From: Kees Cook <keescook@chromium.org>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: casey.schaufler@intel.com, jmorris@namei.org,
linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp,
paul@paul-moore.com, sds@tycho.nsa.gov
Subject: Re: [PATCH v2 18/25] LSM: Use lsmcontext in security_dentry_init_security
Date: Thu, 20 Jun 2019 10:25:29 -0700 [thread overview]
Message-ID: <201906201024.C5936F66C@keescook> (raw)
In-Reply-To: <063644f9-be64-175e-0bf2-cfa1afadc3d7@schaufler-ca.com>
On Wed, Jun 19, 2019 at 10:31:45AM -0700, Casey Schaufler wrote:
> On 6/18/2019 10:41 PM, Kees Cook wrote:
> > I think this is wrong: for NUL-terminated strings, "context.len" isn't
> > currently including the NUL byte (it's set to strlen()).
> >
> > So, if kmemdup() is used here, it means strlen() isn't correct in the
> > context init helper, it should be using the "size" argument, etc.
>
> Would all be true if the context where being set by lsmcontext_init,
> but it's not. It's coming from the dentry_init_security hook, and
> the one instance of that, selinux_dentry_init_security() sets the
> size to strlen() + 1. The kmemdup() will include the terminating NUL.
Ah-ha! Okay, thanks, yes. I see now. Carry on! :)
> I too wish that the hooks and their use where more consistent.
> My sincere hope is that this revision of the infrastructure will
> help that to some extent.
Once these changes land it should be much much easier to find ways to
refactor for greater sanity. :)
> > Should label be set to NULL here and len reduced to 0?
>
> It wasn't before, and I'd hate to make too many assumptions
> about what might be fragile in the NFS code.
Gotcha.
--
Kees Cook
next prev parent reply other threads:[~2019-06-20 17:25 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-18 23:05 [PATCH v2 00/25] LSM: Module stacking for AppArmor Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 01/25] LSM: Infrastructure management of the superblock Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 02/25] LSM: Infrastructure management of the sock security Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 03/25] LSM: Infrastructure management of the key blob Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 04/25] LSM: Create and manage the lsmblob data structure Casey Schaufler
2019-06-19 4:52 ` Kees Cook
2019-06-19 6:17 ` Kees Cook
2019-06-19 16:34 ` Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 05/25] Use lsmblob in security_audit_rule_match Casey Schaufler
2019-06-19 4:55 ` Kees Cook
2019-06-18 23:05 ` [PATCH v2 06/25] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 07/25] net: Prepare UDS for secuirty module stacking Casey Schaufler
2019-06-19 4:59 ` Kees Cook
2019-06-19 16:42 ` Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 08/25] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 09/25] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2019-06-19 5:03 ` Kees Cook
2019-06-18 23:05 ` [PATCH v2 10/25] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 11/25] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 12/25] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 13/25] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2019-06-19 5:11 ` Kees Cook
2019-06-18 23:05 ` [PATCH v2 14/25] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 15/25] LSM: Specify which LSM to display Casey Schaufler
2019-06-19 4:33 ` Kees Cook
2019-06-19 15:33 ` Casey Schaufler
2019-06-19 5:28 ` Kees Cook
2019-06-19 17:00 ` Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 16/25] LSM: Ensure the correct LSM context releaser Casey Schaufler
2019-06-19 5:34 ` Kees Cook
2019-06-19 17:10 ` Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 17/25] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2019-06-19 5:36 ` Kees Cook
2019-06-18 23:05 ` [PATCH v2 18/25] LSM: Use lsmcontext in security_dentry_init_security Casey Schaufler
2019-06-19 5:41 ` Kees Cook
2019-06-19 17:31 ` Casey Schaufler
2019-06-20 17:25 ` Kees Cook [this message]
2019-06-18 23:05 ` [PATCH v2 19/25] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 20/25] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 21/25] Audit: Store LSM audit information in an lsmblob Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 22/25] LSM: Return the lsmblob slot on initialization Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 23/25] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 24/25] Fix slotted list and getpeersec_d Casey Schaufler
2019-06-19 5:50 ` Kees Cook
2019-06-19 17:36 ` Casey Schaufler
2019-06-18 23:05 ` [PATCH v2 25/25] AppArmor: Remove the exclusive flag Casey Schaufler
2019-06-19 4:34 ` [PATCH v2 00/25] LSM: Module stacking for AppArmor Kees Cook
2019-06-19 15:39 ` Casey Schaufler
2019-06-19 20:08 ` James Morris
2019-06-20 17:33 ` Stacked LSMs (was Re: [PATCH v2 00/25] LSM: Module stacking for AppArmor) Kees Cook
2019-06-22 14:15 ` Mickaël Salaün
2019-06-19 5:21 ` [PATCH v2 00/25] LSM: Module stacking for AppArmor Kees Cook
2019-06-19 16:48 ` Casey Schaufler
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