ACK to these patches from me. I'm not sure who should pick them up.... --b. On Tue, Dec 05, 2017 at 12:05:09PM -0200, Thiago Rafael Becker wrote: > In cases where group_info is cached (e.g. sunrpc), multiplpe > threads may call set_groups with a freshly created group_info > cache (e.g. nfsd), and attempt to sort them simultaneously, > which configures a race condition that can overwrite some > groups in the cache and lead to errors. In the case of nfsd, > the client was receiving EPERM if the group used to provide > authorization was overwritten by this race condition. > > In an email exchange with bfields, we agreed that it seems > unintuitive that the groups are sorted on set_groups, and that > it would be better to move the responsibility of sorting to > the caller of set_groups. > > These patches: > - Export groups_sort in include/linux/cred.h > - Add a call to groups_sort after the groups are inserted in > group_info > - Remove the call to sort_groups from set_groups > > Thiago Rafael Becker (3): > kernel: make groups_sort globally visible > kernel: Move groups_sort to the caller of set_groups. > kernel: set_groups doesn't call groups_sort anymore. > > include/linux/cred.h | 1 + > kernel/groups.c | 6 ++++-- > kernel/uid16.c | 1 + > net/sunrpc/svcauth_unix.c | 7 +++++++ > 4 files changed, 13 insertions(+), 2 deletions(-) > > -- > 2.9.5
