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75045f77f7
Currently, most fixups for attempting to access userspace memory are handled using _ASM_EXTABLE, which is also used for various other types of fixups (e.g. safe MSR access, IRET failures, and a bunch of other things). In order to make it possible to add special safety checks to uaccess fixups (in particular, checking whether the fault address is actually in userspace), introduce a new exception table handler ex_handler_uaccess() and wire it up to all the user access fixups (excluding ones that already use _ASM_EXTABLE_EX). Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: dvyukov@google.com Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Cc: Borislav Petkov <bp@alien8.de> Link: https://lkml.kernel.org/r/20180828201421.157735-5-jannh@google.com
229 lines
3.8 KiB
ArmAsm
229 lines
3.8 KiB
ArmAsm
/*
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* Copyright 2002, 2003 Andi Kleen, SuSE Labs.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of this archive
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* for more details. No warranty for anything given at all.
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*/
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#include <linux/linkage.h>
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#include <asm/errno.h>
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#include <asm/asm.h>
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/*
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* Checksum copy with exception handling.
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* On exceptions src_err_ptr or dst_err_ptr is set to -EFAULT and the
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* destination is zeroed.
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*
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* Input
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* rdi source
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* rsi destination
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* edx len (32bit)
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* ecx sum (32bit)
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* r8 src_err_ptr (int)
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* r9 dst_err_ptr (int)
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*
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* Output
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* eax 64bit sum. undefined in case of exception.
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*
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* Wrappers need to take care of valid exception sum and zeroing.
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* They also should align source or destination to 8 bytes.
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*/
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.macro source
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10:
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_ASM_EXTABLE_UA(10b, .Lbad_source)
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.endm
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.macro dest
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20:
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_ASM_EXTABLE_UA(20b, .Lbad_dest)
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.endm
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/*
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* No _ASM_EXTABLE_UA; this is used for intentional prefetch on a
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* potentially unmapped kernel address.
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*/
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.macro ignore L=.Lignore
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30:
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_ASM_EXTABLE(30b, \L)
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.endm
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ENTRY(csum_partial_copy_generic)
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cmpl $3*64, %edx
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jle .Lignore
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.Lignore:
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subq $7*8, %rsp
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movq %rbx, 2*8(%rsp)
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movq %r12, 3*8(%rsp)
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movq %r14, 4*8(%rsp)
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movq %r13, 5*8(%rsp)
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movq %r15, 6*8(%rsp)
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movq %r8, (%rsp)
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movq %r9, 1*8(%rsp)
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movl %ecx, %eax
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movl %edx, %ecx
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xorl %r9d, %r9d
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movq %rcx, %r12
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shrq $6, %r12
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jz .Lhandle_tail /* < 64 */
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clc
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/* main loop. clear in 64 byte blocks */
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/* r9: zero, r8: temp2, rbx: temp1, rax: sum, rcx: saved length */
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/* r11: temp3, rdx: temp4, r12 loopcnt */
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/* r10: temp5, r15: temp6, r14 temp7, r13 temp8 */
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.p2align 4
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.Lloop:
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source
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movq (%rdi), %rbx
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source
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movq 8(%rdi), %r8
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source
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movq 16(%rdi), %r11
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source
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movq 24(%rdi), %rdx
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source
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movq 32(%rdi), %r10
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source
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movq 40(%rdi), %r15
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source
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movq 48(%rdi), %r14
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source
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movq 56(%rdi), %r13
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ignore 2f
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prefetcht0 5*64(%rdi)
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2:
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adcq %rbx, %rax
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adcq %r8, %rax
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adcq %r11, %rax
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adcq %rdx, %rax
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adcq %r10, %rax
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adcq %r15, %rax
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adcq %r14, %rax
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adcq %r13, %rax
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decl %r12d
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dest
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movq %rbx, (%rsi)
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dest
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movq %r8, 8(%rsi)
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dest
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movq %r11, 16(%rsi)
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dest
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movq %rdx, 24(%rsi)
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dest
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movq %r10, 32(%rsi)
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dest
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movq %r15, 40(%rsi)
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dest
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movq %r14, 48(%rsi)
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dest
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movq %r13, 56(%rsi)
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3:
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leaq 64(%rdi), %rdi
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leaq 64(%rsi), %rsi
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jnz .Lloop
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adcq %r9, %rax
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/* do last up to 56 bytes */
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.Lhandle_tail:
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/* ecx: count */
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movl %ecx, %r10d
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andl $63, %ecx
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shrl $3, %ecx
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jz .Lfold
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clc
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.p2align 4
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.Lloop_8:
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source
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movq (%rdi), %rbx
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adcq %rbx, %rax
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decl %ecx
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dest
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movq %rbx, (%rsi)
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leaq 8(%rsi), %rsi /* preserve carry */
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leaq 8(%rdi), %rdi
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jnz .Lloop_8
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adcq %r9, %rax /* add in carry */
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.Lfold:
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/* reduce checksum to 32bits */
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movl %eax, %ebx
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shrq $32, %rax
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addl %ebx, %eax
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adcl %r9d, %eax
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/* do last up to 6 bytes */
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.Lhandle_7:
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movl %r10d, %ecx
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andl $7, %ecx
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shrl $1, %ecx
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jz .Lhandle_1
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movl $2, %edx
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xorl %ebx, %ebx
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clc
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.p2align 4
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.Lloop_1:
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source
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movw (%rdi), %bx
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adcl %ebx, %eax
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decl %ecx
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dest
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movw %bx, (%rsi)
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leaq 2(%rdi), %rdi
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leaq 2(%rsi), %rsi
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jnz .Lloop_1
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adcl %r9d, %eax /* add in carry */
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/* handle last odd byte */
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.Lhandle_1:
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testb $1, %r10b
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jz .Lende
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xorl %ebx, %ebx
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source
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movb (%rdi), %bl
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dest
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movb %bl, (%rsi)
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addl %ebx, %eax
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adcl %r9d, %eax /* carry */
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.Lende:
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movq 2*8(%rsp), %rbx
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movq 3*8(%rsp), %r12
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movq 4*8(%rsp), %r14
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movq 5*8(%rsp), %r13
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movq 6*8(%rsp), %r15
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addq $7*8, %rsp
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ret
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/* Exception handlers. Very simple, zeroing is done in the wrappers */
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.Lbad_source:
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movq (%rsp), %rax
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testq %rax, %rax
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jz .Lende
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movl $-EFAULT, (%rax)
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jmp .Lende
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.Lbad_dest:
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movq 8(%rsp), %rax
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testq %rax, %rax
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jz .Lende
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movl $-EFAULT, (%rax)
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jmp .Lende
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ENDPROC(csum_partial_copy_generic)
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