From: Mimi Zohar via Ocfs2-devel <ocfs2-devel@oss.oracle.com> To: Roberto Sassu <roberto.sassu@huaweicloud.com>, mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com, dmitry.kasatkin@gmail.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, stephen.smalley.work@gmail.com, eparis@parisplace.org, casey@schaufler-ca.com Cc: nicolas.bouchinet@clip-os.org, keescook@chromium.org, selinux@vger.kernel.org, Roberto Sassu <roberto.sassu@huawei.com>, reiserfs-devel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org, ocfs2-devel@oss.oracle.com Subject: Re: [Ocfs2-devel] [PATCH v5 0/6] evm: Prepare for moving to the LSM infrastructure Date: Wed, 23 Nov 2022 08:06:38 -0500 [thread overview] Message-ID: <bddfe0f41b05dd8efd6991487ff2525a8503dd84.camel@linux.ibm.com> (raw) In-Reply-To: <22f47b9d2cade322f9037133b0940640423f9590.camel@huaweicloud.com> On Wed, 2022-11-23 at 13:44 +0100, Roberto Sassu wrote: > On Wed, 2022-11-23 at 07:28 -0500, Mimi Zohar wrote: > > Hi Roberto, > > > > On Wed, 2022-11-23 at 10:51 +0100, Roberto Sassu wrote: > > > From: Roberto Sassu <roberto.sassu@huawei.com> > > > > > > One of the challenges that must be tackled to move IMA and EVM to the LSM > > > infrastructure is to ensure that EVM is capable to correctly handle > > > multiple stacked LSMs providing an xattr at file creation. At the moment, > > > there are few issues that would prevent a correct integration. This patch > > > set aims at solving them. > > > > Let's take a step back and understand the purpose of this patch set. > > Regardless of whether IMA and EVM are moved to the "LSM > > infrastructure", EVM needs to support per LSM xattrs. A side affect is > > the removal of the security_old_inode_init_security hook. This patch > > set cover letter and patch descriptions should be limited to EVM > > support for per LSM (multiple) xattrs. The motivation, concerns, and > > problems of making IMA and EVM LSMs will be documented in the patch set > > that actual makes them LSMs. Please remove all references to "move IMA > > and EVM to the LSM infrastructure". > > Hi Mimi > > ok, will do. > > > When EVM was upstreamed, there were filesystem limitations on the > > number and size of the extended attributes. In addition there were > > performance concerns, which resulted in staging the LSM, IMA and EVM > > xattrs, before calling initxattrs to write them at the same time. With > > this patch set, not only are per LSM xattrs supported, but multiple per > > LSM xattrs are supported as well. Have the size limitation concerns > > been addressed by the different filesystems? If not, then at minimum > > this patch set needs to at least mention it and the possible > > ramifications. > > With your patch, 9d8f13ba3f483 ("security: new > security_inode_init_security API adds function callback") you made it > possible to set multiple xattrs at inode creation time. True, and even then there were concerns. > This patch set pushes further to the limits, as there could be more > xattrs to be added to the inode. I will mention that. Thanks > If there are too many xattrs, I guess the only solution would be to use > less LSMs, or a different filesystem. The per filesystem limit could be > increased separately case by case. Agreed, but unless it is documented somewhere, nobody but us will know there is a potential problem. At least document it here in the cover letter, which we'll include in the merge message. FYI, the xattr.7 man page contains a section "Filesystem differences". -- thanks, Mimi _______________________________________________ Ocfs2-devel mailing list Ocfs2-devel@oss.oracle.com https://oss.oracle.com/mailman/listinfo/ocfs2-devel
WARNING: multiple messages have this Message-ID (diff)
From: Mimi Zohar <zohar@linux.ibm.com> To: Roberto Sassu <roberto.sassu@huaweicloud.com>, mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com, dmitry.kasatkin@gmail.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, stephen.smalley.work@gmail.com, eparis@parisplace.org, casey@schaufler-ca.com Cc: ocfs2-devel@oss.oracle.com, reiserfs-devel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-kernel@vger.kernel.org, keescook@chromium.org, nicolas.bouchinet@clip-os.org, Roberto Sassu <roberto.sassu@huawei.com> Subject: Re: [PATCH v5 0/6] evm: Prepare for moving to the LSM infrastructure Date: Wed, 23 Nov 2022 08:06:38 -0500 [thread overview] Message-ID: <bddfe0f41b05dd8efd6991487ff2525a8503dd84.camel@linux.ibm.com> (raw) In-Reply-To: <22f47b9d2cade322f9037133b0940640423f9590.camel@huaweicloud.com> On Wed, 2022-11-23 at 13:44 +0100, Roberto Sassu wrote: > On Wed, 2022-11-23 at 07:28 -0500, Mimi