From patchwork Mon Apr 12 15:37:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florent Revest X-Patchwork-Id: 12198391 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB738C43461 for ; Mon, 12 Apr 2021 15:38:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 81BD361381 for ; Mon, 12 Apr 2021 15:38:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243078AbhDLPi2 (ORCPT ); Mon, 12 Apr 2021 11:38:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243133AbhDLPiW (ORCPT ); Mon, 12 Apr 2021 11:38:22 -0400 Received: from mail-wr1-x434.google.com (mail-wr1-x434.google.com [IPv6:2a00:1450:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D602DC06138D for ; Mon, 12 Apr 2021 08:38:02 -0700 (PDT) Received: by mail-wr1-x434.google.com with SMTP id x7so13394080wrw.10 for ; Mon, 12 Apr 2021 08:38:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=CuzQ/6A2N5ZM/MLeCczyCzdZJ2gUp3DLKaA8Zo0z3tA=; b=hcBxdGm8hyc/c1oVz2NkKIF8nVsBm1kIQYzGpprm+NGk9W0Ir67ZpiNG8y/8RqHQrS ST7++vY/dndbq666+yIFBm8O/K84ZzrOmKA+3BY+RqDDoBpNsK0FP34nzFgohSUT40za SM/mdcygfICMxSNYrU/mVzZoqtvMFbdtjZ0Qo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=CuzQ/6A2N5ZM/MLeCczyCzdZJ2gUp3DLKaA8Zo0z3tA=; b=Fw0cZAqtDTG3DJGYQU+3CwajPf+eM8RRb9MRcY1G1Hqc+cGsUQyo/XbDulZf6QcjG9 61Cb4h3RvhM6bhPR6hlpPRSmMg08RmGJcx3Yy+YqisnAWpt2o5ZcCnl4h9AuA5SwYGM3 ai90PtOctgcheAqDso9kopxzhimUj4iNHF+jBPCUk1DIgQBdrMxRvM2eQPFoqtSDDM5x UxfDaX1MkIOdbJnScCLtGJRgMf3qcKsUGEF1UByAJTVHJFV37kki/hiBb8SJr1lztg1v WN+UeuslkOwkrWYXMPjuRPMGhnRaFLldeauy2Aswh4Z5ihsV3cg5mV3x0lbAdgSSoXYu cXZw== X-Gm-Message-State: AOAM5328+gUFtDePTs5Q6bBwkmobvpNBTpU8Gb2GCEH0uKDP68Hyrk3r Jlqu5UD7BrgT2eUiBNaIXI/W8jCGHdQp5A== X-Google-Smtp-Source: ABdhPJyTOUz9/7GEZxMSMI/Djq62oxjg3nFP32lEwvKPgiQSNam5oyaaOPxlKb5j5cdUW5V9XvW2Fg== X-Received: by 2002:adf:e647:: with SMTP id b7mr22413216wrn.43.1618241881068; Mon, 12 Apr 2021 08:38:01 -0700 (PDT) Received: from revest.zrh.corp.google.com ([2a00:79e0:42:204:a372:3c3b:eeb:ad14]) by smtp.gmail.com with ESMTPSA id i4sm2501449wrx.56.2021.04.12.08.38.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Apr 2021 08:38:00 -0700 (PDT) From: Florent Revest To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, yhs@fb.com, kpsingh@kernel.org, jackmanb@chromium.org, linux-kernel@vger.kernel.org, Florent Revest Subject: [PATCH bpf-next v3 1/6] bpf: Factorize bpf_trace_printk and bpf_seq_printf Date: Mon, 12 Apr 2021 17:37:49 +0200 Message-Id: <20210412153754.235500-2-revest@chromium.org> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog In-Reply-To: <20210412153754.235500-1-revest@chromium.org> References: <20210412153754.235500-1-revest@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Two helpers (trace_printk and seq_printf) have very similar implementations of format string parsing and a third one is coming (snprintf). To avoid code duplication and make the code easier to maintain, this moves the operations associated with format string parsing (validation and argument sanitization) into one generic function. The implementation of the two existing helpers already drifted quite a bit so unifying them entailed a lot of changes: - bpf_trace_printk always expected fmt[fmt_size] to be the terminating NULL character, this is no longer true, the first 0 is terminating. - bpf_trace_printk now supports %% (which produces the percentage char). - bpf_trace_printk now skips width formating fields. - bpf_trace_printk now supports the X modifier (capital hexadecimal). - bpf_trace_printk now supports %pK, %px, %pB, %pi4, %pI4, %pi6 and %pI6 - argument casting on 32 bit has been simplified into one macro and using an enum instead of obscure int increments. - bpf_seq_printf now uses bpf_trace_copy_string instead of strncpy_from_kernel_nofault and handles the %pks %pus specifiers. - bpf_seq_printf now prints longs correctly on 32 bit architectures. - both were changed to use a global per-cpu tmp buffer instead of one stack buffer for trace_printk and 6 small buffers for seq_printf. - to avoid per-cpu buffer usage conflict, these helpers disable preemption while the per-cpu buffer is in use. - both helpers now support the %ps and %pS specifiers to print symbols. Signed-off-by: Florent Revest --- kernel/trace/bpf_trace.c | 529 ++++++++++++++++++--------------------- 1 file changed, 248 insertions(+), 281 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 0d23755c2747..3ce9aeee6681 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -372,7 +372,7 @@ static const struct bpf_func_proto *bpf_get_probe_write_proto(void) return &bpf_probe_write_user_proto; } -static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype, +static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype, size_t bufsz) { void __user *user_ptr = (__force void __user *)unsafe_ptr; @@ -382,178 +382,292 @@ static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype, switch (fmt_ptype) { case 's': #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE - if ((unsigned long)unsafe_ptr < TASK_SIZE) { - strncpy_from_user_nofault(buf, user_ptr, bufsz); - break; - } + if ((unsigned long)unsafe_ptr < TASK_SIZE) + return strncpy_from_user_nofault(buf, user_ptr, bufsz); fallthrough; #endif case 'k': - strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz); - break; + return strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz); case 'u': - strncpy_from_user_nofault(buf, user_ptr, bufsz); - break; + return strncpy_from_user_nofault(buf, user_ptr, bufsz); } + + return -EINVAL; } static DEFINE_RAW_SPINLOCK(trace_printk_lock); -#define BPF_TRACE_PRINTK_SIZE 1024 +enum bpf_printf_mod_type { + BPF_PRINTF_INT, + BPF_PRINTF_LONG, + BPF_PRINTF_LONG_LONG, +}; + +/* Workaround for getting va_list handling working with different argument type + * combinations generically for 32 and 64 bit archs. + */ +#define BPF_CAST_FMT_ARG(arg_nb, args, mod) \ + (mod[arg_nb] == BPF_PRINTF_LONG_LONG || \ + (mod[arg_nb] == BPF_PRINTF_LONG && __BITS_PER_LONG == 64) \ + ? (u64)args[arg_nb] \ + : (u32)args[arg_nb]) -static __printf(1, 0) int bpf_do_trace_printk(const char *fmt, ...) +/* Per-cpu temp buffers which can be used by printf-like helpers for %s or %p + */ +#define MAX_PRINTF_BUF_LEN 512 + +struct bpf_printf_buf { + char tmp_buf[MAX_PRINTF_BUF_LEN]; +}; +static DEFINE_PER_CPU(struct bpf_printf_buf, bpf_printf_buf); +static