Messages in this thread | | | Date | Fri, 18 Nov 2022 10:32:15 +0100 | Subject | Re: [PATCH v4 3/5] security: Allow all LSMs to provide xattrs for inode_init_security hook | From | Roberto Sassu <> |
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On 11/17/2022 6:18 PM, Casey Schaufler wrote: > On 11/17/2022 8:05 AM, Mimi Zohar wrote: >> hOn Thu, 2022-11-10 at 10:46 +0100, Roberto Sassu wrote: >>> From: Roberto Sassu <roberto.sassu@huawei.com> >>> >>> Currently, security_inode_init_security() supports only one LSM providing >>> an xattr and EVM calculating the HMAC on that xattr, plus other inode >>> metadata. >>> >>> Allow all LSMs to provide one or multiple xattrs, by extending the security >>> blob reservation mechanism. Introduce the new lbs_xattr field of the >>> lsm_blob_sizes structure, so that each LSM can specify how many xattrs it >>> needs, and the LSM infrastructure knows how many xattr slots it should >>> allocate. >> Perhaps supporting per LSM multiple xattrs is a nice idea, but EVM >> doesn't currently support it. The LSM xattrs are hard coded in >> evm_config_default_xattrnames[], based on whether the LSM is >> configured. Additional security xattrs may be included in the >> security.evm calculation, by extending the list via >> security/integrity/evm/evm_xattrs. > > Smack uses multiple xattrs. All file system objects have a SMACK64 > attribute, which is used for access control. A program file may have > a SMACK64EXEC attribute, which is the label the program will run with. > A library may have a SMACK64MMAP attribute to restrict loading. A > directory may have a SMACK64TRANSMUTE attribute, which modifies the > new object creation behavior. > > The point being that it may be more than a "nice idea" to support > multiple xattrs. It's not a hypothetical situation.
Ok, that means that I have to change the number of xattrs reserved by Smack in patch 3.
Thanks
Roberto
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