Hi,
This patch series (based on next-20210816) implements stricter (no struct member overflows) bounds checking for memcpy(), memmove(), and memset() under CONFIG_FORTIFY_SOURCE. To quote a later patch in the series:
tl;dr: In order to eliminate a large class of common buffer overflow flaws that continue to persist in the kernel, have memcpy() (under CONFIG_FORTIFY_SOURCE) perform bounds checking of the destination struct member when they have a known size. This would have caught all of the memcpy()-related buffer write overflow flaws identified in at least the last three years.
As this series introduces various helpers and performs several phases of treewide cleanups, I'm expecting to carry this series in my tree, so I'd love to get some Reviews and Acks. Given the size, I've mostly aimed this series at various mailing lists, otherwise the CC size got really big. :)
I have separated a few things off of this submission, as things continue to grow: - run-time bounds checking (which now has a better solution for unknown bounds besides "oh well") - __alloc_size enablement (sent separately[1]) - -Warray-bounds enablement (several cleanups have been sent)
The remaining portions (here) haven't seen as much change, so I think it's better to get these compile-time portions landed first -- they're big enough. My intention is to put this in -next soon via my "overflow" tree, assuming people are happy with it. :)
Another random thing of note, I'm using the "Enhanced-by:" tag to mean "this was improved by...", inspired by the existing "Fixed-by:" tag (for "folded fixes"). "Fixed-by:" seemed inaccurate (it wasn't broken; it is just better now), and "Suggested-by:" seemed too nebulous (what was suggested?).
Thanks!
-Kees
[1] https://lore.kernel.org/lkml/20210818050841.2226600-1-keescook@chromium.org/
v2: - fix CC_IS_CLANG typo (nathan) - bug.h hunk moved later (ndesaulnier) - various commit log typos (ndesaulnier) - omap3isp: fix read source (gustavo) - struct_group can be variadic (rasmus) - add struct_group_tagged (dan williams) - move raw __struct_group() to UAPI (gregkh, dan vetter) - ibmvscsi: add BUILD_BUG_ON() size checks - net: use memset_after() instead of struct_group() (jakob) - swap some memset_after() to memset_startat() for readability - add missing __NO_FORTIFY to arm boot stub (lkp) - powerpc signal32 struct_group() added (lkp) - powerpc sata_fsl struct_group() added - add fortify failure condition arguments to warning funcs to assist debugging - add ray_cs compile-time fix - add flexcan compile-time fix - add af_iucv compile-time fix - fix dropped strcpy() compile-time write overflow check - add missing strscpy() compile-time read overflow check - fix more boot stub build instances where fortification must be disabled - add reviewed-bys/acks v1: https://lore.kernel.org/lkml/20210727205855.411487-1-keescook@chromium.org/
Specifically, this series is logically split into several steps:
Clean up remaining simple compile-time memcpy() warnings: ipw2x00: Avoid field-overflowing memcpy() net/mlx5e: Avoid field-overflowing memcpy() rpmsg: glink: Replace strncpy() with strscpy_pad() pcmcia: ray_cs: Split memcpy() to avoid bounds check warning
