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From: Michael Ellerman <mpe@ellerman.id.au>
To: Jordan Niethe <jniethe5@gmail.com>, linuxppc-dev@lists.ozlabs.org
Cc: christophe.leroy@c-s.fr, alistair@popple.id.au,
	npiggin@gmail.com, bala24@linux.ibm.com,
	Jordan Niethe <jniethe5@gmail.com>,
	naveen.n.rao@linux.vnet.ibm.com, dja@axtens.net
Subject: Re: [PATCH v8 16/30] powerpc: Define and use __get_user_instr{, inatomic}()
Date: Thu, 14 May 2020 00:18:06 +1000	[thread overview]
Message-ID: <878shvc40x.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20200506034050.24806-17-jniethe5@gmail.com>

Jordan Niethe <jniethe5@gmail.com> writes:
> Define specific __get_user_instr() and __get_user_instr_inatomic()
> macros for reading instructions from user space.

At least for fix_alignment() we could be coming from the kernel, not
sure about the other cases.

I can tweak the change log.

> diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
> index 2f500debae21..c0a35e4586a5 100644
> --- a/arch/powerpc/include/asm/uaccess.h
> +++ b/arch/powerpc/include/asm/uaccess.h
> @@ -105,6 +105,11 @@ static inline int __access_ok(unsigned long addr, unsigned long size,
>  #define __put_user_inatomic(x, ptr) \
>  	__put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
>  
> +#define __get_user_instr(x, ptr) \
> +	__get_user_nocheck((x).val, (u32 *)(ptr), sizeof(u32), true)
> +
> +#define __get_user_instr_inatomic(x, ptr) \
> +	__get_user_nosleep((x).val, (u32 *)(ptr), sizeof(u32))

I'm not super keen on adding new __ versions, which lack the access_ok()
check, but I guess we have to.

> diff --git a/arch/powerpc/kernel/vecemu.c b/arch/powerpc/kernel/vecemu.c
> index 3dd70eeb10c5..60ed5aea8d4e 100644
> --- a/arch/powerpc/kernel/vecemu.c
> +++ b/arch/powerpc/kernel/vecemu.c
> @@ -266,7 +266,7 @@ int emulate_altivec(struct pt_regs *regs)
>  	unsigned int va, vb, vc, vd;
>  	vector128 *vrs;
>  
> -	if (get_user(instr.val, (unsigned int __user *)regs->nip))
> +	if (__get_user_instr(instr, (void __user *)regs->nip))
>  		return -EFAULT;

That drops the access_ok() check, which is not OK, at least without a
reasonable justification.

Given it's regs->nip I guess it should be safe, but it should still be
called out. Or preferably switched to __get_user() in a precursor patch.