DEFINE_PER_CPU(int, bpf_printf_buf_used); + +static int try_get_fmt_tmp_buf(char **tmp_buf) { - static char buf[BPF_TRACE_PRINTK_SIZE]; - unsigned long flags; - va_list ap; - int ret; + struct bpf_printf_buf *bufs = this_cpu_ptr(&bpf_printf_buf); + int used; - raw_spin_lock_irqsave(&trace_printk_lock, flags); - va_start(ap, fmt); - ret = vsnprintf(buf, sizeof(buf), fmt, ap); - va_end(ap); - /* vsnprintf() will not append null for zero-length strings */ - if (ret == 0) - buf[0] = '\0'; - trace_bpf_trace_printk(buf); - raw_spin_unlock_irqrestore(&trace_printk_lock, flags); + if (*tmp_buf) + return 0; - return ret; + preempt_disable(); + used = this_cpu_inc_return(bpf_printf_buf_used); + if (WARN_ON_ONCE(used > 1)) { + this_cpu_dec(bpf_printf_buf_used); + return -EBUSY; + } + *tmp_buf = bufs->tmp_buf; + + return 0; +} + +static void put_fmt_tmp_buf(void) +{ + if (this_cpu_read(bpf_printf_buf_used)) { + this_cpu_dec(bpf_printf_buf_used); + preempt_enable(); + } } /* - * Only limited trace_printk() conversion specifiers allowed: - * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pB %pks %pus %s + * bpf_parse_fmt_str - Generic pass on format strings for printf-like helpers + * + * Returns a negative value if fmt is an invalid format string or 0 otherwise. + * + * This can be used in two ways: + * - Format string verification only: when final_args and mod are NULL + * - Arguments preparation: in addition to the above verification, it writes in + * final_args a copy of raw_args where pointers from BPF have been sanitized + * into pointers safe to use by snprintf. This also writes in the mod array + * the size requirement of each argument, usable by BPF_CAST_FMT_ARG for ex. + * + * In argument preparation mode, if 0 is returned, safe temporary buffers are + * allocated and put_fmt_tmp_buf should be called to free them after use. */ -BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, - u64, arg2, u64, arg3) -{ - int i, mod[3] = {}, fmt_cnt = 0; - char buf[64], fmt_ptype; - void *unsafe_ptr = NULL; - bool str_seen = false; +int bpf_printf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args, + u64 *final_args, enum bpf_printf_mod_type *mod, + u32 num_args) +{ + int err, i, curr_specifier = 0, copy_size; + char *unsafe_ptr = NULL, *tmp_buf = NULL; + size_t tmp_buf_len = MAX_PRINTF_BUF_LEN; + enum bpf_printf_mod_type current_mod; + u64 current_arg; + char fmt_ptype; + + if ((final_args && !mod) || (mod && !final_args)) + return -EINVAL; - /* - * bpf_check()->check_func_arg()->check_stack_boundary() - * guarantees that fmt points to bpf program stack, - * fmt_size bytes of it were initialized and fmt_size > 0 - */ - if (fmt[--fmt_size] != 0) + fmt_size = (strnchr(fmt, fmt_size, 0) - fmt); + if (!fmt_size) return -EINVAL; - /* check format string for allowed specifiers */ for (i = 0; i < fmt_size; i++) { - if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) - return -EINVAL; + if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) { + err = -EINVAL; + goto out; + } if (fmt[i] != '%') continue; - if (fmt_cnt >= 3) - return -EINVAL; + if (fmt[i + 1] == '%') { + i++; + continue; + } + + if (curr_specifier >= num_args) { + err = -EINVAL; + goto out; + } /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */ i++; - if (fmt[i] == 'l') { - mod[fmt_cnt]++; + + /* skip optional "[0 +-][num]" width formatting field */ + while (fmt[i] == '0' || fmt[i] == '+' || fmt[i] == '-' || + fmt[i] == ' ') i++; - } else if (fmt[i] == 'p') { - mod[fmt_cnt]++; - if ((fmt[i + 1] == 'k' || - fmt[i + 1] == 'u') && + if (fmt[i] >= '1' && fmt[i] <= '9') { + i++; + while (fmt[i] >= '0' && fmt[i] <= '9') + i++; + } + + if (fmt[i] == 'p') { + current_mod = BPF_PRINTF_LONG; + + if ((fmt[i + 1] == 'k' || fmt[i + 1] == 'u') && fmt[i + 2] == 's') { fmt_ptype = fmt[i + 1]; i += 2; goto fmt_str; } - if (fmt[i + 1] == 'B') { - i++; + if (fmt[i + 1] == 0 || isspace(fmt[i + 1]) || + ispunct(fmt[i + 1]) || fmt[i + 1] == 'K' || + fmt[i + 1] == 'x' || fmt[i + 1] == 'B' || + fmt[i + 1] == 's' || fmt[i + 1] == 'S') { + /* just kernel pointers */ + if (final_args) + current_arg = raw_args[curr_specifier]; goto fmt_next; } - /* disallow any further format extensions */ - if (fmt[i + 1] != 0 && - !isspace(fmt[i + 1]) && - !ispunct(fmt[i + 1])) - return -EINVAL; + /* only support "%pI4", "%pi4", "%pI6" and "%pi6". */ + if ((fmt[i + 1] != 'i' && fmt[i + 1] != 'I') || + (fmt[i + 2] != '4' && fmt[i + 2] != '6')) { + err = -EINVAL; + goto out; + } + + i += 2; + if (!final_args) + goto fmt_next; + + if (try_get_fmt_tmp_buf(&tmp_buf)) { + err = -EBUSY; + goto out; + } + + copy_size = (fmt[i + 2] == '4') ? 4 : 16; + if (tmp_buf_len < copy_size) { + err = -ENOSPC; + goto out; + } + + unsafe_ptr = (char *)(long)raw_args[curr_specifier]; + err = copy_from_kernel_nofault(tmp_buf, unsafe_ptr, + copy_size); + if (err < 0) + memset(tmp_buf, 0, copy_size); + current_arg = (u64)(long)tmp_buf; + tmp_buf += copy_size; + tmp_buf_len -= copy_size; goto fmt_next; } else if (fmt[i] == 's') { - mod[fmt_cnt]++; + current_mod = BPF_PRINTF_LONG; fmt_ptype = fmt[i]; fmt_str: - if (str_seen) - /* allow only one '%s' per fmt string */ - return -EINVAL; - str_seen = true; - if (fmt[i + 1] != 0 && !isspace(fmt[i + 1]) && - !ispunct(fmt[i + 1])) - return -EINVAL; + !ispunct(fmt[i + 1])) { + err = -EINVAL; + goto out; + } - switch (fmt_cnt) { - case 0: - unsafe_ptr = (void *)(long)arg1; - arg1 = (long)buf; - break; - case 1: - unsafe_ptr = (void *)(long)arg2; - arg2 = (long)buf; - break; - case 2: - unsafe_ptr = (void *)(long)arg3; - arg3 = (long)buf; - break; + if (!final_args) + goto fmt_next; + + if (try_get_fmt_tmp_buf(&tmp_buf)) { + err = -EBUSY; + goto out; + } + + if (!tmp_buf_len) { + err = -ENOSPC; + goto out; } - bpf_trace_copy_string(buf, unsafe_ptr, fmt_ptype, - sizeof(buf)); + unsafe_ptr = (char *)(long)raw_args[curr_specifier]; + err = bpf_trace_copy_string(tmp_buf, unsafe_ptr, + fmt_ptype, tmp_buf_len); + if (err < 0) { + tmp_buf[0] = '\0'; + err = 1; + } + + current_arg = (u64)(long)tmp_buf; + tmp_buf += err; + tmp_buf_len -= err; + goto fmt_next; } + current_mod = BPF_PRINTF_INT; + + if (fmt[i] == 'l') { + current_mod = BPF_PRINTF_LONG; + i++; + } if (fmt[i] == 'l') { - mod[fmt_cnt]++; + current_mod = BPF_PRINTF_LONG_LONG; i++; } - if (fmt[i] != 'i' && fmt[i] != 'd' && - fmt[i] != 'u' && fmt[i] != 'x') - return -EINVAL; + if (fmt[i] != 'i' && fmt[i] != 'd' && fmt[i] != 'u' && + fmt[i] != 'x' && fmt[i] != 'X') { + err = -EINVAL; + goto out; + } + + if (final_args) + current_arg = raw_args[curr_specifier]; fmt_next: - fmt_cnt++; + if (final_args) { + mod[curr_specifier] = current_mod; + final_args[curr_specifier] = current_arg; + } + curr_specifier++; } -/* Horrid workaround for getting va_list handling working with different - * argument type combinations generically for 32 and 64 bit archs. - */ -#define __BPF_TP_EMIT() __BPF_ARG3_TP() -#define __BPF_TP(...) \ - bpf_do_trace_printk(fmt, ##__VA_ARGS__) - -#define __BPF_ARG1_TP(...) \ - ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ - ? __BPF_TP(arg1, ##__VA_ARGS__) \ - : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32)) \ - ? __BPF_TP((long)arg1, ##__VA_ARGS__) \ - : __BPF_TP((u32)arg1, ##__VA_ARGS__))) - -#define __BPF_ARG2_TP(...) \ - ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64)) \ - ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__) \ - : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32)) \ - ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__) \ - : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__))) - -#define __BPF_ARG3_TP(...) \ - ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64)) \ - ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__) \ - : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32)) \ - ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__) \ - : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__))) - - return __BPF_TP_EMIT(); + err = 0; +out: + put_fmt_tmp_buf(); + return err; +} + +#define MAX_TRACE_PRINTK_VARARGS 3 +#define BPF_TRACE_PRINTK_SIZE 1024 + +BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, + u64, arg2, u64, arg3) +{ + u64 args[MAX_TRACE_PRINTK_VARARGS] = { arg1, arg2, arg3 }; + enum bpf_printf_mod_type mod[MAX_TRACE_PRINTK_VARARGS]; + static char buf[BPF_TRACE_PRINTK_SIZE]; + unsigned long flags; + int ret; + + ret = bpf_printf_prepare(fmt, fmt_size, args, args, mod, + MAX_TRACE_PRINTK_VARARGS); + if (ret < 0) + return ret; + + ret = snprintf(buf, sizeof(buf), fmt, BPF_CAST_FMT_ARG(0, args, mod), + BPF_CAST_FMT_ARG(1, args, mod), BPF_CAST_FMT_ARG(2, args, mod)); + /* snprintf() will not append null for zero-length strings */ + if (ret == 0) + buf[0] = '\0'; + + raw_spin_lock_irqsave(&trace_printk_lock, flags); + trace_bpf_trace_printk(buf); + raw_spin_unlock_irqrestore(&trace_printk_lock, flags); + + put_fmt_tmp_buf(); + + return ret; } static const struct bpf_func_proto bpf_trace_printk_proto = { @@ -581,184 +695,37 @@ const struct bpf_func_proto *bpf_get_trace_printk_proto(void) } #define MAX_SEQ_PRINTF_VARARGS 12 -#define MAX_SEQ_PRINTF_MAX_MEMCPY 6 -#define MAX_SEQ_PRINTF_STR_LEN 128 - -struct bpf_seq_printf_buf { - char buf[MAX_SEQ_PRINTF_MAX_MEMCPY][MAX_SEQ_PRINTF_STR_LEN]; -}; -static DEFINE_PER_CPU(struct bpf_seq_printf_buf, bpf_seq_printf_buf); -static DEFINE_PER_CPU(int, bpf_seq_printf_buf_used); BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size, const void *, data, u32, data_len) { - int err = -EINVAL, fmt_cnt = 0, memcpy_cnt = 0; - int i, buf_used, copy_size, num_args; - u64 params[MAX_SEQ_PRINTF_VARARGS]; - struct bpf_seq_printf_buf *bufs; - const u64 *args = data; - - buf_used = this_cpu_inc_return(bpf_seq_printf_buf_used); - if (WARN_ON_ONCE(buf_used > 1)) { - err = -EBUSY; - goto out; - } - - bufs = this_cpu_ptr(&bpf_seq_printf_buf); - - /* - * bpf_check()->check_func_arg()->check_stack_boundary() - * guarantees that fmt points to bpf program stack, - * fmt_size bytes of it were initialized and fmt_size > 0 - */ - if (fmt[--fmt_size] != 0) - goto out; - - if (data_len & 7) - goto out; - - for (i = 0; i < fmt_size; i++) { - if (fmt[i] == '%') { - if (fmt[i + 1] == '%') - i++; - else if (!data || !data_len) - goto out; - } - } + enum bpf_printf_mod_type mod[MAX_SEQ_PRINTF_VARARGS]; + u64 args[MAX_SEQ_PRINTF_VARARGS]; + int err, num_args; + if (data_len & 7 || data_len > MAX_SEQ_PRINTF_VARARGS * 8 || + (data_len && !data)) + return -EINVAL; num_args = data_len / 8; - /* check format string for allowed specifiers */ - for (i = 0; i < fmt_size; i++) { - /* only printable ascii for now. */ - if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) { - err = -EINVAL; - goto out; - } - - if (fmt[i] != '%') - continue; - - if (fmt[i + 1] == '%') { - i++; - continue; - } - - if (fmt_cnt >= MAX_SEQ_PRINTF_VARARGS) { - err = -E2BIG; - goto out; - } - - if (fmt_cnt >= num_args) { - err = -EINVAL; - goto out; - } - - /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */ - i++; - - /* skip optional "[0 +-][num]" width formating field */ - while (fmt[i] == '0' || fmt[i] == '+' || fmt[i] == '-' || - fmt[i] == ' ') - i++; - if (fmt[i] >= '1' && fmt[i] <= '9') { - i++; - while (fmt[i] >= '0' && fmt[i] <= '9') - i++; - } - - if (fmt[i] == 's') { - void *unsafe_ptr; - - /* try our best to copy */ - if (memcpy_cnt >= MAX_SEQ_PRINTF_MAX_MEMCPY) { - err = -E2BIG; - goto out; - } - - unsafe_ptr = (void *)(long)args[fmt_cnt]; - err = strncpy_from_kernel_nofault(bufs->buf[memcpy_cnt], - unsafe_ptr, MAX_SEQ_PRINTF_STR_LEN); - if (err < 0) - bufs->buf[memcpy_cnt][0] = '\0'; - params[fmt_cnt] = (u64)(long)bufs->buf[memcpy_cnt]; - - fmt_cnt++; - memcpy_cnt++; - continue; - } - - if (fmt[i] == 'p') { - if (fmt[i + 1] == 0 || - fmt[i + 1] == 'K' || - fmt[i + 1] == 'x' || - fmt[i + 1] == 'B') { - /* just kernel pointers */ - params[fmt_cnt] = args[fmt_cnt]; - fmt_cnt++; - continue; - } - - /* only support "%pI4", "%pi4", "%pI6" and "%pi6". */ - if (fmt[i + 1] != 'i' && fmt[i + 1] != 'I') { - err = -EINVAL; - goto out; - } - if (fmt[i + 2] != '4' && fmt[i + 2] != '6') { - err = -EINVAL; - goto out; - } - - if (memcpy_cnt >= MAX_SEQ_PRINTF_MAX_MEMCPY) { - err = -E2BIG; - goto out; - } - - - copy_size = (fmt[i + 2] == '4') ? 