From patchwork Mon Dec 4 07:52:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= X-Patchwork-Id: 13477850 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b="dnPHjEVw" Received: from todd.t-8ch.de (todd.t-8ch.de [IPv6:2a01:4f8:c010:41de::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E9B3107; Sun, 3 Dec 2023 23:52:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=weissschuh.net; s=mail; t=1701676351; bh=+ww9ozMh9wAF4pWHTJZYSE+udfVfSh/C+2C1r4/VF/s=; h=From:Subject:Date:To:Cc:From; b=dnPHjEVwIoAaUNrJmfgUcDTgDY+kMfYuLAXeYssKs0PP5lDHtRYa5ZQIkuwFRQ19I G9VVlPqY05uo4DwJxYm6SjoQ66Xlf4PtNdI1YTREJEz4/QZG75Cny25A1SPPtSjR4m fJXZxK4uWx9k+wZH5A7s7afVWeMLQP6lvu8RGh34= From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= Subject: [PATCH v2 00/18] sysctl: constify sysctl ctl_tables Date: Mon, 04 Dec 2023 08:52:13 +0100 Message-Id: <20231204-const-sysctl-v2-0-7a5060b11447@weissschuh.net> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAC2FbWUC/1XMQQ6CMBCF4auQWVvTGYGAK+5hWGgd7CSmmE5FC eHuVuLG5f+S9y2gHIUVjsUCkSdRGUMO2hXg/Dnc2Mg1N5ClAyLWxo1Bk9FZXbobxrKmckBqKwf 58og8yHvjTn1uL5rGOG/6hN/1B1H1D01orKm4afBi2VJruxeLqjr/9PvACfp1XT8AeYzlrQAAA A== To: Kees Cook , "Gustavo A. R. Silva" , Luis Chamberlain , Iurii Zaikin , Greg Kroah-Hartman , Joel Granados Cc: linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, =?utf-8?q?Thomas_Wei=C3=9Fschuh?= X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=ed25519-sha256; t=1701676350; l=9179; i=linux@weissschuh.net; s=20221212; h=from:subject:message-id; bh=+ww9ozMh9wAF4pWHTJZYSE+udfVfSh/C+2C1r4/VF/s=; b=BIozzZhBNLoGF0P6eemlxPCmLd/ipkDabVbbZkpiglLWYk8z0bHRbPG+91EvUuA2HFcfXtAz8 hbqU7Y6xCjwDgZn/Y14rfdrClcjKUg615vxDC7TNGIOqySyrONghN/Y X-Developer-Key: i=linux@weissschuh.net; a=ed25519; pk=KcycQgFPX2wGR5azS7RhpBqedglOZVgRPfdFSPB1LNw= Problem description: The kernel contains a lot of struct ctl_table throught the tree. These are very often 'static' definitions. It would be good to make the tables unmodifiable by marking them "const" to avoid accidental or malicious modifications. This is in line with a general effort to move as much data as possible into .rodata. (See for example[0] and [1]) Unfortunately the tables can not be made const right now because the core registration functions expect mutable tables. This is for two main reasons: 1) sysctl_{set,clear}_perm_empty_ctl_header in the sysctl core modify the table. 2) The table is passed to the handler function as a non-const pointer. This series migrates the core and all handlers. Structure of the series: Patch 1-3: Cleanup patches Patch 4-7: Non-logic preparation patches Patch 8: Preparation patch changing a bit of logic Patch 9-12: Treewide changes to handler function signature Patch 13-14: Adaption of the sysctl core implementation Patch 15: Adaption of the sysctl core interface Patch 16: New entry for checkpatch Patch 17-18: Constification of existing "struct ctl_table"s Tested by booting and with the sysctl selftests on x86. Note: This is intentionally sent only to a small number of people as I'd like to get some more sysctl core-maintainer feedback before sending this to essentially everybody. [0] 43a7206b0963 ("driver core: class: make class_register() take a const *") [1] https://lore.kernel.org/lkml/20230930050033.41174-1-wedsonaf@gmail.com/ Signed-off-by: Thomas Weißschuh --- Changes in v2: - Migrate all handlers. - Remove intermediate "proc_handler_new" step (Thanks Joel). - Drop RFC status. - Prepare other parts of the tree. - Link to v1: https://lore.kernel.org/r/20231125-const-sysctl-v1-0-5e881b0e0290@weissschuh.net --- Thomas Weißschuh (18): watchdog/core: remove sysctl handlers from public header sysctl: delete unused define SYSCTL_PERM_EMPTY_DIR sysctl: drop sysctl_is_perm_empty_ctl_table cgroup: bpf: constify ctl_table arguments and fields seccomp: constify ctl_table arguments of utility functions hugetlb: constify ctl_table arguments of utility functions utsname: constify ctl_table arguments of utility function stackleak: don't modify ctl_table argument sysctl: treewide: constify ctl_table_root::set_ownership sysctl: treewide: constify ctl_table_root::permissions sysctl: treewide: constify ctl_table_header::ctl_table_arg sysctl: treewide: constify the ctl_table argument of handlers sysctl: move sysctl type to ctl_table_header sysctl: move internal interfaces to const struct ctl_table sysctl: allow registration of const struct ctl_table const_structs.checkpatch: add ctl_table sysctl: make ctl_table sysctl_mount_point const sysctl: constify standard sysctl tables arch/arm64/kernel/armv8_deprecated.c | 2 +- arch/arm64/kernel/fpsimd.c | 2 +- arch/s390/appldata/appldata_base.c | 8 +-- arch/s390/kernel/debug.c | 2 +- arch/s390/kernel/topology.c | 2 +- arch/s390/mm/cmm.c | 6 +- arch/x86/kernel/itmt.c | 2 +- drivers/cdrom/cdrom.c | 4 +- drivers/char/random.c | 4 +- drivers/macintosh/mac_hid.c | 2 +- drivers/net/vrf.c | 4 +- drivers/parport/procfs.c | 12 ++-- fs/coredump.c | 2 +- fs/dcache.c | 4 +- fs/drop_caches.c | 2 +- fs/exec.c | 4 +- fs/file_table.c | 2 +- fs/fs-writeback.c | 2 +- fs/inode.c | 4 +- fs/pipe.c | 2 +- fs/proc/internal.h | 2 +- fs/proc/proc_sysctl.c | 102 +++++++++++++++--------------- fs/quota/dquot.c | 2 +- fs/xfs/xfs_sysctl.c | 6 +- include/linux/bpf-cgroup.h | 2 +- include/linux/filter.h | 2 +- include/linux/ftrace.h | 4 +- include/linux/mm.h | 8 +-- include/linux/nmi.h | 7 -- include/linux/perf_event.h | 6 +- include/linux/security.h | 2 +- include/linux/sysctl.h | 78 +++++++++++------------ include/linux/vmstat.h | 6 +- include/linux/writeback.h | 2 +- include/net/ndisc.h | 2 +- include/net/neighbour.h | 6 +- include/net/netfilter/nf_hooks_lwtunnel.h | 2 +- ipc/ipc_sysctl.c | 12 ++-- ipc/mq_sysctl.c | 2 +- kernel/bpf/cgroup.c | 2 +- kernel/bpf/syscall.c | 4 +- kernel/delayacct.c | 4 +- kernel/events/callchain.c | 2 +- kernel/events/core.c | 4 +- kernel/fork.c | 2 +- kernel/hung_task.c | 4 +- kernel/kexec_core.c | 2 +- kernel/kprobes.c | 2 +- kernel/latencytop.c | 4 +- kernel/pid_namespace.c | 2 +- kernel/pid_sysctl.h | 2 +- kernel/printk/internal.h | 2 +- kernel/printk/printk.c | 2 +- kernel/printk/sysctl.c | 5 +- kernel/sched/core.c | 8 +-- kernel/sched/rt.c | 12 ++-- kernel/sched/topology.c | 2 +- kernel/seccomp.c | 8 +-- kernel/stackleak.c | 9 +-- kernel/sysctl.c | 84 ++++++++++++------------ kernel/time/timer.c | 2 +- kernel/trace/ftrace.c | 2 +- kernel/trace/trace.c | 2 +- kernel/trace/trace_events_user.c | 2 +- kernel/trace/trace_stack.c | 2 +- kernel/ucount.c | 4 +- kernel/umh.c | 2 +- kernel/utsname_sysctl.c | 4 +- kernel/watchdog.c | 15 +++-- mm/compaction.c | 8 +-- mm/hugetlb.c | 10 +-- mm/page-writeback.c | 18 +++--- mm/page_alloc.c | 22 +++---- mm/util.c | 12 ++-- mm/vmstat.c | 4 +- net/ax25/sysctl_net_ax25.c | 2 +- net/bridge/br_netfilter_hooks.c | 6 +- net/core/neighbour.c | 24 +++---- net/core/sysctl_net_core.c | 22 +++---- net/ieee802154/6lowpan/reassembly.c | 2 +- net/ipv4/devinet.c | 8 +-- net/ipv4/ip_fragment.c | 2 +- net/ipv4/route.c | 4 +- net/ipv4/sysctl_net_ipv4.c | 35 +++++----- net/ipv4/xfrm4_policy.c | 2 +- net/ipv6/addrconf.c | 29 +++++---- net/ipv6/ndisc.c | 4 +- net/ipv6/netfilter/nf_conntrack_reasm.c | 2 +- net/ipv6/reassembly.c | 2 +- net/ipv6/route.c | 2 +- net/ipv6/sysctl_net_ipv6.c | 10 +-- net/ipv6/xfrm6_policy.c | 2 +- net/mpls/af_mpls.c | 8 +-- net/mptcp/ctrl.c | 2 +- net/netfilter/ipvs/ip_vs_ctl.c | 16 ++--- net/netfilter/nf_conntrack_standalone.c | 4 +- net/netfilter/nf_hooks_lwtunnel.c | 2 +- net/netfilter/nf_log.c | 4 +- net/phonet/sysctl.c | 2 +- net/rds/tcp.c | 4 +- net/sctp/sysctl.c | 30 ++++----- net/smc/smc_sysctl.c | 2 +- net/sunrpc/sysctl.c | 6 +- net/sunrpc/xprtrdma/svc_rdma.c | 2 +- net/sysctl_net.c | 4 +- net/unix/sysctl_net_unix.c | 2 +- net/xfrm/xfrm_sysctl.c | 2 +- scripts/const_structs.checkpatch | 1 + security/apparmor/lsm.c | 2 +- security/min_addr.c | 2 +- security/yama/yama_lsm.c | 2 +- 111 files changed, 427 insertions(+), 428 deletions(-) --- base-commit: 33cc938e65a98f1d29d0a18403dbbee050dcad9a change-id: 20231116-const-sysctl-e14624f1295c Best regards,