cheers

  reply	other threads:[~2020-05-13 14:20 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-06  3:40 [PATCH v8 00/30] Initial Prefixed Instruction support Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 01/30] powerpc/xmon: Remove store_inst() for patch_instruction() Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 02/30] powerpc/xmon: Move breakpoint instructions to own array Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 03/30] powerpc/xmon: Move breakpoints to text section Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 04/30] powerpc/xmon: Use bitwise calculations in_breakpoint_table() Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 05/30] powerpc: Change calling convention for create_branch() et. al Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 06/30] powerpc: Use a macro for creating instructions from u32s Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 07/30] powerpc: Use an accessor for instructions Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 08/30] powerpc: Use a function for getting the instruction op code Jordan Niethe
2020-05-15  7:48   ` Jordan Niethe
2020-05-16 11:08     ` Michael Ellerman
2020-05-17  7:41       ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 09/30] powerpc: Use a function for byte swapping instructions Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 10/30] powerpc: Introduce functions for instruction equality Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 11/30] powerpc: Use a datatype for instructions Jordan Niethe
2020-05-08  1:51   ` Jordan Niethe
2020-05-08  7:17     ` Christophe Leroy
2020-05-11  1:19       ` Jordan Niethe
2020-05-08  2:15   ` Jordan Niethe
2020-05-17 10:48   ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 12/30] powerpc: Use a function for reading instructions Jordan Niethe
2020-05-16 18:39   ` Christophe Leroy
2020-05-17 10:44     ` Jordan Niethe
2020-05-19  4:05       ` Michael Ellerman
2020-05-19  5:03         ` Christophe Leroy
2020-05-20  4:16           ` Michael Ellerman
2020-05-06  3:40 ` [PATCH v8 13/30] powerpc: Add a probe_user_read_inst() function Jordan Niethe
2020-05-13 12:52   ` Michael Ellerman
2020-05-13 23:51     ` Jordan Niethe
2020-05-14  5:46   ` Christophe Leroy
2020-05-15  3:46     ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 14/30] powerpc: Add a probe_kernel_read_inst() function Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 15/30] powerpc/kprobes: Use patch_instruction() Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 16/30] powerpc: Define and use __get_user_instr{, inatomic}() Jordan Niethe
2020-05-13 14:18   ` Michael Ellerman [this message]
2020-05-13 23:54     ` Jordan Niethe
2020-05-14  1:43       ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 17/30] powerpc: Introduce a function for reporting instruction length Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 18/30] powerpc/xmon: Use a function for reading instructions Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 19/30] powerpc/xmon: Move insertion of breakpoint for xol'ing Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 20/30] powerpc: Make test_translate_branch() independent of instruction length Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 21/30] powerpc: Enable Prefixed Instructions Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 22/30] powerpc: Define new SRR1 bits for a future ISA version Jordan Niethe
2020-05-08  2:26   ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 23/30] powerpc: Add prefixed instructions to instruction data type Jordan Niethe
2020-05-14  1:40   ` Jordan Niethe
2020-05-14  6:11   ` Christophe Leroy
2020-05-14 12:06     ` Alistair Popple
2020-05-14 12:29       ` Jordan Niethe
2020-05-14 12:57       ` Christophe Leroy
2020-05-14 12:28     ` Jordan Niethe
2020-05-15  1:33     ` Michael Ellerman
2020-05-15  7:52       ` Jordan Niethe
2020-05-16 11:54   ` [PATCH v8 22.5/30] powerpc/optprobes: Add register argument to patch_imm64_load_insns() Michael Ellerman
2020-06-09  5:51     ` Michael Ellerman
2020-05-06  3:40 ` [PATCH v8 24/30] powerpc: Test prefixed code patching Jordan Niethe
2020-05-15  7:54   ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 25/30] powerpc: Test prefixed instructions in feature fixups Jordan Niethe
2020-05-15  7:57   ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 26/30] powerpc/xmon: Don't allow breakpoints on suffixes Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 27/30] powerpc/kprobes: " Jordan Niethe
2021-05-18 18:43   ` Christophe Leroy
2021-05-18 19:52     ` Gabriel Paubert
2021-05-19  8:11     ` Naveen N. Rao
2021-05-20  3:45       ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 28/30] powerpc: Support prefixed instructions in alignment handler Jordan Niethe
2020-05-14  6:14   ` Christophe Leroy
2020-05-14 12:15     ` Alistair Popple
2020-05-14 12:59       ` Christophe Leroy
2020-05-06  3:40 ` [PATCH v8 29/30] powerpc sstep: Add support for prefixed load/stores Jordan Niethe
2020-05-14  6:15   ` Christophe Leroy
2020-05-14 12:19     ` Alistair Popple
2020-05-14 13:00       ` Christophe Leroy
2020-05-15  7:59   ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 30/30] powerpc sstep: Add support for prefixed fixed-point arithmetic Jordan Niethe
2020-05-14  6:15   ` Christophe Leroy
2020-05-15  8:02   ` Jordan Niethe
2020-05-14  5:31 ` [PATCH v8 00/30] Initial Prefixed Instruction support Christophe Leroy
2020-05-14 10:33   ` Jordan Niethe
2020-05-20 10:59 ` Michael Ellerman

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