From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3FA7C3537F8; Wed, 10 Jun 2026 16:52:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781110381; cv=none; b=iydBXe4Y0z2F1i72xEhPvwCVUrkLkzTNyc+3EqRAHzE9d3gQmDaaDBPTNglJPiZpGys8CBk9F954m9JPy1cyUqNGIkPIXhf5ilbjHMQxH3uaOpjwaOGb/o4sDuKZBCQjPS50zpmmkc1o+o5CPvo0AkG3l88rLmcGtLdRSMa2SGM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781110381; c=relaxed/simple; bh=7n6+PW6fm4CnN5i0Kkq2sFG6oHBydJcqFEad0lVdCCY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=X0zF++tHdBmjA8lA8UaPamrMOiI8AyxcvdjnM2/44NvIg9qzOa+w77uAmn0yb47a8MDTT2g1doPgA7fX7tZ9uWOV1kd2SHqv90wXfbGHjwA8YQbM1UoHLQsolqU6gtDBgAKOLT6TDHS8IJbGw7KGIqwZtkv8QovIoLaZ58yOwWQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JSbiAm/z; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JSbiAm/z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1CCA51F00893; Wed, 10 Jun 2026 16:52:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781110379; bh=9Sna/5EcUpDAGkIvriG0r7m33IdzGdkBg8h/2wBoRA4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JSbiAm/zpozYjFF+z1B7Se+I1nlMQ1hjQM7gJFPRc1ZjCyhAd4kj5P1i9qdhcDv39 gzgMRlGMjsfrz3Vrb1yjJzyvNQuguEjgGq+dEWt1lHtp8h8nv9YMSH170TuJV5Y2y1 xL0TVbth/HcAu61jp3sEtclOCTG0P6KXTd5HXGJqDMlKhn/xvQoiYVLkAkUHj35sMk QJj1ixsu5oKFU2XJBGGc4gxhu77AKn3Q6StgIVMIT1pfEtwoipZJXseSpLT5LOPtcS QpZheylskyuAcO7OU4cNMls/xjgGULAUeWj49X7nW8MEKlutdiRqcE7UBksVzzx1zJ OQcaaMbWkNXzw== From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ingo Molnar , Thomas Gleixner , James Clark , Jiri Olsa , Ian Rogers , Adrian Hunter , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , sashiko-bot , Song Liu , "Claude Opus 4.6" Subject: [PATCH 08/11] perf bpf: Use scnprintf() in snprintf_hex() and synthesize_bpf_prog_name() Date: Wed, 10 Jun 2026 13:52:02 -0300 Message-ID: <20260610165207.2077258-9-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260610165207.2077258-1-acme@kernel.org> References: <20260610165207.2077258-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo Both functions accumulate formatted output via ret += snprintf(buf + ret, size - ret, ...). If the buffer is too small and snprintf() returns more than the remaining space, ret exceeds size and the next 'size - ret' underflows, causing snprintf() to write past the buffer end. Switch to scnprintf() which returns the actual number of bytes written, making the accumulation safe. Fixes: 7b612e291a5affb1 ("perf tools: Synthesize PERF_RECORD_* for loaded BPF programs") Reported-by: sashiko-bot Reviewed-by: Ian Rogers Cc: Song Liu Assisted-by: Claude Opus 4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/bpf-event.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c index a27945c279efb779..2c09842469f1f28c 100644 --- a/tools/perf/util/bpf-event.c +++ b/tools/perf/util/bpf-event.c @@ -36,7 +36,7 @@ static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len) size_t i; for (i = 0; i < len; i++) - ret += snprintf(buf + ret, size - ret, "%02x", data[i]); + ret += scnprintf(buf + ret, size - ret, "%02x", data[i]); return ret; } @@ -140,7 +140,7 @@ static int synthesize_bpf_prog_name(char *buf, int size, const struct btf_type *t; int name_len; - name_len = snprintf(buf, size, "bpf_prog_"); + name_len = scnprintf(buf, size, "bpf_prog_"); name_len += snprintf_hex(buf + name_len, size - name_len, prog_tags[sub_id], BPF_TAG_SIZE); if (btf) { @@ -153,9 +153,10 @@ static int synthesize_bpf_prog_name(char *buf, int size, short_name = info->name; } else short_name = "F"; - if (short_name) - name_len += snprintf(buf + name_len, size - name_len, - "_%s", short_name); + if (short_name) { + name_len += scnprintf(buf + name_len, size - name_len, + "_%s", short_name); + } return name_len; } -- 2.54.0