Introduce struct_group() and apply it treewide to avoid compile-time memcpy() warnings: stddef: Introduce struct_group() helper macro cxl/core: Replace unions with struct_group() skbuff: Switch structure bounds to struct_group() bnxt_en: Use struct_group_attr() for memcpy() region mwl8k: Use struct_group() for memcpy() region libertas: Use struct_group() for memcpy() region libertas_tf: Use struct_group() for memcpy() region thermal: intel: int340x_thermal: Use struct_group() for memcpy() region iommu/amd: Use struct_group() for memcpy() region cxgb3: Use struct_group() for memcpy() region intersil: Use struct_group() for memcpy() region cxgb4: Use struct_group() for memcpy() region bnx2x: Use struct_group() for memcpy() region drm/amd/pm: Use struct_group() for memcpy() region staging: wlan-ng: Use struct_group() for memcpy() region drm/mga/mga_ioc32: Use struct_group() for memcpy() region net/mlx5e: Use struct_group() for memcpy() region HID: cp2112: Use struct_group() for memcpy() region media: omap3isp: Use struct_group() for memcpy() region sata_fsl: Use struct_group() for memcpy() region
Prepare fortify for additional hardening: compiler_types.h: Remove __compiletime_object_size() lib/string: Move helper functions out of string.c fortify: Move remaining fortify helpers into fortify-string.h fortify: Explicitly disable Clang support fortify: Fix dropped strcpy() compile-time write overflow check fortify: Prepare to improve strnlen() and strlen() warnings fortify: Allow strlen() and strnlen() to pass compile-time known lengths
Add compile-time and run-time tests: fortify: Add compile-time FORTIFY_SOURCE tests lib: Introduce CONFIG_TEST_MEMCPY
Enable new compile-time memcpy() and memmove() bounds checking: fortify: Detect struct member overflows in memcpy() at compile-time fortify: Detect struct member overflows in memmove() at compile-time
Clean up remaining simple compile-time memset() warnings: scsi: ibmvscsi: Avoid multi-field memset() overflow by aiming at srp
Introduce memset_after() and memset_startat() helpers and apply them (and struct_group()): string.h: Introduce memset_after() for wiping trailing members/padding xfrm: Use memset_after() to clear padding ipv6: Use memset_after() to zero rt6_info netfilter: conntrack: Use memset_startat() to zero struct nf_conn net: 802: Use memset_startat() to clear struct fields net: dccp: Use memset_startat() for TP zeroing net: qede: Use memset_startat() for counters mac80211: Use memset_after() to clear tx status ath11k: Use memset_startat() for clearing queue descriptors iw_cxgb4: Use memset_startat() for cpl_t5_pass_accept_rpl intel_th: msu: Use memset_startat() for clearing hw header IB/mthca: Use memset_startat() for clearing mpt_entry btrfs: Use memset_startat() to clear end of struct tracing: Use memset_startat() to zero struct trace_iterator drbd: Use struct_group() to zero algs cm4000_cs: Use struct_group() to zero struct cm4000_dev region KVM: x86: Use struct_group() to zero decode cache dm integrity: Use struct_group() to zero struct journal_sector HID: roccat: Use struct_group() to zero kone_mouse_event RDMA/mlx5: Use struct_group() to zero struct mlx5_ib_mr powerpc/signal32: Use struct_group() to zero spe regs ethtool: stats: Use struct_group() to clear all stats at once can: flexcan: Use struct_group() to zero struct flexcan_regs regions net/af_iucv: Use struct_group() to zero struct iucv_sock region powerpc: Split memset() to avoid multi-field overflow
Enable new compile-time memset() bounds checking: fortify: Detect struct member overflows in memset() at compile-time
