From patchwork Mon Sep 30 23:59:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: tyrone-wu X-Patchwork-Id: 831662 Received: from mail-yb1-f178.google.com (mail-yb1-f178.google.com [209.85.219.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A7E8E2C1B4; Mon, 30 Sep 2024 23:59:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.178 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727740778; cv=none; b=TYDqnuASONInZUgYAmVIxC3lu0K6+0Sdq/A6yvwV/s1BM1rr+sxE9XCPxSqzxZwmIqvBElH+DxJj60hz5FLwBaC6eT8RtSeIPScQozc/3lWrmoDe15nOrAXWu/xlNos3SE05QFficbCxU1wjBIT9YoVO3MCmSlrZC6J/0WppT5s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727740778; c=relaxed/simple; bh=bHJTfIv/bQKEaDRRNzyllEiHmX2BmrRj0mXBc5jpiMo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dfzypiRkN8xEdNQKl1ZTM1a+jQLwshmCSkLynBXkdYNnqgOT2Y82MEhuDzyINp1Ct5jIO7BbE6exAuBBF5be9bP3EivYXxQtul27q/OBi890Y2YFxeUvoKXkucKVWa7qiuXVwu4kiNM5LCw0V1vNgJnFm9Pl9IKVEjGsdeqTyyM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=H5yxE/fh; arc=none smtp.client-ip=209.85.219.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="H5yxE/fh" Received: by mail-yb1-f178.google.com with SMTP id 3f1490d57ef6-e260754066cso3028164276.1; Mon, 30 Sep 2024 16:59:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1727740775; x=1728345575; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=0Omp0TCRUqYPq/kqA2kywyGRQS2WH8xmPRfAWQrDh08=; b=H5yxE/fhiA+XdAzS1wFlIZdwYJF5FajVlA3HPr9KgYr6Z0u45bMU4jxTRv3ByGN6AC FnTGlgd3Vlrcag6A0ea+isZgv1cJszVQToq6JjLIpTrqqtskKksfw79rJkdUMgO2EF7T CT4/x3pGxgjRv19HIRTStiVzxanYrx4bMSk8eHIsU4B9L3ipb8lwqmiK9xhI/jw3fUNi beg0c1wRWIidN8f1xQFSXTQtlb+vynuRPUvGmVKIV/6ofPDwVlk5s7xEl9aPkxvKrg5G dSKi7aa62BdeksYOhoxcuMD5yRthuBQgc5iyzXIRH+FGOzyn+z79Rbg3eJvveiN8HMew Ge7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727740775; x=1728345575; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=0Omp0TCRUqYPq/kqA2kywyGRQS2WH8xmPRfAWQrDh08=; b=qS1v6nCAvC+s1sTXR8DwDYqNBwlklLw1wOkMyCj8iQjlssgPk5zqfQhk3YEO8nLHd1 skV9MOPDXCSajWMuDvNDHuybWFFc17kVQnh69t9LREjY4162HKdW7uUfAH2iofxse7X/ LaKCSuMdzCb9fNkoPz0I0mL8EiaLn0Bw4zZXshfucUY9ogzQjZ2v7PhdhHZbBphmWGCr CWiHrcQoZHouAdEJ9sniK5TvF9R7OE8vlX+AhiNFgjNKVze2UiRzfEeGkfkMRquYQnZp +u6LQreeFneC9kzrsMcf8jUvDAjDNcGJam0AwkHSfM1JWPISO8lWgB50+lSbiEsbBdO1 cefQ== X-Forwarded-Encrypted: i=1; AJvYcCVall4QuH+77d2oq32Jf60MG1rAse5UKpaq8ayZ3NUK2e+o5XoHOGYngPyQxwHdgZDcTJhNEJVUcpU/4TfKVCQt@vger.kernel.org, AJvYcCVjQ4dF+wkZcaYH1vlnoGCobUxeEzE+xUsvHsN11cD6JWyDPT33u6AtkOaB0a9xiFzRGuORbhq3oJbF9jQG@vger.kernel.org, AJvYcCX4XMNINf2bNzlJ3G1kB+Znyc7hby8Zn1lwnzXE/K2BiSGcwzaCwW3Nzwu6dCtWKHDYtdI=@vger.kernel.org X-Gm-Message-State: AOJu0YyybaoNrNBw+Fz+KCDaVDTDlb/OFZXXS7O0guhFccLzhQ8IwTtU WTWQvMw7QYBN17HhlvnuLKkd5VlerfkZds8seLjgV5ARmb7Flxwy X-Google-Smtp-Source: AGHT+IGfhUcsgW0vXTpQM/RQpsEALLTzaOy9gzajslyDHkJNDwRuqCj3icvML3SzIvbGJP83yw/24A== X-Received: by 2002:a05:6902:a0a:b0:e25:e38b:a46e with SMTP id 3f1490d57ef6-e2604b158ddmr10631946276.1.1727740775564; Mon, 30 Sep 2024 16:59:35 -0700 (PDT) Received: from dev-ubuntu-0.. (104-15-236-76.lightspeed.rlghnc.sbcglobal.net. [104.15.236.76]) by smtp.googlemail.com with ESMTPSA id 3f1490d57ef6-e25e42210acsm2701553276.35.2024.09.30.16.59.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Sep 2024 16:59:34 -0700 (PDT) From: tyrone-wu To: olsajiri@gmail.com, laoar.shao@gmail.com, andrii.nakryiko@gmail.com, wudevelops@gmail.com, bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, mykolal@fb.com, shuah@kernel.org, kernel-patches-bot@fb.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH bpf] bpf: fix unpopulated name_len field in perf_event link info Date: Mon, 30 Sep 2024 23:59:20 +0000 Message-ID: <20240930235920.125417-1-wudevelops@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`). This patch fills `name_len` with the actual size of the string name. The relevant selftests have also been updated to assert that `name_len` contains the correct size rather than 0. Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu --- kernel/bpf/syscall.c | 25 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++--- 2 files changed, 20 insertions(+), 11 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..90b6add4d0c9 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,7 +3565,7 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { @@ -3574,18 +3574,20 @@ static int bpf_perf_link_fill_common(const struct perf_event *event, size_t len; int err; - if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + len = strlen(buf); + *ulen = len + 1; if (!uname) return 0; if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, *ulen, len); if (err) return err; } else { @@ -3609,7 +3611,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3619,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3641,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3650,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3676,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; } static int bpf_perf_link_fill_perf_event(const struct perf_event *event, diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie"); + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset"); + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again;