From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 736C6282F29; Sun, 10 May 2026 03:36:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778384189; cv=none; b=hs7kPdhk5BTlfqNMSTxoUb9feeIT3kklPk9FEcxroorrKJ0laNHdoxUhJoOJt0+gBwesvxSbr+py2qommNnVgQMQ19sir7QpgBxlVhQkNnndjFVEh9xVFlHxx/uIzV+XaIgESoGLlAdy9NXfWmwZYca1icDaNb9JSk175Y+gSNQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778384189; c=relaxed/simple; bh=Uo4Aj5hoW5Le1FOXzlcX4O+kIwQ370Wtq6/SPTihl34=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=u255jwqaHGU+q7w5zA6jRHdphUccue6LSJy4bwrZbDxG+Q+Y2iO/mIlI/VK+MiaGW25es4C3FhkTk9E9UK4KlyAGjHI8pRQcJiBhzqtaSuuVcgbgR7g2CnGZ1TJAVPtkFbbDu2ll6Xi/tYb3q/MGmVJJOAr1Mu3wb1jLLjGmw6I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=O7l9hfj7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="O7l9hfj7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67D0CC2BCB8; Sun, 10 May 2026 03:36:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778384189; bh=Uo4Aj5hoW5Le1FOXzlcX4O+kIwQ370Wtq6/SPTihl34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=O7l9hfj7Dp14b8jc6MInjVvey1O+Z883IU0uWN6O0o4Xpfov/9NE0IKPkvqv04l9+ R5lhDK6ywGW3l1QRCd6MIj2A75x2kmhnpnyrzH4RAeQA8q+s82hCDQAMYx/rnjmNg8 C5VpUaGyUEmcSdPglXA/oAWgqI6dU5KTAKE5g6ti0b91ins8mC26Vux63xo+48lsGH U9BjbU1L0HBAhn9PM+wVAxhL+XqaZIsRif7eZm22d26u2EGk5+z4CVdxcgFUd8xazi HG89K6Q6PdGBCQii/yhTTxoyumvHCxIffHzKw07e8JwCMePbsG/iUP7Rfxsw8F2jnQ UiM5pqYh1obvA== From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ingo Molnar , Thomas Gleixner , James Clark , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , sashiko-bot@kernel.org, Wang Nan , "Claude Opus 4.6 (1M context)" Subject: [PATCH 20/28] perf header: Sanity check HEADER_EVENT_DESC attr.size before swap Date: Sun, 10 May 2026 00:34:11 -0300 Message-ID: <20260510033424.255812-21-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260510033424.255812-1-acme@kernel.org> References: <20260510033424.255812-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@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 read_event_desc() reads nre (event count), sz (attr size), and nr (IDs per event) from the file and uses them to control allocations and loops without validating them against the section size. A crafted perf.data could trigger large allocations or many loop iterations before __do_read() eventually rejects the reads. Add bounds checks in read_event_desc(): - Reject sz smaller than PERF_ATTR_SIZE_VER0. - Require at least one event (nre > 0). - Check that nre events fit in the remaining section, using the minimum per-event footprint of sz + sizeof(u32). - Reject attr->size > sz before calling perf_event__attr_swap() to prevent heap out-of-bounds access. - Check that nr IDs fit in the remaining section before allocating. Fixes: b30b61729246 ("perf tools: Fix a problem when opening old perf.data with different byte order") Reported-by: sashiko-bot@kernel.org # Running on a local machine Cc: Wang Nan Cc: Jiri Olsa Cc: Ian Rogers Assisted-by: Claude Opus 4.6 (1M context) Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/header.c | 50 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 49 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index a8655a784eaa5ba9..0bbe90865e9c1ceb 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -2170,9 +2170,25 @@ static struct evsel *read_event_desc(struct feat_fd *ff) if (do_read_u32(ff, &nre)) goto error; + /* Size of each of the nre attributes. */ if (do_read_u32(ff, &sz)) goto error; + /* + * Require at least one event with an attr no smaller than the + * first published struct, and reject sz values where + * sz + sizeof(u32) would overflow size_t (possible on 32-bit) + * or nre == UINT32_MAX where nre + 1 wraps to 0 in the calloc. + * + * The minimum section footprint per event is sz bytes for the + * attr plus a u32 for the id count, check that nre events fit. + */ + if (!nre || sz < PERF_ATTR_SIZE_VER0 || + sz > ff->size || (size_t)sz > SIZE_MAX - sizeof(u32) || + nre == UINT32_MAX || + nre > (ff->size - ff->offset) / (sz + sizeof(u32))) + goto error; + /* buffer to hold on file attr struct */ buf = malloc(sz); if (!buf) @@ -2188,6 +2204,9 @@ static struct evsel *read_event_desc(struct feat_fd *ff) msz = sz; for (i = 0, evsel = events; i < nre; evsel++, i++) { + struct perf_event_attr *attr = buf; + u32 attr_size; + evsel->core.idx = i; /* @@ -2197,6 +2216,32 @@ static struct evsel *read_event_desc(struct feat_fd *ff) if (__do_read(ff, buf, sz)) goto error; + /* Reject before attr_swap to prevent OOB via bswap_safe() */ + attr_size = ff->ph->needs_swap ? bswap_32(attr->size) : attr->size; + /* ABI0: size == 0 means the producer didn't set it */ + if (!attr_size) { + attr_size = PERF_ATTR_SIZE_VER0; + /* + * Write back so free_event_desc() doesn't + * treat this event as the end-of-array sentinel + * (it iterates while attr.size != 0). + * + * Only for native — the swap path must NOT + * write native-endian VER0 here because + * perf_event__attr_swap() would re-swap it + * to 0x40000000, defeating bswap_safe() bounds. + * perf_event__attr_swap() has its own ABI0 + * fallback that sets VER0 after swapping. + */ + if (!ff->ph->needs_swap) + attr->size = attr_size; + } + if (attr_size < PERF_ATTR_SIZE_VER0 || attr_size > sz) { + pr_err("Event %d attr.size (%u) invalid (min: %d, max: %u)\n", + i, attr_size, PERF_ATTR_SIZE_VER0, sz); + goto error; + } + if (ff->ph->needs_swap) perf_event__attr_swap(buf); @@ -2218,6 +2263,10 @@ static struct evsel *read_event_desc(struct feat_fd *ff) if (!nr) continue; + /* Prevent oversized allocation from crafted nr */ + if (nr > (ff->size - ff->offset) / sizeof(*id)) + goto error; + id = calloc(nr, sizeof(*id)); if (!id) goto error; @@ -4995,7 +5044,6 @@ int perf_session__read_header(struct perf_session *session) } err = -ENOMEM; - if (perf_file_header__read(&f_header, header, fd) < 0) return -EINVAL; -- 2.54.0