diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/syscall.c | 26 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 21 | ||||
| -rw-r--r-- | kernel/kallsyms.c | 4 | ||||
| -rw-r--r-- | kernel/trace/bpf_trace.c | 342 |
4 files changed, 385 insertions, 8 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 9beb585be5a6..cdaa1152436a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -32,6 +32,7 @@ #include <linux/bpf-netns.h> #include <linux/rcupdate_trace.h> #include <linux/memcontrol.h> +#include <linux/trace_events.h> #define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \ (map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || \ @@ -3022,6 +3023,11 @@ out_put_file: fput(perf_file); return err; } +#else +static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + return -EOPNOTSUPP; +} #endif /* CONFIG_PERF_EVENTS */ #define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd @@ -4255,7 +4261,7 @@ static int tracing_bpf_link_attach(const union bpf_attr *attr, bpfptr_t uattr, return -EINVAL; } -#define BPF_LINK_CREATE_LAST_FIELD link_create.iter_info_len +#define BPF_LINK_CREATE_LAST_FIELD link_create.kprobe_multi.cookies static int link_create(union bpf_attr *attr, bpfptr_t uattr) { enum bpf_prog_type ptype; @@ -4279,7 +4285,6 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) ret = tracing_bpf_link_attach(attr, uattr, prog); goto out; case BPF_PROG_TYPE_PERF_EVENT: - case BPF_PROG_TYPE_KPROBE: case BPF_PROG_TYPE_TRACEPOINT: if (attr->link_create.attach_type != BPF_PERF_EVENT) { ret = -EINVAL; @@ -4287,6 +4292,14 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) } ptype = prog->type; break; + case BPF_PROG_TYPE_KPROBE: + if (attr->link_create.attach_type != BPF_PERF_EVENT && + attr->link_create.attach_type != BPF_TRACE_KPROBE_MULTI) { + ret = -EINVAL; + goto out; + } + ptype = prog->type; + break; default: ptype = attach_type_to_prog_type(attr->link_create.attach_type); if (ptype == BPF_PROG_TYPE_UNSPEC || ptype != prog->type) { @@ -4318,13 +4331,16 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) ret = bpf_xdp_link_attach(attr, prog); break; #endif -#ifdef CONFIG_PERF_EVENTS case BPF_PROG_TYPE_PERF_EVENT: case BPF_PROG_TYPE_TRACEPOINT: - case BPF_PROG_TYPE_KPROBE: ret = bpf_perf_link_attach(attr, prog); break; -#endif + case BPF_PROG_TYPE_KPROBE: + if (attr->link_create.attach_type == BPF_PERF_EVENT) + ret = bpf_perf_link_attach(attr, prog); + else + ret = bpf_kprobe_multi_link_attach(attr, prog); + break; default: ret = -EINVAL; } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index cf92f9c01556..0287176bfe9a 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -13678,7 +13678,7 @@ patch_map_ops_generic: continue; } - /* Implement bpf_get_func_ip inline. */ + /* Implement tracing bpf_get_func_ip inline. */ if (prog_type == BPF_PROG_TYPE_TRACING && insn->imm == BPF_FUNC_get_func_ip) { /* Load IP address from ctx - 16 */ @@ -13693,6 +13693,25 @@ patch_map_ops_generic: continue; } +#ifdef CONFIG_X86 + /* Implement kprobe_multi bpf_get_func_ip inline. */ + if (prog_type == BPF_PROG_TYPE_KPROBE && + eatype == BPF_TRACE_KPROBE_MULTI && + insn->imm == BPF_FUNC_get_func_ip) { + /* Load IP address from ctx (struct pt_regs) ip */ + insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, + offsetof(struct pt_regs, ip)); + + new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1); + if (!new_prog) + return -ENOMEM; + + env->prog = prog = new_prog; + insn = new_prog->insnsi + i + delta; + continue; + } +#endif + patch_call_imm: fn = env->ops->get_func_proto(insn->imm, env->prog); /* all functions that have prototype and verifier allowed diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 951c93216fc4..79f2eb617a62 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -212,6 +212,10 @@ unsigned long kallsyms_lookup_name(const char *name) unsigned long i; unsigned int off; + /* Skip the search for empty string. */ + if (!