On Mon, Sep 21, 2020 at 03:36:50PM +0100, Dmitry Safonov wrote: > Changes since v2: > - added struct xfrm_translator as API to register xfrm_compat.ko with > xfrm_state.ko. This allows compilation of translator as a loadable > module > - fixed indention and collected reviewed-by (Johannes Berg) > - moved boilerplate from commit messages into cover-letter (Steffen > Klassert) > - found on KASAN build and fixed non-initialised stack variable usage > in the translator > > The resulting v2/v3 diff can be found here: > https://gist.github.com/0x7f454c46/8f68311dfa1f240959fdbe7c77ed2259 > > Patches as a .git branch: > https://github.com/0x7f454c46/linux/tree/xfrm-compat-v3 > > Changes since v1: > - reworked patches set to use translator > - separated the compat layer into xfrm_compat.c, > compiled under XFRM_USER_COMPAT config > - 32-bit messages now being sent in frag_list (like wext-core does) > - instead of __packed add compat_u64 members in compat structures > - selftest reworked to kselftest lib API > - added netlink dump testing to the selftest > > XFRM is disabled for compatible users because of the UABI difference. > The difference is in structures paddings and in the result the size > of netlink messages differ. > > Possibility for compatible application to manage xfrm tunnels was > disabled by: the commmit 19d7df69fdb2 ("xfrm: Refuse to insert 32 bit > userspace socket policies on 64 bit systems") and the commit 74005991b78a > ("xfrm: Do not parse 32bits compiled xfrm netlink msg on 64bits host"). > > This is my second attempt to resolve the xfrm/compat problem by adding > the 64=>32 and 32=>64 bit translators those non-visibly to a user > provide translation between compatible user and kernel. > Previous attempt was to interrupt the message ABI according to a syscall > by xfrm_user, which resulted in over-complicated code [1]. > > Florian Westphal provided the idea of translator and some draft patches > in the discussion. In these patches, his idea is reused and some of his > initial code is also present. > > There were a couple of attempts to solve xfrm compat problem: > https://lkml.org/lkml/2017/1/20/733 > https://patchwork.ozlabs.org/patch/44600/ > http://netdev.vger.kernel.narkive.com/2Gesykj6/patch-net-next-xfrm-correctly-parse-netlink-msg-from-32bits-ip-command-on-64bits-host > > All the discussions end in the conclusion that xfrm should have a full > compatible layer to correctly work with 32-bit applications on 64-bit > kernels: > https://lkml.org/lkml/2017/1/23/413 > https://patchwork.ozlabs.org/patch/433279/ > > In some recent lkml discussion, Linus said that it's worth to fix this > problem and not giving people an excuse to stay on 32-bit kernel: > https://lkml.org/lkml/2018/2/13/752 > > There is also an selftest for ipsec tunnels. > It doesn't depend on any library and compat version can be easy > build with: make CFLAGS=-m32 net/ipsec > > [1]: https://lkml.kernel.org/r/20180726023144.31066-1-dima@xxxxxxxxxx > > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> > Cc: Florian Westphal <fw@xxxxxxxxx> > Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> > Cc: Jakub Kicinski <kuba@xxxxxxxxxx> > Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> > Cc: Steffen Klassert <steffen.klassert@xxxxxxxxxxx> > Cc: Stephen Suryaputra <ssuryaextr@xxxxxxxxx> > Cc: Dmitry Safonov <0x7f454c46@xxxxxxxxx> > Cc: netdev@xxxxxxxxxxxxxxx > > Dmitry Safonov (7): > xfrm: Provide API to register translator module > xfrm/compat: Add 64=>32-bit messages translator > xfrm/compat: Attach xfrm dumps to 64=>32 bit translator > netlink/compat: Append NLMSG_DONE/extack to frag_list > xfrm/compat: Add 32=>64-bit messages translator > xfrm/compat: Translate 32-bit user_policy from sockptr > selftest/net/xfrm: Add test for ipsec tunnel Series applied to ipsec-next. Thanks a lot for your work Dmitry!
