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 1CD5B471257; Tue, 21 Jul 2026 18:04:10 +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=1784657051; cv=none; b=kmFKQqMsqavgOjzN+ZHQ9/VQjy1Dvq6uZi2MEgPTOzNTzErinJTOcUVNWLhsiMufsk/O2DsaUvR2UxwsM+czzs4l8qjIV63ZoC/iyuRPO6VPMxaiQJrgXb6j4IOUJztYxBpb5bLG8PaoSQDLSgVAJYDjxPOoeop37Upzhdghgzo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657051; c=relaxed/simple; bh=3ea2hj8mwfD/u0qdZDQjzYUH/kXNhUXYFGahfz8Dlds=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=gSy0+/NQrZ545ed3MwrAnWJNT14ijmrch8cRPse4SrQYXxBCUdmXK1zKU/gfKf1UdpLHyehFruN53q3iAUGTH40SpkJrGETQzKcY+wttY0Q4B8DB0KgTFrMur6bfTcVZ8p9Ipf95PIBRNbDr+kTsSzS73D0TxFWogrvDnpaBuTw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VFVba96C; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="VFVba96C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 865C61F000E9; Tue, 21 Jul 2026 18:04:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784657050; bh=zRBr5IDiLlmQakChZvOVn9voyd8VAQnUFJjQEyXLYUQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=VFVba96CW8xYS7B0i2WhmJjgnAyexi57sYnQG8WeE7g5teWad0DYxk0oD0gJgxqS2 mO8+2uRWb2qPSjDrVo4A4aTIK87FY+obmbcr/+lYu7ZtY+QFYktsjMAfizbWdWY8kJ CyZufOkoyQN72n5y2O6T81hTBkUf7aTbMJr85QJk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ian Rogers , Jiri Olsa , Namhyung Kim , Wang Nan , Arnaldo Carvalho de Melo , Sasha Levin , sashiko-bot@kernel.org Subject: [PATCH 6.18 0619/1611] perf header: Sanity check HEADER_EVENT_DESC attr.size before swap Date: Tue, 21 Jul 2026 17:12:15 +0200 Message-ID: <20260721152529.309919501@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnaldo Carvalho de Melo [ Upstream commit 944f65c8b8231d26d4db6be67bcb641142603cb4 ] 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). - Pre-swap attr->size to native byte order, then reject values below PERF_ATTR_SIZE_VER0 or above sz before calling perf_event__attr_swap() to prevent heap out-of-bounds access. - Handle ABI0 (attr.size == 0): substitute PERF_ATTR_SIZE_VER0, and on native-endian files write the value back so free_event_desc() does not treat the zero as its end-of-array sentinel (it iterates while attr.size != 0). The swap path skips the write-back — perf_event__attr_swap() has its own ABI0 fallback that sets VER0 after swapping. - 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 Reviewed-by: Ian Rogers Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Assisted-by: Claude:claude-opus-4.6-1m Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/util/header.c | 54 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 4e12be579140aa..131fdbe9cefda5 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -1919,9 +1919,28 @@ 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))) { + pr_err("Invalid HEADER_EVENT_DESC: nre=%u sz=%u (min %d)\n", + nre, sz, PERF_ATTR_SIZE_VER0); + goto error; + } + /* buffer to hold on file attr struct */ buf = malloc(sz); if (!buf) @@ -1937,6 +1956,9 @@ 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; /* @@ -1946,6 +1968,32 @@ 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); @@ -1967,6 +2015,12 @@ 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)) { + pr_err("Event %d: id count %u exceeds remaining section\n", i, nr); + goto error; + } + id = calloc(nr, sizeof(*id)); if (!id) goto error; -- 2.53.0