kernel.git/arch/mips/include/asm/uaccess.h, branch linux-5.13.y

MIPS: Fix strnlen_user access check

2021-04-15T21:42:21Z

Commit 04324f44cb69 ("MIPS: Remove get_fs/set_fs") changed the access_ok for strnlen_user to check the whole range, which broke some callers of strndup_user(). Restore the old behaviour and just check the first byte. Fixes: 04324f44cb69 ("MIPS: Remove get_fs/set_fs") Signed-off-by: Thomas Bogendoerfer

MIPS: Fix access_ok() for the last byte of user space

2021-04-13T12:28:19Z

The MIPS implementation of access_ok() incorrectly reports that access to the final byte of user memory is not OK, much as the alpha & SH versions did prior to commit 94bd8a05cd4d ("Fix 'acccess_ok()' on alpha and SH"). For example on a MIPS64 system with __UA_LIMIT == 0xffff000000000000 we incorrectly fail in the following cases: access_ok(0xffffffffffff, 0x1) = 0 access_ok(0xfffffffffffe, 0x2) = 0 Fix MIPS in the same way as alpha & SH, by subtracting one from the addr + size condition when size is non-zero. With this the access_ok() calls above return 1 indicating that the access may be valid. The cost of the improved check is pretty minimal - we gain 2410 bytes, or 0.03%, in kernel code size for a 64r6el_defconfig kernel built using GCC 8.1.0. Signed-off-by: Paul Burton Reported-by: Linus Torvalds Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Thomas Bogendoerfer

MIPS: uaccess: Reduce number of nested macros

2021-04-12T14:42:20Z

Clean up macros even further after removal get_fs/set_fs. Signed-off-by: Thomas Bogendoerfer Reviewed-by: Christoph Hellwig

MIPS: Remove get_fs/set_fs

2021-04-06T13:12:58Z

All get_fs/set_fs calls in MIPS code are gone, so remove implementation of it. With the clear separation of user/kernel space access we no longer need the EVA special handling, so get rid of that, too. Signed-off-by: Thomas Bogendoerfer Reviewed-by: Christoph Hellwig

MIPS: uaccess: Added get/put_kernel_nofault

2021-04-06T12:36:56Z

Added __get/__put_kernel_nofault as preparation for removing get/set_fs. Signed-off-by: Thomas Bogendoerfer Reviewed-by: Christoph Hellwig

MIPS: Remove KVM_GUEST support

2021-03-10T14:18:40Z

KVM_GUEST is broken and unmaintained, so let's remove it. Reviewed-by: Huacai Chen Reviewed-by: Jiaxun Yang Signed-off-by: Thomas Bogendoerfer

uaccess: remove segment_eq

2020-08-12T17:57:58Z

segment_eq is only used to implement uaccess_kernel. Just open code uaccess_kernel in the arch uaccess headers and remove one layer of indirection. Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Acked-by: Linus Torvalds Acked-by: Greentime Hu Acked-by: Geert Uytterhoeven Cc: Nick Hu Cc: Vincent Chen Cc: Paul Walmsley Cc: Palmer Dabbelt Link: http://lkml.kernel.org/r/20200710135706.537715-5-hch@lst.de Signed-off-by: Linus Torvalds

get rid of legacy 'get_ds()' function

2019-03-04T18:50:14Z

Every in-kernel use of this function defined it to KERNEL_DS (either as an actual define, or as an inline function). It's an entirely historical artifact, and long long long ago used to actually read the segment selector valueof '%ds' on x86. Which in the kernel is always KERNEL_DS. Inspired by a patch from Jann Horn that just did this for a very small subset of users (the ones in fs/), along with Al who suggested a script. I then just took it to the logical extreme and removed all the remaining gunk. Roughly scripted with git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/' git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d' plus manual fixups to remove a few unusual usage patterns, the couple of inline function cases and to fix up a comment that had become stale. The 'get_ds()' function remains in an x86 kvm selftest, since in user space it actually does something relevant. Inspired-by: Jann Horn Inspired-by: Al Viro Signed-off-by: Linus Torvalds

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57Z

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds

MIPS: uaccess: Add micromips clobbers to bzero invocation

2018-04-18T21:02:29Z

The micromips implementation of bzero additionally clobbers registers t7 & t8. Specify this in the clobbers list when invoking bzero. Fixes: 26c5e07d1478 ("MIPS: microMIPS: Optimise 'memset' core library function.") Reported-by: James Hogan Signed-off-by: Matt Redfearn Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: # 3.10+ Patchwork: https://patchwork.linux-mips.org/patch/19110/ Signed-off-by: James Hogan