RFC uaccess: Convert small fixed size copy_{to/from}_user() to scoped user access
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- v1 RFC Latest9 patches 20 repliesIn review
Patches in v1 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/9 | uaccess: Split check_zeroed_user() out of usercopy.clib/ lib/ lib/ | +1 | 0 replies | |
| 2/9 | uaccess: Convert INLINE_COPY_{TO/FROM}_USER to kconfig and reduce ifdeferyarch/ arch/ arch/ +25 more | +25 | 5 replies | |
| 3/9 | x86/umip: Be stricter in fixup_umip_exception()arch/ | +1 | 0 replies | |
| 4/9 | uaccess: Introduce copy_{to/from}_user_partial()include/ | +4 | 1 reply | |
| 5/9 | uaccess: Switch to copy_{to/from}_user_partial() when relevantarch/ arch/ arch/ +59 more | +122 | 4 replies | |
| 6/9 | uaccess: Change copy_{to/from}_user to return -EFAULTinclude/ | +24 | 0 replies | |
| 7/9 | x86: Add unsafe_copy_from_user()arch/ | +24 | 7 replies | |
| 8/9 | arm64: Add unsafe_copy_from_user()arch/ | +24 | 1 reply | |
| 9/9 | uaccess: Convert small fixed size copy_{to/from}_user() to scoped user accessinclude/ | +47 | 1 reply |
Reviews trailers per patch
No Reviewed-by, Acked-by or Tested-by trailers for v1 yet.
Cover letter [RFC PATCH v1 0/9] uaccess: Convert small fixed size copy_{to/from}_user() to scoped user access
A lot of copy_from_user() and copy_to_user() perform copies of small fixed size pieces of data between kernel and userspace, and don't care about partial copies.
copy_from_user() and copy_to_user() are big functions optimised for copying large amount of data, with cache management, etc ... This is often overkill for small copies that could just be inlined instead.
What makes things a bit more tricky is that those copy functions are designed to handle partial copies in case of page fault. But among the 6000 callers of those functions, only 2% really care about the quantity of no-copied data that those functions return. All other ones fails as soon as the returned value is not 0, returning -EACCESS.
So first step in this series is to introduce variants called copy_from_user_partial() and copy_to_user_partial() which will be called by the 2% users that care about the partial copy, then the original copy_from_user() and copy_to_user() are changed to return -EFAULT when the copy fails.
Then the second step is to implement copy of small fixed-size data with scoped user access instead of calling the arch specific heavy user copy functions.
Patch 5, can be split in different patches for each archicture or subsystem, but let's get a first feedback and agree on the principle.
Christophe Leroy (CS GROUP) (9):
uaccess: Split check_zeroed_user() out of usercopy.c
uaccess: Convert INLINE_COPY_{TO/FROM}_USER to kconfig and reduce
ifdefery
x86/umip: Be stricter in fixup_umip_exception()
uaccess: Introduce copy_{to/from}_user_partial()
uaccess: Switch to copy_{to/from}_user_partial() when relevant
uaccess: Change copy_{to/from}_user to return -EFAULT
x86: Add unsafe_copy_from_user()
arm64: Add unsafe_copy_from_user()
uaccess: Convert small fixed size copy_{to/from}_user() to scoped user
access
arch/alpha/Kconfig | 1 +
arch/alpha/kernel/osf_sys.c | 4 +-
arch/alpha/kernel/termios.c | 2 +-