4 : 16; - - err = copy_from_kernel_nofault(bufs->buf[memcpy_cnt], - (void *) (long) args[fmt_cnt], - copy_size); - if (err < 0) - memset(bufs->buf[memcpy_cnt], 0, copy_size); - params[fmt_cnt] = (u64)(long)bufs->buf[memcpy_cnt]; - - i += 2; - fmt_cnt++; - memcpy_cnt++; - continue; - } - - if (fmt[i] == 'l') { - i++; - if (fmt[i] == 'l') - i++; - } - - if (fmt[i] != 'i' && fmt[i] != 'd' && - fmt[i] != 'u' && fmt[i] != 'x' && - fmt[i] != 'X') { - err = -EINVAL; - goto out; - } - - params[fmt_cnt] = args[fmt_cnt]; - fmt_cnt++; - } + err = bpf_printf_prepare(fmt, fmt_size, data, args, mod, num_args); + if (err < 0) + return err; /* Maximumly we can have MAX_SEQ_PRINTF_VARARGS parameter, just give * all of them to seq_printf(). */ - seq_printf(m, fmt, params[0], params[1], params[2], params[3], - params[4], params[5], params[6], params[7], params[8], - params[9], params[10], params[11]); + seq_printf(m, fmt, BPF_CAST_FMT_ARG(0, args, mod), + BPF_CAST_FMT_ARG(1, args, mod), BPF_CAST_FMT_ARG(2, args, mod), + BPF_CAST_FMT_ARG(3, args, mod), BPF_CAST_FMT_ARG(4, args, mod), + BPF_CAST_FMT_ARG(5, args, mod), BPF_CAST_FMT_ARG(6, args, mod), + BPF_CAST_FMT_ARG(7, args, mod), BPF_CAST_FMT_ARG(8, args, mod), + BPF_CAST_FMT_ARG(9, args, mod), BPF_CAST_FMT_ARG(10, args, mod), + BPF_CAST_FMT_ARG(11, args, mod)); - err = seq_has_overflowed(m) ? -EOVERFLOW : 0; -out: - this_cpu_dec(bpf_seq_printf_buf_used); - return err; + put_fmt_tmp_buf(); + + return seq_has_overflowed(m) ? -EOVERFLOW : 0; } BTF_ID_LIST_SINGLE(btf_seq_file_ids, struct, seq_file) From patchwork Mon Apr 12 15:37:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florent Revest X-Patchwork-Id: 12198387 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADD8BC433B4 for ; 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Mon, 12 Apr 2021 08:38:01 -0700 (PDT) Received: from revest.zrh.corp.google.com ([2a00:79e0:42:204:a372:3c3b:eeb:ad14]) by smtp.gmail.com with ESMTPSA id i4sm2501449wrx.56.2021.04.12.08.38.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Apr 2021 08:38:01 -0700 (PDT) From: Florent Revest To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, yhs@fb.com, kpsingh@kernel.org, jackmanb@chromium.org, linux-kernel@vger.kernel.org, Florent Revest Subject: [PATCH bpf-next v3 2/6] bpf: Add a ARG_PTR_TO_CONST_STR argument type Date: Mon, 12 Apr 2021 17:37:50 +0200 Message-Id: <20210412153754.235500-3-revest@chromium.org> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog In-Reply-To: <20210412153754.235500-1-revest@chromium.org> References: <20210412153754.235500-1-revest@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This type provides the guarantee that an argument is going to be a const pointer to somewhere in a read-only map value. It also checks that this pointer is followed by a zero character before the end of the map value. Signed-off-by: Florent Revest Acked-by: Andrii Nakryiko --- include/linux/bpf.h | 1 + kernel/bpf/verifier.c | 41 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index ff8cd68c01b3..7d389eeee0b3 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -309,6 +309,7 @@ enum bpf_arg_type { ARG_PTR_TO_PERCPU_BTF_ID, /* pointer to in-kernel percpu type */ ARG_PTR_TO_FUNC, /* pointer to a bpf program function */ ARG_PTR_TO_STACK_OR_NULL, /* pointer to stack or NULL */ + ARG_PTR_TO_CONST_STR, /* pointer to a null terminated read-only string */ __BPF_ARG_TYPE_MAX, }; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 852541a435ef..5f46dd6f3383 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4787,6 +4787,7 @@ static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALU static const struct bpf_reg_types percpu_btf_ptr_types = { .types = { PTR_TO_PERCPU_BTF_ID } }; static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } }; static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } }; +static const struct bpf_reg_types const_str_ptr_types = { .types = { PTR_TO_MAP_VALUE } }; static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = { [ARG_PTR_TO_MAP_KEY] = &map_key_value_types, @@ -4817,6 +4818,7 @@ static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = { [ARG_PTR_TO_PERCPU_BTF_ID] = &percpu_btf_ptr_types, [ARG_PTR_TO_FUNC] = &func_ptr_types, [ARG_PTR_TO_STACK_OR_NULL] = &stack_ptr_types, + [ARG_PTR_TO_CONST_STR] = &const_str_ptr_types, }; static int check_reg_type(struct bpf_verifier_env *env, u32 regno, @@ -5067,6 +5069,45 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, if (err) return err; err = check_ptr_alignment(env, reg, 0, size, true); + } else if (arg_type == ARG_PTR_TO_CONST_STR) { + struct bpf_map *map = reg->map_ptr; + int map_off; + u64 map_addr; + char *str_ptr; + + if (reg->type != PTR_TO_MAP_VALUE || !map || + !bpf_map_is_rdonly(map)) { + verbose(env, "R%d does not point to a readonly map'\n", regno); + return -EACCES; + } + + if (!tnum_is_const(reg->var_off)) { + verbose(env, "R%d is not a constant address'\n", regno); + return -EACCES; + } + + if (!map->ops->map_direct_value_addr) { + verbose(env, "no direct value access support for this map type\n"); + return -EACCES; + } + + err = check_map_access(env, regno, reg->off, + map->value_size - reg->off, false); + if (err) + return err; + + map_off = reg->off + reg->var_off.value; + err = map->ops->map_direct_value_addr(map, &map_addr, map_off); + if (err) { + verbose(env, "direct value access on string failed\n"); + return err; + } + + str_ptr = (char *)(long)(map_addr); + if (!strnchr(str_ptr + map_off, map->value_size - map_off, 0)) { + verbose(env, "string is not zero-terminated\n"); + return -EINVAL; + } } return err; From patchwork Mon Apr 12 15:37:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florent Revest X-Patchwork-Id: 12198389 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32512C433ED for ; Mon, 12 Apr 2021 15:38:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1559E6124C for ; Mon, 12 Apr 2021 15:38:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243155AbhDLPi1 (ORCPT ); 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Mon, 12 Apr 2021 08:38:02 -0700 (PDT) From: Florent Revest To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, yhs@fb.com, kpsingh@kernel.org, jackmanb@chromium.org, linux-kernel@vger.kernel.org, Florent Revest Subject: [PATCH bpf-next v3 3/6] bpf: Add a bpf_snprintf helper Date: Mon, 12 Apr 2021 17:37:51 +0200 Message-Id: <20210412153754.235500-4-revest@chromium.org> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog In-Reply-To: <20210412153754.235500-1-revest@chromium.org> References: <20210412153754.235500-1-revest@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net The implementation takes