On Fri, Jun 22, 2018 at 07:37:00AM -0700, Casey Schaufler wrote: > There is a regression in behavior regarding xattrs in /proc after: > > commit 1bbc55131e59bd099fdc568d3aa0b42634dbd188 > Author: Al Viro <[email protected]> > Date: Wed May 2 21:26:16 2018 -0400 > > procfs: get rid of ancient BS in pid_revalidate() uses > > > Prior to this change lgetxattr() would provide the correct attributes > for entries in /proc. With this change I see that while the behavior > remains correct if the procid is specified, it is not when "self" is > used. On a system with Smack enabled, where the shell has the Smack label > "Crackle" I see: > > [root@localhost linux]# attr -S -g SMACK64 /proc/self/attr/current > Attribute "SMACK64" had a 1 byte value for /proc/self/attr/current: > _ > [root@localhost linux]# attr -S -g SMACK64 /proc/$BASHPID/attr/current > Attribute "SMACK64" had a 7 byte value for /proc/1716/attr/current: > Crackle
Wait a sec - the former will be that of attr, the latter - of bash; it's not the same file at all. > These should be the same, and in the past have been. I don't know > what SELinux expects as far as attributes in /proc, so I can't say > if the problem is manifest with SELinux. Very interesting... About the only thing changed here seems to be the relative order of smack_d_instantiate() and smack_task_to_inode()... Would setting SMK_INODE_INSTANT in isp->smk_flags in smack_task_to_inode() be the right thing to do, anyway?
