linux-kernel - Re: [PATCH 1/2] security: Handle dentries without inode in security_path_post

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Fri, 29 Mar 2024 16:42:50 +0100
From: Roberto Sassu <roberto.sassu@...weicloud.com>
To: Mimi Zohar <zohar@...ux.ibm.com>, dmitry.kasatkin@...il.com,
 eric.snowberg@...cle.com, paul@...l-moore.com, jmorris@...ei.org,
 serge@...lyn.com
Cc: linux-integrity@...r.kernel.org, linux-security-module@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
 linux-cifs@...r.kernel.org, viro@...iv.linux.org.uk, pc@...guebit.com,
 christian@...uner.io, Roberto Sassu <roberto.sassu@...wei.com>,
 stable@...r.kernel.org, Steve French <smfrench@...il.com>
Subject: Re: [PATCH 1/2] security: Handle dentries without inode in
 security_path_post_mknod()

On 3/29/2024 4:05 PM, Mimi Zohar wrote:
> On Fri, 2024-03-29 at 11:56 +0100, Roberto Sassu wrote:
>> From: Roberto Sassu <roberto.sassu@...wei.com>
>>
>> Commit 08abce60d63fi ("security: Introduce path_post_mknod hook")
>> introduced security_path_post_mknod(), to replace the IMA-specific call to
>> ima_post_path_mknod().
>>
>> For symmetry with security_path_mknod(), security_path_post_mknod() is
>> called after a successful mknod operation, for any file type, rather than
>> only for regular files at the time there was the IMA call.
>>
>> However, as reported by VFS maintainers, successful mknod operation does
>> not mean that the dentry always has an inode attached to it (for example,
>> not for FIFOs on a SAMBA mount).
>>
>> If that condition happens, the kernel crashes when
>> security_path_post_mknod() attempts to verify if the inode associated to
>> the dentry is private.
>>
>> Add an extra check to first verify if there is an inode attached to the
>> dentry, before checking if the inode is private. Also add the same check to
>> the current users of the path_post_mknod hook, ima_post_path_mknod() and
>> evm_post_path_mknod().
>>
>> Finally, use the proper helper, d_backing_inode(), to retrieve the inode
>> from the dentry in ima_post_path_mknod().
>>
>> Cc: stable@...r.kernel.org # 6.8.x
> 
> Huh?  It doesn't need to be backported.

Ehm, sorry. To be removed.

>> Reported-by: Steve French <smfrench@...il.com>
>> Closes:
>> https://lore.kernel.org/linux-kernel/CAH2r5msAVzxCUHHG8VKrMPUKQHmBpE6K9_vjhgDa1uAvwx4ppw@mail.gmail.com/
>> Fixes: 08abce60d63fi ("security: Introduce path_post_mknod hook")
> 
> -> 08abce60d63f

Ok.

Thanks

Roberto

>> Signed-off-by: Roberto Sassu <roberto.sassu@...wei.com>
> 
> Acked-by: Mimi Zohar <zohar@...ux.ibm.com>
>