inspiration from the existing bpf_trace_printk helper but there are a few differences: To allow for a large number of format-specifiers, parameters are provided in an array, like in bpf_seq_printf. Because the output string takes two arguments and the array of parameters also takes two arguments, the format string needs to fit in one argument. Thankfully, ARG_PTR_TO_CONST_STR is guaranteed to point to a zero-terminated read-only map so we don't need a format string length arg. Because the format-string is known at verification time, we also do a first pass of format string validation in the verifier logic. This makes debugging easier. Signed-off-by: Florent Revest Reported-by: kernel test robot Reported-by: kernel test robot Reported-by: kernel test robot --- include/linux/bpf.h | 6 ++++ include/uapi/linux/bpf.h | 28 +++++++++++++++++++ kernel/bpf/helpers.c | 2 ++ kernel/bpf/verifier.c | 41 ++++++++++++++++++++++++++++ kernel/trace/bpf_trace.c | 50 ++++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 28 +++++++++++++++++++ 6 files changed, 155 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 7d389eeee0b3..a3650fc93068 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1953,6 +1953,7 @@ extern const struct bpf_func_proto bpf_skc_to_tcp_request_sock_proto; extern const struct bpf_func_proto bpf_skc_to_udp6_sock_proto; extern const struct bpf_func_proto bpf_copy_from_user_proto; extern const struct bpf_func_proto bpf_snprintf_btf_proto; +extern const struct bpf_func_proto bpf_snprintf_proto; extern const struct bpf_func_proto bpf_per_cpu_ptr_proto; extern const struct bpf_func_proto bpf_this_cpu_ptr_proto; extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto; @@ -2078,4 +2079,9 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, struct btf_id_set; bool btf_id_set_contains(const struct btf_id_set *set, u32 id); +enum bpf_printf_mod_type; +int bpf_printf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args, + u64 *final_args, enum bpf_printf_mod_type *mod, + u32 num_args); + #endif /* _LINUX_BPF_H */ diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 49371eba98ba..40546d4676f1 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -4671,6 +4671,33 @@ union bpf_attr { * Return * The number of traversed map elements for success, **-EINVAL** for * invalid **flags**. + * + * long bpf_snprintf(char *str, u32 str_size, const char *fmt, u64 *data, u32 data_len) + * Description + * Outputs a string into the **str** buffer of size **str_size** + * based on a format string stored in a read-only map pointed by + * **fmt**. + * + * Each format specifier in **fmt** corresponds to one u64 element + * in the **data** array. For strings and pointers where pointees + * are accessed, only the pointer values are stored in the *data* + * array. The *data_len* is the size of *data* in bytes. + * + * Formats **%s** and **%p{i,I}{4,6}** require to read kernel + * memory. Reading kernel memory may fail due to either invalid + * address or valid address but requiring a major memory fault. If + * reading kernel memory fails, the string for **%s** will be an + * empty string, and the ip address for **%p{i,I}{4,6}** will be 0. + * Not returning error to bpf program is consistent with what + * **bpf_trace_printk**\ () does for now. + * + * Return + * The strictly positive length of the formatted string, including + * the trailing zero character. If the return value is greater than + * **str_size**, **str** contains a truncated string, guaranteed to + * be zero-terminated except when **str_size** is 0. + * + * Or **-EBUSY** if the per-CPU memory copy buffer is busy. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -4838,6 +4865,7 @@ union bpf_attr { FN(sock_from_file), \ FN(check_mtu), \ FN(for_each_map_elem), \ + FN(snprintf), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index f306611c4ddf..ec45c7526924 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -757,6 +757,8 @@ bpf_base_func_proto(enum bpf_func_id func_id) return &bpf_probe_read_kernel_str_proto; case BPF_FUNC_snprintf_btf: return &bpf_snprintf_btf_proto; + case BPF_FUNC_snprintf: + return &bpf_snprintf_proto; default: return NULL; } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5f46dd6f3383..d4020e5f91ee 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5918,6 +5918,41 @@ static int check_reference_leak(struct bpf_verifier_env *env) return state->acquired_refs ? -EINVAL : 0; } +static int check_bpf_snprintf_call(struct bpf_verifier_env *env, + struct bpf_reg_state *regs) +{ + struct bpf_reg_state *fmt_reg = ®s[BPF_REG_3]; + struct bpf_reg_state *data_len_reg = ®s[BPF_REG_5]; + struct bpf_map *fmt_map = fmt_reg->map_ptr; + int err, fmt_map_off, num_args; + u64 fmt_addr; + char *fmt; + + /* data must be an array of u64 */ + if (data_len_reg->var_off.value % 8) + return -EINVAL; + num_args = data_len_reg->var_off.value / 8; + + /* fmt being ARG_PTR_TO_CONST_STR guarantees that var_off is const + * and map_direct_value_addr is set. + */ + fmt_map_off = fmt_reg->off + fmt_reg->var_off.value; + err = fmt_map->ops->map_direct_value_addr(fmt_map, &fmt_addr, + fmt_map_off); + if (err) + return err; + fmt = (char *)fmt_addr + fmt_map_off; + + /* We are also guaranteed that fmt+fmt_map_off is NULL terminated, we + * can focus on validating the format specifiers. + */ + err = bpf_printf_prepare(fmt, UINT_MAX, NULL, NULL, NULL, num_args); + if (err < 0) + verbose(env, "Invalid format string\n"); + + return err; +} + static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn, int *insn_idx_p) { @@ -6032,6 +6067,12 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn return -EINVAL; } + if (func_id == BPF_FUNC_snprintf) { + err = check_bpf_snprintf_call(env, regs); + if (err < 0) + return err; + } + /* reset caller saved regs */ for (i = 0; i < CALLER_SAVED_REGS; i++) { mark_reg_not_init(env, regs, caller_saved[i]); diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 3ce9aeee6681..990ed98d2842 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1238,6 +1238,54 @@ const struct bpf_func_proto bpf_snprintf_btf_proto = { .arg5_type = ARG_ANYTHING, }; +#define MAX_SNPRINTF_VARARGS 12 + +BPF_CALL_5(bpf_snprintf, char *, str, u32, str_size, char *, fmt, + const void *, data, u32, data_len) +{ + enum bpf_printf_mod_type