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b968e84b50
Since commitc8137ace56("x86/iopl: Restrict iopl() permission scope") it's possible to emulate iopl(3) using ioperm(), except for the CLI/STI usage. Userspace CLI/STI usage is very dubious (read broken), since any exception taken during that window can lead to rescheduling anyway (or worse). The IOPL(2) manpage even states that usage of CLI/STI is highly discouraged and might even crash the system. Of course, that won't stop people and HP has the dubious honour of being the first vendor to be found using this in their hp-health package. In order to enable this 'software' to still 'work', have the #GP treat the CLI/STI instructions as NOPs when iopl(3). Warn the user that their program is doing dubious things. Fixes:a24ca99768("x86/iopl: Remove legacy IOPL option") Reported-by: Ondrej Zary <linux@zary.sk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org # v5.5+ Link: https://lkml.kernel.org/r/20210918090641.GD5106@worktop.programming.kicks-ass.net
32 lines
1.3 KiB
C
32 lines
1.3 KiB
C
#ifndef _ASM_X86_INSN_EVAL_H
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#define _ASM_X86_INSN_EVAL_H
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/*
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* A collection of utility functions for x86 instruction analysis to be
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* used in a kernel context. Useful when, for instance, making sense
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* of the registers indicated by operands.
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*/
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#include <linux/compiler.h>
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#include <linux/bug.h>
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#include <linux/err.h>
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#include <asm/ptrace.h>
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#define INSN_CODE_SEG_ADDR_SZ(params) ((params >> 4) & 0xf)
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#define INSN_CODE_SEG_OPND_SZ(params) (params & 0xf)
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#define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4))
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bool insn_has_rep_prefix(struct insn *insn);
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void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs);
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int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs);
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int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs);
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unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx);
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int insn_get_code_seg_params(struct pt_regs *regs);
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int insn_get_effective_ip(struct pt_regs *regs, unsigned long *ip);
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int insn_fetch_from_user(struct pt_regs *regs,
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unsigned char buf[MAX_INSN_SIZE]);
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int insn_fetch_from_user_inatomic(struct pt_regs *regs,
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unsigned char buf[MAX_INSN_SIZE]);
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bool insn_decode_from_regs(struct insn *insn, struct pt_regs *regs,
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unsigned char buf[MAX_INSN_SIZE], int buf_size);
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#endif /* _ASM_X86_INSN_EVAL_H */
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