On 11/17/2022 9:24 AM, Mimi Zohar wrote: > On Thu, 2022-11-17 at 09:18 -0800, 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@xxxxxxxxxx> >>>> >>>> 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. > And each of these addiitonal Smack xattrs are already defined in > evm_config_default_xattrnames[]. Then I'm confused by the statement that "EVM doesn't currently support it".
