From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f73.google.com (mail-oa1-f73.google.com [209.85.160.73]) (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 AD67D313280 for ; Thu, 18 Sep 2025 17:24:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758216263; cv=none; b=fKERUMn11Vj3smmfhiYQ8oip3fZaXbHZAvqK1Q6+bGSjOJNRkR5XFa4vOA72h8twd6kGIVoCuJx1aU4wl90G6Y75Rz1wtlAcb5VEOyl6/ZsooRmsRQMGZppD+2VFTKjKZ8WrB0Br4kehGvnSpxkB5ByZqJDnRUf/cTrU/WWTUHk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758216263; c=relaxed/simple; bh=h+y2Um0sWiG++m2eQ4n+7CATo8zmvy0N5uykStccMxU=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=D3dYZSVqMrRiEQ7eekVtX3PhwMwYjzWpi/zMoeI3X8/bPtmIwDwjGZR14yXp1AoTNI2Lhu1g7cOnL8fUDWfzrlTzdMCeFIPpelisgU7fdSioAiWe7WvHEcTiX1WufALh5tYQie2JALy9Br0viJR8RuZ3b1NVZzZ6aJTIjawguOw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=SmBM6LLj; arc=none smtp.client-ip=209.85.160.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SmBM6LLj" Received: by mail-oa1-f73.google.com with SMTP id 586e51a60fabf-33103aaaea3so1161841fac.3 for ; Thu, 18 Sep 2025 10:24:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1758216261; x=1758821061; darn=vger.kernel.org; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=XsfmL0ulg/CT1LMIENsj8BUyC9tsKVtVKqCgN4jh7dI=; b=SmBM6LLjBSsTIGMHdNg3CmFo7TRLz0eY6MzvQeOjBhEWXwoLdLN3Qxg3NvhxT266w+ akTZs2AkLVnHOSLwgPEslqXioU9ndl/M4jzKzN2lIc4Y9OGKVzw/e9tkxs7ps4Wpdf54 yYEYe5i/vyPnXXYj1yuQCRPo9PlI6+t+nqUYdwdYYkMqlO39TnSL+K8mYmehrMb0n41U oLiJI6reecauan35sHXAXdJexCLZdCZLEJv13yG2sz2FjvggF6WKbL/uRf36zE7wNuSk OyI7xcJY3aYYx3ed8fd1FZH9aY98QzQFWyNCvv+YHaXVbvz8i/Msh9DS21xVDcS0Ywz/ P/eQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758216261; x=1758821061; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=XsfmL0ulg/CT1LMIENsj8BUyC9tsKVtVKqCgN4jh7dI=; b=JHGriNmiUDU6VDamXn1x7/kKAJO53b6m+mhJWY8n9lEZFUilchk6FzZpuwl05thQZf /8GR3VyT/MipkJOVlJ8KPCY/fijSmam8Jdr0cehXMDrgJTRmebuTq48JisHOspwxFqXN fo0Qkg9bkwCiaJ5ORBGL2/mCD1STPit59wGM/Vnfb3djy7//EkTVWK/jSYzWkLFsq/7E 8m75zoM3m1AFb3T+ePxDqSoTFbeWTjtxupKwVjpHp7eqTTUypO1fH+udolvxadYag1fW MM/Qpo+vurMwKjrqG+XsGzBNOEs8q1VBqolloJji8rt6yaqWl9d3vDFRMC5W0KJFnKqq z2Kg== X-Forwarded-Encrypted: i=1; AJvYcCUBPh0QMspkbKjzeQoBay5/mJyxhYLWdLLLPHGNFN0fbyOvW+lt0/IgPiAbXfM6TIZa/GbuAwmUNZyA73H3OLDM@vger.kernel.org X-Gm-Message-State: AOJu0YwstXPND3tf6ADLcdsY796YOCyVco3xqsIlpCrfAXDa+/OHDqhy /gsFtOc5nHWUhqRFoC0NaYzulU2ZcoYIWyLOYqdPFOjVUTZR45qPl7Zje7RCjv/aITmZkNVc/OG xH/AF0iyHdQ== X-Google-Smtp-Source: AGHT+IGWB/VXAS3RnF6arcEmZeiuRWFqDcSNYAyDvKYDCL+F0KRVx4cJ1GKjg8GNB3EYMyo2OmRye3CO7CG7 X-Received: from oablc18.prod.google.com ([2002:a05:6871:4192:b0:332:c618:867f]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6870:d88d:b0:31d:8edc:3d1a with SMTP id 586e51a60fabf-33bb38a30ebmr282005fac.7.1758216260804; Thu, 18 Sep 2025 10:24:20 -0700 (PDT) Date: Thu, 18 Sep 2025 10:24:16 -0700 In-Reply-To: <20250918172416.1247940-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250918172416.1247940-1-irogers@google.com> X-Mailer: git-send-email 2.51.0.470.ga7dc726c21-goog Message-ID: <20250918172416.1247940-2-irogers@google.com> Subject: [PATCH v1 2/2] perf build-id: Ensure snprintf string is empty when size is 0 From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , James Clark , Howard Chu , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" The string result of build_id__snprintf is unconditionally used in places like dsos__fprintf_buildid_cb. If the build id has size 0 then this creates a use of uninitialized memory. Add null termination for the size 0 case. A similar fix was written by Jiri Olsa in commit 6311951d4f8f ("perf tools: Initialize output buffer in build_id__sprintf") but lost in the transition to snprintf. Fixes: fccaaf6fbbc5 ("perf build-id: Change sprintf functions to snprintf") Signed-off-by: Ian Rogers --- tools/perf/util/build-id.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c index bf7f3268b9a2..35505a1ffd11 100644 --- a/tools/perf/util/build-id.c +++ b/tools/perf/util/build-id.c @@ -86,6 +86,13 @@ int build_id__snprintf(const struct build_id *build_id, char *bf, size_t bf_size { size_t offs = 0; + if (build_id->size == 0) { + /* Ensure bf is always \0 terminated. */ + if (bf_size > 0) + bf[0] = '\0'; + return 0; + } + for (size_t i = 0; i < build_id->size && offs < bf_size; ++i) offs += snprintf(bf + offs, bf_size - offs, "%02x", build_id->data[i]); -- 2.51.0.470.ga7dc726c21-goog