| Message ID | 20200921143657.604020-1-dima@arista.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | xfrm: Add compat layer | expand |
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@arista.com > > Cc: "David S. Miller" <davem@davemloft.net> > Cc: Florian Westphal <fw@strlen.de> > Cc: Herbert Xu <herbert@gondor.apana.org.au> > Cc: Jakub Kicinski <kuba@kernel.org> > Cc: Johannes Berg <johannes@sipsolutions.net> > Cc: Steffen Klassert <steffen.klassert@secunet.com> > Cc: Stephen Suryaputra <ssuryaextr@gmail.com> > Cc: Dmitry Safonov <0x7f454c46@gmail.com> > Cc: netdev@vger.kernel.org > > 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!
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@arista.com Cc: "David S. Miller" <davem@davemloft.net> Cc: Florian Westphal <fw@strlen.de> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Stephen Suryaputra <ssuryaextr@gmail.com> Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: netdev@vger.kernel.org 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 MAINTAINERS | 1 + include/net/xfrm.h | 33 + net/netlink/af_netlink.c | 47 +- net/xfrm/Kconfig | 11 + net/xfrm/Makefile | 1 + net/xfrm/xfrm_compat.c | 625 +++++++ net/xfrm/xfrm_state.c | 77 +- net/xfrm/xfrm_user.c | 110 +- tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/Makefile | 1 + tools/testing/selftests/net/ipsec.c | 2195 ++++++++++++++++++++++++ 11 files changed, 3066 insertions(+), 36 deletions(-) create mode 100644 net/xfrm/xfrm_compat.c create mode 100644 tools/testing/selftests/net/ipsec.c base-commit: ba4f184e126b751d1bffad5897f263108befc780