*name) + return 0; + for (i = 0, off = 0; i < kallsyms_num_syms; i++) { off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index a2024ba32a20..9a7b6be655e4 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -17,6 +17,9 @@ #include <linux/error-injection.h> #include <linux/btf_ids.h> #include <linux/bpf_lsm.h> +#include <linux/fprobe.h> +#include <linux/bsearch.h> +#include <linux/sort.h> #include <net/bpf_sk_storage.h> @@ -77,6 +80,7 @@ u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); static int bpf_btf_printf_prepare(struct btf_ptr *ptr, u32 btf_ptr_size, u64 flags, const struct btf **btf, s32 *btf_id); +static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx, u64 ip); /** * trace_call_bpf - invoke BPF program @@ -1036,6 +1040,31 @@ static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe = { .arg1_type = ARG_PTR_TO_CTX, }; +BPF_CALL_1(bpf_get_func_ip_kprobe_multi, struct pt_regs *, regs) +{ + /* This helper call is inlined by verifier on x86. */ + return instruction_pointer(regs); +} + +static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe_multi = { + .func = bpf_get_func_ip_kprobe_multi, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + +BPF_CALL_1(bpf_get_attach_cookie_kprobe_multi, struct pt_regs *, regs) +{ + return bpf_kprobe_multi_cookie(current->bpf_ctx, instruction_pointer(regs)); +} + +static const struct bpf_func_proto bpf_get_attach_cookie_proto_kmulti = { + .func = bpf_get_attach_cookie_kprobe_multi, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + BPF_CALL_1(bpf_get_attach_cookie_trace, void *, ctx) { struct bpf_trace_run_ctx *run_ctx; @@ -1279,9 +1308,13 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_override_return_proto; #endif case BPF_FUNC_get_func_ip: - return &bpf_get_func_ip_proto_kprobe; + return prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI ? + &bpf_get_func_ip_proto_kprobe_multi : + &bpf_get_func_ip_proto_kprobe; case BPF_FUNC_get_attach_cookie: - return &bpf_get_attach_cookie_proto_trace; + return prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI ? + &bpf_get_attach_cookie_proto_kmulti : + &bpf_get_attach_cookie_proto_trace; default: return bpf_tracing_func_proto(func_id, prog); } @@ -2181,3 +2214,308 @@ static int __init bpf_event_init(void) fs_initcall(bpf_event_init); #endif /* CONFIG_MODULES */ + +#ifdef CONFIG_FPROBE +struct bpf_kprobe_multi_link { + struct bpf_link link; + struct fprobe fp; + unsigned long *addrs; + /* + * The run_ctx here is used to get struct bpf_kprobe_multi_link in + * get_attach_cookie helper, so it can't be used to store data. + */ + struct bpf_run_ctx run_ctx; + u64 *cookies; + u32 cnt; +}; + +static void bpf_kprobe_multi_link_release(struct bpf_link *link) +{ + struct bpf_kprobe_multi_link *kmulti_link; + + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); + unregister_fprobe(&kmulti_link->fp); +} + +static void bpf_kprobe_multi_link_dealloc(struct bpf_link *link) +{ + struct bpf_kprobe_multi_link *kmulti_link; + + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); + kvfree(kmulti_link->addrs); + kvfree(kmulti_link->cookies); + kfree(kmulti_link); +} + +static const struct bpf_link_ops bpf_kprobe_multi_link_lops = { + .release = bpf_kprobe_multi_link_release, + .dealloc = bpf_kprobe_multi_link_dealloc, +}; + +static void bpf_kprobe_multi_cookie_swap(void *a, void *b, int size, const void *priv) +{ + const struct bpf_kprobe_multi_link *link = priv; + unsigned long *addr_a = a, *addr_b = b; + u64 *cookie_a, *cookie_b; + unsigned long tmp1; + u64 tmp2; + + cookie_a = link->cookies + (addr_a - link->addrs); + cookie_b = link->cookies + (addr_b - link->addrs); + + /* swap addr_a/addr_b and cookie_a/cookie_b values */ + tmp1 = *addr_a; *addr_a = *addr_b; *addr_b = tmp1; + tmp2 = *cookie_a; *cookie_a = *cookie_b; *cookie_b = tmp2; +} + +static int __bpf_kprobe_multi_cookie_cmp(const void *a, const void *b) +{ + const unsigned long *addr_a = a, *addr_b = b; + + if (*addr_a == *addr_b) + return 0; + return *addr_a < *addr_b ? -1 : 1; +} + +static int bpf_kprobe_multi_cookie_cmp(const void *a, const void *b, const void *priv) +{ + return __bpf_kprobe_multi_cookie_cmp(a, b); +} + +static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx, u64 ip) +{ + struct bpf_kprobe_multi_link *link; + unsigned long *addr; + u64 *cookie; + + if (WARN_ON_ONCE(!ctx)) + return 0; + link = container_of(ctx, struct bpf_kprobe_multi_link, run_ctx); + if (!link->cookies) + return 0; + addr = bsearch(&ip, link->addrs, link->cnt, sizeof(ip), + __bpf_kprobe_multi_cookie_cmp); + if (!addr) + return 0; + cookie = link->cookies + (addr - link->addrs); + return *cookie; +} + +static int +kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, + struct pt_regs *regs) +{ + struct bpf_run_ctx *old_run_ctx; + int err; + + if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { + err = 0; + goto out; + } + + migrate_disable(); + rcu_read_lock(); + old_run_ctx = bpf_set_run_ctx(&link->run_ctx); + err = bpf_prog_run(link->link.prog, regs); + bpf_reset_run_ctx(old_run_ctx); + rcu_read_unlock(); + migrate_enable(); + + out: + __this_cpu_dec(bpf_prog_active); + return err; +} + +static void +kprobe_multi_link_handler(struct fprobe *fp, unsigned long entry_ip, + struct pt_regs *regs) +{ + unsigned long saved_ip = instruction_pointer(regs); + struct bpf_kprobe_multi_link *link; + + /* + * Because fprobe's regs->ip is set to the next instruction of + * dynamic-ftrace instruction, correct entry ip must be set, so + * that the bpf program can access entry address via regs as same + * as kprobes. + * + * Both kprobe and kretprobe see the entry ip of traced function + * as instruction pointer. + */ + instruction_pointer_set(regs, entry_ip); + + link = container_of(fp, struct bpf_kprobe_multi_link, fp); + kprobe_multi_link_prog_run(link, regs); + + instruction_pointer_set(regs, saved_ip); +} + +static int +kprobe_multi_resolve_syms(const void *usyms, u32 cnt, + unsigned long *addrs) +{ + unsigned long addr, size; + const char **syms; + int err = -ENOMEM; + unsigned int i; + char *func; + + size = cnt * sizeof(*syms); + syms = kvzalloc(size, GFP_KERNEL); + if (!syms) + return -ENOMEM; + + func = kmalloc(KSYM_NAME_LEN, GFP_KERNEL); + if (!func) + goto error; + + if (copy_from_user(syms, usyms, size)) { + err = -EFAULT; + goto error; + } + + for (i = 0; i < cnt; i++) { + err = strncpy_from_user(func, syms[i], KSYM_NAME_LEN); + if (err == KSYM_NAME_LEN) + err = -E2BIG; + if (err < 0) + goto error; + err = -EINVAL; + addr = kallsyms_lookup_name(func); + if (!addr) + goto error; + if (!kallsyms_lookup_size_offset(addr, &size, NULL)) + goto error; + addr = ftrace_location_range(addr, addr + size - 1); + if (!addr) + goto error; + addrs[i] = addr; + } + + err = 0; +error: + kvfree(syms); + kfree(func); + return err; +} + +int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + struct bpf_kprobe_multi_link *link = NULL; + struct bpf_link_primer link_primer; + void __user *ucookies; + unsigned long *addrs; + u32 flags, cnt, size; + void __user *uaddrs; + u64 *cookies = NULL; + void __user *usyms; + int err; + + /* no support for 32bit archs yet */ + if (sizeof(u64) != sizeof(void *)) + return -EOPNOTSUPP; + + if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI) + return -EINVAL; + + flags = attr->link_create.kprobe_multi.flags; + if (flags & ~BPF_F_KPROBE_MULTI_RETURN) + return -EINVAL; + + uaddrs = u64_to_user_ptr(attr->link_create.kprobe_multi.addrs); + usyms = u64_to_user_ptr(attr->link_create.kprobe_multi.syms); + if (!!uaddrs == !!usyms) + return -EINVAL; + + cnt = attr->link_create.kprobe_multi.cnt; + if (!cnt) + return -EINVAL; + + size = cnt * sizeof(*addrs); + addrs = kvmalloc(size, GFP_KERNEL); + if (!addrs) + return -ENOMEM; + + if (uaddrs) { + if (copy_from_user(addrs, uaddrs, size)) { + err = -EFAULT; + goto error; + } + } else { + err = kprobe_multi_resolve_syms(usyms, cnt, addrs); + if (err) + goto error; + } + + ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies); + if (ucookies) { + cookies = kvmalloc(size, GFP_KERNEL); + if (!cookies) { + err = -ENOMEM; + goto error; + } + if (copy_from_user(cookies, ucookies, size)) { + err = -EFAULT; + goto error; + } + } + + link = kzalloc(sizeof(*link), GFP_KERNEL); + if (!link) { + err = -ENOMEM; + goto error; + } + + bpf_link_init(&link->link, BPF_LINK_TYPE_KPROBE_MULTI, + &bpf_kprobe_multi_link_lops, prog); + + err = bpf_link_prime(&link->link, &link_primer); + if (err) + goto error; + + if (flags & BPF_F_KPROBE_MULTI_RETURN) + link->fp.exit_handler = kprobe_multi_link_handler; + else + link->fp.entry_handler = kprobe_multi_link_handler; + + link->addrs = addrs; + link->cookies = cookies; + link->cnt = cnt; + + if (cookies) { + /* + * Sorting addresses will trigger sorting cookies as well + * (check bpf_kprobe_multi_cookie_swap). This way we can + * find cookie based on the address in bpf_get_attach_cookie + * helper. + */ + sort_r(addrs, cnt, sizeof(*addrs), + bpf_kprobe_multi_cookie_cmp, + bpf_kprobe_multi_cookie_swap, + link); + } + + err = register_fprobe_ips(&link->fp, addrs, cnt); + if (err) { + bpf_link_cleanup(&link_primer); + return err; + } + + return bpf_link_settle(&link_primer); + +error: + kfree(link); + kvfree(addrs); + kvfree(cookies); + return err; +} +#else /* !CONFIG_FPROBE */ +int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + return -EOPNOTSUPP; +} +static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx, u64 ip) +{ + return 0; +} +#endif |