On Thu, May 31, 2018 at 09:04:25AM -0700, Casey Schaufler wrote: > On 5/31/2018 8:39 AM, Tejun Heo wrote: > > (cc'ing more security folks and copying whole body) > > > > So, I'm sure the patch fixes the memory leak but API wise it looks > > super confusing. Can security folks chime in here? Is this the right > > fix? > > security_inode_getsecctx() provides a security context. Technically, > this is a data blob, although both provider provide a null terminated > string. security_inode_getsecurity(), on the other hand, provides a > string to match an attribute name. The former releases the security > context with security_release_secctx(), where the later releases the > string with kfree(). > > When the Smack hook smack_inode_getsecctx() was added in 2009 > for use by labeled NFS the alloc value passed to > smack_inode_getsecurity() was set incorrectly. This wasn't a > major issue, since labeled NFS is a fringe case. When kernfs > started using the hook, it became the issue you discovered. > > The reason that we have all this confusion is that SELinux > generates security contexts as needed, while Smack keeps them > around all the time. Releasing an SELinux context frees memory, > while releasing a Smack context is a null operation. Any chance this detail can be hidden behind security api? This looks pretty error-prone, no? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
