a->key < node_b->key; +} + static __always_inline long add_with_cb(bool (cb)(struct bpf_rb_node *a, const struct bpf_rb_node *b)) { @@ -330,4 +371,18 @@ long rbtree_api_add_bad_cb_res_spin_unlock(void *ctx) return 0; } +SEC("?tc") +__failure __msg("can't spin_{lock,unlock} in rbtree cb") +long rbtree_api_add_bad_cb_subprog_unlock(void *ctx) +{ + return add_with_cb(less__bad_subprog_unlock); +} + +SEC("?tc") +__success +long rbtree_api_add_cb_subprog_allowed(void *ctx) +{ + return add_with_cb(less__subprog_allowed); +} + char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/verifier_async_cb_context.c b/tools/testing/selftests/bpf/progs/verifier_async_cb_context.c index a7c84d3fa4c7..e0926767bbd3 100644 --- a/tools/testing/selftests/bpf/progs/verifier_async_cb_context.c +++ b/tools/testing/selftests/bpf/progs/verifier_async_cb_context.c @@ -108,6 +108,30 @@ int timer_sys_close_prog(void *ctx) return 0; } +static int timer_btf_find_cb(void *map, int *key, struct bpf_timer *timer) +{ + char name[] = "task_struct"; + + bpf_btf_find_by_name_kind(name, sizeof(name), BTF_KIND_STRUCT, 0); + return 0; +} + +SEC("syscall") +__failure __msg("sleepable helper bpf_btf_find_by_name_kind#{{[0-9]+}} in non-sleepable prog") +int timer_btf_find_prog(void *ctx) +{ + struct timer_elem *val; + int key = 0; + + val = bpf_map_lookup_elem(&timer_map, &key); + if (!val) + return 0; + + bpf_timer_init(&val->t, &timer_map, 0); + bpf_timer_set_callback(&val->t, timer_btf_find_cb); + return 0; +} + SEC("syscall") __success int syscall_sys_bpf_prog(void *ctx) @@ -126,6 +150,16 @@ int syscall_sys_close_prog(void *ctx) return 0; } +SEC("syscall") +__success +int syscall_btf_find_prog(void *ctx) +{ + char name[] = "task_struct"; + + bpf_btf_find_by_name_kind(name, sizeof(name), BTF_KIND_STRUCT, 0); + return 0; +} + /* Workqueue tests */ struct wq_elem { diff --git a/tools/testing/selftests/bpf/progs/verifier_ld_ind.c b/tools/testing/selftests/bpf/progs/verifier_ld_ind.c index 09e81b99eecb..32989f981fb6 100644 --- a/tools/testing/selftests/bpf/progs/verifier_ld_ind.c +++ b/tools/testing/selftests/bpf/progs/verifier_ld_ind.c @@ -194,6 +194,102 @@ __naked void ld_ind_subprog_both_paths_safe(void) ::: __clobber_all); } +__naked __noinline __used +static int ld_abs_callback(void) +{ + asm volatile ( + "r6 = *(u64 *)(r2 + 0);" + ".8byte %[ld_abs];" + "r0 = 0;" + "exit;" + : + : __imm_insn(ld_abs, BPF_LD_ABS(BPF_W, 0)) + : __clobber_all); +} + +SEC("socket") +__description("ld_abs: reject in callback") +__failure __msg("cannot use BPF_LD_[ABS|IND] within callback") +int ld_abs_callback_reject(struct __sk_buff *skb) +{ + bpf_loop(1, ld_abs_callback, &skb, 0); + return 0; +} + +__naked __noinline __used +static int ld_ind_callback_subprog(void) +{ + asm volatile ( + "r6 = r1;" + "r7 = 0;" + ".8byte %[ld_ind];" + "r0 = 0;" + "exit;" + : + : __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_7, 0)) + : __clobber_all); +} + +__naked __noinline __used +static int ld_ind_callback(void) +{ + asm volatile ( + "r1 = *(u64 *)(r2 + 0);" + "call ld_ind_callback_subprog;" + "exit;" + ::: __clobber_all); +} + +SEC("socket") +__description("ld_ind: reject in callback subprog") +__failure __msg("cannot use BPF_LD_[ABS|IND] within callback") +int ld_ind_callback_subprog_reject(struct __sk_buff *skb) +{ + bpf_loop(1, ld_ind_callback, &skb, 0); + return 0; +} + +static __noinline int ld_ind_global_static(struct __sk_buff *skb) +{ + asm volatile ( + "r6 = %[skb];" + "r7 = 0;" + ".8byte %[ld_ind];" + : + : [skb] "r"(skb), + __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_7, 0)) + : __clobber_common, "r6", "r7"); + return skb->mark; +} + +__noinline int ld_ind_global(struct __sk_buff *skb) +{ + return ld_ind_global_static(skb); +} + +static int ld_ind_global_callback(__u32 index, struct __sk_buff **ctx) +{ + ld_ind_global(*ctx); + return 0; +} + +SEC("socket") +__description("ld_ind: reject in callback global subprog") +__failure __msg("cannot use BPF_LD_[ABS|IND] within callback") +int ld_ind_global_callback_reject(struct __sk_buff *skb) +{ + bpf_loop(1, ld_ind_global_callback, &skb, 0); + return 0; +} + +SEC("socket") +__description("ld_ind: allow in non-callback global subprog") +__success +int ld_ind_global_subprog_ok(struct __sk_buff *skb) +{ + return ld_ind_global(skb); +} + /* * ld_{abs,ind} in subprogs require scalar (int) return type in BTF. * A test with void return must be rejected.