mod[MAX_SNPRINTF_VARARGS]; + u64 args[MAX_SNPRINTF_VARARGS]; + int err, num_args; + + if (data_len % 8 || data_len > MAX_SNPRINTF_VARARGS * 8 || + (data_len && !data)) + return -EINVAL; + num_args = data_len / 8; + + /* ARG_PTR_TO_CONST_STR guarantees that fmt is zero-terminated so we + * can safely give an unbounded size. + */ + err = bpf_printf_prepare(fmt, UINT_MAX, data, args, mod, num_args); + if (err < 0) + return err; + + /* Maximumly we can have MAX_SNPRINTF_VARARGS parameters, just give + * all of them to snprintf(). + */ + err = snprintf(str, str_size, fmt, BPF_CAST_FMT_ARG(0, args, mod), + BPF_CAST_FMT_ARG(1, args, mod), BPF_CAST_FMT_ARG(2, args, mod), + BPF_CAST_FMT_ARG(3, args, mod), BPF_CAST_FMT_ARG(4, args, mod), + BPF_CAST_FMT_ARG(5, args, mod), BPF_CAST_FMT_ARG(6, args, mod), + BPF_CAST_FMT_ARG(7, args, mod), BPF_CAST_FMT_ARG(8, args, mod), + BPF_CAST_FMT_ARG(9, args, mod), BPF_CAST_FMT_ARG(10, args, mod), + BPF_CAST_FMT_ARG(11, args, mod)); + + put_fmt_tmp_buf(); + + return err + 1; +} + +const struct bpf_func_proto bpf_snprintf_proto = { + .func = bpf_snprintf, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_MEM_OR_NULL, + .arg2_type = ARG_CONST_SIZE_OR_ZERO, + .arg3_type = ARG_PTR_TO_CONST_STR, + .arg4_type = ARG_PTR_TO_MEM_OR_NULL, + .arg5_type = ARG_CONST_SIZE_OR_ZERO, +}; + const struct bpf_func_proto * bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -1340,6 +1388,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_task_storage_delete_proto; case BPF_FUNC_for_each_map_elem: return &bpf_for_each_map_elem_proto; + case BPF_FUNC_snprintf: + return &bpf_snprintf_proto; default: return NULL; } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 69902603012c..ffdd2ae18c69 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -4665,6 +4665,33 @@ union bpf_attr { * Return * The number of traversed map elements for success, **-EINVAL** for * invalid **flags**. + * + * long bpf_snprintf(char *str, u32 str_size, const char *fmt, u64 *data, u32 data_len) + * Description + * Outputs a string into the **str** buffer of size **str_size** + * based on a format string stored in a read-only map pointed by + * **fmt**. + * + * Each format specifier in **fmt** corresponds to one u64 element + * in the **data** array. For strings and pointers where pointees + * are accessed, only the pointer values are stored in the *data* + * array. The *data_len* is the size of *data* in bytes. + * + * Formats **%s** and **%p{i,I}{4,6}** require to read kernel + * memory. Reading kernel memory may fail due to either invalid + * address or valid address but requiring a major memory fault. If + * reading kernel memory fails, the string for **%s** will be an + * empty string, and the ip address for **%p{i,I}{4,6}** will be 0. + * Not returning error to bpf program is consistent with what + * **bpf_trace_printk**\ () does for now. + * + * Return + * The strictly positive length of the formatted string, including + * the trailing zero character. If the return value is greater than + * **str_size**, **str** contains a truncated string, guaranteed to + * be zero-terminated except when **str_size** is 0. + * + * Or **-EBUSY** if the per-CPU memory copy buffer is busy. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -4832,6 +4859,7 @@ union bpf_attr { FN(sock_from_file), \ FN(check_mtu), \ FN(for_each_map_elem), \ + FN(snprintf), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper From patchwork Mon Apr 12 15:37:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florent Revest X-Patchwork-Id: 12198397 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDED3C43462 for ; Mon, 12 Apr 2021 15:38:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B80446124C for ; Mon, 12 Apr 2021 15:38:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242917AbhDLPid (ORCPT ); Mon, 12 Apr 2021 11:38:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41796 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243123AbhDLPiZ (ORCPT ); Mon, 12 Apr 2021 11:38:25 -0400 Received: from mail-wr1-x434.google.com (mail-wr1-x434.google.com [IPv6:2a00:1450:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D507AC061346 for ; Mon, 12 Apr 2021 08:38:04 -0700 (PDT) Received: by mail-wr1-x434.google.com with SMTP id a6so13426484wrw.8 for ; Mon, 12 Apr 2021 08:38:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=HieyIFDYADVp9hdpXGUE06JI+EqmG9gWTrz44DpsDOA=; b=Y12irK4UC1V+WHktYjO6tKjeJ4qK6i36Es1wCrG6pt8Ixl+LUk2nOnVDdINIkSVq58 X9rN3k1lVCiZPezh5XtCnRatn1ZOoSsbQuTtQygROTFB2qidJK1+tpaF8Sf3x60eVyMQ zRLIW5jYR+PctjzAiMbayXltvAB2SPL+vNv4k= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=HieyIFDYADVp9hdpXGUE06JI+EqmG9gWTrz44DpsDOA=; b=hA6FBe/2FjW868TF4mM7PFj8mpYWEnDb7cAZ6+w4a8NBkGDnFa4SyFYQ1tF3WA4D9E 7G7e8F1mTnYlUKIeYjYmdx50XeHeFB7btw7iYWPVkSlIJ3punaTOX87yalkcOB5s+3wL cXY0uRbSS4i6LOdBFis8An/JfXmv8r8fpfJBrBAKMLteGnPGzO8W2UqJ6mKqZ54UJ0Se 5NRWGthmiPmrmmC2q21ILnRDn+hk7U6rDqSjw/jzOQ55tsqaiwwpQ9H3zEvMwNxumgvi FxUq6GiTbdDYthN0fZOsBu8LCoaeWmgAAWCz8LxH1TrXRkRXoh9Dt9aO2SVSrzVQugvm KZZQ== X-Gm-Message-State: AOAM531bI2sKDZJIfU9HrSBaF805JFM9pyZVqN3Uq7DL1MQyIsC8XUoT yGbDjAB+e/bcsbemEPmwPNAaQbo2Z+aoeA== X-Google-Smtp-Source: ABdhPJw0naPqHzam6FP++PjaREc0bH6auYYcPBnDJ+3ie+6p/R29ECfQVy09Fc/xyH0XjgiJZ7WWog== X-Received: by 2002:a5d:610f:: with SMTP id v15mr32345740wrt.236.1618241883304; Mon, 12 Apr 2021 08:38:03 -0700 (PDT) Received: from revest.zrh.corp.google.com ([2a00:79e0:42:204:a372:3c3b:eeb:ad14]) by smtp.gmail.com with ESMTPSA id i4sm2501449wrx.56.2021.04.12.08.38.