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 6921B17E019; Wed, 18 Sep 2024 20:57:47 +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=1726693067; cv=none; b=sL3ZfQnqsrug1V6oIGn8TWM7lGp+WE3KxTqYYXQUCLWEjeYBnXTU9LK1OpUzE5UuV72gonF5OD6ANSMkfIclfsWmvOgOBlThwcfCDJ5WIdQTd0DRiA7DdxrDiDLxqk8VDE6dWA9AP6SVzXh1aY9McUxwgj2BTTKzLn30I3lmfr4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726693067; c=relaxed/simple; bh=TtUVSbWnkZDmRjZByD6OwGNHt8dNi+VAQtbRHJxuvIw=; h=Mime-Version:Content-Type:Date:Message-Id:To:Cc:Subject:From: References:In-Reply-To; b=j4kqvZAfSCgd2gg/ixRev5lik6ch3xG6e5zqMahFN2M0h3d1A7qVVbUkxeWSPgro3AXDDgbDiJbqtW/Wvhl6Ao2S4Ifmgh+Lt9bxewHg8solnCodjIZhE4yHKRucImwHyBTnbqrHGDL3m1IkJNbbcnzTB/eCl/TClYGGVGOqtSI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dU+x1z73; 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="dU+x1z73" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC5B0C4CEC2; Wed, 18 Sep 2024 20:57:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726693067; bh=TtUVSbWnkZDmRjZByD6OwGNHt8dNi+VAQtbRHJxuvIw=; h=Date:To:Cc:Subject:From:References:In-Reply-To:From; b=dU+x1z73gtS3ZrP0Vzo6deR8WT0zwFRJxc/KxynAHjX/fvT96VH9E1M6Y60sDGCHg gIrAbsrCpZQEjlM3D8hKnuP31zMZ81rhfm3cwg9fXsfdVY4lyiiNtHvUIRuYWy/btW 9wiK1byI2uma9jrYWTR+pHQswTsfKbJ7div9Zwyqzt5zhDdgrTull7VY7IPfXdc9BV jqC0BUmO7e8kJoQzPcplzrg0+iPHLMaSJVex4+E44z9DTkTqLaShXXjJ4wH49xT0jN 6iKc2kL92MOGnxYRdC1iZxqLMv1m0RTuCN5eHn24mBUUVRfl06MiHGVwB6mf/z3WhV pVZiLK0fOg9hA== Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 18 Sep 2024 23:57:42 +0300 Message-Id: To: "Chen Ridong" , "Chen Ridong" , , , , Cc: , , Subject: Re: [PATCH] security/keys: fix slab-out-of-bounds in key_task_permission From: "Jarkko Sakkinen" X-Mailer: aerc 0.18.2 References: <20240913070928.1670785-1-chenridong@huawei.com> <4079d020-edcc-4e27-9815-580f83a6c0ca@huaweicloud.com> <1cfa878e-8c7b-4570-8606-21daf5e13ce7@huaweicloud.com> In-Reply-To: <1cfa878e-8c7b-4570-8606-21daf5e13ce7@huaweicloud.com> On Wed Sep 18, 2024 at 10:30 AM EEST, Chen Ridong wrote: > > > On 2024/9/15 21:59, Jarkko Sakkinen wrote: > > On Sun Sep 15, 2024 at 3:55 AM EEST, Chen Ridong wrote: > >> > >> > >> On 2024/9/14 19:33, Jarkko Sakkinen wrote: > >>> On Fri Sep 13, 2024 at 10:09 AM EEST, Chen Ridong wrote: > >>>> We meet the same issue with the LINK, which reads memory out of boun= ds: > >>> > >>> Nit: don't use "we" anywhere". > >>> > >>> Tbh, I really don't understand the sentence above. I don't what > >>> "the same issue with the LINK" really is. > >>> > >> > >> Hello, Jarkko. > >> I apologize for any confusion caused. > >> > >> I've encountered a bug reported by syzkaller. I also found the same bu= g > >> reported at this LINK: > >> https://syzkaller.appspot.com/bug?id=3D68a5e206c2a8e08d317eb83f05610c0= 484ad10b9. > >> > >>>> BUG: KASAN: slab-out-of-bounds in __kuid_val include/linux/uidgid.h:= 36 > >>>> BUG: KASAN: slab-out-of-bounds in uid_eq include/linux/uidgid.h:63 [= inline] > >>>> BUG: KASAN: slab-out-of-bounds in key_task_permission+0x394/0x410 > >>>> security/keys/permission.c:54 > >>>> Read of size 4 at addr ffff88813c3ab618 by task stress-ng/4362 > >>>> > >>>> CPU: 2 PID: 4362 Comm: stress-ng Not tainted 5.10.0-14930-gafbffd6c3= ede #15 > >>>> Call Trace: > >>>> __dump_stack lib/dump_stack.c:82 [inline] > >>>> dump_stack+0x107/0x167 lib/dump_stack.c:123 > >>>> print_address_description.constprop.0+0x19/0x170 mm/kasan/report.