arch/arc/include/asm/uaccess.h | 3 -
arch/arc/kernel/disasm.c | 2 +-
arch/arm/include/asm/uaccess.h | 2 -
arch/arm64/include/asm/gcs.h | 2 +-
arch/arm64/include/asm/uaccess.h | 30 +++--
arch/arm64/kernel/signal32.c | 2 +-
arch/csky/Kconfig | 1 +
arch/hexagon/include/asm/uaccess.h | 3 -
arch/loongarch/include/asm/uaccess.h | 3 -
arch/m68k/include/asm/uaccess.h | 3 -
arch/microblaze/include/asm/uaccess.h | 2 -
arch/mips/include/asm/uaccess.h | 3 -
arch/mips/kernel/rtlx.c | 8 +-
arch/mips/kernel/vpe.c | 2 +-
arch/nios2/include/asm/uaccess.h | 2 -
arch/openrisc/include/asm/uaccess.h | 2 -
arch/parisc/include/asm/uaccess.h | 3 -
arch/powerpc/Kconfig | 1 +
arch/powerpc/kvm/book3s_64_mmu_hv.c | 4 +-
arch/powerpc/kvm/book3s_64_mmu_radix.c | 4 +-
arch/powerpc/kvm/book3s_hv.c | 2 +-
arch/riscv/Kconfig | 1 +
arch/riscv/kernel/signal.c | 2 +-
arch/s390/include/asm/idals.h | 8 +-
arch/s390/include/asm/uaccess.h | 3 -
arch/sh/include/asm/uaccess.h | 2 -
arch/sparc/include/asm/uaccess_32.h | 3 -
arch/sparc/include/asm/uaccess_64.h | 2 -
arch/sparc/kernel/termios.c | 2 +-
arch/um/include/asm/uaccess.h | 3 -
arch/um/kernel/process.c | 2 +-
arch/x86/Kconfig | 1 +
arch/x86/include/asm/uaccess.h | 29 ++++-
arch/x86/kernel/umip.c | 2 +-
arch/x86/lib/insn-eval.c | 2 +-
arch/x86/um/signal.c | 2 +-
arch/xtensa/include/asm/uaccess.h | 2 -
drivers/android/binder_alloc.c | 2 +-
drivers/comedi/comedi_fops.c | 4 +-
drivers/dma/idxd/cdev.c | 2 +-
drivers/firmware/efi/test/efi_test.c | 2 +-
drivers/fsi/fsi-scom.c | 2 +-
.../amd/display/amdgpu_dm/amdgpu_dm_debugfs.c | 2 +-
drivers/gpu/drm/i915/gt/intel_sseu.c | 4 +-
drivers/gpu/drm/i915/i915_gem.c | 4 +-
drivers/hwtracing/intel_th/msu.c | 2 +-
drivers/misc/ibmvmc.c | 2 +-
drivers/misc/vmw_vmci/vmci_host.c | 2 +-
drivers/most/most_cdev.c | 2 +-
drivers/net/ieee802154/ca8210.c | 4 +-
drivers/net/wireless/ath/wil6210/debugfs.c | 2 +-
.../intel/iwlwifi/pcie/gen1_2/trans.c | 2 +-
drivers/net/wireless/ti/wlcore/debugfs.c | 2 +-
drivers/ps3/ps3-lpm.c | 2 +-
drivers/s390/crypto/zcrypt_api.h | 4 +-
drivers/spi/spidev.c | 2 +-
.../staging/media/atomisp/pci/atomisp_cmd.c | 8 +-
drivers/tty/tty_ioctl.c | 14 +--
drivers/tty/vt/vc_screen.c | 4 +-
drivers/usb/gadget/function/f_hid.c | 4 +-
drivers/usb/gadget/function/f_printer.c | 2 +-
drivers/vfio/vfio_iommu_type1.c | 4 +-
drivers/xen/xenbus/xenbus_dev_frontend.c | 2 +-
fs/namespace.c | 2 +-
fs/ocfs2/dlmfs/dlmfs.c | 2 +-
fs/proc/base.c | 4 +-
include/asm-generic/uaccess.h | 2 -
include/linux/bpfptr.h | 2 +-
include/linux/sockptr.h | 4 +-
include/linux/uaccess.h | 107 ++++++++++++++----
ipc/msg.c | 8 +-
ipc/sem.c | 8 +-
ipc/shm.c | 18 +--
kernel/regset.c | 2 +-
kernel/sys.c | 4 +-
lib/Kconfig | 3 +
lib/Makefile | 4 +-
lib/kfifo.c | 8 +-
lib/{usercopy.c => usercheck.c} | 22 ----
lib/usercopy.c | 66 -----------
mm/kasan/kasan_test_c.c | 4 +-
mm/memory.c | 2 +-
net/x25/af_x25.c | 2 +-
rust/helpers/uaccess.c | 6 +-
sound/pci/emu10k1/emufx.c | 4 +-
sound/pci/rme9652/hdsp.c | 6 +-
sound/soc/intel/avs/probes.c | 6 +-
sound/soc/sof/compress.c | 12 +-
sound/soc/sof/sof-client-probes.c | 6 +-
92 files changed, 269 insertions(+), 288 deletions(-)
copy lib/{usercopy.c => usercheck.c} (73%)Signature · 1 line
2.49.0