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Apr 2021 08:38:02 -0700 (PDT) From: Florent Revest To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, yhs@fb.com, kpsingh@kernel.org, jackmanb@chromium.org, linux-kernel@vger.kernel.org, Florent Revest Subject: [PATCH bpf-next v3 4/6] libbpf: Initialize the bpf_seq_printf parameters array field by field Date: Mon, 12 Apr 2021 17:37:52 +0200 Message-Id: <20210412153754.235500-5-revest@chromium.org> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog In-Reply-To: <20210412153754.235500-1-revest@chromium.org> References: <20210412153754.235500-1-revest@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net When initializing the __param array with a one liner, if all args are const, the initial array value will be placed in the rodata section but because libbpf does not support relocation in the rodata section, any pointer in this array will stay NULL. Fixes: c09add2fbc5a ("tools/libbpf: Add bpf_iter support") Signed-off-by: Florent Revest Acked-by: Andrii Nakryiko --- tools/lib/bpf/bpf_tracing.h | 40 +++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 11 deletions(-) diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h index f9ef37707888..1c2e91ee041d 100644 --- a/tools/lib/bpf/bpf_tracing.h +++ b/tools/lib/bpf/bpf_tracing.h @@ -413,20 +413,38 @@ typeof(name(0)) name(struct pt_regs *ctx) \ } \ static __always_inline typeof(name(0)) ____##name(struct pt_regs *ctx, ##args) +#define ___bpf_fill0(arr, p, x) do {} while (0) +#define ___bpf_fill1(arr, p, x) arr[p] = x +#define ___bpf_fill2(arr, p, x, args...) arr[p] = x; ___bpf_fill1(arr, p + 1, args) +#define ___bpf_fill3(arr, p, x, args...) arr[p] = x; ___bpf_fill2(arr, p + 1, args) +#define ___bpf_fill4(arr, p, x, args...) arr[p] = x; ___bpf_fill3(arr, p + 1, args) +#define ___bpf_fill5(arr, p, x, args...) arr[p] = x; ___bpf_fill4(arr, p + 1, args) +#define ___bpf_fill6(arr, p, x, args...) arr[p] = x; ___bpf_fill5(arr, p + 1, args) +#define ___bpf_fill7(arr, p, x, args...) arr[p] = x; ___bpf_fill6(arr, p + 1, args) +#define ___bpf_fill8(arr, p, x, args...) arr[p] = x; ___bpf_fill7(arr, p + 1, args) +#define ___bpf_fill9(arr, p, x, args...) arr[p] = x; ___bpf_fill8(arr, p + 1, args) +#define ___bpf_fill10(arr, p, x, args...) arr[p] = x; ___bpf_fill9(arr, p + 1, args) +#define ___bpf_fill11(arr, p, x, args...) arr[p] = x; ___bpf_fill10(arr, p + 1, args) +#define ___bpf_fill12(arr, p, x, args...) arr[p] = x; ___bpf_fill11(arr, p + 1, args) +#define ___bpf_fill(arr, args...) \ + ___bpf_apply(___bpf_fill, ___bpf_narg(args))(arr, 0, args) + /* * BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values * in a structure. */ -#define BPF_SEQ_PRINTF(seq, fmt, args...) \ - ({ \ - _Pragma("GCC diagnostic push") \ - _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ - static const char ___fmt[] = fmt; \ - unsigned long long ___param[] = { args }; \ - _Pragma("GCC diagnostic pop") \ - int ___ret = bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \ - ___param, sizeof(___param)); \ - ___ret; \ - }) +#define BPF_SEQ_PRINTF(seq, fmt, args...) \ +({ \ + static const char ___fmt[] = fmt; \ + unsigned long long ___param[___bpf_narg(args)]; \ + \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ + ___bpf_fill(___param, args); \ + _Pragma("GCC diagnostic pop") \ + \ + bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \ + ___param, sizeof(___param)); \ +}) #endif From patchwork Mon Apr 12 15:37:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florent Revest X-Patchwork-Id: 12198393 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A71CBC433B4 for ; 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Mon, 12 Apr 2021 08:38:04 -0700 (PDT) Received: from revest.zrh.corp.google.com ([2a00:79e0:42:204:a372:3c3b:eeb:ad14]) by smtp.gmail.com with ESMTPSA id i4sm2501449wrx.56.2021.04.12.08.38.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Apr 2021 08:38:03 -0700 (PDT) From: Florent Revest To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, yhs@fb.com, kpsingh@kernel.org, jackmanb@chromium.org, linux-kernel@vger.kernel.org, Florent Revest Subject: [PATCH bpf-next v3 5/6] libbpf: Introduce a BPF_SNPRINTF helper macro Date: Mon, 12 Apr 2021 17:37:53 +0200 Message-Id: <20210412153754.235500-6-revest@chromium.org> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog In-Reply-To: <20210412153754.235500-1-revest@chromium.org> References: <20210412153754.235500-1-revest@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Similarly to BPF_SEQ_PRINTF, this macro turns variadic arguments into an array of u64, making it more natural to call the bpf_snprintf helper. Signed-off-by: Florent Revest Acked-by: Andrii Nakryiko --- tools/lib/bpf/bpf_tracing.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h index 1c2e91ee041d..8c954ebc0c7c 100644 --- a/tools/lib/bpf/bpf_tracing.h +++ b/tools/lib/bpf/bpf_tracing.h @@ -447,4 +447,22 @@ static __always_inline typeof(name(0)) ____##name(struct pt_regs *ctx, ##args) ___param, sizeof(___param)); \ }) +/* + * BPF_SNPRINTF wraps the bpf_snprintf helper with variadic arguments instead of + * an array of u64. + */ +#define BPF_SNPRINTF(out, out_size, fmt, args...) \ +({ \ + static const char ___fmt[] = fmt; \ + unsigned long long ___param[___bpf_narg(args)]; \ + \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ + ___bpf_fill(___param, args); \ + _Pragma("GCC diagnostic pop") \ + \ + bpf_snprintf(out, out_size, ___fmt, \ + ___param, sizeof(___param)); \ +}) + #endif From patchwork Mon Apr 12 15:37:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florent Revest X-Patchwork-Id: 12198395 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5CBADC43461 for ; Mon, 12 Apr 2021 15:38:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 37AE26124C for ; Mon, 12 Apr 2021 15:38:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243181AbhDLPic (ORCPT ); Mon, 12 Apr 2021 11:38:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243117AbhDLPiZ (ORCPT ); Mon, 12 Apr 2021 11:38:25 -0400 Received: from mail-wr1-x433.google.com (mail-wr1-x433.google.com [IPv6:2a00:1450:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66AD0C061349 for ; Mon, 12 Apr 2021 08:38:06 -0700 (PDT) Received: by mail-wr1-x433.google.com with SMTP id s7so13298398wru.6 for ; Mon, 12 Apr 2021 08:38:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=LDBRTVwC0javmeAAY2NKan0r3dVftRGxpYXcgw4nO4U=; b=UaYbxJnGfvh6WT53HHOwbp6ArYa8y+T1R6zqrN31jdyLCTt9x1Sv56kFFZrxzbxPTv UmVLQTLOCi4DxQUyyxz1D0cmOIL/wH26GSB4yfv+2dFS8cf1dmax0s0s1TdxrUQVDF+F j6hp/vGCEv5hf7CVYmGiPZgNrwlUlMV+d097c= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=LDBRTVwC0javmeAAY2NKan0r3dVftRGxpYXcgw4nO4U=; b=PpVTMTp6RXxq8PyjHTJS4cj4sfWA0Nj1f1kERn9ASZWhd8QmA8qDwUc/Zs0af9VwJf TGAQ78aoHF2GVF77ZkVRlSGpXP7UlwJnxWDjM5RzEf08M9XqQrF6JJdZbJzGD05S4+Zj 5/gtBXbryZgoGMmK+8pA7lKBTRK9WB4W+xx326B7kBt/Wke//wLyGhRr7wNZbm8o4Md/ VGMsk53q2Gn0QvtaO6FoegWI4Mz7katxCXf72pjakmD8Q0lM4BLQP0gBFbPPg9pSiF6g sBdTF4kG3jG82O48W0EXR+vxTYcm5RFS5cETtctV4GcOXlDZ/Yf2MZtTpGvSpoDqdNmd Fs7g== X-Gm-Message-State: AOAM530z6Sh4mjtLAVq8Ev0FpYh+zUc93hSp+QEHtvR9lv2A4FF1W4SG UyD8MWL924MTAavJScBHlIlCen0Y596hRA== X-Google-Smtp-Source: ABdhPJwTIwCsHYH0HJsKVTXFy+wZaI/vFRfQCX+wR3smmsgo13dcjGXg4V0UPaoHfo4b+51IqP3vMA== X-Received: by 2002:adf:eec1:: with SMTP id a1mr26872515wrp.81.1618241884929; Mon, 12 Apr 2021 08:38:04 -0700 (PDT) Received: from revest.zrh.corp.google.com ([2a00:79e0:42:204:a372:3c3b:eeb:ad14]) by smtp.gmail.com with ESMTPSA id i4sm2501449wrx.56.2021.04.12.08.38.