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 A6F7837BE60; Wed, 10 Jun 2026 19:53:23 +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=1781121204; cv=none; b=Z7QsqtgnyoCnYIYeNt8Sj9aVQCOvvgapExiEGkvfTixhDDkRv3UfpN4QZ9mO2SnCLd+D7LUvnBZc/Sfyk+GBowFIbS4BalmfdcgImGgGg1aT4U3h4rpJu+uHb3sPlt0Tohd70sW5+w5wEbZIHDPsfPKsoa5kB2QJwBAxvTUrs4c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781121204; c=relaxed/simple; bh=tSuNoyEus6B/PhxaI810nD2tj4zGzVYkVBkHmDSKz0M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=f5trzTYNzLf41djF+iI0KBq0vHGy5A/qpBI5bSbLCkM5cI9D35OtWOqqIc5+MdGOf7/oGg4FN2E6i2/cOZR3yNZUD7LSVPK7tMWjtswwaggcwUvahu7yHQITbKmMF2EXP6kiygSI7aIpNEG25OT5gKefW+pFY1hTRRbj/c38pRU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=G4a2HnlY; 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="G4a2HnlY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C7AEC1F00893; Wed, 10 Jun 2026 19:53:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781121203; bh=e6pq4Pi2rTvQzgwveR9OLs8WTJXKO4Z+OmvvL6+9sQw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=G4a2HnlYCTEviNdTvw14pudrIxB6mHxbTCmnI+pnakJ9L8CpolnIb4ZZZQHAHtvfS O0834DewF9gTb62UL9Lba3IrR+1sZO8xV7LislIdFGSn96rpH+0ro5bVAiT1W/midH IBfkN2L0+AxwqZt2HSx3uG30gB59fPfIxgANUsguUvm5MC3fhRP07BIqCFh421Bc0S u7urd+f3s7EcTr1ETnaAUO34h7fiMOahNW+m+0CmrcqYh/2i8TzHKmOFlwtBWoj0S9 HBBamN5NytCSAYQbh6x6s5H/0Hqrz4FUdbcIHSTeu/okoKHz2E9CKdyRG/Igks4bNK wXRv5sU2ed6bQ== 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 , Cody P Schafer , "Claude Opus 4.6" Subject: [PATCH 15/23] perf pmu: Use scnprintf() in format_alias() Date: Wed, 10 Jun 2026 16:51:48 -0300 Message-ID: <20260610195157.2091137-16-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260610195157.2091137-1-acme@kernel.org> References: <20260610195157.2091137-1-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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo format_alias() accumulates strings into a caller-provided buffer using snprintf(). On truncation, snprintf() returns the would-have-written count, which can exceed the buffer size. When used is larger than len, buf + used computes a pointer past the buffer end — undefined behavior even though sub_non_neg() clamps the subsequent write size to zero. Switch to scnprintf() which returns the actual number of bytes written, keeping used within bounds. Reported-by: sashiko-bot Fixes: aaea36174991ff39 ("perf tools: Extend format_alias() to include event parameters") Cc: Cody P Schafer Cc: Ian Rogers Assisted-by: Claude Opus 4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/pmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 4ddccc863727d6ca..2fce38140eb8af2a 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -2155,11 +2155,11 @@ static char *format_alias(char *buf, int len, const struct perf_pmu *pmu, snprintf(buf, len, "%.*s/%s/", (int)pmu_name_len, pmu->name, alias->name); return buf; } - used = snprintf(buf, len, "%.*s/%s", (int)pmu_name_len, pmu->name, alias->name); + used = scnprintf(buf, len, "%.*s/%s", (int)pmu_name_len, pmu->name, alias->name); list_for_each_entry(term, &terms.terms, list) { if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR) - used += snprintf(buf + used, sub_non_neg(len, used), + used += scnprintf(buf + used, sub_non_neg(len, used), ",%s=%s", term->config, term->val.str); } -- 2.54.0