= c:400 > >>>> __kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560 > >>>> kasan_report+0x3a/0x50 mm/kasan/report.c:585 > >>>> __kuid_val include/linux/uidgid.h:36 [inline] > >>>> uid_eq include/linux/uidgid.h:63 [inline] > >>>> key_task_permission+0x394/0x410 security/keys/permission.c:54 > >>>> search_nested_keyrings+0x90e/0xe90 security/keys/keyring.c:793 > >>>> keyring_search_rcu+0x1b6/0x310 security/keys/keyring.c:922 > >>>> search_cred_keyrings_rcu+0x111/0x2e0 security/keys/process_keys.c= :459 > >>>> search_process_keyrings_rcu+0x1d/0x310 security/keys/process_keys= .c:544 > >>>> lookup_user_key+0x782/0x12e0 security/keys/process_keys.c:762 > >>>> keyctl_invalidate_key+0x20/0x190 security/keys/keyctl.c:434 > >>>> __do_sys_keyctl security/keys/keyctl.c:1978 [inline] > >>>> __se_sys_keyctl+0x1de/0x5b0 security/keys/keyctl.c:1880 > >>>> do_syscall_64+0x30/0x40 arch/x86/entry/common.c:46 > >>>> entry_SYSCALL_64_after_hwframe+0x67/0xd1 > >>>> > >>>> However, we can't reproduce this issue. > >>> > >>> "The issue cannot be easily reproduced but by analyzing the code > >>> it can be broken into following steps:" > >> > >> Thank you for your correction. > >> Does this patch address the issue correctly? Is this patch acceptable? > >=20 > > I only comment new patch versions so not giving any promises but I can > > say that it is I think definitely in the correct direction :-) > >=20 > > BR, Jarkko > > Hello, Jarkko. I have reproduced this issue. It can be reproduced by=20 > following these steps: > > 1. Add the helper patch. > > @@ -205,6 +205,9 @@ static void hash_key_type_and_desc(struct=20 > keyring_index_key *index_key) > else if (index_key->type =3D=3D &key_type_keyring && (hash &=20 > fan_mask) !=3D 0) > hash =3D (hash + (hash << level_shift)) & ~fan_mask; > index_key->hash =3D hash; > + if ((index_key->hash & 0xff) =3D=3D 0xe6) { > + pr_err("hash_key_type_and_desc: type %s %s=20 > 0x%x\n", index_key->type->name, index_key->description, index_key->hash)= ; > + } > } > > 2. Pick up the inputs whose hash is xxe6 using the following cmd. If a=20 > key's hash is xxe6, it will be printed. > > for ((i=3D0; i<=3D10000; i++)); do ./test_key user user$i "Some payload";= done > > You have complile test_key whith following code. > > #include > #include > #include > #include > #include > #include > > int > main(int argc, char *argv[]) > { > key_serial_t key; > > if (argc !=3D 4) { > fprintf(stderr, "Usage: %s type description payload\n", > argv[0]); > exit(EXIT_FAILURE); > } > > key =3D add_key(argv[1], argv[2], argv[3], strlen(argv[3]), > KEY_SPEC_SESSION_KEYRING); > if (key =3D=3D -1) { > perror("add_key"); > exit(EXIT_FAILURE); > } > > printf("Key ID is %jx\n", (uintmax_t) key); > > exit(EXIT_SUCCESS); > } > > > 3. Have more than 32 inputs now. their hashes are xxe6. > eg. > hash_key_type_and_desc: type user user438 0xe3033fe6 > hash_key_type_and_desc: type user user526 0xeb7eade6 > ... > hash_key_type_and_desc: type user user9955 0x44bc99e6 > > 4. Reboot and add the keys obtained from step 3. > When adding keys to the ROOT that their hashes are all xxe6, and up to=20 > 16, the ROOT has keys with hashes that are not xxe6 (e.g., slot 0), so=20 > the keys are dissimilar. The ROOT will then split NODE A without using a= =20 > shortcut. When NODE A is filled with keys that have hashes of xxe6, the= =20 > keys are similar. NODE A will split with a shortcut. > > As my analysis, if a slot of the root is a shortcut(slot 6), it may be=20 > mistakenly be transferred to a key*, leading to an read out-of-bounds rea= d. > > NODE A > +------>+---+ > ROOT | | 0 | xxe6 > +---+ | +---+ > xxxx | 0 | shortcut : : xxe6 > +---+ | +---+ > xxe6 : : | | | xxe6 > +---+ | +---+ > | 6 |---+ : : xxe6 > +---+ +---+ > xxe6 : : | f | xxe6 > +---+ +---+ > xxe6 | f | > +---+ > > 5. cat /proc/keys. and the issue is reproduced. Hi, I'll try to run through your procedure next week and give my comments.= =20 Thanks for doing this. BR, Jarkko