From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f45.google.com (mail-wm1-f45.google.com [209.85.128.45]) (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 969FA38423F for ; Tue, 14 Apr 2026 21:21:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776201705; cv=none; b=px8LfigWJ7c55OQ+bf7krralD/5I2BDaUXR5TyE4gZxybowB28CR+4CRfk29cfARzhQLR+Y5TFVn2nH65UKNlDgGMcHWPBb8u8JnLuwrUTFhMTwe9sxi6SecLebMPArsthDYoMG+uiBAGW5i4yEk8Mo1j4gjgmbKfYipR6LsQ30= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776201705; c=relaxed/simple; bh=wuAEnKKJTwUfAlU0Ey6cCScDDJKhL+c1QL6KEVKuXXs=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=c3BMH53+brff/faYdb2LYySyn+e701G2zkrR7NE1hHvilomZoQOzw4ICPIAZhM0VMFuo4b51URayxmtiti8EJgDH1xE3desJjcyfC5g5jJDNcY+XBi2/7u4A1ALRCbFUXfNQK1IBK4f49V3OSkCK4sfOjDxSgo7YyiOBLKrOCwA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=gmP+Q2ve; arc=none smtp.client-ip=209.85.128.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="gmP+Q2ve" Received: by mail-wm1-f45.google.com with SMTP id 5b1f17b1804b1-48374014a77so82310235e9.3 for ; Tue, 14 Apr 2026 14:21:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1776201702; x=1776806502; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=jGEMxnrfL1fBp0DuNJTVhthMPiZzYFbcoG57oqu7KwQ=; b=gmP+Q2vef/4U8XCtVs82i6L/r/z4EWv0baauZlQGAQQa1jepFm2zP+BBuO8B88+sOx OP2dJnGedzPg82bMM82oFCKBJRgI/Je/oWWe6UmUoUg/mH/C0lJ8sdnZ5BA5SE4lpoQN a6oCQpMa4rx11IKH0XcRfX7CNmwNe2i+D4JSO9IyuVyMMR9M9ZbjGc6DfjJVMtS2xAUD SG3tjsVAeKC9aGD0zU6OYA7J/YYNWSwXSya2CJ59UcZ1JVsaNr4gNdAfmcVdnI7GURK8 r3rMn38lCasBIVfBurPqB60G9xLGlNejKW1Jshp+xEYy2MMJ0EZ7LkzvMoUEFjmq8E4Q gRkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776201702; x=1776806502; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=jGEMxnrfL1fBp0DuNJTVhthMPiZzYFbcoG57oqu7KwQ=; b=NRFmLkXxkOMJVxu57IoFQ+AlI76wvExVNGQ3RdkKiDCqtPjF8DlVV9GpeGTC0qvkE0 dThiVRnx7G75W7FxyUBms7dy1NJzckXuUMvzjPosncI/bKSimqjGhCIfaIcVlJJ969Sd tHUE9nxEQOW9fPB+4x8oSaornxMDGkrw0euPxp3uXf5fTS/pg/WhAp1FEkSo2KKzR8oI ilg0UmYrF2iiOUcgrHDhYuGMDRX6iFXPnr4HqFxPObmEapx9gl6Tt0CU1npkQt3xDKUJ ohE7Ui2VdATWtB92NV4XEC5uVDmlWxGdDzfZLZIujbOOtVKop8kxna/lLjYIlovPZNp1 EUjA== X-Forwarded-Encrypted: i=1; AFNElJ8Zi1ChG2+BSbbGAHkeoXP+vkN5shKMYrEBb+zSzNWhOqOP0Zd8VsT7iXmmEeMD8DlWzS3alRllf1DRpzk=@vger.kernel.org X-Gm-Message-State: AOJu0YyMzRbyIF1kWZGI+eCIBqyDPgUuWTCQKNO4qcwdykswjNi1UqPg Aj7K7yu4dMmPK3Upv6xWEt+nuT3h+nBLBjRLGRu5xnbsLcJ+lKUtseQ5 X-Gm-Gg: AeBDietC6M9gI8GocOI51To6HS+nmDfQlthrofnpcpXxPlgQWakW+yE70NliHmI9uMX 7ZKSTqO2WK6qFLA/n21E36Mx2II4ObLM7fDYfQx6kKjmiXoR8UgK4/PO4uQoCubfkmHIHNXn3zG RO6jHvdC3trpc0fDSBtnHyPuAvEAe5TwJKJIApriRcdS/k1XRj5UN5wOIwbA3nZNXsk1IcHn9mI SamJd7BRLqAhf8yX3iHkI1AzRnT1qDuczUGSsKg8Kmee8PJmmoeWiu6VWz8eERNeYrIdAThe5k7 bJK8G5mXfTLQ8enBs/NjFlPC2JCn+opf1vFDtMhyGu9y0fJgvhuVoiU2dg9ZvAaTcxnaAjREBrg YxUR2Fzpm3GA73eOe1WCD4LcQitMXPA5ASM985/kD7y4BPh1x6pekpl3vCCbmnCXVnn7EmBE4Tj sQ0fptMRsTCrGRjpWGJdpjWbtnFYzEFidnw20WnVuOCMB+Y0aQRbI9iISJN90HM57l X-Received: by 2002:a05:600c:8904:b0:488:c257:a73b with SMTP id 5b1f17b1804b1-488d67effd0mr178298195e9.9.1776201701817; Tue, 14 Apr 2026 14:21:41 -0700 (PDT) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-488ede1e217sm132187635e9.5.2026.04.14.14.21.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Apr 2026 14:21:41 -0700 (PDT) Date: Tue, 14 Apr 2026 22:21:40 +0100 From: David Laight To: Ian Rogers Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Adrian Hunter , James Clark , Swapnil Sapkal , Anubhav Shelat , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1] perf header: Ensure read strings are '\0' terminated Message-ID: <20260414222140.2c9b8cee@pumpkin> In-Reply-To: <20260414205725.2211169-1-irogers@google.com> References: <20260414205725.2211169-1-irogers@google.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) 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=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 14 Apr 2026 13:57:25 -0700 Ian Rogers wrote: > Sashiko reviews were complaining do_read_string didn't necessarily > ensure strings were correctly terminated. Add checking for this and if > a string isn't correctly terminated return NULL. Actually I'd be just as worried about corrupt data giving insane lengths (eg if it processes some ascii text). For that you want a better error than just 'return NULL'. David > > Signed-off-by: Ian Rogers > --- > tools/perf/util/header.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c > index f30e48eb3fc3..fa4f6d773874 100644 > --- a/tools/perf/util/header.c > +++ b/tools/perf/util/header.c > @@ -269,6 +269,9 @@ static char *do_read_string(struct feat_fd *ff) > if (do_read_u32(ff, &len)) > return NULL; > > + if (len == 0) > + return NULL; > + > buf = malloc(len); > if (!buf) > return NULL; > @@ -279,7 +282,10 @@ static char *do_read_string(struct feat_fd *ff) > * thus the actual strlen of buf > * may be less than len > */ > - return buf; > + for (int i = (int)len - 1; i >= 0; i--) { > + if (buf[i] == '\0') > + return buf; > + } > } > > free(buf);