Zohar wrote: > > Hi Roberto, > > > > On Wed, 2022-11-23 at 10:51 +0100, Roberto Sassu wrote: > > > From: Roberto Sassu <roberto.sassu@huawei.com> > > > > > > One of the challenges that must be tackled to move IMA and EVM to the LSM > > > infrastructure is to ensure that EVM is capable to correctly handle > > > multiple stacked LSMs providing an xattr at file creation. At the moment, > > > there are few issues that would prevent a correct integration. This patch > > > set aims at solving them. > > > > Let's take a step back and understand the purpose of this patch set. > > Regardless of whether IMA and EVM are moved to the "LSM > > infrastructure", EVM needs to support per LSM xattrs. A side affect is > > the removal of the security_old_inode_init_security hook. This patch > > set cover letter and patch descriptions should be limited to EVM > > support for per LSM (multiple) xattrs. The motivation, concerns, and > > problems of making IMA and EVM LSMs will be documented in the patch set > > that actual makes them LSMs. Please remove all references to "move IMA > > and EVM to the LSM infrastructure". > > Hi Mimi > > ok, will do. > > > When EVM was upstreamed, there were filesystem limitations on the > > number and size of the extended attributes. In addition there were > > performance concerns, which resulted in staging the LSM, IMA and EVM > > xattrs, before calling initxattrs to write them at the same time. With > > this patch set, not only are per LSM xattrs supported, but multiple per > > LSM xattrs are supported as well. Have the size limitation concerns > > been addressed by the different filesystems? If not, then at minimum > > this patch set needs to at least mention it and the possible > > ramifications. > > With your patch, 9d8f13ba3f483 ("security: new > security_inode_init_security API adds function callback") you made it > possible to set multiple xattrs at inode creation time. True, and even then there were concerns. > This patch set pushes further to the limits, as there could be more > xattrs to be added to the inode. I will mention that. Thanks > If there are too many xattrs, I guess the only solution would be to use > less LSMs, or a different filesystem. The per filesystem limit could be > increased separately case by case. Agreed, but unless it is documented somewhere, nobody but us will know there is a potential problem. At least document it here in the cover letter, which we'll include in the merge message. FYI, the xattr.7 man page contains a section "Filesystem differences". -- thanks, Mimi
next prev parent reply other threads:[~2022-11-23 13:07 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-11-23 9:51 [Ocfs2-devel] [PATCH v5 0/6] evm: Prepare for moving to the LSM infrastructure Roberto Sassu via Ocfs2-devel 2022-11-23 9:51 ` Roberto Sassu 2022-11-23 9:51 ` [Ocfs2-devel] [PATCH v5 1/6] reiserfs: Switch to security_inode_init_security() Roberto Sassu via Ocfs2-devel 2022-11-23 9:51 ` Roberto Sassu 2022-11-23 13:12 ` [Ocfs2-devel] " Mimi Zohar via Ocfs2-devel 2022-11-23 13:12 ` Mimi Zohar 2022-11-23 9:51 ` [Ocfs2-devel] [PATCH v5 2/6] ocfs2: " Roberto Sassu via Ocfs2-devel 2022-11-23 9:51 ` Roberto Sassu 2022-11-23 17:46 ` Mimi Zohar 2022-11-23 17:46 ` [Ocfs2-devel] " Mimi Zohar via Ocfs2-devel 2022-11-24 8:11 ` Roberto Sassu via Ocfs2-devel 2022-11-24 8:11 ` Roberto Sassu 2022-11-29 13:14 ` [Ocfs2-devel] " Mimi Zohar via Ocfs2-devel 2022-11-29 13:14 ` Mimi Zohar 2022-12-13 8:05 ` Roberto Sassu 2022-12-13 8:05 ` [Ocfs2-devel] " Roberto Sassu via Ocfs2-devel 2022-11-23 9:51 ` [Ocfs2-devel] [PATCH v5 3/6] security: Remove security_old_inode_init_security() Roberto Sassu via Ocfs2-devel 2022-11-23 9:51 ` Roberto Sassu 2022-11-23 9:52 ` [Ocfs2-devel] [PATCH v5 4/6] security: Allow all LSMs to provide xattrs for inode_init_security hook Roberto Sassu via Ocfs2-devel 2022-11-23 9:52 ` Roberto Sassu 2022-11-23 9:52 ` [Ocfs2-devel] [PATCH v5 5/6] evm: Align evm_inode_init_security() definition with LSM infrastructure Roberto Sassu via Ocfs2-devel 2022-11-23 9:52 ` Roberto Sassu 2022-11-23 9:52 ` [Ocfs2-devel] [PATCH v5 6/6] evm: Support multiple LSMs providing an xattr Roberto Sassu via Ocfs2-devel 2022-11-23 9:52 ` Roberto Sassu 2022-11-23 12:28 ` [Ocfs2-devel] [PATCH v5 0/6] evm: Prepare for moving to the LSM infrastructure Mimi Zohar via Ocfs2-devel 2022-11-23 12:28 ` Mimi Zohar 2022-11-23 12:44 ` [Ocfs2-devel] " Roberto Sassu via Ocfs2-devel 2022-11-23 12:44 ` Roberto Sassu 2022-11-23 13:06 ` Mimi Zohar via Ocfs2-devel [this message] 2022-11-23 13:06 ` Mimi Zohar
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