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Apr 2021 08:38:04 -0700 (PDT) From: Florent Revest To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, yhs@fb.com, kpsingh@kernel.org, jackmanb@chromium.org, linux-kernel@vger.kernel.org, Florent Revest Subject: [PATCH bpf-next v3 6/6] selftests/bpf: Add a series of tests for bpf_snprintf Date: Mon, 12 Apr 2021 17:37:54 +0200 Message-Id: <20210412153754.235500-7-revest@chromium.org> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog In-Reply-To: <20210412153754.235500-1-revest@chromium.org> References: <20210412153754.235500-1-revest@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This exercises most of the format specifiers. Signed-off-by: Florent Revest Acked-by: Andrii Nakryiko --- .../selftests/bpf/prog_tests/snprintf.c | 81 +++++++++++++++++++ .../selftests/bpf/progs/test_snprintf.c | 74 +++++++++++++++++ 2 files changed, 155 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/snprintf.c create mode 100644 tools/testing/selftests/bpf/progs/test_snprintf.c diff --git a/tools/testing/selftests/bpf/prog_tests/snprintf.c b/tools/testing/selftests/bpf/prog_tests/snprintf.c new file mode 100644 index 000000000000..3ad1ee885273 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/snprintf.c @@ -0,0 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Google LLC. */ + +#include +#include "test_snprintf.skel.h" + +#define EXP_NUM_OUT "-8 9 96 -424242 1337 DABBAD00" +#define EXP_NUM_RET sizeof(EXP_NUM_OUT) + +#define EXP_IP_OUT "127.000.000.001 0000:0000:0000:0000:0000:0000:0000:0001" +#define EXP_IP_RET sizeof(EXP_IP_OUT) + +/* The third specifier, %pB, depends on compiler inlining so don't check it */ +#define EXP_SYM_OUT "schedule schedule+0x0/" +#define MIN_SYM_RET sizeof(EXP_SYM_OUT) + +/* The third specifier, %p, is a hashed pointer which changes on every reboot */ +#define EXP_ADDR_OUT "0000000000000000 ffff00000add4e55 " +#define EXP_ADDR_RET sizeof(EXP_ADDR_OUT "unknownhashedptr") + +#define EXP_STR_OUT "str1 longstr" +#define EXP_STR_RET sizeof(EXP_STR_OUT) + +#define EXP_OVER_OUT "%over" +#define EXP_OVER_RET 10 + +#define EXP_PAD_OUT " 4 000" +#define EXP_PAD_RET 900007 + +#define EXP_NO_ARG_OUT "simple case" +#define EXP_NO_ARG_RET 12 + +#define EXP_NO_BUF_RET 29 + +void test_snprintf(void) +{ + char exp_addr_out[] = EXP_ADDR_OUT; + char exp_sym_out[] = EXP_SYM_OUT; + struct test_snprintf *skel; + + skel = test_snprintf__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + if (!ASSERT_OK(test_snprintf__attach(skel), "skel_attach")) + goto cleanup; + + /* trigger tracepoint */ + usleep(1); + + ASSERT_STREQ(skel->bss->num_out, EXP_NUM_OUT, "num_out"); + ASSERT_EQ(skel->bss->num_ret, EXP_NUM_RET, "num_ret"); + + ASSERT_STREQ(skel->bss->ip_out, EXP_IP_OUT, "ip_out"); + ASSERT_EQ(skel->bss->ip_ret, EXP_IP_RET, "ip_ret"); + + ASSERT_OK(memcmp(skel->bss->sym_out, exp_sym_out, + sizeof(exp_sym_out) - 1), "sym_out"); + ASSERT_LT(MIN_SYM_RET, skel->bss->sym_ret, "sym_ret"); + + ASSERT_OK(memcmp(skel->bss->addr_out, exp_addr_out, + sizeof(exp_addr_out) - 1), "addr_out"); + ASSERT_EQ(skel->bss->addr_ret, EXP_ADDR_RET, "addr_ret"); + + ASSERT_STREQ(skel->bss->str_out, EXP_STR_OUT, "str_out"); + ASSERT_EQ(skel->bss->str_ret, EXP_STR_RET, "str_ret"); + + ASSERT_STREQ(skel->bss->over_out, EXP_OVER_OUT, "over_out"); + ASSERT_EQ(skel->bss->over_ret, EXP_OVER_RET, "over_ret"); + + ASSERT_STREQ(skel->bss->pad_out, EXP_PAD_OUT, "pad_out"); + ASSERT_EQ(skel->bss->pad_ret, EXP_PAD_RET, "pad_ret"); + + ASSERT_STREQ(skel->bss->noarg_out, EXP_NO_ARG_OUT, "no_arg_out"); + ASSERT_EQ(skel->bss->noarg_ret, EXP_NO_ARG_RET, "no_arg_ret"); + + ASSERT_EQ(skel->bss->nobuf_ret, EXP_NO_BUF_RET, "no_buf_ret"); + +cleanup: + test_snprintf__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_snprintf.c b/tools/testing/selftests/bpf/progs/test_snprintf.c new file mode 100644 index 000000000000..4c36f355dfca --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_snprintf.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Google LLC. */ + +#include +#include +#include +#include + +char num_out[64] = {}; +long num_ret = 0; + +char ip_out[64] = {}; +long ip_ret = 0; + +char sym_out[64] = {}; +long sym_ret = 0; + +char addr_out[64] = {}; +long addr_ret = 0; + +char str_out[64] = {}; +long str_ret = 0; + +char over_out[6] = {}; +long over_ret = 0; + +char pad_out[10] = {}; +long pad_ret = 0; + +char noarg_out[64] = {}; +long noarg_ret = 0; + +long nobuf_ret = 0; + +extern const void schedule __ksym; + +SEC("raw_tp/sys_enter") +int handler(const void *ctx) +{ + /* Convenient values to pretty-print */ + const __u8 ex_ipv4[] = {127, 0, 0, 1}; + const __u8 ex_ipv6[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}; + const char str1[] = "str1"; + const char longstr[] = "longstr"; + + /* Integer types */ + num_ret = BPF_SNPRINTF(num_out, sizeof(num_out), + "%d %u %x %li %llu %lX", + -8, 9, 150, -424242, 1337, 0xDABBAD00); + /* IP addresses */ + ip_ret = BPF_SNPRINTF(ip_out, sizeof(ip_out), "%pi4 %pI6", + &ex_ipv4, &ex_ipv6); + /* Symbol lookup formatting */ + sym_ret = BPF_SNPRINTF(sym_out, sizeof(sym_out), "%ps %pS %pB", + &schedule, &schedule, &schedule); + /* Kernel pointers */ + addr_ret = BPF_SNPRINTF(addr_out, sizeof(addr_out), "%pK %px %p", + 0, 0xFFFF00000ADD4E55, 0xFFFF00000ADD4E55); + /* Strings embedding */ + str_ret = BPF_SNPRINTF(str_out, sizeof(str_out), "%s %+05s", + str1, longstr); + /* Overflow */ + over_ret = BPF_SNPRINTF(over_out, sizeof(over_out), "%%overflow"); + /* Padding of fixed width numbers */ + pad_ret = BPF_SNPRINTF(pad_out, sizeof(pad_out), "%5d %0900000X", 4, 4); + /* No args */ + noarg_ret = BPF_SNPRINTF(noarg_out, sizeof(noarg_out), "simple case"); + /* No buffer */ + nobuf_ret = BPF_SNPRINTF(NULL, 0, "only interested in length %d", 60); + + return 0; +} + +char _license[] SEC("license") = "GPL";