From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f181.google.com (mail-pg1-f181.google.com [209.85.215.181]) (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 C440E770E8; Tue, 6 Aug 2024 19:46:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722973572; cv=none; b=jsQR1ycBJjKWZuYmjmaoydgagXhCXemeA5f/dTbmvYb89qoXR/JGUSciK77Y7XGYwKGZ2furzHavuZz3uJMRf35SPv65VuyGA+b4QxAcxt59ASNs/wLKiSCaZVoocQA7LMYLXhKSKz2ebxSnVlNLb+EFhmDCX/z2LTIjbCuDjFk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722973572; c=relaxed/simple; bh=8OVcb3dZ1VO4XcyfPRDSzFf3tzDg5T8DtRci4AcrYHU=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=Cqe63v1oeV2s1j3beihxgxgWxm6V4Du/AVHaqct+Me49WpDUe3ctWVUkB/YFjsNaCWX83sNe1KAU4+XShAZltdYBnGS8/cg4DEA39n5CvWfe0MZ0j3lOTkkXaS/g6XJXdkFgiuiNBXa9e/dgTz9vEYiqMUx9KSrePLvRji8GHSE= 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=cehIxl6D; arc=none smtp.client-ip=209.85.215.181 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="cehIxl6D" Received: by mail-pg1-f181.google.com with SMTP id 41be03b00d2f7-7bd16405aa7so475892a12.3; Tue, 06 Aug 2024 12:46:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1722973570; x=1723578370; darn=vger.kernel.org; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:from:to:cc:subject :date:message-id:reply-to; bh=lckbPoFrnafIqmtpB7EBRaFzQq1hvN6k/HAUf2JiMUo=; b=cehIxl6D9cbeMvKwGVsSyEfDyXOoIdr/HLEL5fYOCDTj6fB6Ao7f+nTeA0qyA+C9B2 S0yOTItQ840TjqQkp+KzNnSRahMUnbVThO0bKncsSTkFyrOa84trz7ApLNDtRFXKeg2e KrwHRsj2lc09lcEEBQ8ODaipirKBtXXCiLYp87l7/0G7+Dvq28yFWV9CUTi0ZgfZHJcR d/LrN2YtbDHs5ID+c0/pWv/c3JArGCqEqK5Or8WOjZtuNbJ8pKQ6r+03E27MkxVaCVSf P2FULBm6PeV7y/WbMl6lXuB1CAWKE9gLlO8a/CoRPjCrPHUMLpU/bc5OqG/zvQxy9G+n TXqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722973570; x=1723578370; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=lckbPoFrnafIqmtpB7EBRaFzQq1hvN6k/HAUf2JiMUo=; b=ZXZsNdJMRVzGZU/403bS4HwXn0ZnDWtjf2efBQQx1c0pJzrAsW8LyhOKy936WdO92T anLphBW7mw70pHXatCEWgObYglHAXc9BxhN7L57uDsu47dBf2QflxX45CXMfJW5rxVeJ lgxXK3ciaJk3iaz0UgCb6h2ftTZOTtJFboUGvysVxsLzfphDVnJLOqMGXjqoFgKE8rRE B+Grv6LbasIe8UJ7BKB7ctw4Qxk/a9sV99YtxRu8UHAbzKII2m2uM3jmN63eAegnWfBA BDKJxt1WTKBQ7UeKrmLAGVNq64jRmJ8GMIBbtgax1wfMcMdi4eDkI/5Qa7oI+lKFppuw rVnQ== X-Forwarded-Encrypted: i=1; AJvYcCU+kvreBikwfnfmPSQzgA4BzrUfvUDsA5gKtoFt8OHUgoQoym9bTz6kDOsXj91cy+mTl1BVdueFGkeAc4wHKLYZQKpT6q4OpcmD5OvEJ/V3TTQhlUguSblEDjZM2/5GgtozSwwx X-Gm-Message-State: AOJu0YxLqypO5qW+L339I8AZREmV8xHDoh/GNubscD/9L4Umj9n7SIqp 6JpMTQ+vcdsUpnqCmDuzQDJKjLabNiQ3kJovGu2dyC96wvIKXGbE X-Google-Smtp-Source: AGHT+IGUE23FnUmKf1bpId4Cq7YAtT3ivLG+MQoKRKx+bujxGq9pEDXsCjRd81TBYgavPovWcshCJA== X-Received: by 2002:a17:90b:383:b0:2ca:4a6f:1dd with SMTP id 98e67ed59e1d1-2cff955cbcemr14382462a91.41.1722973569960; Tue, 06 Aug 2024 12:46:09 -0700 (PDT) Received: from [192.168.0.235] ([38.34.87.7]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2cffb390ca3sm9494819a91.57.2024.08.06.12.46.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Aug 2024 12:46:09 -0700 (PDT) Message-ID: Subject: Re: [PATCH] libbpf: check the btf_type kind to prevent error From: Eduard Zingerman To: Ma Ke Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Yonghong Song , jolsa@kernel.org Date: Tue, 06 Aug 2024 12:46:04 -0700 In-Reply-To: <57d88cd3-3cbc-4d30-be82-92990a7a50fd@linux.dev> References: <20240806105142.2420140-1-make24@iscas.ac.cn> <57d88cd3-3cbc-4d30-be82-92990a7a50fd@linux.dev> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.52.3 (3.52.3-1.fc40) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2024-08-06 at 10:38 -0700, Yonghong Song wrote: > On 8/6/24 3:51 AM, Ma Ke wrote: > > To prevent potential error return values, it is necessary to check the > > return value of btf__type_by_id. We can add a kind checking to fix the > > issue. > >=20 > > Cc: stable@vger.kernel.org > > Fixes: 430025e5dca5 ("libbpf: Add subskeleton scaffolding") > > Signed-off-by: Ma Ke > > --- > > tools/lib/bpf/libbpf.c | 3 +++ > > 1 file changed, 3 insertions(+) > >=20 > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > > index a3be6f8fac09..d1eb45d16054 100644 > > --- a/tools/lib/bpf/libbpf.c > > +++ b/tools/lib/bpf/libbpf.c > > @@ -13850,6 +13850,9 @@ int bpf_object__open_subskeleton(struct bpf_obj= ect_subskeleton *s) > > var =3D btf_var_secinfos(map_type); > > for (i =3D 0; i < len; i++, var++) { > > var_type =3D btf__type_by_id(btf, var->type); > > + if (!var_type) > > + return libbpf_err(-ENOENT); >=20 > Could you give a detailed example when this error could be triggered? I'm curious as well, tools/lib/bpf/btf.c:btf_validate_type() has the follow= ing code: static int btf_validate_type(const struct btf *btf, const struct btf_type *= t, __u32 id) { ... switch (kind) { ... case ... case BTF_KIND_VAR: case ... err =3D btf_validate_id(btf, t->type, id); if (err) return err; break; That should catch situations exactly like this one. >=20 > > + > > var_name =3D btf__name_by_offset(btf, var_type->name_off); > > if (strcmp(var_name, var_skel->name) =3D=3D 0) { > > *var_skel->addr =3D map->mmaped + var->offset;