Messages in this thread | | | From | Josh Poimboeuf <> | Subject | [PATCH v4 0/4] x86/uaccess: Use pointer masking to limit uaccess speculation | Date | Tue, 4 May 2021 22:54:28 -0500 |
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This one managed to fall through the cracks back in September. Here's a fresh new version.
Ideally, we'd switch all access_ok() users to access_ok_mask() or something, but that's a much bigger change.
I dropped all the ack/review tags because the rebase was significant.
Please review carefully :-)
v4 changes:
- Rebased on the latest.
- Split up into multiple logical patches.
- Renamed "force_user_ptr()" -> "mask_user_ptr()" to prevent confusing it with '__force' casting. [based on Dan's comment]
- Instead of reusing array_index_nospec(), made a new separate inline asm statement. Otherwise it fails the build on recent toolchains and/or kernels because the "g" constraint in array_index_mask_nospec() isn't big enough for TASK_SIZE_MAX. I could have changed "g" to "r", but that would negatively impact code generation for the other users.
v3 was here:
https://lore.kernel.org/lkml/1d06ed6485b66b9f674900368b63d7ef79f666ca.1599756789.git.jpoimboe@redhat.com/
Josh Poimboeuf (4): uaccess: Always inline strn*_user() helper functions uaccess: Fix __user annotations for copy_mc_to_user() x86/uaccess: Use pointer masking to limit uaccess speculation x86/nospec: Remove barrier_nospec()
Documentation/admin-guide/hw-vuln/spectre.rst | 6 +-- arch/x86/include/asm/barrier.h | 3 -- arch/x86/include/asm/futex.h | 5 ++ arch/x86/include/asm/uaccess.h | 48 +++++++++++++------ arch/x86/include/asm/uaccess_64.h | 12 ++--- arch/x86/kernel/cpu/sgx/virt.c | 6 ++- arch/x86/lib/copy_mc.c | 10 ++-- arch/x86/lib/csum-wrappers_64.c | 5 +- arch/x86/lib/getuser.S | 16 ++----- arch/x86/lib/putuser.S | 8 ++++ arch/x86/lib/usercopy_32.c | 6 +-- arch/x86/lib/usercopy_64.c | 7 +-- lib/iov_iter.c | 2 +- lib/strncpy_from_user.c | 6 ++- lib/strnlen_user.c | 4 +- 15 files changed, 89 insertions(+), 55 deletions(-)
-- 2.31.1
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