Enable Clang support: fortify: Work around Clang inlining bugs
arch/arm/boot/compressed/string.c | 1 + arch/powerpc/include/asm/processor.h | 6 +- arch/powerpc/kernel/signal_32.c | 6 +- arch/s390/lib/string.c | 3 + arch/x86/boot/compressed/misc.c | 3 +- arch/x86/boot/compressed/misc.h | 2 + arch/x86/boot/compressed/pgtable_64.c | 2 + arch/x86/kvm/emulate.c | 3 +- arch/x86/kvm/kvm_emulate.h | 19 +- arch/x86/lib/memcpy_32.c | 1 + arch/x86/lib/string_32.c | 1 + drivers/ata/sata_fsl.c | 10 +- drivers/block/drbd/drbd_main.c | 3 +- drivers/block/drbd/drbd_protocol.h | 6 +- drivers/block/drbd/drbd_receiver.c | 3 +- drivers/char/pcmcia/cm4000_cs.c | 9 +- drivers/cxl/cxl.h | 61 +--- drivers/gpu/drm/amd/include/atomfirmware.h | 9 +- .../drm/amd/pm/inc/smu11_driver_if_arcturus.h | 3 +- .../drm/amd/pm/inc/smu11_driver_if_navi10.h | 3 +- .../amd/pm/inc/smu13_driver_if_aldebaran.h | 3 +- .../gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c | 6 +- .../gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c | 12 +- .../drm/amd/pm/swsmu/smu13/aldebaran_ppt.c | 6 +- drivers/gpu/drm/mga/mga_ioc32.c | 27 +- drivers/hid/hid-cp2112.c | 14 +- drivers/hid/hid-roccat-kone.c | 2 +- drivers/hid/hid-roccat-kone.h | 12 +- drivers/hwtracing/intel_th/msu.c | 4 +- drivers/infiniband/hw/cxgb4/cm.c | 5 +- drivers/infiniband/hw/mlx5/mlx5_ib.h | 4 +- drivers/infiniband/hw/mthca/mthca_mr.c | 3 +- drivers/iommu/amd/init.c | 9 +- drivers/macintosh/smu.c | 3 +- drivers/md/dm-integrity.c | 9 +- drivers/media/platform/omap3isp/ispstat.c | 5 +- drivers/net/can/flexcan.c | 68 ++-- .../net/ethernet/broadcom/bnx2x/bnx2x_stats.c | 7 +- .../net/ethernet/broadcom/bnx2x/bnx2x_stats.h | 14 +- drivers/net/ethernet/broadcom/bnxt/bnxt_dcb.c | 4 +- drivers/net/ethernet/broadcom/bnxt/bnxt_dcb.h | 14 +- drivers/net/ethernet/chelsio/cxgb3/sge.c | 9 +- drivers/net/ethernet/chelsio/cxgb4/sge.c | 8 +- drivers/net/ethernet/chelsio/cxgb4/t4_msg.h | 2 +- drivers/net/ethernet/chelsio/cxgb4/t4fw_api.h | 10 +- drivers/net/ethernet/chelsio/cxgb4vf/sge.c | 7 +- drivers/net/ethernet/mellanox/mlx5/core/en.h | 4 +- .../net/ethernet/mellanox/mlx5/core/en/xdp.c | 4 +- .../net/ethernet/mellanox/mlx5/core/en_tx.c | 2 +- drivers/net/ethernet/qlogic/qede/qede_main.c | 2 +- drivers/net/wireguard/queueing.h | 4 +- drivers/net/wireless/ath/ath11k/hal_rx.c | 13 +- drivers/net/wireless/ath/carl9170/tx.c | 11 +- .../net/wireless/intel/ipw2x00/libipw_rx.c | 56 +--- .../net/wireless/intersil/hostap/hostap_hw.c | 5 +- .../wireless/intersil/hostap/hostap_wlan.h | 14 +- drivers/net/wireless/intersil/p54/txrx.c | 6 +- drivers/net/wireless/marvell/libertas/host.h | 10 +- drivers/net/wireless/marvell/libertas/tx.c | 5 +- .../marvell/libertas_tf/libertas_tf.h | 10 +- .../net/wireless/marvell/libertas_tf/main.c | 3 +- drivers/net/wireless/marvell/mwl8k.c | 10 +- drivers/net/wireless/ray_cs.c | 4 +- drivers/rpmsg/qcom_glink_native.c | 2 +- drivers/scsi/ibmvscsi/ibmvscsi.c | 3 +- drivers/staging/wlan-ng/hfa384x.h | 16 +- drivers/staging/wlan-ng/hfa384x_usb.c | 4 +- .../intel/int340x_thermal/acpi_thermal_rel.c | 5 +- .../intel/int340x_thermal/acpi_thermal_rel.h | 48 +-- fs/btrfs/root-tree.c | 6 +- include/linux/compiler-gcc.h | 2 - include/linux/compiler_types.h | 4 - include/linux/fortify-string.h | 308 +++++++++++++----- include/linux/if_vlan.h | 6 +- include/linux/skbuff.h | 9 +- include/linux/stddef.h | 47 +++ include/linux/string.h | 43 ++- include/linux/thread_info.h | 2 +- include/net/iucv/af_iucv.h | 10 +- include/net/mac80211.h | 7 +- include/uapi/drm/mga_drm.h | 22 +- include/uapi/linux/omap3isp.h | 21 +- include/uapi/linux/stddef.h | 21 ++ kernel/trace/trace.c | 4 +- lib/.gitignore | 2 + lib/Kconfig.debug | 7 + lib/Makefile | 35 ++ lib/string.c | 210 +----------- lib/string_helpers.c | 201 ++++++++++++ lib/test_fortify/read_overflow-memchr.c | 5 + lib/test_fortify/read_overflow-memchr_inv.c | 5 + lib/test_fortify/read_overflow-memcmp.c | 5 + lib/test_fortify/read_overflow-memscan.c | 5 + lib/test_fortify/read_overflow2-memcmp.c | 5 + lib/test_fortify/read_overflow2-memcpy.c | 5 + lib/test_fortify/read_overflow2-memmove.c | 5 + .../read_overflow2_field-memcpy.c | 5 + .../read_overflow2_field-memmove.c | 5 + lib/test_fortify/test_fortify.h | 35 ++ lib/test_fortify/write_overflow-memcpy.c | 5 + lib/test_fortify/write_overflow-memmove.c | 5 + lib/test_fortify/write_overflow-memset.c | 5 + lib/test_fortify/write_overflow-strcpy-lit.c | 5 + lib/test_fortify/write_overflow-strcpy.c | 5 + lib/test_fortify/write_overflow-strlcpy-src.c | 5 + lib/test_fortify/write_overflow-strlcpy.c | 5 + lib/test_fortify/write_overflow-strncpy-src.c | 5 + lib/test_fortify/write_overflow-strncpy.c | 5 + lib/test_fortify/write_overflow-strscpy.c | 5 + .../write_overflow_field-memcpy.c | 5 + .../write_overflow_field-memmove.c | 5 + .../write_overflow_field-memset.c | 5 + lib/test_memcpy.c | 288 ++++++++++++++++ net/802/hippi.c | 2 +- net/core/skbuff.c | 14 +- net/dccp/trace.h | 4 +- net/ethtool/stats.c | 15 +- net/ipv6/route.c | 4 +- net/iucv/af_iucv.c | 2 +- net/netfilter/nf_conntrack_core.c | 4 +- net/xfrm/xfrm_policy.c | 4 +- net/xfrm/xfrm_user.c | 2 +- scripts/test_fortify.sh | 59 ++++ security/Kconfig | 3 + 124 files changed, 1489 insertions(+), 686 deletions(-) create mode 100644 lib/test_fortify/read_overflow-memchr.c create mode 100644 lib/test_fortify/read_overflow-memchr_inv.c create mode 100644 lib/test_fortify/read_overflow-memcmp.c create mode 100644 lib/test_fortify/read_overflow-memscan.c create mode 100644 lib/test_fortify/read_overflow2-memcmp.c create mode 100644 lib/test_fortify/read_overflow2-memcpy.c create mode 100644 lib/test_fortify/read_overflow2-memmove.c create mode 100644 lib/test_fortify/read_overflow2_field-memcpy.c create mode 100644 lib/test_fortify/read_overflow2_field-memmove.c create mode 100644 lib/test_fortify/test_fortify.h create mode 100644 lib/test_fortify/write_overflow-memcpy.c create mode 100644 lib/test_fortify/write_overflow-memmove.c create mode 100644 lib/test_fortify/write_overflow-memset.c create mode 100644 lib/test_fortify/write_overflow-strcpy-lit.c create mode 100644 lib/test_fortify/write_overflow-strcpy.c create mode 100644 lib/test_fortify/write_overflow-strlcpy-src.c create mode 100644 lib/test_fortify/write_overflow-strlcpy.c create mode 100644 lib/test_fortify/write_overflow-strncpy-src.c create mode 100644 lib/test_fortify/write_overflow-strncpy.c create mode 100644 lib/test_fortify/write_overflow-strscpy.c create mode 100644 lib/test_fortify/write_overflow_field-memcpy.c create mode 100644 lib/test_fortify/write_overflow_field-memmove.c create mode 100644 lib/test_fortify/write_overflow_field-memset.c create mode 100644 lib/test_memcpy.c create mode 100644 scripts/test_fortify.sh