On Wed, Jul 13, 2016 at 10:44 AM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > Hi All, > > Please find attached the V3 of patches. Changes since V2 are as follows. > > - Fixed the build issue with CONFIG_SECURITY=n. > > - Dan Walsh was writing more tests for selinux-testsuite and noted couple > of issues. I have fixed those issues and added two more patches in series. > > 1. We are resetting MAY_WRITE check for lower inode assuming file will > be coiped up. But this is not true for special_file() as these files > are not copied up. So checks should not be reset in case of special > file. > > 2. We are resetting MAY_WRITE check for lower inode assuming file will > be copied up. But this also should mean that mounter has permission > to MAY_READ lower file for copy up to succeed. So add MAY_READ > check while resetting MAY_WRITE. > > Original description of patches follows. > > Following are RFC patches to support SELinux with overlayfs. I started > with David Howells's latest posting on this topic and started modifying > patches. These patches apply on top of overlayfs-next branch of miklos > vfs git tree. > > git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git overlayfs-next > > These patches can be pulled from my branch too. > > https://github.com/rhvgoyal/linux/commits/overlayfs-selinux-mounter-next > > Thanks to Dan Walsh, Stephen Smalley and Miklos Szeredi for numerous > conversation and ideas in helping figuring out what one reasonable > implementation might look like. > > Dan Walsh has been writing tests for selinux overlayfs in selinux-testsuite. > These patches pass those tests now > > https://github.com/rhatdan/selinux-testsuite/commits/master > > Posting these patches for review and comments. > > These patches introduce 3 new security hooks. > > - security_inode_copy_up(), is called when a file is copied up. This hook > prepares a new set of cred which is used for copy up operation. And > new set of creds are prepared so that ->create_sid can be set appropriately > and newly created file is labeled properly. > > When a file is copied up, label of lower file is retained except for the > case of context= mount where new file gets the label from context= option. > > - security_inode_copy_up_xattr(), is called when xattrs of a file are > being copied up. Before this we already called security_inode_copy_up() > and created new file and copied up data. That means file already got > labeled properly and there is no need to take SELINUX xattr of lower > file and overwrite the upper file xattr. So this hook is used to avoid > copying up of SELINUX xattr. > > - dentry_create_files_as(), is called when a new file is about to be created. > This hook determines what the label of the file should be if task had > created that file in upper/ and sets create_sid accordingly in the passed > in creds. > > Normal transition rules don't work for the case of context mounts as > underlying file system is not aware of context option which only overlay > layer is aware of. For non-context mounts, creation can happen in work/ > dir first and then file might be renamed into upper/, and it might get > label based on work/ dir. So this hooks helps avoiding all these issues. > > When a new file is created in upper/, it gets its label based on transition > rules. For the case of context mount, it gets the label from context= > option. > > Any feedback is welcome. Hi Vivek, These patches look fine to me, thanks for all your hard work and to everyone who helped review and provide feedback. I have tagged these patches for merging into the SELinux next branch after this merge window. Miklos, this patchset depends on patches in your overlayfs-next branch, I assume you're pushing that branch during the upcoming merge window? James, assuming the overlayfs-next branch is pulled during the merge window, can you rebase your linux-security#next branch to v4.8-rc1 once Linus tags it? -- paul moore www.paul-moore.com -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
