From patchwork Mon Mar 25 09:56:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xu Kuohai X-Patchwork-Id: 13601841 X-Patchwork-Delegate: paul@paul-moore.com Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) (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 ED2A616F29D; Mon, 25 Mar 2024 09:52:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711360382; cv=none; b=OMFzRKYdUuBa5pWzTJpwpUTVSfEq3yXMUanYXrWn31ENgGb5bpU6cUYHlfKsyEvRkcvBC/d6eLdAJ7LSrEjo2+mvEelhcs0YwPb36kk96BbDkf4DZEpJ8lVjAYJkQ3O8AwhJOybGpPI0Db2rhK447qbid7he4y29JHWdAqwLRkg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711360382; c=relaxed/simple; bh=/CxeULT5kR+RD3NSe0u40FOQAIPQdqzrfrThysSCq1k=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=h1/exMDy6g3GLEBg5mrGRM57EXePx20bj2mMyUsWXRse1hU/G7CkyjWRE3Ma0iN8hIhbEuwUjffe84haf/ilXM9b3h/3n8QLx/PqcCdvglp1zNPRz15PyWwwwhuYfkRxd2zQuxLiOh0XMiwEkcZVFiLvMh5FTDjaUEzyxY0tBLQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4V37XN5dcGz4f3l8C; Mon, 25 Mar 2024 17:52:52 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.252]) by mail.maildlp.com (Postfix) with ESMTP id C40B61A01A8; Mon, 25 Mar 2024 17:52:56 +0800 (CST) Received: from k01.huawei.com (unknown [10.67.174.197]) by APP3 (Coremail) with SMTP id _Ch0CgDn9Jx1SQFmHl6fHw--.8953S7; Mon, 25 Mar 2024 17:52:56 +0800 (CST) From: Xu Kuohai To: bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Florent Revest , Brendan Jackman , Paul Moore , James Morris , "Serge E . Hallyn" , Khadija Kamran , Casey Schaufler , Ondrej Mosnacek , Kees Cook , John Johansen , Lukas Bulwahn , Roberto Sassu , Shung-Hsi Yu Subject: [PATCH bpf-next v2 5/7] bpf: Fix compare error in function retval_range_within Date: Mon, 25 Mar 2024 17:56:51 +0800 Message-Id: <20240325095653.1720123-6-xukuohai@huaweicloud.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240325095653.1720123-1-xukuohai@huaweicloud.com> References: <20240325095653.1720123-1-xukuohai@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: _Ch0CgDn9Jx1SQFmHl6fHw--.8953S7 X-Coremail-Antispam: 1UD129KBjvJXoW7uFyfWF4kKw15tF1kuw13twb_yoW8Zr1fpF 1rGr1qyw4DXr43W3yjyr4kA3yrK3Wjqw47KFWkC34Fyw15tryqgF4UKw4akrW5KrW8Ww1S vF12v3yYqa4UuaDanT9S1TB71UUUUUJqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUP2b4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E 14v26rxl6s0DM2kKe7AKxVWUXVWUAwAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFc xC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_ Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2 IY04v7MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAF wI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc4 0Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1I6r4UMIIF0xvE2Ix0cI8IcVCY1x0267AK xVW8Jr0_Cr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JV WxJwCI42IY6I8E87Iv6xkF7I0E14v26r4UJVWxJrUvcSsGvfC2KfnxnUUI43ZEXa7IU1tr cDUUUUU== X-CM-SenderInfo: 50xn30hkdlqx5xdzvxpfor3voofrz/ From: Xu Kuohai After checking lsm hook return range in verifier, the test case "test_progs -t test_lsm" failed, and the failure log says: libbpf: prog 'test_int_hook': BPF program load failed: Invalid argument libbpf: prog 'test_int_hook': -- BEGIN PROG LOAD LOG -- 0: R1=ctx() R10=fp0 ; int BPF_PROG(test_int_hook, struct vm_area_struct *vma, @ lsm.c:89 0: (79) r0 = *(u64 *)(r1 +24) ; R0_w=scalar(smin=smin32=-4095,smax=smax32=0) R1=ctx() [...] 24: (b4) w0 = -1 ; R0_w=0xffffffff ; int BPF_PROG(test_int_hook, struct vm_area_struct *vma, @ lsm.c:89 25: (95) exit At program exit the register R0 has smin=4294967295 smax=4294967295 should have been in [-4095, 0] It can be seen that instruction "w0 = -1" zero extended -1 to 64-bit register r0, setting both smin and smax values of r0 to 4294967295. This resulted in a false reject when r0 was checked with range [-4095, 0]. Given bpf_retval_range is a 32-bit range, this patch fixes it by changing the compare between r0 and return range from 64-bit operation to 32-bit operation. Fixes: 8fa4ecd49b81 ("bpf: enforce exact retval range on subprog/callback exit") Signed-off-by: Xu Kuohai --- kernel/bpf/verifier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c3387357bc0d..36cd13982926 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -9864,7 +9864,7 @@ static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env) static bool retval_range_within(struct bpf_retval_range range, const struct bpf_reg_state *reg) { - return range.minval <= reg->smin_value && reg->smax_value <= range.maxval; + return range.minval <= reg->s32_min_value && reg->s32_max_value <= range.maxval; } static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)