On Sat, Dec 26, 2015 at 1:51 PM, Serge E. Hallyn <serge.hal...@ubuntu.com> wrote: > On Sat, Dec 26, 2015 at 03:52:31AM +0100, Jann Horn wrote: >> ptrace_has_cap() checks whether the current process should be >> treated as having a certain capability for ptrace checks >> against another process. Until now, this was equivalent to >> has_ns_capability(current, target_ns, CAP_SYS_PTRACE). >> >> However, if a root-owned process wants to enter a user >> namespace for some reason without knowing who owns it and >> therefore can't change to the namespace owner's uid and gid >> before entering, as soon as it has entered the namespace, >> the namespace owner can attach to it via ptrace and thereby >> gain access to its uid and gid. >> >> While it is possible for the entering process to switch to >> the uid of a claimed namespace owner before entering, >> causing the attempt to enter to fail if the claimed uid is >> wrong, this doesn't solve the problem of determining an >> appropriate gid. >> >> With this change, the entering process can first enter the >> namespace and then safely inspect the namespace's >> properties, e.g. through /proc/self/{uid_map,gid_map}, >> assuming that the namespace owner doesn't have access to >> uid 0. >> >> Changed in v2: The caller needs to be capable in the >> namespace into which tcred's uids/gids can be mapped. >> >> Signed-off-by: Jann Horn <j...@thejh.net> > > Acked-by: Serge Hallyn <serge.hal...@ubuntu.com>
Acked-by: Andy Lutomirski <l...@kernel.org> Who's going to apply this? Linus? Eric? --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/