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 A2FD918C32D; Thu, 26 Sep 2024 08:53:46 +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=1727340826; cv=none; b=q2UFn/8LlPu7/yPYkExTcEf+0jiWo9MBj0sUp62z+ASnFyX8gOV9W+FSKRhpDoalcNWirrC4Bg082R+Zuq42v2rMyaxIgDD8YCwFF+m/QZiAoDrgzBRNbfmzpLUt2Ak5flWuCVVdoDUtnq1A/+ov8/DN8ghOtDkLBBDcKZPyThk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727340826; c=relaxed/simple; bh=3qOEoeFneXXnCFdM07mV4UmfEdk7I5R0u0M1OVNlQHA=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=AbMVlSm7OqGEL42bT/hNVW+bj3wwRy6Hjx6RTFIsr5yxdteDFFMjXx754rEhWqjrsYn0IMqk7RHSSNjsEKuIMySAPIwHYlxJSapNnVeGYPpopei+3OuhoP5xIBFY2yU9l3mYCvfu6VSPvXZ90lngWK2f/6HGiSQ+SmrzosM53Pw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JmTK5cyu; 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="JmTK5cyu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB085C4CEC5; Thu, 26 Sep 2024 08:53:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727340826; bh=3qOEoeFneXXnCFdM07mV4UmfEdk7I5R0u0M1OVNlQHA=; h=Date:Cc:Subject:From:To:References:In-Reply-To:From; b=JmTK5cyu/3LJyqi573gPW3bkubI6QGDsy5pyQS/1p/OE1CXkOAJH69SD4VNRAjfEd /4DGG0w1ni83KRUj+IB2mfIqUI56/BKHit/ANW77Lxe6VbGz+5g/ZkzAo3olxk41yX TEj9FuL/s+dFw2+kNHEExowsSIOTxoGu3Jz118V78XSUNX9s6aSiBRQ/6orx9TCPoM 3g2aE+UMdnF8OchOSjhVJvecLRo13spsj49IZZ46JeKuOHZXiW4OlWx6AEWmIixWQJ u0XPMb5WB0rpJamsH+3FfzLg0gFcNfkb4+1TwhdDwRFKn8dZsFUnwO97E8OlO4Vg3M IngkAuYSDzjGg== 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: Thu, 26 Sep 2024 11:53:42 +0300 Message-Id: Cc: , , , , Subject: Re: [PATCH] security/keys: fix slab-out-of-bounds in key_task_permission From: "Jarkko Sakkinen" To: "Chen Ridong" , "Chen Ridong" , , , , 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: On Thu Sep 26, 2024 at 6:48 AM EEST, Chen Ridong wrote: > > On 2024/9/19 4:57, Jarkko Sakkinen wrote: > > 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 bo= unds: > >>>>> > >>>>> 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 = bug > >>>> reported at this LINK: > >>>> https://syzkaller.appspot.com/bug?id=3D68a5e206c2a8e08d317eb83f05610= c0484ad10b9. > >>>> > >>>>>> 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-gafbffd6= c3ede #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/repo= rt.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_key= s.c:459 > >>>>>> search_process_keyrings_rcu+0x1d/0x310 security/keys/process_k= eys.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 acceptabl= e? > >>> > >>> I only comment new patch versions so not giving any promises but I ca= n > >>> say that it is I think definitely in the correct direction :-) > >>> > >>> BR, Jarkko > >> > >> Hello, Jarkko. I have reproduced this issue. It can be reproduced by > >> following these steps: > >> > >> 1. Add the helper patch. > >> > >> @@ -205,6 +205,9 @@ static void hash_key_type_and_desc(struct > >> keyring_index_key *index_key) > >> else if (index_key->type =3D=3D &key_type_keyring && (hash & > >> 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 > >> 0x%x\n", index_key->type->name, index_key->description, index_key->ha= sh); > >> + } > >> } > >> > >> 2. Pick up the inputs whose hash is xxe6 using the following cmd. If a > >> key's hash is xxe6, it will be printed. > >> > >> for ((i=3D0; i<=3D10000; i++)); do ./test_key user user$i "Some payloa= d"; 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 > >> 16, the ROOT has keys with hashes that are not xxe6 (e.g., slot 0), so > >> the keys are dissimilar. The ROOT will then split NODE A without using= a > >> shortcut. When NODE A is filled with keys that have hashes of xxe6, th= e > >> 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 > >> mistakenly be transferred to a key*, leading to an read out-of-bounds = read. > >> > >> 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. > >=20 > > Hi, I'll try to run through your procedure next week and give my commen= ts. > > Thanks for doing this. > >=20 > > BR, Jarkko > > Hi, Jarkko, have you run these procedure? > I have tested this patch with LTP and a pressure test(stress-ng --key),= =20 > and this patch have fixed this issue. Additionally, no new bugs have=20 > been found so far. > > I am looking forward to your reply. > > Best regards, > Ridong Nope because we are apparently stuck with release critical bug: https://lore.kernel.org/linux-integrity/D4EPMF7G3E05.1VHS9CVG3DZDE@kernel.o= rg/T/#t Might take several weeks before I look into this. BR, Jarkko